;; ulex: Distributed sqlite3 db
;;;
;; Copyright (C) 2018 Matt Welland
;; Redistribution and use in source and binary forms, with or without
;; modification, is permitted.
;;
;; THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
;; OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
;; WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
;; ARE DISCLAIMED.  IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE
;; LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
;; CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT
;; OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
;; BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF
;; LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
;; (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE
;; USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH
;; DAMAGE.

;;======================================================================
;; ABOUT:
;;   See README in the distribution at https://www.kiatoa.com/fossils/ulex
;; NOTES:
;;   Why sql-de-lite and not say, dbi?  - performance mostly, then simplicity.
;;
;;======================================================================

(use mailbox)

(module ulex
 *

(import scheme posix chicken data-structures ports extras files mailbox)
(import srfi-18 pkts matchable regex
	typed-records srfi-69 srfi-1
	srfi-4 regex-case
	(prefix sqlite3 sqlite3:)
	foreign
	tcp6
	;; ulex-netutil
	hostinfo
	)

;; make it a global? Well, it is local to area module

(define *captain-pktspec*
  `((captain (host     . h)
	     (port     . p)
	     (pid      . i)
	     (ipaddr   . a)
	     )
    #;(data   (hostname . h)  ;; sender hostname
	    (port     . p)  ;; sender port
	    (ipaddr   . a)  ;; sender ip
	    (hostkey  . k)  ;; sending host key - store info at server under this key
	    (servkey  . s)  ;; server key - this needs to match at server end or reject the msg
	    (format   . f)  ;; sb=serialized-base64, t=text, sx=sexpr, j=json
	    (data     . d)  ;; base64 encoded slln data
	    )))

;; struct for keeping track of our world

(defstruct udat
  ;; captain info
  (captain-address #f)
  (captain-host    #f)
  (captain-port    #f)
  (captain-pid     #f)
  (captain-lease   0)    ;; time (unix epoc) seconds when the lease is up
  (ulex-dir        (conc (get-environment-variable "HOME") "/.ulex"))
  (cpkts-dir       (conc (get-environment-variable "HOME") "/.ulex/pkts"))
  (cpkt-spec       *captain-pktspec*)
  ;; this processes info
  (my-cpkt-key     #f)   ;; put Z card here when I create a pkt for myself as captain
  (my-address      #f)
  (my-hostname     #f)
  (my-port         #f)
  (my-pid          (current-process-id))
  (my-dbs          '())
  ;; server and handler thread
  (serv-listener   #f)                 ;; this processes server info
  (handler-thread  #f)
  (mboxes          (make-hash-table))  ;; key => mbox
  ;; other servers
  (peers           (make-hash-table))  ;; host-port => peer record
  (dbowners        (make-hash-table))  ;; dbfile => host-port
  (handlers        (make-hash-table))  ;; dbfile => proc
  ;; (outgoing-conns  (make-hash-table))  ;; host:port -> conn
  (work-queue      (make-queue))       ;; most stuff goes here
  ;; (fast-queue      (make-queue))       ;; super quick stuff goes here (e.g. ping)
  (busy            #f)                 ;; is either of the queues busy, use to switch between queuing tasks or doing immediately
  ;; app info
  (appname         #f)
  (dbtypes         (make-hash-table))  ;; this should be an alist but hash is easier. dbtype => [ initproc syncproc ]
  ;; cookies
  (cnum            0) ;; cookie num
  )

;;======================================================================
;; NEW APPROACH
;;======================================================================

;;  start-server-find-port  ;; gotta have a server port ready from the very begining

;; udata    - all the connection info, captain, server, ulex db etc. MUST BE PASSED IN
;; dbpath   - full path and filename of the db to talk to or a symbol naming the db?
;; callname - the remote call to execute
;; params   - parameters to pass to the remote call
;;
(define (remote-call udata dbpath dbtype callname params)
  (start-server-find-port udata) ;; ensure we have a local server
  (find-or-setup-captain udata)
  ;; look at connect, process-request, send, send-receive
  (let-values (((cookie-key host-port)(get-db-owner udata dbpath dbtype)))
    (if (and cookie-key host-port)
	(send-receive udata host-port callname cookie-key params)
	#f)))

;;======================================================================
;; KEY FUNCTIONS - THESE ARE TOO BE EXPOSED AND USED
;;======================================================================

;; connection setup and management functions

;; This is the basic setup command. Must always be
;; called before connecting to a db using connect.
;;
;; find or become the captain
;; setup and return a ulex object
;;
(define (find-or-setup-captain udata #!optional (tries 0))
  ;; see if we already have a captain and if the lease is ok
  (if (and (udat-captain-address udata)
	   (udat-captain-port    udata)
	   (< (current-seconds) (udat-captain-lease udata)))
      udata
      (let* ((cpkts (get-all-captain-pkts udata)) ;; read captain pkts
	     (captn (get-winning-pkt cpkts)))
	(if captn
	    (let* ((port   (alist-ref 'port   captn))
		   (host   (alist-ref 'host   captn))
		   (ipaddr (alist-ref 'ipaddr captn))
		   (pid    (alist-ref 'pid    captn))
		   (Z      (alist-ref 'Z      captn)))
	      (udat-captain-address-set! udata ipaddr)
	      (udat-captain-host-set!    udata host)
	      (udat-captain-port-set!    udata port)
	      (udat-captain-pid-set!     udata pid)
	      (udat-captain-lease-set!   udata (+ (current-seconds) 10))
	      (let-values (((success pingtime)(ping udata (conc ipaddr ":" port))))
		(if success
		    udata
		    (begin
		      (print "Found unreachable captain at " ipaddr ":" port ", removing pkt")
		      (remove-captain-pkt udata captn)
		      (if (< tries 20)
			  (find-or-setup-captain udata (+ tries 1))
			  #f)))))
	    (begin
	      (setup-as-captain udata)  ;; this saves the thread to captain-thread and starts the thread
	      (if (< tries 20)
		  (find-or-setup-captain udata (+ tries 1))
		  #f))))))

;; connect to a specific dbfile
;;   - if already connected - return the dbowner host-port
;;   - ask the captain who to talk to for this db
;;   - put the entry in the dbowners hash as dbfile => host-port
;;
(define (connect udata dbfname dbtype)
  (or (hash-table-ref/default (udat-dbowners udata) dbfname #f)
      (let-values (((success dbowner-host-port)(get-db-owner udata dbfname dbtype)))
	(if success
	    (begin
	      ;; just clobber the record, this is the new data no matter what
	      (hash-table-set! (udat-dbowners udata) dbfname dbowner-host-port)
	      dbowner-host-port)
	    #f))))

;; returns: success pingtime
;;
;; NOTE: causes the callee to store the info on this host along with the dbs this host currently owns
;;
(define (ping udata host-port)
  (let* ((start  (current-milliseconds))
	 (cookie (make-cookie udata))
	 (dbs    (udat-my-dbs udata))
	 (msg    (string-intersperse dbs " "))
	 (res (send udata host-port 'ping cookie msg retval: #t))
	 (delta (- (current-milliseconds) start)))
    (values (equal? res cookie) delta)))

;; returns: success pingtime
;;
;; NOTE: causes all references to this worker to be wiped out in the
;; callee (ususally the captain)
;;
(define (goodbye-ping udata host-port)
  (let* ((start  (current-milliseconds))
	 (cookie (make-cookie udata))
	 (dbs    (udat-my-dbs udata))
	 (res (send udata host-port 'goodbye cookie "nomsg" retval: #t))
	 (delta (- (current-milliseconds) start)))
    (values (equal? res cookie) delta)))

(define (goodbye-captain udata)
  (let* ((host-port (udat-captain-host-port udata)))
    (if host-port
	(goodbye-ping udata host-port)
	(values #f -1))))

(define (get-db-owner udata dbname dbtype)
  (let* ((host-port (udat-captain-host-port udata)))
    (if host-port
	(let* ((cookie (make-cookie udata))
	       (msg    #f) ;; (conc dbname " " dbtype))
	       (params `(,dbname ,dbtype))
	       (res    (send udata host-port 'db-owner cookie msg
			     params: params retval: #t)))
	  (match (and res (string-split res))
	    ((retcookie owner-host-port)
	     (values (equal? retcookie cookie) owner-host-port))
	    (else (values #f #f))))
	(values #f -1))))

;; called in ulex-handler to dispatch work, called on the workers side
;;     calls (proc params data)
;;     returns result with cookie
;;
;; pdat is the info of the caller, used to send the result data
;; prockey is key into udat-handlers hash dereferencing a proc
;; procparam is a first param handed to proc - often to do further derefrencing
;; NOTE: params is intended to be a list of strings, encoding on data
;;       is up to the user but data must be a single line
;;
(define (process-request udata pdat dbname cookie prockey procparam data)
  (let* ((dbrec (ulex-open-db udata dbname))     ;; this will be a dbconn record, looks for in udata first
	 (proc  (hash-table-ref udata prockey)))
    (let* ((result (proc dbrec procparam data)))
      result)))

;; remote-request - send to remote to process in process-request
;; uconn comes from a call to connect and can be used instead of calling connect again
;; uconn is the host-port to call
;; we send dbname to the worker so they know which file to open
;; data must be a string with no newlines, it will be handed to the proc
;; at the remote site unchanged. It is up to the user to encode/decode it's contents
;;
;;   rtype: immediate, read-only, normal, low-priority
;; 
(define (remote-request udata uconn rtype dbname prockey procparam data)
  (let* ((cookie    (make-cookie udata)))
    (send-receive udata uconn rtype cookie data `(,prockey procparam))))

(define (ulex-open-db udata dbname)
  #f)


;;======================================================================
;; Ulex db
;;
;;   - track who is captain, lease expire time
;;   - track who owns what db, lease
;;
;;======================================================================

;;
;;
(define (ulex-dbfname)
  (let ((dbdir (conc (get-environment-variable "HOME") "/.ulex")))
    (if (not (file-exists? dbdir))
	(create-directory dbdir #t))
    (conc dbdir "/network.db")))
	 
;; always goes in ~/.ulex/network.db
;; role is captain, adjutant, node
;;
(define (ulexdb-setup)
  (let* ((dbfname (ulex-dbfname))
	 (have-db (file-exists? dbfname))
	 (db      (sqlite3:open-database dbfname)))
    (sqlite3:set-busy-handler! db (sqlite3:make-busy-timeout 136000))
    (sqlite3:execute db "PRAGMA synchronous = 0;")
    (if (not have-db)
	(sqlite3:with-transaction
	 db
	 (lambda ()
	   (for-each
	    (lambda (stmt)
	      (if stmt (sqlite3:execute db stmt)))
	    `("CREATE TABLE IF NOT EXISTS nodes
                 (id INTEGER PRIMARY KEY,
                  role  TEXT NOT NULL,
                  host  TEXT NOT NULL,
                  port TEXT NOT NULL,
                  ipadr TEXT NOT NULL,
                  pid   INTEGER NOT NULL,
                  zcard TEXT NOT NULL,
                  regtime INTEGER DEFAULT (strftime('%s','now')),
                  lease_thru INTEGER DEFAULT (strftime('%s','now')),
                  last_update INTEGER DEFAULT (strftime('%s','now')));"
	      "CREATE TRIGGER  IF NOT EXISTS update_nodes_trigger AFTER UPDATE ON nodes
                             FOR EACH ROW
                               BEGIN 
                                 UPDATE nodes SET last_update=(strftime('%s','now'))
                                   WHERE id=old.id;
                               END;"
	      "CREATE TABLE IF NOT EXISTS dbs
                 (id INTEGER PRIMARY KEY,
                  dbname TEXT NOT NULL,
                  dbfile TEXT NOT NULL,
                  dbtype TEXT NOT NULL,
                  host_port TEXT NOT NULL,
                  regtime INTEGER DEFAULT (strftime('%s','now')),
                  lease_thru INTEGER DEFAULT (strftime('%s','now')),
                  last_update INTEGER DEFAULT (strftime('%s','now')));"
	      "CREATE TRIGGER  IF NOT EXISTS update_dbs_trigger AFTER UPDATE ON dbs
                             FOR EACH ROW
                               BEGIN 
                                 UPDATE dbs SET last_update=(strftime('%s','now'))
                                   WHERE id=old.id;
                               END;")))))
    db))

(define (get-host-port-lease db dbfname)
  (sqlite3:fold-row
   (lambda (rem host-port lease-thru)
     (list host-port lease-thru))
   #f db "SELECT host_port,lease_thru FROM dbs WHERE dbfile = ?" dbfname))
  
(define (register-captain db host ipadr port pid zcard #!key (lease 20))
  (let* ((dbfname (ulex-dbfname))
	 (host-port  (conc host ":" port)))
    (sqlite3:with-transaction
     db
     (lambda ()
       (match (get-host-port-lease db dbfname)
	 ((host-port lease-thru)
	  (if (> (current-seconds) lease-thru)
	      (begin
		(sqlite3:execute db "UPDATE dbs SET host_port=?,lease_thru=? WHERE dbname=?"
				 (conc host ":" port)
				 (+ (current-seconds) lease)
				 dbfname)
		#t)
	      #f))
	 (#f  (sqlite3:execute db "INSERT INTO dbs (dbname,dbfile,dbtype,host_port,lease_thru) VALUES (?,?,?,?,?)"
			       "captain" dbfname "captain" host-port (+ (current-seconds) lease)))
	 (else (print "ERROR: Unrecognised result from fold-row")
	       (exit 1)))))))
							    
;;======================================================================
;; network utilities
;;======================================================================

(define (rate-ip ipaddr)
  (regex-case ipaddr
    ( "^127\\..*" _ 0 )
    ( "^(10\\.0|192\\.168)\\..*" _ 1 )
    ( else 2 ) ))

;; Change this to bias for addresses with a reasonable broadcast value?
;;
(define (ip-pref-less? a b)
  (> (rate-ip a) (rate-ip b)))
  

(define (get-my-best-address)
  (let ((all-my-addresses (get-all-ips))
        ;;(all-my-addresses-old (vector->list (hostinfo-addresses (hostname->hostinfo (get-host-name)))))
        )
    (cond
     ((null? all-my-addresses)
      (get-host-name))                                          ;; no interfaces?
     ((eq? (length all-my-addresses) 1)
      (car all-my-addresses))                      ;; only one to choose from, just go with it
     
     (else
      (car (sort all-my-addresses ip-pref-less?)))
     ;; (else 
     ;;  (ip->string (car (filter (lambda (x)                      ;; take any but 127.
     ;;    			 (not (eq? (u8vector-ref x 0) 127)))
     ;;    		       all-my-addresses))))

     )))

(define (get-all-ips-sorted)
  (sort (get-all-ips) ip-pref-less?))

(define (get-all-ips)
  (map ip->string (vector->list 
		   (hostinfo-addresses
		    (host-information (current-hostname))))))

(define (udat-my-host-port udata)
  (if (and (udat-my-address udata)(udat-my-port udata))
      (conc (udat-my-address udata) ":" (udat-my-port udata))
      #f))

(define (udat-captain-host-port udata)
  (if (and (udat-captain-address udata)(udat-captain-port udata))
      (conc (udat-captain-address udata) ":" (udat-captain-port udata))
      #f))

(define (udat-get-peer udata host-port)
  (hash-table-ref/default (udat-peers udata) host-port #f))

;; struct for keeping track of others we are talking to

(defstruct peer
  (addr-port       #f)
  (hostname        #f)
  (pid             #f)
  ;; (inp             #f)
  ;; (oup             #f)
  (dbs            '()) ;; list of databases this peer is currently handling
  )

(defstruct work
  (peer-dat   #f)
  (handlerkey #f)
  (qrykey     #f)
  (data       #f)
  (start      (current-milliseconds)))

#;(defstruct dbowner
  (pdat        #f)
  (last-update (current-seconds)))

;;======================================================================
;; Captain functions
;;======================================================================

;; NB// This needs to be started in a thread
;;
;; setup to be a captain
;;   - local server MUST be started already
;;   - create pkt
;;   - start server port handler
;;
(define (setup-as-captain udata)
  (if (create-captain-pkt udata)
      (let* ((my-addr (udat-my-address udata))
	     (my-port (udat-my-port    udata))
	     (th (make-thread (lambda ()
				(ulex-handler-loop udata)) "Captain handler")))
	(udat-handler-thread-set! udata th)
	(udat-captain-address-set! udata my-addr)
	(udat-captain-port-set!    udata my-port)
	(thread-start! th)
	(print "Captain setup complete and thread started. Address: " my-addr ", port: " my-port))
      (begin
	(print "ERROR: failed to create captain pkt")
	#f)))

;; given a pkts dir read 
;;
(define (get-all-captain-pkts udata)
  (let* ((pktsdir       (let ((d (udat-cpkts-dir udata)))
			  (if (file-exists? d)
			      d
			      (begin
				(create-directory d #t)
				d))))
	 (all-pkt-files (glob (conc pktsdir "/*.pkt")))
	 (pkt-spec      (udat-cpkt-spec udata)))
    (map (lambda (pkt-file)
	   (read-pkt->alist pkt-file pktspec: pkt-spec))
	 all-pkt-files)))

;; sort by D then Z, return one, choose the oldest then
;; differentiate if needed using the Z key
;;l
(define (get-winning-pkt pkts)
  (if (null? pkts)
      #f
      (car (sort pkts (lambda (a b)
			(let ((ad (string->number (alist-ref 'D a)))
			      (bd (string->number (alist-ref 'D b))))
			  (if (eq? a b)
			      (let ((az (alist-ref 'Z a))
				    (bz (alist-ref 'Z b)))
				(string>=? az bz))
			      (> ad bd))))))))

;; put the host, ip, port and pid into a pkt in
;; the captain pkts dir
;;  - assumes user has already fired up a server
;;    which will be in the udata struct
;;
(define (create-captain-pkt udata)
  (if (not (udat-serv-listener udata))
      (begin
	(print "ERROR: create-captain-pkt called with out a listener")
	#f)
      (let* ((pktdat `((port   . ,(udat-my-port udata))
		       (host   . ,(udat-my-hostname udata))
		       (ipaddr . ,(udat-my-address udata))
		       (pid    . ,(udat-my-pid     udata))))
	     (pktdir  (udat-cpkts-dir udata))
	     (pktspec (udat-cpkt-spec udata))
	     )
	(udat-my-cpkt-key-set!
	 udata
	 (write-alist->pkt
	  pktdir
	  pktdat
	  pktspec: pktspec
	  ptype:   'captain))
	(udat-my-cpkt-key udata))))

;; remove pkt associated with captn (the Z key .pkt)
;;
(define (remove-captain-pkt udata captn)
  (let ((Z       (alist-ref 'Z captn))
	(cpktdir (udat-cpkts-dir udata)))
    (delete-file* (conc cpktdir "/" Z ".pkt"))))

;; call all known peers and tell them to delete their info on the captain
;; thus forcing them to re-read pkts and connect to a new captain
;; call this when the captain needs to exit and if an older captain is
;; detected. Due to delays in sending file meta data in NFS multiple
;; captains can be initiated in a "Storm of Captains", book soon to be
;; on Amazon
;;
(define (drop-captain udata)
  (let* ((peers (hash-table-keys (udat-peers udata)))
	 (cookie (make-cookie udata)))
    (for-each
     (lambda (host-port)
       (send udata host-port 'dropcaptain cookie "nomsg" retval: #t))
     peers)))

;;======================================================================
;; server primitives
;;======================================================================

(define (make-cookie udata)
  (let ((newcnum (+ (udat-cnum udata) 1)))
    (udat-cnum-set! udata newcnum)
    (conc (udat-my-address udata) ":"
	  (udat-my-port    udata) "-"
	  (udat-my-pid     udata) "-"
	  newcnum)))

;; create a tcp listener and return a populated udat struct with
;; my port, address, hostname, pid etc.
;; return #f if fail to find a port to allocate.
;;
;;  does not actually start a server thread
;;
;;  if udata-in is #f create the record
;;  if there is already a serv-listener return the udata
;;
(define (start-server-find-port udata-in #!optional (port 4242)(tries 0))
  (let ((udata (or udata-in (make-udat))))
    (if (udat-serv-listener udata) ;; TODO - add check that the listener is alive and ready?
	udata
	(let ((res (connect-server udata port)))
	  (if res
	      res
	      (begin
		;; (print "Could not connect to " port)
		(if (and (< port  65535)
			 (< tries 10000)) ;; make this number bigger when things are working
		    (start-server-find-port udata (+ port 1)(+ tries 1))
		    #f)))))))

(define (connect-server udata port)
  ;; (tcp-listener-socket LISTENER)(socket-name so)
  ;; sockaddr-address, sockaddr-port, sockaddr->string
  (let* ((tlsn (handle-exceptions
		   exn
		   #f ;; NB// NEED BETTER HANDLING HERE ASAP
		 (tcp-listen port 1000 #f))) ;; (tcp-listen TCPPORT [BACKLOG [HOST]])
	 (addr (get-my-best-address))) ;; (hostinfo-addresses (host-information (current-hostname)))
    (if tlsn
	(begin
	  (udat-my-address-set!    udata addr)
	  (udat-my-port-set!       udata port)
	  (udat-my-hostname-set!   udata (get-host-name))
	  (udat-serv-listener-set! udata tlsn)
	  udata)
	#f)))

(define (get-peer-dat udata host-port #!optional (hostname #f)(pid #f))
  (let* ((pdat (or (udat-get-peer udata host-port)
		   (handle-exceptions ;; ERROR - MAKE THIS EXCEPTION HANDLER MORE SPECIFIC
		    exn
		    #f
		    (let ((npdat (make-peer addr-port: host-port)))
		      (if hostname (peer-hostname-set! npdat hostname))
		      (if pid (peer-pid-set! npdat pid))
		      npdat)))))
    pdat))

;; send structured data to recipient
;;
;;  NOTE: qrykey is what was called the "cookie" previously
;;
;;     retval tells send to expect and wait for return data (one line) and return it or time out
;;       this is for ping where we don't want to necessarily have set up our own server yet.
;;
(define (send udata host-port handler qrykey data
	      #!key (hostname #f)(pid #f)(params '())(retval #f))
  (let* ((my-host-port (udat-my-host-port udata))
	 (isme         (equal? host-port my-host-port)) ;; am I calling
							;; myself?
	 (dat          (list
			handler              ;; " "
			my-host-port         ;; " "
			(udat-my-pid  udata) ;; " "
			qrykey
			params ;;(if (null? params) "" (conc " "
			       ;;(string-intersperse params " ")))
			)))
    ;; (print "send isme is " (if isme "true!" "false!") ",
    ;; my-host-port: " my-host-port ", host-port: " host-port)
    (if isme
	(ulex-handler udata dat data)
	(handle-exceptions ;; ERROR - MAKE THIS EXCEPTION HANDLER MORE
			   ;; SPECIFIC
	    exn
	    #f 
	  (let-values (((inp oup)(tcp-connect host-port)))
	    ;;
	    ;; CONTROL LINE:
	    ;;    handlerkey host:port pid qrykey params ...
	    ;;
	    (let ((res
		   (if (and inp oup)
		       (let* ()
			 (if my-host-port
			     (begin
			       (write dat  oup)
			       (write data oup) ;; send as sexpr
			       ;; (print "Sent dat: " dat " data: " data)
			       (if retval
				   (read inp)
				   #t))
			     (begin
			       (print "ERROR: send called but no receiver has been setup. Please call setup first!")
			       #f))
			 ;; NOTE: DO NOT BE TEMPTED TO LOOK AT ANY DATA ON INP HERE!
			 ;;       (there is a listener for handling that)
			 )
		       #f))) ;; #f means failed to connect and send
	      (close-input-port inp)
	      (close-output-port oup)
	      res))))))

;; send a request to the given host-port and register a mailbox in udata
;; wait for the mailbox data and return it
;;
(define (send-receive udata host-port handler qrykey data #!key (hostname #f)(pid #f)(params '())(timeout 20))
  (let ((mbox      (make-mailbox))
	(mbox-time (current-milliseconds))
	(mboxes    (udat-mboxes udata)))
    (hash-table-set! mboxes qrykey mbox)
    (if (send udata host-port handler qrykey data hostname: hostname pid: pid params: params)
	(let* ((mbox-timeout-secs    timeout)
	       (mbox-timeout-result 'MBOX_TIMEOUT)
	       (res                  (mailbox-receive! mbox mbox-timeout-secs mbox-timeout-result))
	       (mbox-receive-time    (current-milliseconds)))
	  (hash-table-delete! mboxes qrykey)
	  (if (eq? res 'MBOX_TIMEOUT)
	      #f
	      res))
	#f))) ;; #f means failed to communicate

;; 
(define (ulex-handler udata controldat data)
  (print "controldat: " controldat " data: " data)
  (match controldat ;;  (string-split controldat)
    ((handlerkey host-port pid qrykey params ...)
     ;; (print "handlerkey: " handlerkey " host-port: " host-port " pid: " pid " qrykey: " qrykey " params: " params)
     (case handlerkey ;; (string->symbol handlerkey)
       ((ack)(print "Got ack!"))
       ((ping) ;; special case - return result immediately on the same connection
	(let* ((proc  (hash-table-ref/default (udat-handlers udata) 'ping #f))
	       (val   (if proc (proc) "gotping"))
	       (peer  (make-peer addr-port: host-port pid: pid))
	       (dbshash (udat-dbowners udata)))
	  (peer-dbs-set! peer params) ;; params for ping is list of dbs owned by pinger
	  (for-each (lambda (dbfile)
		      (hash-table-set! dbshash dbfile host-port)) ;; WRONG?
		    params) ;; register each db in the dbshash
	  (if (not (hash-table-exists? (udat-peers udata) host-port))
	      (hash-table-set! (udat-peers udata) host-port peer)) ;; save the details of this caller in peers
	  qrykey)) ;; End of ping
       ((goodbye)
	;; remove all traces of the caller in db ownership etc.
	(let* ((peer  (hash-table-ref/default (udat-peers udata) host-port #f))
	       (dbs   (if peer (peer-dbs peer) '()))
	       (dbshash (udat-dbowners udata)))
	  (for-each (lambda (dbfile)(hash-table-delete! dbshash dbfile)) dbs)
	  (hash-table-delete! (udat-peers udata) host-port)
	  qrykey))
       ((dropcaptain)
	;; remove all traces of the captain
	(udat-captain-address-set! udata #f)
	(udat-captain-host-set!    udata #f)
	(udat-captain-port-set!    udata #f)
	(udat-captain-pid-set!     udata #f)
	qrykey)
       ((rucaptain) ;; remote is asking if I'm the captain
	(if (udat-my-cpkt-key udata) "yes" "no"))
       ((db-owner) ;; given a db name who do I send my queries to
	;; look up the file in handlers, if have an entry ping them to be sure
	;; they are still alive and then return that host:port.
	;; if no handler found or if the ping fails pick from peers the oldest that
	;; is managing the fewest dbs
	(match params
	  ((dbfile dbtype)
	   (let* ((owner-host-port (hash-table-ref/default (udat-dbowners udata) dbfile #f)))
	     (if owner-host-port
		 (conc qrykey " " owner-host-port)
		 (let* ((pdat (or (hash-table-ref/default (udat-peers udata) host-port #f) ;; no owner - caller gets to own it!
				  (make-peer addr-port: host-port pid: pid dbs: `(,dbfile)))))
		   (hash-table-set! (udat-peers udata) host-port pdat)
		   (hash-table-set! (udat-dbowners udata) dbfile host-port)
		   (conc qrykey " " host-port)))))
	  (else (conc qrykey " BADDATA"))))
       ;; for work items:
       ;;    handler is one of; immediate, read-only, read-write, high-priority
       ((immediate read-only normal low-priority) ;; do this work immediately
	;; host-port (caller), pid (caller), qrykey (cookie), params <= all from first line
	;; data => a single line encoded however you want, or should I build json into it?
	(print "handlerkey=" handlerkey)
	(let* ((pdat (get-peer-dat udata host-port)))
	  (match params ;; dbfile prockey procparam
	    ((dbfile prockey procparam)
	     (case handlerkey
	       ((immediate read-only)
		(process-request udata pdat dbfile qrykey prockey procparam data))
	       ((normal low-priority) ;; split off later and add logic to support low priority
		(add-to-work-queue udata pdat dbfile qrykey prockey procparam data))
	       (else
		#f)))
	    (else
	     (print "INFO: params=" params " handlerkey=" handlerkey " controldat=" controldat)
	     #f))))
       (else
	;; (add-to-work-queue udata (get-peer-dat udata host-port) handlerkey qrykey data)
	#f)))
    (else
     (print "BAD DATA? controldat=" controldat " data=" data)
     #f)));; handles the incoming messages and dispatches to queues

;;
(define (ulex-handler-loop udata)
  (let* ((serv-listener (udat-serv-listener udata)))
    ;; data comes as two lines
    ;;   handlerkey resp-addr:resp-port hostname pid qrykey [dbpath/dbfile.db]
    ;;   data
    (let loop ((state 'start))
      (let-values (((inp oup)(tcp-accept serv-listener)))
	(let* ((controldat (read inp))
	       (data       (read inp))
	       (resp       (ulex-handler udata controldat data)))
	  (if resp (write resp oup))
	  (close-input-port inp)
	  (close-output-port oup))
	(loop state)))))

;; add a proc to the handler list, these are done symetrically (i.e. in all instances)
;; so that the proc can be dereferenced remotely
;;
(define (register-handler udata key proc)
  (hash-table-set! (udat-handlers udata) key proc))


;;======================================================================
;; work queues
;;======================================================================

(define (add-to-work-queue udata peer-dat handlerkey qrykey data)
  (let ((wdat (make-work peer-dat: peer-dat handlerkey: handlerkey qrykey: qrykey data: data)))
    (if (udat-busy udata)
	(queue-add! (udat-work-queue udata) wdat)
	(process-work udata wdat)) ;; passing in wdat tells process-work to first process the passed in wdat
    ))

(define (do-work udata wdat)
  #f)

(define (process-work udata #!optional wdat)
  (if wdat (do-work udata wdat)) ;; process wdat
  (let ((wqueue (udat-work-queue udata)))
    (if (not (queue-empty? wqueue))
	(let loop ((wd (queue-remove! wqueue)))
	  (do-work udata wd)
	  (if (not (queue-empty? wqueue))
	      (loop (queue-remove! wqueue)))))))

;;======================================================================
;; Generic db handling
;;   setup a inmem db instance
;;   open connection to on-disk db
;;   sync on-disk db to inmem
;;   get lock in on-disk db for dbowner of this db
;;   put sync-proc, init-proc, on-disk handle, inmem handle in dbconn stuct
;;   return the stuct
;;======================================================================

(defstruct dbconn
  (fname  #f)
  (inmem  #f)
  (conn   #f)
  (sync   #f) ;; sync proc
  (init   #f) ;; init proc
  (lastsync (current-seconds))
  )

(defstruct dbinfo
  (initproc #f)
  (syncproc #f))

;; open inmem and disk database
;;   init with initproc
;;   return db struct
;;
;;   appname; megatest, ulex or something else.
;;
(define (setup-db-connection udata fname-in appname dbtype)
  (let* ((is-ulex (eq? appname 'ulex))
	 (dbinf   (if is-ulex ;; ulex is a built-in special case
		      (make-dbinfo initproc: ulexdb-init syncproc: ulexdb-sync)
		      (hash-table-ref/default (udat-dbtypes udata) dbtype #f)))
	 (initproc (dbinfo-initproc dbinf))
	 (syncproc (dbinfo-syncproc dbinf))
	 (fname   (if is-ulex
		      (conc (udat-ulex-dir udata) "/ulex.db")
		      fname-in))
	 (inmem-db (open-and-initdb udata #f 'inmem (dbinfo-initproc dbinf)))
	 (disk-db  (open-and-initdb udata fname 'disk (dbinfo-initproc dbinf))))
    (make-dbconn inmem: inmem-db conn: disk-db sync: syncproc init: initproc)))

;; dest='inmem or 'disk
;;
(define (open-and-initdb udata filename dest init-proc)
  (let* ((inmem    (eq? dest 'inmem))
	 (dbfile   (if inmem
		       ":INMEM:"
		       filename))
	 (dbexists (if inmem #t (file-exists? dbfile)))
	 (db       (sqlite3:open-database dbfile)))
    (sqlite3:set-busy-handler! db (sqlite3:make-busy-timeout 136000))
    (if (not dbexists)
	(init-proc db))
    db))


;;======================================================================
;; Previous Ulex db stuff
;;======================================================================

(define (ulexdb-init db inmem)
  (sqlite3:with-transaction
   db
   (lambda ()
     (for-each
      (lambda (stmt)
	(if stmt (sqlite3:execute db stmt)))
      `("CREATE TABLE IF NOT EXISTS processes 
                 (id INTEGER PRIMARY KEY,
                  host  TEXT NOT NULL,
                  ipadr TEXT NOT NULL,
                  port  INTEGER NOT NULL,
                  pid   INTEGER NOT NULL,
                  regtime INTEGER DEFAULT (strftime('%s','now')),
                  last_update INTEGER DEFAULT (strftime('%s','now')));"
	(if inmem
	    "CREATE TRIGGER  IF NOT EXISTS update_proces_trigger AFTER UPDATE ON processes
                             FOR EACH ROW
                               BEGIN 
                                 UPDATE processes SET last_update=(strftime('%s','now'))
                                   WHERE id=old.id;
                               END;"
	    #f))))))

;; open databases, do initial sync
(define (ulexdb-sync dbconndat udata)
  #f)


) ;; END OF ULEX


;;; ;;======================================================================
;;; ;; D E B U G   H E L P E R S
;;; ;;======================================================================
;;;     
;;; (define (dbg> . args)
;;;   (with-output-to-port (current-error-port)
;;;     (lambda ()
;;;       (apply print "dbg> " args))))
;;; 
;;; (define (debug-pp . args)
;;;   (if (get-environment-variable "ULEX_DEBUG")
;;;       (with-output-to-port (current-error-port)
;;; 	(lambda ()
;;; 	  (apply pp args)))))
;;; 
;;; (define *default-debug-port* (current-error-port))
;;; 
;;; (define (sdbg> fn stage-name stage-start stage-end start-time . message)
;;;   (if (get-environment-variable "ULEX_DEBUG")
;;;       (with-output-to-port *default-debug-port* 
;;; 	(lambda ()
;;; 	  (apply print "ulex:" fn " " stage-name " took " (- (if stage-end stage-end (current-milliseconds)) stage-start) " ms. "
;;; 		 (if start-time
;;; 		     (conc "total time " (- (current-milliseconds) start-time)
;;; 			   " ms.")
;;; 		     "")
;;; 		 message
;;; 		 )))))

;;======================================================================
;; M A C R O S
;;======================================================================
;; iup callbacks are not dumping the stack, this is a work-around
;;

;; Some of these routines use:
;;
;;     http://www.cs.toronto.edu/~gfb/scheme/simple-macros.html
;;
;; Syntax for defining macros in a simple style similar to function definiton,
;;  when there is a single pattern for the argument list and there are no keywords.
;;
;; (define-simple-syntax (name arg ...) body ...)
;;
;; 
;; (define-syntax define-simple-syntax
;;   (syntax-rules ()
;;     ((_ (name arg ...) body ...)
;;      (define-syntax name (syntax-rules () ((name arg ...) (begin body ...)))))))
;; 
;; (define-simple-syntax (catch-and-dump proc procname)
;;   (handle-exceptions
;;    exn
;;    (begin
;;      (print-call-chain (current-error-port))
;;      (with-output-to-port (current-error-port)
;;        (lambda ()
;;          (print ((condition-property-accessor 'exn 'message) exn))
;;          (print "Callback error in " procname)
;;          (print "Full condition info:\n" (condition->list exn)))))
;;    (proc)))
;; 
;; 
;;======================================================================
;;  R E C O R D S
;;======================================================================

;;; ;; information about me as a server
;;; ;;
;;; (defstruct area
;;;   ;; about this area
;;;   (useportlogger #f)
;;;   (lowport       32768)
;;;   (server-type   'auto)  ;; auto=create up to five servers/pkts, main=create pkts, passive=no pkt (unless there are no pkts at all)
;;;   (conn          #f)
;;;   (port          #f)
;;;   (myaddr        (get-my-best-address))
;;;   pktid          ;; get pkt from hosts table if needed
;;;   pktfile
;;;   pktsdir
;;;   dbdir
;;;   (dbhandles     (make-hash-table)) ;; fname => list-of-dbh, NOTE: Should really never need more than one?
;;;   (mutex         (make-mutex))
;;;   (rtable        (make-hash-table)) ;; registration table of available actions
;;;   (dbs           (make-hash-table)) ;; filename => random number, used for choosing what dbs I serve
;;;   ;; about other servers
;;;   (hosts         (make-hash-table)) ;; key => hostdat
;;;   (hoststats     (make-hash-table)) ;; key => alist of fname => ( qcount . qtime )
;;;   (reqs          (make-hash-table)) ;; uri => queue
;;;   ;; work queues
;;;   (wqueues       (make-hash-table)) ;; fname => qdat
;;;   (stats         (make-hash-table)) ;; fname => totalqueries
;;;   (last-srvup    (current-seconds)) ;; last time we updated the known servers
;;;   (cookie2mbox   (make-hash-table)) ;; map cookie for outstanding request to mailbox of awaiting call
;;;   (ready #f)
;;;   (health        (make-hash-table)) ;; ipaddr:port => num failed pings since last good ping
;;;   )
;;; 
;;; ;; host stats
;;; ;;
;;; (defstruct hostdat
;;;   (pkt      #f)
;;;   (dbload   (make-hash-table))  ;; "dbfile.db" => queries/min
;;;   (hostload #f)                 ;; normalized load ( 5min load / numcpus )
;;;   )
;;; 
;;; ;; dbdat
;;; ;;
;;; (defstruct dbdat
;;;   (dbh    #f)
;;;   (fname  #f)
;;;   (write-access #f)
;;;   (sths   (make-hash-table))  ;; hash mapping query strings to handles
;;;   )
;;; 
;;; ;; qdat
;;; ;;
;;; (defstruct qdat
;;;   (writeq  (make-queue))
;;;   (readq   (make-queue))
;;;   (rwq     (make-queue))
;;;   (logq    (make-queue)) ;; do we need a queue for logging? yes, if we use sqlite3 db for logging
;;;   (osshort (make-queue))
;;;   (oslong  (make-queue))
;;;   (misc    (make-queue)) ;; used for things like ping-full
;;;   )
;;; 
;;; ;; calldat
;;; ;;
;;; (defstruct calldat
;;;   (ctype 'dbwrite)
;;;   (obj   #f)              ;; this would normally be an SQL statement e.g. SELECT, INSERT etc.
;;;   (rtime (current-milliseconds)))
;;; 
;;; ;; make it a global? Well, it is local to area module
;;; 
;;; (define *pktspec*
;;;   `((server (hostname . h)
;;; 	    (port     . p)
;;; 	    (pid      . i)
;;; 	    (ipaddr   . a)
;;; 	    )
;;;     (data   (hostname . h)  ;; sender hostname
;;; 	    (port     . p)  ;; sender port
;;; 	    (ipaddr   . a)  ;; sender ip
;;; 	    (hostkey  . k)  ;; sending host key - store info at server under this key
;;; 	    (servkey  . s)  ;; server key - this needs to match at server end or reject the msg
;;; 	    (format   . f)  ;; sb=serialized-base64, t=text, sx=sexpr, j=json
;;; 	    (data     . d)  ;; base64 encoded slln data
;;; 	    )))
;;; 
;;; ;; work item
;;; ;;
;;; (defstruct witem
;;;   (rhost #f)   ;; return host
;;;   (ripaddr #f) ;; return ipaddr
;;;   (rport #f)   ;; return port
;;;   (servkey #f) ;; the packet representing the client of this workitem, used by final send-message
;;;   (rdat  #f)   ;; the request - usually an sql query, type is rdat
;;;   (action #f)  ;; the action: immediate, dbwrite, dbread,oslong, osshort
;;;   (cookie #f)  ;; cookie id for response
;;;   (data   #f)  ;; the data payload, i.e. parameters
;;;   (result #f)  ;; the result from processing the data
;;;   (caller #f)) ;; the calling peer according to rpc itself
;;; 
;;; (define (trim-pktid pktid)
;;;   (if (string? pktid)
;;;       (substring pktid 0 4)
;;;       "nopkt"))
;;; 
;;; (define (any->number num)
;;;   (cond
;;;    ((number? num) num)
;;;    ((string? num) (string->number num))
;;;    (else num)))
;;; 
;;; (use trace)
;;; (trace-call-sites #t)
;;; 
;;; ;;======================================================================
;;; ;; D A T A B A S E   H A N D L I N G 
;;; ;;======================================================================
;;; 
;;; ;; look in dbhandles for a db, return it, else return #f
;;; ;;
;;; (define (get-dbh acfg fname)
;;;   (let ((dbh-lst (hash-table-ref/default (area-dbhandles acfg) fname '())))
;;;     (if (null? dbh-lst)
;;; 	(begin
;;; 	  ;; (print "opening db for " fname)
;;; 	  (open-db acfg fname)) ;; Note that the handles get put back in the queue in the save-dbh calls
;;; 	(let ((rem-lst (cdr dbh-lst)))
;;; 	  ;; (print "re-using saved connection for " fname)
;;; 	  (hash-table-set! (area-dbhandles acfg) fname rem-lst)
;;; 	  (car dbh-lst)))))
;;; 
;;; (define (save-dbh acfg fname dbdat)
;;;     ;; (print "saving dbh for " fname)
;;;     (hash-table-set! (area-dbhandles acfg) fname (cons dbdat (hash-table-ref/default (area-dbhandles acfg) fname '()))))
;;; 
;;; ;; open the database, if never before opened init it. put the handle in the
;;; ;; open db's hash table
;;; ;; returns: the dbdat
;;; ;;
;;; (define (open-db acfg fname)
;;;   (let* ((fullname     (conc (area-dbdir acfg) "/" fname))
;;; 	 (exists       (file-exists? fullname))
;;; 	 (write-access (if exists
;;; 			   (file-write-access? fullname)
;;; 			   (file-write-access? (area-dbdir acfg))))
;;; 	 (db           (sqlite3:open-database fullname))
;;; 	 (handler      (sqlite3:make-busy-timeout 136000))
;;; 	 )
;;;     (sqlite3:set-busy-handler! db handler)
;;;     (sqlite3:execute db "PRAGMA synchronous = 0;")
;;;     (if (not exists) ;; need to init the db
;;; 	(if write-access
;;; 	    (let ((isql (get-rsql acfg 'dbinitsql))) ;; get the init sql statements
;;; 	      ;; (sqlite3:with-transaction
;;; 	      ;;  db
;;; 	      ;;  (lambda ()
;;; 		 (if isql
;;; 		     (for-each
;;; 		      (lambda (sql)
;;; 			(sqlite3:execute db sql))
;;; 		      isql)))
;;; 	    (print "ERROR: no write access to " (area-dbdir acfg))))
;;;     (make-dbdat dbh: db fname: fname write-access: write-access)))
;;; 
;;; ;; This is a low-level command to retrieve or to prepare, save and return a prepared statment
;;; ;; you must extract the db handle
;;; ;;
;;; (define (get-sth db cache stmt)
;;;   (if (hash-table-exists? cache stmt)
;;;       (begin
;;; 	;; (print "Reusing cached stmt for " stmt)
;;; 	(hash-table-ref/default cache stmt #f))
;;;       (let ((sth (sqlite3:prepare db stmt)))
;;; 	(hash-table-set! cache stmt sth)
;;; 	;; (print "prepared stmt for " stmt)
;;; 	sth)))
;;; 
;;; ;; a little more expensive but does all the tedious deferencing - only use if you don't already
;;; ;; have dbdat and db sitting around
;;; ;;
;;; (define (full-get-sth acfg fname stmt)
;;;   (let* ((dbdat  (get-dbh acfg fname))
;;; 	 (db     (dbdat-dbh dbdat))
;;; 	 (sths   (dbdat-sths dbdat)))
;;;     (get-sth db sths stmt)))
;;; 
;;; ;; write to a db
;;; ;; acfg: area data
;;; ;; rdat: request data
;;; ;; hdat: (host . port)
;;; ;;
;;; ;; (define (dbwrite acfg rdat hdat data-in)
;;; ;;   (let* ((dbname (car data-in))
;;; ;; 	 (dbdat  (get-dbh acfg dbname))
;;; ;; 	 (db     (dbdat-dbh dbdat))
;;; ;; 	 (sths   (dbdat-sths dbdat))
;;; ;; 	 (stmt   (calldat-obj rdat))
;;; ;; 	 (sth    (get-sth db sths stmt))
;;; ;; 	 (data   (cdr data-in)))
;;; ;;     (print "dbname: " dbname " acfg: " acfg " rdat: " (calldat->alist rdat) " hdat: " hdat " data: " data)
;;; ;;     (print "dbdat: " (dbdat->alist dbdat))
;;; ;;     (apply sqlite3:execute sth data)
;;; ;;     (save-dbh acfg dbname dbdat)
;;; ;;     #t
;;; ;;     ))
;;; 
;;; (define (finalize-all-db-handles acfg)
;;;   (let* ((dbhandles (area-dbhandles acfg))  ;; dbhandles is hash of fname ==> dbdat
;;; 	 (num       0))
;;;     (for-each
;;;      (lambda (area-name)
;;;        (print "Closing handles for " area-name)
;;;        (let ((dbdats (hash-table-ref/default dbhandles area-name '())))
;;; 	 (for-each
;;; 	  (lambda (dbdat)
;;; 	    ;; first close all statement handles
;;; 	    (for-each
;;; 	     (lambda (sth)
;;; 	       (sqlite3:finalize! sth)
;;; 	       (set! num (+ num 1)))
;;; 	     (hash-table-values (dbdat-sths dbdat)))
;;; 	    ;; now close the dbh
;;; 	    (set! num (+ num 1))
;;; 	    (sqlite3:finalize! (dbdat-dbh dbdat)))
;;; 	  dbdats)))
;;;      (hash-table-keys dbhandles))
;;;     (print "FINALIZED " num " dbhandles")))
;;; 
;;; ;;======================================================================
;;; ;; W O R K   Q U E U E   H A N D L I N G 
;;; ;;======================================================================
;;; 
;;; (define (register-db-as-mine acfg dbname)
;;;   (let ((ht (area-dbs acfg)))
;;;     (if (not (hash-table-ref/default ht dbname #f))
;;; 	(hash-table-set! ht dbname (random 10000)))))
;;; 	
;;; (define (work-queue-add acfg fname witem)
;;;   (let* ((work-queue-start (current-milliseconds))
;;; 	 (action           (witem-action witem)) ;; NB the action is the index into the rdat actions
;;; 	 (qdat             (or (hash-table-ref/default (area-wqueues acfg) fname #f)
;;; 			       (let ((newqdat (make-qdat)))
;;; 				 (hash-table-set! (area-wqueues acfg) fname newqdat)
;;; 				 newqdat)))
;;; 	 (rdat             (hash-table-ref/default (area-rtable acfg) action #f)))
;;;     (if rdat
;;; 	(queue-add!
;;; 	 (case (calldat-ctype rdat)
;;; 	   ((dbwrite)   (register-db-as-mine acfg fname)(qdat-writeq qdat))
;;; 	   ((dbread)    (register-db-as-mine acfg fname)(qdat-readq  qdat))
;;; 	   ((dbrw)      (register-db-as-mine acfg fname)(qdat-rwq    qdat))
;;; 	   ((oslong)    (qdat-oslong qdat))
;;; 	   ((osshort)   (qdat-osshort qdat))
;;; 	   ((full-ping) (qdat-misc  qdat))
;;; 	   (else
;;; 	    (print "ERROR: no queue for " action ". Adding to dbwrite queue.")
;;; 	    (qdat-writeq qdat)))
;;; 	 witem)
;;; 	(case action
;;; 	  ((full-ping)(qdat-misc qdat))
;;; 	  (else
;;; 	   (print "ERROR: No action " action " was registered"))))
;;;     (sdbg> "work-queue-add" "queue-add" work-queue-start #f #f)
;;;     #t)) ;; for now, simply return #t to indicate request got to the queue
;;; 
;;; (define (doqueue acfg q fname dbdat dbh)
;;;   ;; (print "doqueue: " fname)
;;;   (let* ((start-time (current-milliseconds))
;;; 	 (qlen       (queue-length q)))
;;;     (if (> qlen 1)
;;; 	(print "Processing queue of length " qlen))
;;;     (let loop ((count      0)
;;; 	       (responses '()))
;;;       (let ((delta (- (current-milliseconds) start-time)))
;;; 	(if (or (queue-empty? q)
;;; 		(> delta 400)) ;; stop working on this queue after 400ms have passed
;;; 	    (list count delta responses) ;; return count, delta and responses list
;;; 	    (let* ((witem  (queue-remove! q))
;;; 		   (action (witem-action witem))
;;; 		   (rdat   (witem-rdat   witem))
;;; 		   (stmt   (calldat-obj rdat))
;;; 		   (sth    (full-get-sth acfg fname stmt))
;;; 		   (ctype  (calldat-ctype rdat))
;;; 		   (data   (witem-data   witem))
;;; 		   (cookie (witem-cookie witem)))
;;; 	      ;; do the processing and save the result in witem-result
;;; 	      (witem-result-set!
;;; 	       witem
;;; 	       (case ctype ;; action
;;; 		 ((noblockwrite) ;; blind write, no ack of success returned
;;; 		  (apply sqlite3:execute sth data)
;;; 		  (sqlite3:last-insert-rowid dbh))
;;; 		 ((dbwrite)      ;; blocking write   
;;; 		  (apply sqlite3:execute sth data)
;;; 		  #t)
;;; 		 ((dbread) ;; TODO: consider breaking this up and shipping in pieces for large query
;;; 		  (apply sqlite3:map-row (lambda x x) sth data))
;;; 		 ((full-ping)  'full-ping)
;;; 		 (else (print "Not ready for action " action) #f)))
;;; 	      (loop (add1 count)
;;; 		    (if cookie
;;; 			(cons witem responses)
;;; 			responses))))))))
;;; 
;;; ;; do up to 400ms of processing on each queue
;;; ;; - the work-queue-processor will allow the max 1200ms of work to complete but it will flag as overloaded
;;; ;; 
;;; (define (process-db-queries acfg fname)
;;;   (if (hash-table-exists? (area-wqueues acfg) fname)
;;;       (let* ((process-db-queries-start-time (current-milliseconds))
;;; 	     (qdat             (hash-table-ref/default (area-wqueues acfg) fname #f))
;;; 	     (queue-sym->queue (lambda (queue-sym)
;;; 				 (case queue-sym  ;; lookup the queue from qdat given a name (symbol)
;;; 				   ((wqueue)  (qdat-writeq qdat))
;;; 				   ((rqueue)  (qdat-readq  qdat))
;;; 				   ((rwqueue) (qdat-rwq    qdat))
;;; 				   ((misc)    (qdat-misc   qdat))
;;; 				   (else #f))))
;;; 	     (dbdat   (get-dbh acfg fname))
;;; 	     (dbh     (if (dbdat? dbdat)(dbdat-dbh dbdat) #f))
;;; 	     (nowtime (current-seconds)))
;;; 	;; handle the queues that require a transaction
;;; 	;;
;;; 	(map ;; 
;;; 	 (lambda (queue-sym)
;;; 	   ;; (print "processing queue " queue-sym)
;;; 	   (let* ((queue (queue-sym->queue queue-sym)))
;;; 	     (if (not (queue-empty? queue))
;;; 		 (let ((responses
;;; 			(sqlite3:with-transaction ;; todo - catch exceptions...
;;; 			 dbh
;;; 			 (lambda ()
;;; 			   (let* ((res (doqueue acfg queue fname dbdat dbh))) ;; this does the work!
;;; 			     ;; (print "res=" res)
;;; 			     (match res
;;; 			      ((count delta responses)
;;; 			       (update-stats acfg fname queue-sym delta count)
;;; 			       (sdbg> "process-db-queries" "sqlite3-transaction" process-db-queries-start-time #f #f)
;;; 			       responses) ;; return responses
;;; 			      (else
;;; 			       (print "ERROR: bad return data from doqueue " res)))
;;; 			     )))))
;;; 		   ;; having completed the transaction, send the responses.
;;; 		   ;; (print "INFO: sending " (length responses) " responses.")
;;; 		   (let loop ((responses-left responses))
;;; 		     (cond
;;; 		      ((null? responses-left)  #t)
;;; 		      (else
;;; 		       (let* ((witem    (car responses-left))
;;; 			      (response (cdr responses-left)))  
;;; 			 (call-deliver-response acfg (witem-ripaddr witem)(witem-rport witem)
;;; 						(witem-cookie witem)(witem-result witem)))
;;; 		       (loop (cdr responses-left))))))
;;; 		 )))
;;; 	 '(wqueue rwqueue rqueue))
;;; 	
;;; 	;; handle misc queue
;;; 	;;
;;; 	;; (print "processing misc queue")
;;; 	(let ((queue (queue-sym->queue 'misc)))
;;; 	  (doqueue acfg queue fname dbdat dbh))
;;; 	;; ....
;;; 	(save-dbh acfg fname dbdat)
;;; 	#t ;; just to let the tests know we got here
;;; 	)
;;;       #f ;; nothing processed
;;;       ))
;;; 
;;; ;; run all queues in parallel per db but sequentially per queue for that db.
;;; ;;  - process the queues every 500 or so ms
;;; ;;  - allow for long running queries to continue but all other activities for that
;;; ;;    db will be blocked.
;;; ;;
;;; (define (work-queue-processor acfg)
;;;   (let* ((threads (make-hash-table))) ;; fname => thread
;;;     (let loop ((fnames      (hash-table-keys (area-wqueues acfg)))
;;; 	       (target-time (+ (current-milliseconds) 50)))
;;;       ;;(if (not (null? fnames))(print "Processing for these databases: " fnames))
;;;       (for-each
;;;        (lambda (fname)
;;; 	 ;; (print "processing for " fname)
;;; 	 ;;(process-db-queries acfg fname))
;;; 	 (let ((th (hash-table-ref/default threads fname #f)))
;;; 	   (if (and th (not (member (thread-state th) '(dead terminated))))
;;; 	       (begin
;;; 		 (print "WARNING: worker thread for " fname " is taking a long time.")
;;; 		 (print "Thread is in state " (thread-state th)))
;;; 	       (let ((th1 (make-thread (lambda ()
;;; 					 ;; (catch-and-dump
;;; 					 ;;  (lambda ()
;;; 					    ;; (print "Process queries for " fname)
;;; 					    (let ((start-time (current-milliseconds)))
;;; 					      (process-db-queries acfg fname)
;;; 					      ;; (thread-sleep! 0.01) ;; need the thread to take at least some time
;;; 					      (hash-table-delete! threads fname)) ;; no mutexes?
;;; 					    fname)
;;; 					  "th1"))) ;; ))
;;; 		 (hash-table-set! threads fname th1)
;;; 		 (thread-start! th1)))))
;;;        fnames)
;;;       ;; (thread-sleep! 0.1) ;; give the threads some time to process requests
;;;       ;; burn time until 400ms is up
;;;       (let ((now-time (current-milliseconds)))
;;; 	(if (< now-time target-time)
;;; 	    (let ((delta (- target-time now-time)))
;;; 	      (thread-sleep! (/ delta 1000)))))
;;;       (loop (hash-table-keys (area-wqueues acfg))
;;; 	    (+ (current-milliseconds) 50)))))
;;; 
;;; ;;======================================================================
;;; ;; S T A T S   G A T H E R I N G
;;; ;;======================================================================
;;; 
;;; (defstruct stat
;;;   (qcount-avg  0)                  ;; coarse running average
;;;   (qtime-avg   0)                  ;; coarse running average
;;;   (qcount      0)                  ;; total
;;;   (qtime       0)                  ;; total
;;;   (last-qcount 0)                  ;; last 
;;;   (last-qtime  0)                  ;; last
;;;   (dbs        '())                 ;; list of db files handled by this node
;;;   (when        0))                 ;; when the last query happened - seconds
;;; 
;;; 
;;; (define (update-stats acfg fname bucket duration numqueries)
;;;   (let* ((key   fname) ;; for now do not use bucket. Was: (conc fname "-" bucket)) ;; lazy but good enough
;;; 	 (stats (or (hash-table-ref/default (area-stats acfg) key #f)
;;; 		    (let ((newstats (make-stat)))
;;; 		      (hash-table-set! (area-stats acfg) key newstats)
;;; 		      newstats))))
;;;     ;; when the last query happended (used to remove the fname from the active list)
;;;     (stat-when-set! stats (current-seconds))
;;;     ;; last values
;;;     (stat-last-qcount-set! stats numqueries)
;;;     (stat-last-qtime-set!  stats duration)
;;;     ;; total over process lifetime
;;;     (stat-qcount-set! stats (+ (stat-qcount stats) numqueries))
;;;     (stat-qtime-set!  stats (+ (stat-qtime  stats) duration))
;;;     ;; coarse average
;;;     (stat-qcount-avg-set! stats (/ (+ (stat-qcount-avg stats) numqueries) 2))
;;;     (stat-qtime-avg-set!  stats (/ (+ (stat-qtime-avg  stats) duration)   2))
;;; 
;;;     ;; here is where we add the stats for a given dbfile
;;;     (if (not (member fname (stat-dbs stats)))
;;; 	(stat-dbs-set! stats (cons fname (stat-dbs stats))))
;;; 
;;;     ))
;;; 
;;; ;;======================================================================
;;; ;; S E R V E R   S T U F F 
;;; ;;======================================================================
;;; 
;;; ;; this does NOT return!
;;; ;;
;;; (define (find-free-port-and-open acfg)
;;;   (let ((port (or (area-port acfg) 3200)))
;;;     (handle-exceptions
;;; 	exn
;;; 	(begin
;;; 	  (print "INFO: cannot bind to port " (rpc:default-server-port) ", trying next port")
;;; 	  (area-port-set! acfg (+ port 1))
;;; 	  (find-free-port-and-open acfg))
;;;       (rpc:default-server-port port)
;;;       (area-port-set! acfg port)
;;;       (tcp-read-timeout 120000)
;;;       ;; ((rpc:make-server (tcp-listen port)) #t)
;;;       (tcp-listen (rpc:default-server-port)
;;;       ))))
;;; 
;;; ;; register this node by putting a packet into the pkts dir.
;;; ;; look for other servers
;;; ;; contact other servers and compile list of servers
;;; ;; there are two types of server
;;; ;;     main servers - dashboards, runners and dedicated servers - need pkt
;;; ;;     passive servers - test executers, step calls, list-runs - no pkt
;;; ;;
;;; (define (register-node acfg hostip port-num)
;;;   ;;(mutex-lock! (area-mutex acfg))
;;;   (let* ((server-type  (area-server-type acfg)) ;; auto, main, passive (no pkt created)
;;; 	 (best-ip      (or hostip (get-my-best-address)))
;;; 	 (mtdir        (area-dbdir acfg))
;;; 	 (pktdir       (area-pktsdir acfg))) ;; conc mtdir "/.server-pkts")))
;;;     (print "Registering node " best-ip ":" port-num)
;;;     (if (not mtdir) ;; require a home for this node to put or find databases
;;; 	#f
;;; 	(begin
;;; 	  (if  (not (directory? pktdir))(create-directory pktdir))
;;; 	  ;; server is started, now create pkt if needed
;;; 	  (print "Starting server in " server-type " mode with port " port-num)
;;; 	  (if (member server-type '(auto main)) ;; TODO: if auto, count number of servers registers, if > 3 then don't put out a pkt
;;; 	      (begin
;;; 		(area-pktid-set! acfg
;;; 				 (write-alist->pkt
;;; 				  pktdir 
;;; 				  `((hostname . ,(get-host-name))
;;; 				    (ipaddr   . ,best-ip)
;;; 				    (port     . ,port-num)
;;; 				    (pid      . ,(current-process-id)))
;;; 				  pktspec: *pktspec*
;;; 				  ptype:   'server))
;;; 		(area-pktfile-set! acfg (conc pktdir "/" (area-pktid acfg) ".pkt"))))
;;; 	  (area-port-set!    acfg port-num)
;;; 	  #;(mutex-unlock! (area-mutex acfg))))))
;;; 
;;; (define *cookie-seqnum* 0)
;;; (define (make-cookie key)
;;;   (set! *cookie-seqnum* (add1 *cookie-seqnum*))
;;;   ;;(print "MAKE COOKIE CALLED -- on "servkey"-"*cookie-seqnum*)
;;;   (conc key "-" *cookie-seqnum*)
;;;   )
;;; 
;;; ;; dispatch locally if possible
;;; ;;
;;; (define (call-deliver-response acfg ipaddr port cookie data)
;;;   (if (and (equal? (area-myaddr acfg) ipaddr)
;;; 	   (equal? (area-port     acfg) port))
;;;       (deliver-response acfg cookie data)
;;;       ((rpc:procedure 'response ipaddr port) cookie data)))
;;; 
;;; (define (deliver-response acfg cookie data)
;;;   (let ((deliver-response-start (current-milliseconds)))
;;;     (thread-start! (make-thread
;;; 		    (lambda ()
;;; 		      (let loop ((tries-left 5))
;;; 			;;(print "TOP OF DELIVER_RESPONSE LOOP; triesleft="tries-left)
;;; 			;;(pp (hash-table->alist (area-cookie2mbox acfg)))
;;; 			(let* ((mbox (hash-table-ref/default (area-cookie2mbox acfg) cookie #f)))
;;; 			  (cond
;;; 			   ((eq? 0 tries-left)
;;; 			    (print "ulex:deliver-response: I give up. Mailbox never appeared. cookie="cookie)
;;; 			    )
;;; 			   (mbox
;;; 			    ;;(print "got mbox="mbox"  got data="data"  send.")
;;; 			    (mailbox-send! mbox data))
;;; 			   (else
;;; 			    ;;(print "no mbox yet.  look for "cookie)
;;; 			    (thread-sleep! (/ (- 6 tries-left) 10))
;;; 			    (loop (sub1 tries-left))))))
;;; 		      ;; (debug-pp (list (conc "ulex:deliver-response took " (- (current-milliseconds) deliver-response-start) " ms, cookie=" cookie " data=") data))
;;; 		      (sdbg> "deliver-response" "mailbox-send" deliver-response-start #f #f cookie)
;;; 		      )
;;; 		    (conc "deliver-response thread for cookie="cookie))))
;;;   #t)
;;; 
;;; ;; action:
;;; ;;   immediate - quick actions, no need to put in queues
;;; ;;   dbwrite   - put in dbwrite queue
;;; ;;   dbread    - put in dbread queue
;;; ;;   oslong    - os actions, e.g. du, that could take a long time
;;; ;;   osshort   - os actions that should be quick, e.g. df
;;; ;;
;;; (define (request acfg from-ipaddr from-port servkey action cookie fname params) ;; std-peer-handler
;;;   ;; NOTE: Use rpc:current-peer for getting return address
;;;   (let* ((std-peer-handler-start (current-milliseconds))
;;; 	 ;; (raw-data               (alist-ref 'data     dat))
;;; 	 (rdat                   (hash-table-ref/default
;;; 				  (area-rtable acfg) action #f)) ;; this looks up the sql query or other details indexed by the action
;;; 	 (witem                  (make-witem ripaddr: from-ipaddr ;; rhost:   from-host   
;;; 					     rport:   from-port   action:  action
;;; 					     rdat:    rdat        cookie:  cookie
;;; 					     servkey: servkey     data:    params ;; TODO - rename data to params
;;; 					     caller:  (rpc:current-peer))))
;;;     (if (not (equal? servkey (area-pktid acfg)))
;;; 	`(#f . ,(conc "I don't know you servkey=" servkey ", pktid=" (area-pktid acfg))) ;; immediately return this
;;; 	(let* ((ctype (if rdat 
;;; 			  (calldat-ctype rdat) ;; is this necessary? these should be identical
;;; 			  action)))
;;; 	  (sdbg> "std-peer-handler" "immediate" std-peer-handler-start #f #f)
;;; 	  (case ctype
;;; 	    ;; (dbwrite acfg rdat (cons from-ipaddr from-port) data)))
;;; 	    ((full-ping)  `(#t  "ack to full ping"        ,(work-queue-add acfg fname witem) ,cookie))
;;; 	    ((response)   `(#t  "ack from requestor"      ,(deliver-response acfg fname params)))
;;; 	    ((dbwrite)    `(#t  "db write submitted"      ,(work-queue-add acfg fname witem) ,cookie))
;;; 	    ((dbread)     `(#t  "db read submitted"       ,(work-queue-add acfg fname witem) ,cookie  ))
;;; 	    ((dbrw)       `(#t  "db read/write submitted" ,cookie))
;;; 	    ((osshort)    `(#t  "os short submitted"      ,cookie))
;;; 	    ((oslong)     `(#t  "os long submitted"       ,cookie))
;;; 	    (else         `(#f  "unrecognised action"     ,ctype)))))))
;;; 
;;; ;; Call this to start the actual server
;;; ;;
;;; ;; start_server
;;; ;;
;;; ;;   mode: '
;;; ;;   handler: proc which takes pktrecieved as argument
;;; ;;
;;; 
;;; (define (start-server acfg)
;;;   (let* ((conn (find-free-port-and-open acfg))
;;; 	 (port (area-port acfg)))
;;;     (rpc:publish-procedure!
;;;      'delist-db
;;;      (lambda (fname)
;;;        (hash-table-delete! (area-dbs acfg) fname)))
;;;     (rpc:publish-procedure!
;;;      'calling-addr
;;;      (lambda ()
;;;        (rpc:current-peer)))
;;;     (rpc:publish-procedure!
;;;      'ping
;;;      (lambda ()(real-ping acfg)))
;;;     (rpc:publish-procedure!
;;;      'request
;;;      (lambda (from-addr from-port servkey action cookie dbname params)
;;;        (request acfg from-addr from-port servkey action cookie dbname params)))
;;;     (rpc:publish-procedure!
;;;      'response
;;;      (lambda (cookie res-dat)
;;;        (deliver-response acfg cookie res-dat)))
;;;     (area-ready-set! acfg #t)
;;;     (area-conn-set! acfg conn)
;;;     ((rpc:make-server conn) #f)));; ((tcp-listen (rpc:default-server-port)) #t)
;;; 
;;; 
;;; (define (launch acfg) ;;  #!optional (proc std-peer-handler))
;;;   (print "starting launch")
;;;   (update-known-servers acfg) ;; gotta do this on every start (thus why limit number of publicised servers)
;;;   #;(let ((original-handler (current-exception-handler))) ;; is th
;;;     (lambda (exception)
;;;       (server-exit-procedure)
;;;       (original-handler exception)))
;;;   (on-exit (lambda ()
;;; 	     (shutdown acfg))) ;; (finalize-all-db-handles acfg)))
;;;   ;; set up the rpc handler
;;;   (let* ((th1  (make-thread
;;; 		(lambda ()(start-server acfg))
;;; 		"server thread"))
;;; 	 (th2   (make-thread
;;; 		 (lambda ()
;;; 		   (print "th2 starting")
;;; 		   (let loop ()
;;; 		     (work-queue-processor acfg)
;;; 		     (print "work-queue-processor crashed!")
;;; 		     (loop)))
;;; 		 "work queue thread")))
;;;     (thread-start! th1)
;;;     (thread-start! th2)
;;;     (let loop ()
;;;       (thread-sleep! 0.025)
;;;       (if (area-ready acfg)
;;; 	  #t
;;; 	  (loop)))
;;;     ;; attempt to fix my address
;;;     (let* ((all-addr (get-all-ips-sorted)))	     ;; could use (tcp-addresses conn)?
;;;       (let loop ((rem-addrs all-addr))
;;; 	(if (null? rem-addrs)
;;; 	    (begin
;;; 	      (print "ERROR: Failed to figure out the ip address of myself as a server. Giving up.")
;;; 	      (exit 1)) ;; BUG Changeme to raising an exception
;;; 		
;;; 	    (let* ((addr      (car rem-addrs))
;;; 		   (good-addr (handle-exceptions
;;; 				  exn
;;; 				  #f
;;; 				((rpc:procedure 'calling-addr addr (area-port acfg))))))
;;; 	      (if good-addr
;;; 		  (begin
;;; 		    (print "Got good-addr of " good-addr)
;;; 		    (area-myaddr-set! acfg good-addr))
;;; 		  (loop (cdr rem-addrs)))))))
;;;     (register-node acfg (area-myaddr acfg)(area-port acfg))
;;;     (print "INFO: Server started on " (area-myaddr acfg) ":" (area-port acfg))
;;;     ;; (update-known-servers acfg) ;; gotta do this on every start (thus why limit number of publicised servers)
;;;     ))
;;; 
;;; (define (clear-server-pkt acfg)
;;;   (let ((pktf (area-pktfile acfg)))
;;;     (if pktf (delete-file* pktf))))
;;; 
;;; (define (shutdown acfg)
;;;   (let (;;(conn (area-conn    acfg))
;;; 	(pktf (area-pktfile acfg))
;;; 	(port (area-port    acfg)))
;;;     (if pktf (delete-file* pktf))
;;;     (send-all "imshuttingdown")
;;;     ;; (rpc:close-all-connections!) ;; don't know if this is actually needed
;;;     (finalize-all-db-handles acfg)))
;;; 
;;; (define (send-all msg)
;;;   #f)
;;; 
;;; ;; given a area record look up all the packets
;;; ;;
;;; (define (get-all-server-pkts acfg)
;;;   (let ((all-pkt-files (glob (conc (area-pktsdir acfg) "/*.pkt"))))
;;;     (map (lambda (pkt-file)
;;; 	   (read-pkt->alist pkt-file pktspec: *pktspec*))
;;; 	 all-pkt-files)))
;;; 
;;; #;((Z . "9a0212302295a19610d5796fce0370fa130758e9")
;;;   (port . "34827")
;;;   (pid . "28748")
;;;   (hostname . "zeus")
;;;   (T . "server")
;;;   (D . "1549427032.0"))
;;; 
;;; #;(define (get-my-best-address)
;;;   (let ((all-my-addresses (get-all-ips))) ;; (vector->list (hostinfo-addresses (hostname->hostinfo (get-host-name))))))
;;;     (cond
;;;      ((null? all-my-addresses)
;;;       (get-host-name))                                          ;; no interfaces?
;;;      ((eq? (length all-my-addresses) 1)
;;;       (ip->string (car all-my-addresses)))                      ;; only one to choose from, just go with it
;;;      (else 
;;;       (ip->string (car (filter (lambda (x)                      ;; take any but 127.
;;; 				 (not (eq? (u8vector-ref x 0) 127)))
;;; 			       all-my-addresses)))))))
;;; 
;;; ;; whoami? I am my pkt
;;; ;;
;;; (define (whoami? acfg)
;;;   (hash-table-ref/default (area-hosts acfg)(area-pktid acfg) #f))
;;; 
;;; ;;======================================================================
;;; ;; "Client side" operations
;;; ;;======================================================================
;;; 
;;; (define (safe-call call-key host port . params)
;;;   (handle-exceptions
;;;    exn
;;;    (begin
;;;      (print "Call " call-key " to " host ":" port " failed")
;;;      #f)
;;;    (apply (rpc:procedure call-key host port) params)))
;;; 
;;; ;; ;; convert to/from string / sexpr
;;; ;; 
;;; ;; (define (string->sexpr str)
;;; ;;   (if (string? str)
;;; ;;       (with-input-from-string str read)
;;; ;;       str))
;;; ;; 
;;; ;; (define (sexpr->string s)
;;; ;;   (with-output-to-string (lambda ()(write s))))
;;; 
;;; ;; is the server alive?
;;; ;;
;;; (define (ping acfg host port)
;;;   (let* ((myaddr     (area-myaddr acfg))
;;; 	 (myport     (area-port   acfg))
;;; 	 (start-time (current-milliseconds))
;;; 	 (res        (if (and (equal? myaddr host)
;;; 			      (equal? myport port))
;;; 			 (real-ping acfg)
;;; 			 ((rpc:procedure 'ping host port)))))
;;;     (cons (- (current-milliseconds) start-time)
;;; 	  res)))
;;; 
;;; ;; returns ( ipaddr port alist-fname=>randnum )
;;; (define (real-ping acfg)
;;;   `(,(area-myaddr acfg) ,(area-port acfg) ,(get-host-stats acfg)))
;;; 
;;; ;; is the server alive AND the queues processing?
;;; ;;
;;; #;(define (full-ping acfg servpkt)
;;;   (let* ((start-time (current-milliseconds))
;;; 	 (res        (send-message acfg servpkt '(full-ping) 'full-ping)))
;;;     (cons (- (current-milliseconds) start-time)
;;; 	  res))) ;; (equal? res "got ping"))))
;;; 
;;; 
;;; ;; look up all pkts and get the server id (the hash), port, host/ip
;;; ;; store this info in acfg
;;; ;; return the number of responsive servers found
;;; ;;
;;; ;; DO NOT VERIFY THAT THE SERVER IS ALIVE HERE. This is called at times where the current server is not yet alive and cannot ping itself
;;; ;;
;;; (define (update-known-servers acfg)
;;;   ;; readll all pkts
;;;   ;; foreach pkt; if it isn't me ping the server; if alive, add to hosts hash, else rm the pkt
;;;   (let* ((start-time (current-milliseconds))
;;; 	 (all-pkts  (delete-duplicates
;;; 		     (append (get-all-server-pkts acfg)
;;; 			     (hash-table-values (area-hosts acfg)))))
;;; 	 (hostshash (area-hosts acfg))
;;; 	 (my-id     (area-pktid acfg))
;;; 	 (pktsdir   (area-pktsdir acfg)) ;; needed to remove pkts from non-responsive servers
;;; 	 (numsrvs   0)
;;; 	 (delpkt    (lambda (pktsdir sid)
;;; 		      (print "clearing out server " sid)
;;; 		      (delete-file* (conc pktsdir "/" sid ".pkt"))
;;; 		      (hash-table-delete! hostshash sid))))
;;;     (area-last-srvup-set! acfg (current-seconds))
;;;     (for-each
;;;      (lambda (servpkt)
;;;        (if (list? servpkt)
;;; 	   ;; (pp servpkt)
;;; 	   (let* ((shost (alist-ref 'ipaddr servpkt))
;;; 		  (sport (any->number (alist-ref 'port servpkt)))
;;; 		  (res   (handle-exceptions
;;; 			  exn
;;; 			  (begin
;;; 			    ;; (print "INFO: bad server on " shost ":" sport)
;;; 			    #f)
;;; 			  (ping acfg shost sport)))
;;; 		  (sid   (alist-ref 'Z servpkt)) ;; Z code is our name for the server
;;; 		  (url   (conc shost ":" sport))
;;; 		  )
;;; 	     #;(if (or (not res)
;;; 		     (null? res))
;;; 		 (begin
;;; 		   (print "STRANGE: ping of " url " gave " res)))
;;; 	     
;;; 	     ;; (print "Got " res " from " shost ":" sport)
;;; 	     (match res
;;; 		    ((qduration . payload)
;;; 		     ;; (print "Server pkt:" (alist-ref 'ipaddr servpkt) ":" (alist-ref 'port servpkt)
;;; 		     ;;        (if payload
;;; 		     ;;            "Success" "Fail"))
;;; 		     (match payload
;;; 			    ((host port stats)
;;; 			     ;; (print "From " host ":" port " got stats: " stats)
;;; 			     (if (and host port stats)
;;; 				 (let ((url (conc host ":" port)))
;;; 				   (hash-table-set! hostshash sid servpkt)
;;; 				   ;; store based on host:port
;;; 				   (hash-table-set! (area-hoststats acfg) sid stats))
;;; 				 (print "missing data from the server, not sure what that means!"))
;;; 			     (set! numsrvs (+ numsrvs 1)))
;;; 			    (#f
;;; 			     (print "Removing pkt " sid " due to #f from server or failed ping")
;;; 			     (delpkt pktsdir sid))
;;; 			    (else
;;; 			     (print "Got ")(pp res)(print " from server ")(pp servpkt) " but response did not match (#f/#t . msg)")))
;;; 		    (else
;;; 		     ;; here we delete the pkt - can't reach the server, remove it
;;; 		     ;; however this logic is inadequate. we should mark the server as checked
;;; 		     ;; and not good, if it happens a second time - then remove the pkt
;;; 		     ;; or something similar. I.e. don't be too quick to assume the server is wedged or dead
;;; 		     ;; could be it is simply too busy to reply
;;; 		     (let ((bad-pings (hash-table-ref/default (area-health acfg) url 0)))
;;; 		       (if (> bad-pings 1) ;; two bad pings - remove pkt
;;; 			   (begin
;;; 			     (print "INFO: " bad-pings " bad responses from " url ", deleting pkt " sid)
;;; 			     (delpkt pktsdir sid))
;;; 			   (begin
;;; 			     (print "INFO: " bad-pings " bad responses from " shost ":" sport " not deleting pkt yet")
;;; 			     (hash-table-set! (area-health acfg)
;;; 					      url
;;; 					      (+ (hash-table-ref/default (area-health acfg) url 0) 1))
;;; 			     ))
;;; 		       ))))
;;; 	   ;; servpkt is not actually a pkt?
;;; 	   (begin
;;; 	     (print "Bad pkt " servpkt))))
;;;      all-pkts)
;;;     (sdbg> "update-known-servers" "end" start-time #f #f " found " numsrvs
;;; 	   " servers, pkts: " (map (lambda (p)
;;; 				     (alist-ref 'Z p))
;;; 				   all-pkts))
;;;     numsrvs))
;;; 
;;; (defstruct srvstat
;;;   (numfiles 0)   ;; number of db files handled by this server - subtract 1 for the db being currently looked at
;;;   (randnum  #f)  ;; tie breaker number assigned to by the server itself - applies only to the db under consideration
;;;   (pkt      #f)) ;; the server pkt
;;; 
;;; ;;(define (srv->srvstat srvpkt)
;;;   
;;; ;; Get the server best for given dbname and key
;;; ;;
;;; ;;   NOTE: key is not currently used. The key points to the kind of query, this may be useful for directing read-only queries.
;;; ;;
;;; (define (get-best-server acfg dbname key)
;;;   (let* (;; (servers (hash-table-values (area-hosts acfg)))
;;; 	 (servers     (area-hosts acfg))
;;; 	 (skeys       (sort (hash-table-keys servers) string>=?)) ;; a stable listing
;;; 	 (start-time  (current-milliseconds))
;;; 	 (srvstats    (make-hash-table))  ;; srvid => srvstat
;;; 	 (url         (conc (area-myaddr acfg) ":" (area-port acfg))))
;;;     ;; (print "scores for " dbname ": " (map (lambda (k)(cons k (calc-server-score acfg dbname k))) skeys))
;;;     (if (null? skeys)
;;; 	(if (> (update-known-servers acfg) 0)
;;; 	    (get-best-server acfg dbname key) ;; some risk of infinite loop here, TODO add try counter
;;; 	    (begin
;;; 	      (print "ERROR: no server found!") ;; since this process is also a server this should never happen
;;; 	      #f))
;;; 	(begin
;;; 	  ;; (print "in get-best-server with skeys=" skeys)
;;; 	  (if (> (- (current-seconds) (area-last-srvup acfg)) 10)
;;; 	      (begin
;;; 		(update-known-servers acfg)
;;; 		(sdbg> "get-best-server" "update-known-servers" start-time #f #f)))
;;; 
;;; 	  ;; for each server look at the list of dbfiles, total number of dbs being handled
;;; 	  ;; and the rand number, save the best host
;;; 	  ;; also do a delist-db for each server dbfile not used
;;; 	  (let* ((best-server       #f)
;;; 		 (servers-to-delist (make-hash-table)))
;;; 	    (for-each
;;; 	     (lambda (srvid)
;;; 	       (let* ((server    (hash-table-ref/default servers srvid #f))
;;; 		      (stats     (hash-table-ref/default (area-hoststats acfg) srvid '(()))))
;;; 		 ;; (print "stats: " stats)
;;;  		 (if server
;;; 		     (let* ((dbweights (car stats))
;;; 			    (srvload   (length (filter (lambda (x)(not (equal? dbname (car x)))) dbweights)))
;;; 			    (dbrec     (alist-ref dbname dbweights equal?))  ;; get the pair with fname . randscore
;;; 			    (randnum   (if dbrec
;;; 					   dbrec ;; (cdr dbrec)
;;; 					   0)))
;;; 		       (hash-table-set! srvstats srvid (make-srvstat numfiles: srvload randnum: randnum pkt: server))))))
;;; 	     skeys)
;;; 	    
;;; 	    (let* ((sorted    (sort (hash-table-values srvstats) 
;;; 				    (lambda (a b)
;;; 				      (let ((numfiles-a (srvstat-numfiles a))
;;; 					    (numfiles-b (srvstat-numfiles b))
;;; 					    (randnum-a  (srvstat-randnum a))
;;; 					    (randnum-b  (srvstat-randnum b)))
;;; 					(if (< numfiles-a numfiles-b) ;; Note, I don't think adding an offset works here. Goal was only move file handling to a different server if it has 2 less
;;; 					    #t
;;; 					    (if (and (equal? numfiles-a numfiles-b)
;;; 						     (< randnum-a randnum-b))
;;; 						#t
;;; 						#f))))))
;;; 		   (best      (if (null? sorted)
;;; 				  (begin
;;; 				    (print "ERROR: should never be null due to self as server.")
;;; 				    #f)
;;; 				  (srvstat-pkt (car sorted)))))
;;; 	      #;(print "SERVER(" url "): " dbname ": " (map (lambda (srv)
;;; 							    (let ((p (srvstat-pkt srv)))
;;; 							      (conc (alist-ref 'ipaddr p) ":" (alist-ref 'port p)
;;; 								    "(" (srvstat-numfiles srv)","(srvstat-randnum srv)")")))
;;; 							    sorted))
;;; 	      best))))))
;;;     
;;;     ;; send out an "I'm about to exit notice to all known servers"
;;;     ;;
;;; (define (death-imminent acfg)
;;;   '())
;;; 
;;; ;;======================================================================
;;; ;; U L E X  -  T H E   I N T E R E S T I N G   S T U F F ! !
;;; ;;======================================================================
;;; 
;;; ;; register a handler
;;; ;;   NOTES:
;;; ;;     dbinitsql   is reserved for a list of sql statements for initializing the db
;;; ;;     dbinitfn    is reserved for a db init function, if exists called after dbinitsql
;;; ;;     
;;; (define (register acfg key obj #!optional (ctype 'dbwrite))
;;;   (let ((ht (area-rtable acfg)))
;;;     (if (hash-table-exists? ht key)
;;; 	(print "WARNING: redefinition of entry " key))
;;;     (hash-table-set! ht key (make-calldat obj: obj ctype: ctype))))
;;; 
;;; ;; usage: register-batch acfg '((key1 . sql1) (key2 . sql2) ... )
;;; ;; NB// obj is often an sql query
;;; ;;
;;; (define (register-batch acfg ctype data)
;;;   (let ((ht (area-rtable acfg)))
;;;     (map (lambda (dat)
;;; 	   (hash-table-set! ht (car dat)(make-calldat obj: (cdr dat) ctype: ctype)))
;;; 	 data)))
;;; 
;;; (define (initialize-area-calls-from-specfile area specfile)
;;;   (let* ((callspec (with-input-from-file specfile read )))
;;;     (for-each (lambda (group)
;;;                 (register-batch
;;;                  area
;;;                  (car group)
;;;                  (cdr group)))
;;;               callspec)))
;;; 
;;; ;; get-rentry
;;; ;;
;;; (define (get-rentry acfg key)
;;;   (hash-table-ref/default (area-rtable acfg) key #f))
;;; 
;;; (define (get-rsql acfg key)
;;;   (let ((cdat (get-rentry acfg key)))
;;;     (if cdat
;;; 	(calldat-obj cdat)
;;; 	#f)))
;;; 
;;; 
;;; 
;;; ;; blocking call:
;;; ;;    client                         server
;;; ;;    ------                         ------
;;; ;;    call()
;;; ;;    send-message()
;;; ;;    nmsg-send()
;;; ;;                                   nmsg-receive()
;;; ;;                                   nmsg-respond(ack,cookie)
;;; ;;    ack, cookie
;;; ;;    mbox-thread-wait(cookie)
;;; ;;                                   nmsg-send(client,cookie,result)
;;; ;;        nmsg-respond(ack)
;;; ;;        return result
;;; ;;
;;; ;; reserved action:
;;; ;;    'immediate
;;; ;;    'dbinitsql
;;; ;;
;;; (define (call acfg dbname action params #!optional (count 0))
;;;   (let* ((call-start-time     (current-milliseconds))
;;; 	 (srv                 (get-best-server acfg dbname action))
;;; 	 (post-get-start-time (current-milliseconds))
;;; 	 (rdat                (hash-table-ref/default (area-rtable acfg) action #f))
;;; 	 (myid                (trim-pktid (area-pktid acfg)))
;;; 	 (srvid               (trim-pktid (alist-ref 'Z srv)))
;;; 	 (cookie              (make-cookie myid)))
;;;     (sdbg> "call" "get-best-server" call-start-time #f call-start-time " from: " myid " to server: " srvid " for " dbname " action: " action " params: " params " rdat: " rdat)
;;;     (print "INFO: call to " (alist-ref 'ipaddr srv) ":" (alist-ref 'port srv) " from " (area-myaddr acfg) ":" (area-port acfg) " for " dbname)
;;;     (if (and srv rdat) ;; need both to dispatch a request
;;; 	(let* ((ripaddr  (alist-ref 'ipaddr srv))
;;; 	       (rsrvid   (alist-ref 'Z srv))
;;; 	       (rport    (any->number (alist-ref 'port   srv)))
;;; 	       (res-full (if (and (equal? ripaddr (area-myaddr acfg))
;;; 				  (equal? rport   (area-port acfg)))
;;; 			     (request acfg ripaddr rport (area-pktid acfg) action cookie dbname params)
;;; 			     (safe-call 'request ripaddr rport
;;; 					(area-myaddr acfg)
;;; 					(area-port   acfg)
;;; 					#;(area-pktid acfg)
;;; 					rsrvid
;;; 					action cookie dbname params))))
;;; 	  ;; (print "res-full: " res-full)
;;; 	  (match res-full
;;; 	    ((response-ok response-msg rem ...)
;;; 	     (let* ((send-message-time (current-milliseconds))
;;; 		    ;; (match res-full
;;; 		    ;;  ((response-ok response-msg)
;;; 		    ;; (response-ok  (car res-full))
;;; 		    ;; (response-msg (cadr res-full)
;;; 		    )
;;; 	       ;; (res (take res-full 3))) ;; ctype == action, TODO: converge on one term <<=== what was this? BUG 
;;; 	       ;; (print "ulex:call: send-message took " (- send-message-time post-get-start-time) " ms params=" params)
;;; 	       (sdbg> "call" "send-message" post-get-start-time #f call-start-time)
;;; 	       (cond
;;; 		((not response-ok) #f)
;;; 		((member response-msg '("db read submitted" "db write submitted"))
;;; 		 (let* ((cookie-id   (cadddr res-full))
;;; 			(mbox        (make-mailbox))
;;; 			(mbox-time   (current-milliseconds)))
;;; 		   (hash-table-set! (area-cookie2mbox acfg) cookie-id mbox)
;;; 		   (let* ((mbox-timeout-secs    20)
;;; 			  (mbox-timeout-result 'MBOX_TIMEOUT)
;;; 			  (res                  (mailbox-receive! mbox mbox-timeout-secs mbox-timeout-result))
;;; 			  (mbox-receive-time    (current-milliseconds)))
;;; 		     (hash-table-delete! (area-cookie2mbox acfg) cookie-id)
;;; 		     (sdbg> "call" "mailbox-receive" mbox-time #f call-start-time " from: " myid " to server: " srvid " for " dbname)
;;; 		     ;; (print "ulex:call mailbox-receive took " (- mbox-receive-time mbox-time) "ms params=" params)
;;; 		     res)))
;;; 		(else
;;; 		 (print "Unhandled response \""response-msg"\"")
;;; 		 #f))
;;; 	       ;; depending on what action (i.e. ctype) is we will block here waiting for
;;; 	       ;; all the data (mechanism to be determined)
;;; 	       ;;
;;; 	       ;; if res is a "working on it" then wait
;;; 	       ;;    wait for result
;;; 	       ;; mailbox thread wait on 
;;; 	       
;;; 	       ;; if res is a "can't help you" then try a different server
;;; 	       ;; if res is a "ack" (e.g. for one-shot requests) then return res
;;; 	       ))
;;; 	    (else
;;; 	     (if (< count 10)
;;; 		 (let* ((url (conc (alist-ref 'ipaddr srv) ":" (alist-ref 'port srv))))
;;; 		   (thread-sleep! 1)
;;; 		   (print "ERROR: Bad result from " url ", dbname: " dbname ", action: " action ", params: " params ". Trying again in 1 second.")
;;; 		   (call acfg dbname action params (+ count 1)))
;;; 		 (begin
;;; 		   (error (conc "ERROR: " count " tries, still have improper response res-full=" res-full)))))))
;;; 	(begin
;;; 	  (if (not rdat)
;;; 	      (print "ERROR: action " action " not registered.")
;;; 	      (if (< count 10)
;;; 		 (begin
;;; 		   (thread-sleep! 1)
;;; 		   (area-hosts-set! acfg (make-hash-table)) ;; clear out all known hosts
;;; 		   (print "ERROR: no server found, srv=" srv ", trying again in 1 seconds")
;;; 		   (call acfg dbname action params (+ count 1)))
;;; 		 (begin
;;; 		   (error (conc "ERROR: no server found after 10 tries, srv=" srv ", giving up."))
;;; 		   #;(error "No server available"))))))))
;;; 
;;; 
;;; ;;======================================================================
;;; ;; U T I L I T I E S 
;;; ;;======================================================================
;;; 
;;; ;; get a signature for identifing this process
;;; ;;
;;; (define (get-process-signature)
;;;   (cons (get-host-name)(current-process-id)))
;;; 
;;; ;;======================================================================
;;; ;; S Y S T E M   S T U F F
;;; ;;======================================================================
;;; 
;;; ;; get normalized cpu load by reading from /proc/loadavg and
;;; ;; /proc/cpuinfo return all three values and the number of real cpus
;;; ;; and the number of threads returns alist '((adj-cpu-load
;;; ;; . normalized-proc-load) ... etc.  keys: adj-proc-load,
;;; ;; adj-core-load, 1m-load, 5m-load, 15m-load
;;; ;;
;;; (define (get-normalized-cpu-load)
;;;   (let ((res (get-normalized-cpu-load-raw))
;;; 	(default `((adj-proc-load . 2) ;; there is no right answer
;;; 		   (adj-core-load . 2)
;;; 		   (1m-load       . 2)
;;; 		   (5m-load       . 0) ;; causes a large delta - thus causing default of throttling if stuff goes wrong
;;; 		   (15m-load      . 0)
;;; 		   (proc          . 1)
;;; 		   (core          . 1)
;;; 		   (phys          . 1)
;;; 		   (error         . #t))))
;;;     (cond
;;;      ((and (list? res)
;;; 	   (> (length res) 2))
;;;       res)
;;;      ((eq? res #f)   default) ;; add messages?
;;;      ((eq? res #f) default)   ;; this would be the #eof
;;;      (else default))))
;;; 
;;; (define (get-normalized-cpu-load-raw)
;;;   (let* ((actual-host           (get-host-name))) ;; #f is localhost
;;;     (let ((data  (append 
;;; 		  (with-input-from-file "/proc/loadavg" read-lines)
;;; 		  (with-input-from-file "/proc/cpuinfo" read-lines)
;;; 		  (list "end")))
;;; 	  (load-rx  (regexp "^([\\d\\.]+)\\s+([\\d\\.]+)\\s+([\\d\\.]+)\\s+.*$"))
;;; 	  (proc-rx  (regexp "^processor\\s+:\\s+(\\d+)\\s*$"))
;;; 	  (core-rx  (regexp "^core id\\s+:\\s+(\\d+)\\s*$"))
;;; 	  (phys-rx  (regexp "^physical id\\s+:\\s+(\\d+)\\s*$"))
;;; 	  (max-num  (lambda (p n)(max (string->number p) n))))
;;;       ;; (print "data=" data)
;;;       (if (null? data) ;; something went wrong
;;; 	  #f
;;; 	  (let loop ((hed      (car data))
;;; 		     (tal      (cdr data))
;;; 		     (loads    #f)
;;; 		     (proc-num 0)  ;; processor includes threads
;;; 		     (phys-num 0)  ;; physical chip on motherboard
;;; 		     (core-num 0)) ;; core
;;; 	    ;; (print hed ", " loads ", " proc-num ", " phys-num ", " core-num)
;;; 	    (if (null? tal) ;; have all our data, calculate normalized load and return result
;;; 		(let* ((act-proc (+ proc-num 1))
;;; 		       (act-phys (+ phys-num 1))
;;; 		       (act-core (+ core-num 1))
;;; 		       (adj-proc-load (/ (car loads) act-proc))
;;; 		       (adj-core-load (/ (car loads) act-core))
;;; 		       (result
;;; 			(append (list (cons 'adj-proc-load adj-proc-load)
;;; 				      (cons 'adj-core-load adj-core-load))
;;; 				(list (cons '1m-load (car loads))
;;; 				      (cons '5m-load (cadr loads))
;;; 				      (cons '15m-load (caddr loads)))
;;; 				(list (cons 'proc act-proc)
;;; 				      (cons 'core act-core)
;;; 				      (cons 'phys act-phys)))))
;;; 		  result)
;;; 		(regex-case
;;; 		    hed
;;; 		  (load-rx  ( x l1 l5 l15 ) (loop (car tal)(cdr tal)(map string->number (list l1 l5 l15)) proc-num phys-num core-num))
;;; 		  (proc-rx  ( x p         ) (loop (car tal)(cdr tal) loads           (max-num p proc-num) phys-num core-num))
;;; 		  (phys-rx  ( x p         ) (loop (car tal)(cdr tal) loads           proc-num (max-num p phys-num) core-num))
;;; 		  (core-rx  ( x c         ) (loop (car tal)(cdr tal) loads           proc-num phys-num (max-num c core-num)))
;;; 		  (else 
;;; 		   (begin
;;; 		     ;; (print "NO MATCH: " hed)
;;; 		     (loop (car tal)(cdr tal) loads proc-num phys-num core-num))))))))))
;;; 
;;; (define (get-host-stats acfg)
;;;   (let ((stats-hash (area-stats acfg)))
;;;     ;; use this opportunity to remove references to dbfiles which have not been accessed in a while
;;;     (for-each
;;;      (lambda (dbname)
;;;        (let* ((stats       (hash-table-ref stats-hash dbname))
;;; 	      (last-access (stat-when stats)))
;;; 	 (if (and (> last-access 0)                             ;; if zero then there has been no access
;;; 		  (> (- (current-seconds) last-access) 10))     ;; not used in ten seconds
;;; 	     (begin
;;; 	       (print "Removing " dbname " from stats list")
;;; 	       (hash-table-delete! stats-hash dbname) ;; remove from stats hash
;;; 	       (stat-dbs-set! stats (hash-table-keys stats))))))
;;;      (hash-table-keys stats-hash))
;;;     
;;;     `(,(hash-table->alist (area-dbs acfg)) ;; dbname => randnum
;;;       ,(map (lambda (dbname)  ;; dbname is the db name
;;; 	      (cons dbname (stat-when (hash-table-ref stats-hash dbname))))
;;; 	    (hash-table-keys stats-hash))
;;;       (cpuload . ,(get-normalized-cpu-load)))))
;;;     #;(stats   . ,(map (lambda (k) ;; create an alist from the stats data
;;; 		       (cons k (stat->alist (hash-table-ref (area-stats acfg) k))))
;;; 		     (hash-table-keys (area-stats acfg))))
;;; 
;;; #;(trace
;;;  ;; assv
;;;  ;; cdr
;;;  ;; caar
;;;  ;; ;; cdr
;;;  ;; call
;;;  ;; finalize-all-db-handles
;;;  ;; get-all-server-pkts
;;;  ;; get-normalized-cpu-load
;;;  ;; get-normalized-cpu-load-raw
;;;  ;; launch
;;;  ;; nmsg-send
;;;  ;; process-db-queries
;;;  ;; receive-message
;;;  ;; std-peer-handler
;;;  ;; update-known-servers
;;;  ;; work-queue-processor
;;;  )
;;; 
;;; ;;======================================================================
;;; ;; netutil
;;; ;;   move this back to ulex-netutil.scm someday?
;;; ;;======================================================================
;;; 
;;; ;; #include <stdio.h>
;;; ;; #include <netinet/in.h>
;;; ;; #include <string.h>
;;; ;; #include <arpa/inet.h>
;;; 
;;; (foreign-declare "#include \"sys/types.h\"")
;;; (foreign-declare "#include \"sys/socket.h\"")
;;; (foreign-declare "#include \"ifaddrs.h\"")
;;; (foreign-declare "#include \"arpa/inet.h\"")
;;; 
;;; ;; get IP addresses from ALL interfaces
;;; (define get-all-ips
;;;   (foreign-safe-lambda* scheme-object ()
;;;     "
;;; 
;;; // from https://stackoverflow.com/questions/17909401/linux-c-get-default-interfaces-ip-address :
;;; 
;;; 
;;;     C_word lst = C_SCHEME_END_OF_LIST, len, str, *a;
;;; //    struct ifaddrs *ifa, *i;
;;; //    struct sockaddr *sa;
;;; 
;;;     struct ifaddrs * ifAddrStruct = NULL;
;;;     struct ifaddrs * ifa = NULL;
;;;     void * tmpAddrPtr = NULL;
;;; 
;;;     if ( getifaddrs(&ifAddrStruct) != 0)
;;;       C_return(C_SCHEME_FALSE);
;;; 
;;; //    for (i = ifa; i != NULL; i = i->ifa_next) {
;;;     for (ifa = ifAddrStruct; ifa != NULL; ifa = ifa->ifa_next) {
;;;         if (ifa->ifa_addr->sa_family==AF_INET) { // Check it is
;;;             // a valid IPv4 address
;;;             tmpAddrPtr = &((struct sockaddr_in *)ifa->ifa_addr)->sin_addr;
;;;             char addressBuffer[INET_ADDRSTRLEN];
;;;             inet_ntop(AF_INET, tmpAddrPtr, addressBuffer, INET_ADDRSTRLEN);
;;; //            printf(\"%s IP Address %s\\n\", ifa->ifa_name, addressBuffer);
;;;             len = strlen(addressBuffer);
;;;             a = C_alloc(C_SIZEOF_PAIR + C_SIZEOF_STRING(len));
;;;             str = C_string(&a, len, addressBuffer);
;;;             lst = C_a_pair(&a, str, lst);
;;;         } 
;;; 
;;; //        else if (ifa->ifa_addr->sa_family==AF_INET6) { // Check it is
;;; //            // a valid IPv6 address
;;; //            tmpAddrPtr = &((struct sockaddr_in6 *)ifa->ifa_addr)->sin6_addr;
;;; //            char addressBuffer[INET6_ADDRSTRLEN];
;;; //            inet_ntop(AF_INET6, tmpAddrPtr, addressBuffer, INET6_ADDRSTRLEN);
;;; ////            printf(\"%s IP Address %s\\n\", ifa->ifa_name, addressBuffer);
;;; //            len = strlen(addressBuffer);
;;; //            a = C_alloc(C_SIZEOF_PAIR + C_SIZEOF_STRING(len));
;;; //            str = C_string(&a, len, addressBuffer);
;;; //            lst = C_a_pair(&a, str, lst);
;;; //       }
;;; 
;;; //       else {
;;; //         printf(\" not an IPv4 address\\n\");
;;; //       }
;;; 
;;;     }
;;; 
;;;     freeifaddrs(ifa);
;;;     C_return(lst);
;;; 
;;; "))
;;; 
;;; ;; Change this to bias for addresses with a reasonable broadcast value?
;;; ;;
;;; (define (ip-pref-less? a b)
;;;   (let* ((rate (lambda (ipstr)
;;;                  (regex-case ipstr
;;;                              ( "^127\\." _ 0 )
;;;                              ( "^(10\\.0|192\\.168\\.)\\..*" _ 1 )
;;;                              ( else 2 ) ))))
;;;     (< (rate a) (rate b))))
;;;   
;;; 
;;; (define (get-my-best-address)
;;;   (let ((all-my-addresses (get-all-ips))
;;;         ;;(all-my-addresses-old (vector->list (hostinfo-addresses (hostname->hostinfo (get-host-name)))))
;;;         )
;;;     (cond
;;;      ((null? all-my-addresses)
;;;       (get-host-name))                                          ;; no interfaces?
;;;      ((eq? (length all-my-addresses) 1)
;;;       (car all-my-addresses))                      ;; only one to choose from, just go with it
;;;      
;;;      (else
;;;       (car (sort all-my-addresses ip-pref-less?)))
;;;      ;; (else 
;;;      ;;  (ip->string (car (filter (lambda (x)                      ;; take any but 127.
;;;      ;;    			 (not (eq? (u8vector-ref x 0) 127)))
;;;      ;;    		       all-my-addresses))))
;;; 
;;;      )))
;;; 
;;; (define (get-all-ips-sorted)
;;;   (sort (get-all-ips) ip-pref-less?))
;;; 
;;; 

