Megatest

  (socket       #f)
  (thread       #f)
  (host-port    #f)
  (cmd-thread   #f)
  (ro-mode      #f)
  (ro-mode-checked #f)
  (last-access  (current-seconds))
  (servinf-file #f)
  )

(define (tt:make-remote areapath)
  (make-tt areapath: areapath))

;; do all the busy work of finding and setting up conn for
;; connecting to a server
;; 
(define (tt:client-connect-to-server ttdat dbfname run-id testsuite)
  (let* ((conn (hash-table-ref/default (tt-conns ttdat) dbfname #f))
	 (server-start-proc (lambda ()
			      (tt:server-process-run
			       (tt-areapath ttdat)
			       testsuite ;; (dbfile:testsuite-name)
			       (common:find-local-megatest)
			       run-id))))
    (if conn
	conn ;; we are already connected to the server
	(let* ((sdat (tt:get-current-server-info ttdat dbfname)))
	  (match sdat
	    ((host port start-time server-id pid dbfname2 servinffile)
	     (assert (equal? dbfname dbfname2) "FATAL: read server info from wrong file.")
	     (let* ((host-port (conc host":"port))
		    (conn (make-tt-conn
			   host: host
			   port: port
			   host-port: host-port
			   dbfname: dbfname
			   servinf-file: servinffile
			   server-id: server-id
			   server-start: start-time
			   pid: pid)))
	       (hash-table-set! (tt-conns ttdat) dbfname conn)
	       ;; verify we can talk to this server
	       (if (tt:ping host port server-id)
		   conn
		   (begin
		     ;; rm the (last server) would go here
		     (server-start-proc)
		     (thread-sleep! 1)
		     (tt:client-connect-to-server ttdat dbfname run-id testsuite)))))
	    (else
	     (debug:print-info 0 *default-log-port* "Number of records did not match expected. Bad server info?")
	     (server-start-proc)
	     (thread-sleep! 1)
	     (tt:client-connect-to-server ttdat dbfname run-id testsuite)))))))
    
(define (tt:ping host port server-id)
  (let*  ((res (tt:send-receive-direct host port `(ping #f #f #f)))) ;; please send me your server-id
    ;;
    ;; need two threads, one a 5 second timer
    ;;
    (match res
      ((status errmsg result meta)
       (if (equal? result server-id)
	   (begin
	     (debug:print 0 *default-log-port* "Ping to "host":"port" successful.")
	     #t) ;; then we are good
	   (begin
	     (debug:print 0 *default-log-port* "WARNING: server-id does not match, expected: "server-id", got: "result)
	     #f)))
      (else
       ;; (debug:print 0 *default-log-port* "res not in form (status errmsg result meta), got: "res)
       #f))))

;; client side handler
;;
(define (tt:handler ttdat cmd run-id params attemptnum area-dat areapath readonly-mode dbfname testsuite mtexe)
  ;; NOTE: areapath is passed in and in tt struct. We'll use passed in value for now.
  (let* ((conn (tt:client-connect-to-server ttdat dbfname run-id testsuite))) ;; (hash-table-ref/default (tt-conns ttdat) dbfname #f)))

;; 		(thread-sleep! 1)
;; 		(tt:handler  ttdat cmd run-id params attemptnum area-dat areapath
;; 			     readonly-mode dbfname testsuite mtexe)))))))

(define (tt:bid-for-servership run-id)
  #f)

;; gets server info and appends path to server file
;; sorts by age, oldest first
;;
;; returns list of (host port startseconds server-id servinfofile)
;;
(define (tt:get-server-info-sorted ttdat dbfname)
  (let* ((areapath (tt-areapath ttdat))
	 (sfiles   (tt:find-server areapath dbfname))
	 (sdats    (filter car (map tt:server-get-info sfiles))) ;; first element is #f if the file disappeared while being read
	 (sorted   (sort sdats (lambda (a b)
				 (< (list-ref a 2)(list-ref b 2))))))
    sorted))
    
(define (tt:get-current-server-info ttdat dbfname)
  (assert (tt-areapath ttdat) "FATAL: areapath not set in ttdat.")
  ;;
  ;; TODO - replace most of below with tt;get-server-info-sorted
  ;;
  (let* ((areapath (tt-areapath ttdat))
	 (sfiles   (tt:find-server areapath dbfname))
	 (sdats    (filter car (map tt:server-get-info sfiles))) ;; first element is #f if the file disappeared while being read
	 (sorted   (sort sdats (lambda (a b)
				 (< (list-ref a 2)(list-ref b 2))))))
    (if (null? sorted)
	#f  ;; we'll want to wait until extra servers have exited

;; start the listener and start responding to requests
;;
;; NOTE: organise by dbfname, not run-id so we don't need
;;       to pull in more modules
;;
;; This is the routine called in megatest.scm to start a server
;;
;; Server viability is checked in keep-running. Blindly start and run here.
;;
(define (tt:start-server areapath run-id dbfname handler keys)
  (assert areapath "FATAL: areapath not provided for tt:start-server")
  ;; is there already a server for this dbfile? Then exit.
  (let* ((ttdat   (make-tt areapath: areapath)))
    ;; (servers (tt:find-server areapath dbfname))) ;; should use tt:get-current-server-info instead
    ;; (if (null? servers)
    (let* ((dbstruct   (dbmod:open-dbmoddb areapath run-id (dbfile:db-init-proc) keys)))
      (tt-handler-set! ttdat (handler dbstruct))
      (let* ((tcp-thread (make-thread
			  (lambda ()
			    (tt:start-tcp-server ttdat)) ;; start the tcp-server which applies handler to incoming data
			  "tcp-server-thread"))
	     (run-thread (make-thread
			  (lambda ()
			    (tt:keep-running ttdat dbfname dbstruct)))))
	(thread-start! tcp-thread)
	(thread-start! run-thread)
	(thread-join! run-thread) ;; run thread will exit on timeout or other conditions
	;;
	;; set a flag here to tell tcp-thread to stop running
	;;
	;; (thread-join! tcp-thread) ;; can't wait 
	;;
	;; remove the servinfo file
	;;
	;; close the database, remove lock in on-disk db
	;;
	;; close the listener ports
	;;
	(exit)))
    ;;(begin
    ;; (debug:print 0 *default-log-port* "INFO: found server(s) already running for db "dbfname", "(string-intersperse servers ",")" Exiting.")
    ;; (exit)))))
    ))

(define (tt:keep-running ttdat dbfname dbstruct)
  ;; verfiy conn for ready
  ;; listener socket has been started by this stage
  (thread-sleep! 1)
  (let* ((cleanup (lambda ()
		    (if (tt-cleanup-proc ttdat)
			((tt-cleanup-proc ttdat))))))
    (let loop ((count 0))
      (if (> count 60)
	  (begin
	    (debug:print 0 *default-log-port* "FATAL: Could not start a tcp server, giving up.")
	    (exit 1))
	  (if (not (tt-port ttdat)) ;; no connection yet
	      (let* ((last-update (dbr:dbstruct-last-update dbstruct))
		     (curr-secs   (current-seconds)))
		(if (> (- curr-secs last-update) 3) ;; every 3-4 seconds
		    (begin
		      ((dbr:dbstruct-sync-proc dbstruct) last-update)
		      (dbr:dbstruct-last-update-set! curr-secs)))
		(thread-sleep! 1)
		(loop (+ count 1))))))
    
    (tt:create-server-registration-file ttdat dbfname)
    ;; now start watching the last-access, if it hasn't been touched
    ;; in over ten seconds we exit
    (thread-sleep! 1)
    (let loop ()
      (let* ((servers (tt:get-server-info-sorted ttdat dbfname))
	     (ok      (cond
		       ((null? servers) #f) ;; not ok
		       ((equal? (list-ref (car servers) 6) ;; compare the servinfofile
				(tt-servinf-file ttdat))
			(debug:print-info 0 *default-log-port* "Keep running, I'm the top server.")
			#t)
		       (else
			(debug:print-info 0 *default-log-port* "I'm not the lead server: "servers)
			(let* ((leadsrv (car servers)))
			  (match leadsrv
			    ((host port startseconds server-id pid dbfname servinfofile)
			     (if (tt:ping host port server-id)
				 #f ;; not the server, but all good, want to exit
				 (begin
				   ;; what to do here? remove the offending file?
				   (debug:print-info 0 *default-log-port* "Removing apparently dead server info file: "servinfofile)
				   (delete-file* servinfofile)
				   #t ;; not the server but the server is not reachable
				   )))
			    (else
			     (debug:print 0 *default-log-port* "BAD SERVER RECORD: "leadsrv)
			     (assert #f "Bad server record "leadsrv))))))))
	(if (not ok)
	    (begin
	      (cleanup)
	      (exit)))
	
	(if (< (- (current-seconds) (tt-last-access ttdat)) 60)
	    (begin
	      (thread-sleep! 5)
	      (loop)))))

	(cleanup)
	(debug:print 0 *default-log-port* "INFO: Server timed out, exiting.")))

  
;; ;; given an already set up uconn start the cmd-loop
;; ;;
;; (define (tt:cmd-loop ttdat)
;;   (let* ((serv-listener (-socket uconn))
;; 	 (listener      (lambda ()
;; 			  (let loop ((state 'start))
;; 			    (let-values (((inp oup)(tcp-accept serv-listener)))

	 (port     (tt-port ttdat))
	 (servinf (conc servdir"/"host":"port"-"(current-process-id)":"dbfname))
	 (serv-id (tt:mk-signature areapath))
	 (clean-proc (lambda ()
		       (delete-file* servinf))))
    (assert (and host port) "FATAL: tt:create-server-registration-file called with no conn, dbfname="dbfname)
    (tt-cleanup-proc-set! ttdat clean-proc)
    (tt-servinf-file-set! ttdat servinf)
    (with-output-to-file servinf
      (lambda ()
	(print "SERVER STARTED: "host":"port" AT "(current-seconds)" server-id: "serv-id" pid: "(current-process-id)" dbfname: "dbfname)))
      serv-id))

;; find valid server
;; get servers listed, last part of name must match :<dbfname>
;; if more than one, wait one second and look again
;; future: ping oldest, if alive remove other :<dbfname> files
;;
(define (tt:find-server areapath dbfname)
  (let* ((servdir  (tt:get-servinfo-dir areapath))
	 (sfiles   (glob (conc servdir"/*:"dbfname))))
    sfiles))

;; given a path to a server info file return: host port startseconds server-id pid dbfname logf
;; example of what it's looking for in the log file:
;;     SERVER STARTED: 10.38.175.67:50216 AT 1616502350.0 server-id: 4907e90fc55c7a09694e3f658c639cf4 
;;
(define (tt:server-get-info logf)
  (let ((server-rx    (regexp "^SERVER STARTED: (\\S+):(\\d+) AT ([\\d\\.]+) server-id: (\\S+) pid: (\\d+) dbfname: (\\S+)")) ;; SERVER STARTED: host:port AT timesecs server id
        (dbprep-rx    (regexp "^SERVER: dbprep"))
        (dbprep-found 0)
	(bad-dat      (list #f #f #f #f #f #f logf)))
    (handle-exceptions
     exn
     (begin
       ;; WARNING: this is potentially dangerous to blanket ignore the errors
       (if (file-exists? logf)
	   (debug:print-info 2 *default-log-port* "Unable to get server info from "logf", exn=" exn))
       bad-dat) ;; no idea what went wrong, call it a bad server

		     (match mlst
			    ((_ host port start server-id pid dbfname)
			     (list host
				   (string->number port)
				   (string->number start)
				   server-id
				   (string->number pid)
				   dbfname
				   logf))
			    (else
			     (debug:print 0 *default-log-port* "ERROR: did not recognise SERVER line info "mlst)
			     bad-dat))))
	       (begin 
		 (if dbprep-found
		     (begin
		       (debug:print-info 2 *default-log-port* "Server is in dbprep at " (common:human-time))

		     " " profile-mode
		     ))) ;; (conc " >> " logfile " 2>&1 &")))))
    ;; we want the remote server to start in *toppath* so push there
    ;; (push-directory areapath) ;; use cd in the command line instead
    (debug:print 0 *default-log-port* "INFO: Trying to start server in tcp mode (" cmdln ") at "(common:human-time)"...")
    ;; (debug:print 0 *default-log-port* "INFO: starting server at " (common:human-time))
    (setenv "NBFAKE_QUIET" "yes") ;; BUG: change to with-environment-variable ...
    (setenv "NBFAKE_LOG" logfile)
    (system (conc "cd "areapath" ; nbfake " cmdln))
    (unsetenv "NBFAKE_QUIET")
    (unsetenv "NBFAKE_LOG")
    ;;(pop-directory)
    ))

;;======================================================================
;; tcp connection stuff
;;======================================================================