Megatest

(define *run-info-cache*     (make-hash-table)) ;; run info is stable, no need to reget
(define *launch-setup-mutex* (make-mutex))     ;; need to be able to call launch:setup often so mutex it and re-call the real deal only if *toppath* not set
(define *homehost-mutex*     (make-mutex))

(defstruct remote
  (hh-dat            (common:get-homehost)) ;; homehost record ( addr . hhflag )
  (server-url        (if *toppath* (server:read-dotserver->url *toppath*))) ;; (server:check-if-running *toppath*) #f))
  (last-server-check 0)  ;; last time we checked to see if the server was alive
  (conndat           #f)
  (transport         *transport-type*)
  (server-timeout    (or (server:get-timeout) 100))) ;; default to 100 seconds

;; launching and hosts
(defstruct host

			(tasks:server-set-state! (db:delay-if-busy tdbdat) server-id "dbprep")
                        ;;(BB> "http-transport: ->dbprep")
			(thread-sleep! 0.5) ;; give some margin for queries to complete before switching from file based access to server based access
			(set! *dbstruct-db*  (db:setup)) ;;  run-id))
			(set! server-going #t)
			(tasks:server-set-state! (db:delay-if-busy tdbdat) server-id "running")
                        ;;(BB> "http-transport: ->running")
			(server:write-dotserver *toppath* iface port (current-process-id) 'http)
                        (thread-start! *watchdog*)
                        (server:complete-attempt *toppath*))
		      (begin ;; gotta exit nicely
                        ;;(BB> "http-transport: ->collision")
			(tasks:server-set-state! (db:delay-if-busy tdbdat) server-id "collision")
			(http-transport:server-shutdown server-id port))))))
      

      (mutex-unlock! *heartbeat-mutex*)
      
      (if (or (not (equal? sdat (list iface port)))
	      (not server-id))
	  (begin 
	    (debug:print-info 0 *default-log-port* "interface changed, refreshing iface and port info")
	    (set! iface (car sdat))
	    (set! port  (cadr sdat))
            (server:write-dotserver *toppath* iface port (current-process-id) 'http)))
      
      ;; Transfer *db-last-access* to last-access to use in checking that we are still alive
      (mutex-lock! *heartbeat-mutex*)
      (set! last-access *db-last-access*)
      (mutex-unlock! *heartbeat-mutex*)

      ;; (debug:print 11 *default-log-port* "last-access=" last-access ", server-timeout=" server-timeout)
      ;;
      ;; no_traffic, no running tests, if server 0, no running servers
      ;;
      ;; (let ((wait-on-running (configf:lookup *configdat* "server" b"wait-on-running"))) ;; wait on running tasks (if not true then exit on time out)
      ;;
      (let* ((hrs-since-start  (/ (- (current-seconds) server-start-time) 3600))
	     (adjusted-timeout (if (> hrs-since-start 1)
				   (- server-timeout (inexact->exact (round (* hrs-since-start 60))))  ;; subtract 60 seconds per hour
				   server-timeout)))
	(if (common:low-noise-print 120 "server timeout")
	    (debug:print-info 0 *default-log-port* "Adjusted server timeout: " adjusted-timeout))
	(cond
         ((not (server:confirm-dotserver *toppath* iface port (current-process-id) 'http))
          (debug:print-info 0 *default-log-port* "Server .server file does not exist or contents do not match.  Initiate server shutdown.")
          (http-transport:server-shutdown server-id port))
         ((and *server-run*
		 (> (+ last-access server-timeout)
		    (current-seconds)))

          (if (common:low-noise-print 120 "server continuing")
              (debug:print-info 0 *default-log-port* "Server continuing, seconds since last db access: " (- (current-seconds) last-access)))
          ;;
          ;; Consider implementing some smarts here to re-insert the record or kill self is
          ;; the db indicates so
          ;;
          ;; (if (tasks:server-am-i-the-server? tdb run-id)
          ;;     (tasks:server-set-state! tdb server-id "running"))
          ;;
          (loop 0 server-state bad-sync-count (current-milliseconds)))
         (else
          (debug:print-info 0 *default-log-port* "Server timeed out. seconds since last db access: " (- (current-seconds) last-access))
          (http-transport:server-shutdown server-id port)))))))

;; code cut out from above
;;
;; (condition-case
;;  ;; (if (and (member (mutex-state *db-sync-mutex*) '(abandoned not-abandoned))
;;  ;;	      (> (- (current-seconds) *db-last-sync*) 5)) ;; if not currently being synced nor recently synced
;;  (db:sync-touched *dbstruct-db* *run-id* force-sync: #t) ;; usually done in the watchdog, not here.

;;======================================================================
;;  S U P P O R T   F U N C T I O N S
;;======================================================================

;; if a server is either running or in the process of starting call client:setup
;; else return #f to let the calling proc know that there is no server available
;;
(define (rmt:get-connection-info areapath) ;; TODO: push areapath down.
  (let ((cinfo (remote-conndat *runremote*))
        (run-id 0))
    (if cinfo
	cinfo
	(if (tasks:server-running-or-starting? (db:delay-if-busy (tasks:open-db)) run-id)
	    (client:setup run-id)
	    #f))))

(define *send-receive-mutex* (make-mutex)) ;; should have separate mutex per run-id

     ;; ((and (cdr (remote-hh-dat *runremote*))         ;; on homehost
     ;;       (not (member cmd api:read-only-queries)))
     ;;  (mutex-unlock! *rmt-mutex*)
     ;;  (debug:print-info 12 *default-log-port* "rmt:send-receive, case  4.1")
     ;;  (rmt:open-qry-close-locally cmd 0 params))

     
     ;;  on homehost, no server contact made and this is a write, passively start a server 
     ((and (cdr (remote-hh-dat *runremote*)) ; new
           (not (remote-server-url *runremote*))
	   (not (member cmd api:read-only-queries)))
      (debug:print-info 12 *default-log-port* "rmt:send-receive, case  5")
      (let ((server-url (server:read-dotserver->url *toppath*))) ;; (server:check-if-running *toppath*))) ;; Do NOT want to run server:check-if-running - very expensive to do for every write call
	(if server-url
	    (remote-server-url-set! *runremote* server-url) ;; the string can be consumed by the client setup if needed
	    (if (not (server:start-attempted? *toppath*))
		(server:kind-run *toppath*))))


             (mutex-unlock! *rmt-mutex*)
             (debug:print-info 12 *default-log-port* "rmt:send-receive, case  5.1")
             (rmt:open-qry-close-locally cmd 0 params))



     ;;;
           ;;     (begin                            ;; not on homehost, start server and wait
            ;; (mutex-unlock! *rmt-mutex*)
	    ;; (debug:print-info 12 *default-log-port* "rmt:send-receive, case  5.2")
	    ;; (tasks:start-and-wait-for-server (tasks:open-db) 0 15)
            ;; (rmt:send-receive cmd rid params attemptnum: attemptnum))   ;)  ;)
;;;;
     
     ;; if not on homehost ensure we have a connection to a live server
     ;; NOTE: we *have* a homehost record by now
     ((and (not (cdr (remote-hh-dat *runremote*)))        ;; not on a homehost 
           (not (remote-conndat *runremote*))             ;; and no connection
           (server:read-dotserver *toppath*))             ;; .server file exists
      ;; something caused the server entry in tdb to disappear, but the server is still running
      (server:remove-dotserver-file *toppath* ".*")
      (mutex-unlock! *rmt-mutex*)
      (debug:print-info 12 *default-log-port* "rmt:send-receive, case  20")
      (rmt:send-receive cmd rid params attemptnum: (add1 attemptnum)))
     ((and (not (cdr (remote-hh-dat *runremote*)))        ;; not on a homehost 
           (not (remote-conndat *runremote*)))            ;; and no connection
      (debug:print-info 12 *default-log-port* "rmt:send-receive, case  6  hh-dat: " (remote-hh-dat *runremote*) " conndat: " (remote-conndat *runremote*))
      (mutex-unlock! *rmt-mutex*)
      (tasks:start-and-wait-for-server (tasks:open-db) 0 15)
      (remote-conndat-set! *runremote* (rmt:get-connection-info *toppath*)) ;; calls client:setup which calls client:setup-http
      (rmt:send-receive cmd rid params attemptnum: attemptnum)) ;; TODO: add back-off timeout as
     ;; all set up if get this far, dispatch the query
     ((cdr (remote-hh-dat *runremote*)) ;; we are on homehost
      (mutex-unlock! *rmt-mutex*)
      (debug:print-info 12 *default-log-port* "rmt:send-receive, case  7")
      (rmt:open-qry-close-locally cmd (if rid rid 0) params))

     ;; not on homehost, do server query
     (else
      (mutex-unlock! *rmt-mutex*)
      (debug:print-info 12 *default-log-port* "rmt:send-receive, case  9")
      (let* ((conninfo (remote-conndat *runremote*))
	     (dat      (case (remote-transport *runremote*)
			 ((http) (condition-case ;; handling here has caused a lot of problems. However it is needed to deal with attemtped communication to servers that have gone away

;; Copyright 2006-2012, Matthew Welland.
;; 
;;  This program is made available under the GNU GPL version 2.0 or
;;  greater. See the accompanying file COPYING for details.
;; 
;;  This program is distributed WITHOUT ANY WARRANTY; without even the
;;  implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
;;  PURPOSE.

(require-extension (srfi 18) extras tcp s11n)

(use srfi-1 posix regex regex-case srfi-69 hostinfo md5 message-digest directory-utils posix-extras)
;; (use zmq)

(use spiffy uri-common intarweb http-client spiffy-request-vars)

(declare (unit server))

(declare (uses common))

;; all routes though here end in exit ...
;;
;; start_server
;;
(define (server:launch run-id transport-type)
  ;;(BB> "server:launch fired for run-id="run-id" transport-type="transport-type)

  (let ((attempt-in-progress (server:start-attempted? *toppath*))) ; check for .server-starting
    (when attempt-in-progress
      (debug:print-info 0 *default-log-port* "Server start attempt in progress in other process (=> "attempt-in-progress"<=).  Aborting server launch attempt in this process ("(current-process-id)")")
      (exit)))
      
  (let ((dotserver-url (server:check-if-running *toppath*))) ;; check for .server  
    (when dotserver-url
      (debug:print-info 0 *default-log-port* "Server already running (=> "dotserver-url"<=).  Aborting server launch attempt in this process ("(current-process-id)")")
      (exit)
      ))
  
  (case transport-type
    ((http)(http-transport:launch run-id))

                  (file-modification-time flagfile))
               15)) ;; exists and less than 15 seconds old
       (with-input-from-file flagfile (lambda () (read-line))))
      ((file-exists? flagfile) ;; it is stale.
       (server:complete-attempt areapath)
       #f)
      (else #f)))))

(define (server:read-dotserver areapath)
  (let ((dotfile (conc areapath "/.server")))
    (handle-exceptions
     exn
     #f  ;; if things go wrong pretend we can't see the file
     (cond
      ((not (file-exists? dotfile))
       #f)
      ((not (file-read-access? dotfile))
       #f)
      ((> (server:dotserver-age-seconds areapath) (+ 5 (server:get-timeout)))
       (server:remove-dotserver-file areapath ".*")
       #f)
      (else
       (let* ((line
               (with-input-from-file
                   dotfile
                 (lambda ()
                   (read-line))))
              (tokens (if (string? line) (string-split line ":") #f)))
         (cond
          ((eq? 4 (length tokens))
           tokens)
          (else #f))))))))
       
(define (server:read-dotserver->url areapath)
  (let ((dotserver-tokens (server:read-dotserver areapath)))
    (if dotserver-tokens
        (conc (list-ref dotserver-tokens 0) ":" (list-ref dotserver-tokens 1))
        #f)))

;; write a .server file in *toppath* with hostport
;; return #t on success, #f otherwise
;;
(define (server:write-dotserver areapath host port pid transport)
  (let ((lock-file   (conc areapath "/.server.lock"))
	(server-file (conc areapath "/.server")))
    (if (common:simple-file-lock lock-file)
	(let ((res (handle-exceptions
		    exn
		    #f ;; failed for some reason, for the moment simply return #f
		    (with-output-to-file server-file
		      (lambda ()
			(print (conc host ":" port ":" pid ":" transport))))
		    #t)))
	  (debug:print-info 0 *default-log-port* "server file " server-file " for " host ":" port " created pid="pid)
	  (common:simple-file-release-lock lock-file)
	  res)
	#f)))


;; this will check that the .server file present matches the server calling this procedure.
;; if parameters match (this-pid and transport) the file will be touched and #t returned
;; otherwise #f will be returned.
(define (server:confirm-dotserver areapath this-iface this-port this-pid this-transport)
  (let* ((tokens (server:read-dotserver areapath)))
    (cond
     ((not tokens)
      (debug:print-info 0 *default-log-port* "INFO: .server file does not exist.")
      #f)
     ((not (eq? 4 (length tokens)))
      (debug:print-info 0 *default-log-port* "INFO: .server file is corrupt.  There are not 4 tokens as expeted; there are "(length tokens)".")
      #f)
     ((not (equal? this-iface (list-ref tokens 0)))
      (debug:print-info 0 *default-log-port* "INFO: .server file mismatch.  for iface, server has value >"(list-ref tokens 0)"< but this server's value is >"this-iface"<")
      #f)
     ((not (equal? (->string this-port)  (list-ref tokens 1)))
      (debug:print-info 0 *default-log-port* "INFO: .server file mismatch.  for port, .server has value >"(list-ref tokens 1)"< but this server's value is >"(->string this-port)"<")
      #f)
     ((not (equal? (->string this-pid)   (list-ref tokens 2)))
      (debug:print-info 0 *default-log-port* "INFO: .server file mismatch.  for pid, .server has value >"(list-ref tokens 2)"< but this server's value is >"(->string this-pid)"<")
      #f)
     ((not (equal? (->string this-transport) (->string (list-ref tokens 3))))
      (debug:print-info 0 *default-log-port* "INFO: .server file mismatch.  for transport, .server has value >"(list-ref tokens 3)"< but this server's value is >"this-transport"<")
      #f)
     (else (server:touch-dotserver areapath)
      #t))))

(define (server:touch-dotserver areapath)
  (let ((server-file (conc areapath "/.server")))
    (change-file-times server-file (current-seconds) (current-seconds))))

(define (server:dotserver-age-seconds areapath)
  (let ((server-file (conc areapath "/.server")))
    (begin
      (handle-exceptions
       exn
       #f
       (- (current-seconds)
          (file-modification-time server-file))))))
    
(define (server:remove-dotserver-file areapath hostport)
  (let ((dotserver-url   (server:read-dotserver->url areapath))
	(server-file (conc areapath "/.server"))
	(lock-file   (conc areapath "/.server.lock")))
    (if (and dotserver-url (string-match (conc ".*:" hostport "$") dotserver-url)) ;; port matches, good enough info to decide to remove the file
	(if (common:simple-file-lock lock-file)
	    (begin
	      (handle-exceptions
	       exn
	       #f
	       (delete-file* server-file))
	      (debug:print-info 0 *default-log-port* "server file " server-file " for " hostport " removed")
	      (common:simple-file-release-lock lock-file))
            (debug:print-info 0 *default-log-port* "server file " server-file " for " hostport " NOT removed - could not get lock."))
        (debug:print-info 0 *default-log-port* "server file " server-file " for " hostport " NOT removed - dotserver-url("dotserver-url") did not match hostport pattern ("hostport")"))))

;; no longer care if multiple servers are started by accident. older servers will drop off in time.
;;
(define (server:check-if-running areapath)
  (let* ((dotserver-url (server:read-dotserver->url areapath))) ;; tdbdat (tasks:open-db)))
    (if dotserver-url
	(let* ((res (case *transport-type*
		      ((http)(server:ping-server dotserver-url))
		      ;; ((nmsg)(nmsg-transport:ping (tasks:hostinfo-get-interface server)
		      )))
	  (if res
	      dotserver-url
	      (begin
                (server:remove-dotserver-file areapath ".*") ;; remove stale dotserver
                #f)))
	#f)))

;; called in megatest.scm, host-port is string hostname:port
;;
;; NOTE: This is NOT called directly from clients as not all transports support a client running
;;       in the same process as the server.
;;
(define (server:ping host-port-in #!key (do-exit #f))
  (let ((host:port (if (not host-port-in) ;; use read-dotserver to find
		       (server:read-dotserver->url *toppath*)
		       (if (number? host-port-in) ;; we were handed a server-id
			   (let ((srec (tasks:get-server-by-id (db:delay-if-busy (tasks:open-db)) host-port-in)))
			     ;; (print "srec: " srec " host-port-in: " host-port-in)
			     (if srec
				 (conc (vector-ref srec 3) ":" (vector-ref srec 4))
				 (conc "no such server-id " host-port-in)))
			   host-port-in))))