Megatest

(define (tasks:server-register mdb pid interface port priority state)
  (sqlite3:execute 
   mdb 
   "INSERT OR REPLACE INTO servers (pid,hostname,port,start_time,priority,state,mt_version,heartbeat,interface)
                             VALUES(?,  ?,       ?, strftime('%s','now'), ?, ?, ?, strftime('%s','now'),?);"
   pid (get-host-name) port priority (conc state) megatest-version interface)
  (list 
   (tasks:server-get-server-id mdb (get-host-name) interface port pid)
   interface
   port
   ))

;; NB// two servers with same pid on different hosts will be removed from the list if pid: is used!
(define (tasks:server-deregister mdb hostname #!key (port #f)(pid #f)(action 'markdead))
  (debug:print-info 11 "server-deregister " hostname ", port " port ", pid " pid)
  (if pid
      (case action
	((delete)(sqlite3:execute mdb "DELETE FROM servers WHERE pid=?;" pid))
	(else    (sqlite3:execute mdb "UPDATE servers SET state='dead' WHERE pid=?;" pid)))
      (if port
	  (case action
	    ((delete)(sqlite3:execute mdb "DELETE FROM servers WHERE  hostname=? AND port=?;" hostname port))
	    (else    (sqlite3:execute mdb "UPDATE servers SET state='dead' WHERE hostname=? AND port=?;" hostname port)))
	  (debug:print 0 "ERROR: tasks:server-deregister called with neither pid nor port specified"))))

(define (tasks:server-deregister-self mdb hostname)
  (tasks:server-deregister mdb hostname pid: (current-process-id)))

(define (tasks:server-get-server-id mdb hostname iface port pid)
  (let ((res #f))
    (sqlite3:for-each-row
     (lambda (id)
       (set! res id))
     mdb
     (cond
      ((and hostname  pid)  "SELECT id FROM servers WHERE hostname=?  AND pid=?;")
      ((and iface     port) "SELECT id FROM servers WHERE interface=? AND port=?;")
      ((and hostname  port) "SELECT id FROM servers WHERE hostname=?  AND port=?;")
      (else
       (begin
	 (debug:print 0 "ERROR: tasks:server-get-server-id needs (hostname and pid) OR (iface and port) OR (hostname and port)")
	 "SELECT id FROM servers WHERE pid=-999;")))
     (if hostname hostname iface)(if pid pid port))
    res))

(define (tasks:server-update-heartbeat mdb server-id)
  (sqlite3:execute mdb "UPDATE servers SET heartbeat=strftime('%s','now') WHERE id=?;" server-id))

;; alive servers keep the heartbeat field upto date with seconds every 6 or so seconds
(define (tasks:server-alive? mdb server-id #!key (iface #f)(hostname #f)(port #f)(pid #f))
  (let* ((server-id  (if server-id 
			 server-id
			 (tasks:server-get-server-id mdb hostname iface port pid)))
	 (heartbeat-delta 99e9))
    (sqlite3:for-each-row
     (lambda (delta)
       (set! heartbeat-delta delta))
     mdb "SELECT strftime('%s','now')-heartbeat FROM servers WHERE id=?;" server-id)
    (< heartbeat-delta 10)))

(define (tasks:client-register mdb pid hostname cmdline)
  (sqlite3:execute
   mdb
   "INSERT OR REPLACE INTO clients (server_id,pid,hostname,cmdline,login_time) VALUES(?,?,?,?,strftime('%s','now'));")
  (tasks:server-get-server-id mdb hostname #f #f pid)
  pid hostname cmdline)

(define (tasks:client-logout mdb pid hostname cmdline)
  (sqlite3:execute
   mdb
   "UPDATE clients SET logout_time=strftime('%s','now') WHERE pid=? AND hostname=? AND cmdline=?;"
   pid hostname cmdline))

     (lambda (id hostname interface port pid)
       (set! res (cons (list hostname interface port pid) res))
       (debug:print-info 2 "Found existing server " hostname ":" port " registered in db"))
     mdb
     "SELECT id,hostname,interface,port,pid FROM servers
         WHERE strftime('%s','now')-heartbeat < 10
               AND mt_version=? ORDER BY start_time ASC LIMIT 1;" megatest-version)
    ;; for now we are keeping only one server registered in the db, return #f or first server found
    (if (null? res) #f (car res))))

;; BUG: This logic is probably needed unless methodology changes completely...
;;
;;     (if (null? res) #f
;; 	(let loop ((hed (car res))
;; 		   (tal (cdr res)))
;; 	  ;; (print "hed=" hed ", tal=" tal)
;; 	  (let* ((host     (list-ref hed 0))
;; 		 (iface    (list-ref hed 1))
;; 		 (port     (list-ref hed 2))
;; 		 (pid      (list-ref hed 4))
;; 		 (alive    (open-run-close tasks:server-alive? tasks:open-db #f hostname: host port: port)))
;; 	    (if alive
;; 		(begin
;; 		  (debug:print-info 2 "Found an existing, alive, server " host ", " port ".")
;; 		  (list host iface port))
;; 		(begin
;; 		  (debug:print-info 1 "Marking " host ":" port " as dead in server registry.")
;; 		  (if port
;; 		      (open-run-close tasks:server-deregister tasks:open-db host port: port)
;; 		      (open-run-close tasks:server-deregister tasks:open-db host pid:  pid))
;; 		  (if (null? tal)
;; 		      #f
;; 		      (loop (car tal)(cdr tal))))))))))

(define (tasks:remove-server-records mdb)
  (sqlite3:execute mdb "DELETE FROM servers;"))

(define (tasks:mark-server hostname port pid state)
  (if port
      (open-run-close tasks:server-deregister tasks:open-db hostname port: port)
      (open-run-close tasks:server-deregister tasks:open-db hostname pid:  pid)))