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->server-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))))))
      

		    (current-seconds)))
	    (begin
	      (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
              ;;
              ;; BB - added this because servers are hanging about, alive and well
              ;;      but in defunctdefault state in tdb and a .server file
              ;;      preventing replacement servers from starting.
              (tasks:server-set-state! (db:delay-if-busy tdbdat) server-id "running")

              ;;
	      ;; (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)))
	    (http-transport:server-shutdown server-id port))))))

;; code cut out from above

     ;;  (rmt:open-qry-close-locally cmd 0 params))

     
     ;; no server contact made and this is a write, passively start a server 
     ((and (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 ((serverconn (server:read-dotserver->server-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 serverconn
	    (remote-server-url-set! *runremote* serverconn) ;; the string can be consumed by the client setup if needed
	    (if (not (server:start-attempted? *toppath*))
		(server:kind-run *toppath*))))
      (if (cdr (remote-hh-dat *runremote*)) ;; we are on the homehost, just do the call
          (begin
            (mutex-unlock! *rmt-mutex*)

	 (log-rotate  (make-thread common:rotate-logs  "server run, rotate logs thread")))
    ;; we want the remote server to start in *toppath* so push there
    (push-directory areapath)
    (cond
     (attempt-in-progress
      (debug:print 0 *default-log-port* "INFO: Not trying to start server because attempt is in progress: "attempt-in-progress))
     (dot-server-url
      (debug:print 0 *default-log-port* "INFO: Not trying to start server because one is already running : "dot-server-url))
     (else
      (debug:print 0 *default-log-port* "INFO: Trying to start server (" cmdln ") ...")
      (thread-start! log-rotate)

      ;; host.domain.tld match host?
      (if (and target-host 
               ;; look at target host, is it host.domain.tld or ip address and does it 

                  (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
     (if (and (file-exists? dotfile)
	      (file-read-access? dotfile))
	 (with-input-from-file
	     dotfile
	   (lambda ()
	     (read-line)))
	 #f))))

(define (server:read-dotserver->server-url areapath)
  (let* ((temp (server:read-dotserver areapath))
         (tokens (if temp (string-split temp ":") '())))
    (if (eq? 3 (length tokens))
        (string-join (list-ref tokens 0) ":" (list-ref tokens 1))
        #f)))

(define (server:read-dotserver->pid areapath)
  (let* ((temp (server:read-dotserver areapath))
         (tokens (if temp (string-split temp ":") '())))
    (if (eq? 3 (length tokens))
        (list-ref tokens 2)
        #f)))

(define (server:running-or-starting? areapath) ;; Note: may be unreiable on non-homehost due to NFS lag
  (or (server:read-dotserver areapath) (server:start-attempted? areapath)))

;; write a .server file in *toppath* with hostport
;; return #t on success, #f otherwise
;;
(define (server:write-dotserver areapath hostportpid)
  (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 hostportpid)))
		    #t)))
	  (debug:print-info 0 *default-log-port* "server file " server-file " for " hostportpid " created")
	  (common:simple-file-release-lock lock-file)
	  res)
	#f)))

(define (server:remove-dotserver-file areapath hostport)
  (let ((serverurl   (server:read-dotserver->server-url areapath))
	(server-file (conc areapath "/.server"))
	(lock-file   (conc areapath "/.server.lock")))
    (if (and serverurl (string-match (conc ".*:" hostport "$") serverurl)) ;; 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))))))

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

      mdb
      ;; removed:
      ;; strftime('%s','now')-heartbeat < 10 AND mt_version = ?
      "SELECT id,interface,port,pubport,transport,pid,hostname FROM servers
          WHERE run_id=? AND state='running'
          ORDER BY start_time DESC LIMIT 1;" run-id) ;; (common:version-signature) run-id)
     res)))
   
(define (tasks:server-running-or-starting? mdb run-id)







  (server:running-or-starting? *toppath*))








  
(define (tasks:need-server run-id)
  (equal? (configf:lookup *configdat* "server" "required") "yes"))

;; 	(maxqry (cdr (rmt:get-max-query-average run-id)))
;; 	(threshold   (string->number (or (configf:lookup *configdat* "server" "server-query-threshold") "10"))))
;;     (cond
;;      (forced