Megatest

(require-extension (srfi 18) extras tcp) ;;  rpc)
;; (import (prefix rpc rpc:))

(use sqlite3 srfi-1 posix regex regex-case srfi-69 csv-xml s11n md5 message-digest base64)
(import (prefix sqlite3 sqlite3:))
(import (prefix base64 base64:))

;; Note, try to remove this dependency 
(use zmq)

(declare (unit db))
(declare (uses common))
(declare (uses keys))
(declare (uses ods))
(declare (uses fs-transport))

;; (define (db:updater)
;;   (debug:print-info 4 "Starting cache processing")
;;   (let loop ()
;;     (thread-sleep! 10) ;; move save time around to minimize regular collisions?
;;     (db:write-cached-data)
;;     (loop)))

;; NOTE: Can remove the regex and base64 encoding for zmq
(define (db:obj->string obj)
  (case *transport-type*
    ((fs) obj)
	((http)
     (string-substitute
       (regexp "=") "_"
         (base64:base64-encode (with-output-to-string (lambda ()(serialize obj))))
        #t))
    ((zmq)(with-output-to-string (lambda ()(serialize obj))))
    (else obj)))

(define (db:string->obj msg)
  (case *transport-type*
   ((fs) msg)
   ((http)
    (with-input-from-string 
       (base64:base64-decode
         (string-substitute 
	   (regexp "_") "=" msg #t))
       (lambda ()(deserialize))))
   ((zmq)(with-input-from-string msg (lambda ()(deserialize))))
   (else msg)))

(define (cdb:use-non-blocking-mode proc)
  (set! *client-non-blocking-mode* #t)
  (let ((res (proc)))
    (set! *client-non-blocking-mode* #f)
    res))
  

	    (zdat        (db:obj->string (vector client-sig qtype immediate query-sig params (current-seconds))))) ;; (with-output-to-string (lambda ()(serialize params))))
       (debug:print-info 11 "zdat=" zdat)
       (let* ((res  #f)
	      (rawdat      (server:client-send-receive serverdat zdat))
	      (tmp         #f))
	 (debug:print-info 11 "Sent " zdat ", received " rawdat)
	 (set! tmp (db:string->obj rawdat))
	 (vector-ref tmp 2))))
    ((zmq)
     (handle-exceptions
      exn
      (begin
	(thread-sleep! 5) 
	(if (> numretries 0)(apply cdb:client-call zmq-sockets qtype immediate (- numretries 1) params)))
      (let* ((push-socket (vector-ref zmq-sockets 0))
	     (sub-socket  (vector-ref zmq-sockets 1))
	     (client-sig  (server:get-client-signature))
	     (query-sig   (message-digest-string (md5-primitive) (conc qtype immediate params)))
	     (zdat        (db:obj->string (vector client-sig qtype immediate query-sig params (current-seconds)))) ;; (with-output-to-string (lambda ()(serialize params))))
	     (res  #f)
	     (send-receive (lambda ()
			     (debug:print-info 11 "sending message")
			     (send-message push-socket zdat)
			     (debug:print-info 11 "message sent")
			     (let loop ()
			       ;; get the sender info
			       ;; this should match (server:get-client-signature)
			       ;; we will need to process "all" messages here some day
			       (receive-message* sub-socket)
			       ;; now get the actual message
			       (let ((myres (db:string->obj (receive-message* sub-socket))))
				 (if (equal? query-sig (vector-ref myres 1))
				     (set! res (vector-ref myres 2))
				     (loop))))))
	     (timeout (lambda ()
			(let loop ((n numretries))
			  (thread-sleep! 15)
			  (if (not res)
			      (if (> numretries 0)
				  (begin
				    (debug:print 2 "WARNING: no reply to query " params ", trying resend")
				    (debug:print-info 11 "re-sending message")
				    (send-message push-socket zdat)
				    (debug:print-info 11 "message re-sent")
				    (loop (- n 1)))
				  ;; (apply cdb:client-call zmq-sockets qtype immediate (- numretries 1) params))
				  (begin
				    (debug:print 0 "ERROR: cdb:client-call timed out " params ", exiting.")
				    (exit 5))))))))
	(debug:print-info 11 "Starting threads")
	(let ((th1 (make-thread send-receive "send receive"))
	      (th2 (make-thread timeout      "timeout")))
	  (thread-start! th1)
	  (thread-start! th2)
	  (thread-join!  th1)
	  (debug:print-info 11 "cdb:client-call returning res=" res)
	  res))))))
  
(define (cdb:set-verbosity serverdat val)
  (cdb:client-call serverdat 'set-verbosity #f *default-numtries* val))

(define (cdb:login serverdat keyval signature)
  (cdb:client-call serverdat 'login #t *default-numtries* keyval megatest-version signature))

                                username TEXT,
                               CONSTRAINT monitors_constraint UNIQUE (pid,hostname));")
	  (sqlite3:execute mdb "CREATE TABLE IF NOT EXISTS servers (id INTEGER PRIMARY KEY,
                                  pid INTEGER,
                                  interface TEXT,
                                  hostname TEXT,
                                  port INTEGER,
                                  pubport INTEGER,
                                  start_time TIMESTAMP,
                                  priority INTEGER,
                                  state TEXT,
                                  mt_version TEXT,
                                  heartbeat TIMESTAMP,
                               CONSTRAINT servers_constraint UNIQUE (pid,hostname,port));")
	  (sqlite3:execute mdb "CREATE TABLE IF NOT EXISTS clients (id INTEGER PRIMARY KEY,

    mdb))
    
;;======================================================================
;; Server and client management
;;======================================================================

;; state: 'live, 'shutting-down, 'dead
(define (tasks:server-register mdb pid interface port priority state #!key (pubport -1))
  (debug:print-info 11 "tasks:server-register " pid " " interface " " port " " priority " " state)
  (sqlite3:execute 
   mdb 
   "INSERT OR REPLACE INTO servers (pid,hostname,port,pubport,start_time,priority,state,mt_version,heartbeat,interface)
                             VALUES(?,  ?,       ?, strftime('%s','now'), ?, ?, ?, strftime('%s','now'),?);"
   pid (get-host-name) port pubport priority (conc state) megatest-version interface)
  (list 
   (tasks:server-get-server-id mdb (get-host-name) interface port pid)
   interface
   port
   pubport
   ))

;; 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

		(debug:print 0 "WARNING: Can't kill frozen server on remote host " hostname))))))



(define (tasks:get-all-servers mdb)
  (let ((res '()))
    (sqlite3:for-each-row
     (lambda (id pid hostname interface port pubport start-time priority state mt-version last-update)
       (set! res (cons (vector id pid hostname interface port pubport start-time priority state mt-version last-update) res)))
     mdb
     "SELECT id,pid,hostname,interface,port,pubport,start_time,priority,state,mt_version,strftime('%s','now')-heartbeat AS last_update FROM servers ORDER BY start_time DESC;")
    res))
       

;;======================================================================
;; Tasks and Task monitors
;;======================================================================

;;  PURPOSE.

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

(use sqlite3 srfi-1 posix regex regex-case srfi-69 hostinfo md5 message-digest)
(import (prefix sqlite3 sqlite3:))


(use zmq)


(declare (unit server))

(declare (uses common))
(declare (uses db))
(declare (uses tests))
(declare (uses tasks)) ;; tasks are where stuff is maintained about what is running.

(include "common_records.scm")
(include "db_records.scm")

;; Transition to pub --> sub with pull <-- push
;;
;;   1. client sends request to server via push to the pull port
;;   2. server puts request in queue or processes immediately as appropriate
;;   3. server puts responses from completed requests into pub port 
;;
;; TODO
;;
;; Done Tested
;; [x]  [ ]    1. Add columns pullport pubport to servers table
;; [x]  [ ]    2. Add rm of monitor.db if older than 11/12/2012 
;; [x]  [ ]    3. Add create of pullport and pubport with finding of available ports
;; [x]  [ ]    4. Add client compose of request
;; [x]  [ ]        - name of client: testname/itempath-test_id-hostname 
;; [x]  [ ]        - name of request: callname, params
;; [x]  [ ]        - request key: f(clientname, callname, params)
;; [x]  [ ]    5. Add processing of subscription hits
;; [x]  [ ]        - done when get key 
;; [x]  [ ]        - return results
;; [x]  [ ]    6. Add timeout processing
;; [x]  [ ]        - after 60 seconds
;; [ ]  [ ]            i. check server alive, connect to new if necessary
;; [ ]  [ ]           ii. resend request
;; [ ]  [ ]    7. Turn self ping back on

(define (server:make-server-url hostport)
  (if (not hostport)
      #f
      (conc "tcp://" (car hostport) ":" (cadr hostport))))

(define  *server-loop-heart-beat* (current-seconds))
(define *heartbeat-mutex* (make-mutex))

;;======================================================================
;; S E R V E R
;;======================================================================

(define-inline (zmqsock:get-pub  dat)(vector-ref dat 0))

(define-inline (zmqsock:get-pull dat)(vector-ref dat 1))
(define-inline (zmqsock:set-pub! dat s)(vector-set! dat s 0))
(define-inline (zmqsock:set-pull! dat s)(vector-set! dat s 0))

(define (server:run hostn)
  (debug:print 2 "Attempting to start the server ...")
  (if (not *toppath*)
      (if (not (setup-for-run))
	  (begin
	    (debug:print 0 "ERROR: cannot find megatest.config, cannot start server, exiting")
	    (exit))))
  (let* ((zmq-sdat1       #f)
	 (zmq-sdat2       #f)
	 (pull-socket     #f)
	 (pub-socket      #f)
	 (p1              #f)
	 (p2              #f)
	 (zmq-sockets-dat #f)
	 (iface           (if (string=? "-" hostn)
			      "*" ;; (get-host-name) 
			      hostn))

	 (hostname        (get-host-name))
	 (ipaddrstr       (let ((ipstr (if (string=? "-" hostn)
					   (string-intersperse (map number->string (u8vector->list (hostname->ip hostname))) ".")
					   #f)))
			    (if ipstr ipstr hostname)))
	 (last-run       0))
    (set! zmq-sockets-dat (server:setup-ports ipaddrstr (if (args:get-arg "-port")
			    (string->number (args:get-arg "-port"))
							    (+ 5000 (random 1001)))))

    (set! zmq-sdat1    (car   zmq-sockets-dat))
    (set! pull-socket  (cadr  zmq-sdat1)) ;; (iface s  port)
    (set! p1           (caddr zmq-sdat1))
    
    (set! zmq-sdat2    (cadr  zmq-sockets-dat))
    (set! pub-socket   (cadr  zmq-sdat2))
    (set! p2           (caddr zmq-sdat2))

    (set! *cache-on* #t)





    ;; what to do when we quit
    ;;
;;     (on-exit (lambda ()

;; 	       (if (and *toppath* *server-info*)
;; 		   (open-run-close tasks:server-deregister-self tasks:open-db (car *server-info*))
;; 		   (let loop () 
;; 		     (let ((queue-len 0))

;; 		       (thread-sleep! (random 5))

;; 		       (mutex-lock! *incoming-mutex*)
;; 		       (set! queue-len (length *incoming-data*))
;; 		       (mutex-unlock! *incoming-mutex*)
;; 		       (if (> queue-len 0)
;; 			   (begin
;; 			     (debug:print-info 0 "Queue not flushed, waiting ...")
;; 			     (loop))))))))


    ;; The heavy lifting
    ;;

    ;; make-vector-record cdb packet client-sig qtype immediate query-sig params qtime
    ;;
    (let loop ((queue-lst '()))
      (let* ((rawmsg (receive-message* pull-socket))
	     (packet (db:string->obj rawmsg))
					  (qtype  (cdb:packet-get-qtype packet)))
				     (debug:print-info 12 "server=> received packet=" packet)
				     (if (not (member qtype '(sync ping)))
					 (begin
					   (mutex-lock! *heartbeat-mutex*)
					   (set! *last-db-access* (current-seconds))
					   (mutex-unlock! *heartbeat-mutex*)))













	(if #t ;; (cdb:packet-get-immediate packet) ;; process immediately or put in queue















	    (begin



	      (open-run-close db:process-queue #f pub-socket (cons packet queue-lst))

	      (loop '()))
	    (loop (cons packet queue-lst)))))))












;; run server:keep-running in a parallel thread to monitor that the db is being 
;; used and to shutdown after sometime if it is not.

;;
(define (server:keep-running)
  ;; if none running or if > 20 seconds since 
  ;; server last used then start shutdown
  ;; This thread waits for the server to come alive
  (let* ((server-info (let loop ()
			(let ((sdat #f))
			  (mutex-lock! *heartbeat-mutex*)
			  (set! sdat *server-info*)
			  (mutex-unlock! *heartbeat-mutex*)
			  (if sdat sdat
			      (begin
				(sleep 4)
				(loop))))))
	 (iface       (cadr server-info))
	 (pullport    (caddr server-info))
	 (pubport     (cadddr server-info)) ;; id interface pullport pubport)
	 (zmq-sockets (server:client-connect iface pullport pubport))
	 (last-access 0))
    (let loop ((count 0))
      (thread-sleep! 4) ;; no need to do this very often
      ;; NB// sync currently does NOT return queue-length
      (let ((queue-len (cdb:client-call zmq-sockets 'sync #t 1)))
      ;; (print "Server running, count is " count)
	(if (< count 1) ;; 3x3 = 9 secs aprox
	    (loop (+ count 1)))

	;; NOTE: Get rid of this mechanism! It really is not needed...
	(open-run-close tasks:server-update-heartbeat tasks:open-db (car server-info))

	;; (if ;; (or (> numrunning 0) ;; stay alive for two days after last access
	(mutex-lock! *heartbeat-mutex*)
	(set! last-access *last-db-access*)
	(mutex-unlock! *heartbeat-mutex*)
	(if (> (+ last-access
		  ;; (* 50 60 60)    ;; 48 hrs
		  ;; 60              ;; one minute
		  ;; (* 60 60)       ;; one hour
		  (* 45 60)          ;; 45 minutes, until the db deletion bug is fixed.
		  )
	       (current-seconds))
	    (begin
	      (debug:print-info 2 "Server continuing, seconds since last db access: " (- (current-seconds) last-access))
	      (loop 0))
	    (begin
	      (debug:print-info 0 "Starting to shutdown the server.")
	      ;; need to delete only *my* server entry (future use)
	      (set! *time-to-exit* #t)
	      (open-run-close tasks:server-deregister-self tasks:open-db (get-host-name))
	      (thread-sleep! 1)
	      (debug:print-info 0 "Max cached queries was " *max-cache-size*)
	      (debug:print-info 0 "Server shutdown complete. Exiting")
	      (exit)))))))

(define (server:find-free-port-and-open iface s port stype #!key (trynum 50))
  (let ((s (if s s (make-socket stype)))
	(p (if (number? port) port 5555))
 	(old-handler (current-exception-handler)))
  (handle-exceptions
   exn
   (begin
     (print-error-message exn)
     (if (< portnum 9000)
	 (begin 
	   (print "WARNING: failed to start on portnum: " portnum ", trying next port")

(define (server:get-client-signature)
  (if *my-client-signature* *my-client-signature*
      (let ((sig (server:mk-signature)))
	(set! *my-client-signature* sig)
	*my-client-signature*)))

;; 



(define (server:client-socket-connect iface port #!key (context #f)(type 'req)(subscriptions '()))
  (debug:print-info 3 "client-connect " iface ":" port ", type=" type ", subscriptions=" subscriptions)
  (let ((connect-ok #f)
	(zmq-socket (if context 
			(make-socket type context)
			(make-socket type)))
	(conurl     (server:make-server-url (list iface port))))




    (if (socket? zmq-socket)

     (begin

	  ;; first apply subscriptions

	  (for-each (lambda (subscription)


		      (debug:print 2 "Subscribing to " subscription)
		      (socket-option-set! zmq-socket 'subscribe subscription))
		    subscriptions)
	  (connect-socket zmq-socket conurl)
	  zmq-socket)





	(begin


	  (debug:print 0 "ERROR: Failed to open socket to " conurl)




	  #f))))

(define (server:client-login serverdat)
  (max-retry-attempts 100)
  (cdb:login serverdat *toppath* (server:get-client-signature)))

;; Not currently used! But, I think it *should* be used!!!
(define (server:client-logout serverdat)
  (let ((ok (and (socket? serverdat)
		 (cdb:logout serverdat *toppath* (server:get-client-signature)))))
    ;; (close-socket serverdat)
    ok))

(define (server:client-connect iface pullport pubport)
  (let* ((push-socket (server:client-socket-connect iface pullport type: 'push))
	 (sub-socket  (server:client-socket-connect iface pubport
						    type: 'sub
						    subscriptions: (list (server:get-client-signature) "all")))
	 (zmq-sockets (vector push-socket sub-socket))
	 (login-res   #f))

    (set! login-res (server:client-login zmq-sockets))
    (if (and (not (null? login-res))
	     (car login-res))
	(begin
	  (debug:print-info 2 "Logged in and connected to " iface ":" pullport "/" pubport ".")
	  (set! *runremote* zmq-sockets)
	  zmq-sockets)
	(begin
	  (debug:print-info 2 "Failed to login or connect to " conurl)
	  (set! *runremote* #f)
	  #f))))

;; Do all the connection work, start a server if not already running
(define (server:client-setup #!key (numtries 50))
  (if (not *toppath*)
      (if (not (setup-for-run))
	  (begin
	    (debug:print 0 "ERROR: failed to find megatest.config, exiting")
	    (exit))))
  (let ((hostinfo   (open-run-close tasks:get-best-server tasks:open-db)))
    (if hostinfo
	(let ((host     (list-ref hostinfo 0))
	      (iface    (list-ref hostinfo 1))
	      (port     (list-ref hostinfo 2))
          (pubport  (list-ref hostinfo 3))
	      (pid      (list-ref hostinfo 4)))
	  (debug:print-info 2 "Setting up to connect to " hostinfo)
	  ;; (handle-exceptions
	  ;;   exn
	  ;;  (begin
	  ;;    ;; something went wrong in connecting to the server. In this scenario it is ok
	  ;;    ;; to try again
	  ;;    (debug:print 0 "ERROR: Failed to open a connection to the server at: " hostinfo)
	  ;;    (debug:print 0 "   EXCEPTION: " ((condition-property-accessor 'exn 'message) exn))
	  ;;    (debug:print 0 "   perhaps jobs killed with -9? Removing server records")
	  ;;    (open-run-close tasks:server-deregister tasks:open-db host pullport: pullport)
	  ;;    (server:client-setup (- numtries 1))
	  ;;    #f)
	   (server:client-connect iface port pubport)) ;; )
	(if (> numtries 0)
	    (let ((exe (car (argv)))
		  (pid #f))
	      (debug:print-info 0 "No server available, attempting to start one...")
	      ;; (set! pid (process-run exe (list "-server" "-" "-debug" (if (list? *verbosity*)
	      ;;   							  (string-intersperse *verbosity* ",")
	      ;;   							  (conc *verbosity*)))))
	      (set! pid (process-fork (lambda ()
	      ;;   			(current-input-port  (open-input-file  "/dev/null"))
	      ;;   			(current-output-port (open-output-file "/dev/null"))
	      ;;   			(current-error-port  (open-output-file "/dev/null"))
					(server:launch)))) ;; should never get here ....
	      (let loop ((count 0))
		(let ((hostinfo (open-run-close tasks:get-best-server tasks:open-db)))
		  (if (not hostinfo)
		      (begin
			(debug:print-info 0 "Waiting for server pid=" pid " to start")
			(sleep 2) ;; give server time to start
			(if (< count 5)

	    (exit))))
  (debug:print-info 2 "Starting the standalone server")
  (let ((hostinfo (open-run-close tasks:get-best-server tasks:open-db)))
    (debug:print 11 "server:launch hostinfo=" hostinfo)
    (if hostinfo
	(debug:print-info 2 "NOT starting new server, one is already running on " (car hostinfo) ":" (cadr hostinfo))
	(if *toppath* 
	    (let* (;; (th1 (make-thread (lambda ()
		   ;;      	       (let ((server-info #f))
		   ;;      		 ;; wait for the server to be online and available
		   ;;      		 (let loop ()
		   ;;			   (debug:print-info 2 "Waiting for the server to come online before starting heartbeat")
		   ;;      		   (thread-sleep! 2)
		   ;;      		   (mutex-lock! *heartbeat-mutex*)
		   ;;      		   (set! server-info *server-info* )
		   ;;      		   (mutex-unlock! *heartbeat-mutex*)
		   ;;      		   (if (not server-info)(loop)))
		   ;;			 (debug:print 2 "Server alive, starting self-ping")
		   ;;      		 (server:self-ping server-info)
		   ;;      		 ))
		   ;;      	     "Self ping"))
		   (th2 (make-thread (lambda ()
				       (server:run 
					(if (args:get-arg "-server")
					    (args:get-arg "-server")
					    "-"))) "Server run"))
		   (th3 (make-thread (lambda ()(server:keep-running)) "Keep running"))
		   )
	      (set! *client-non-blocking-mode* #t)
	      ;; (thread-start! th1)
	      (thread-start! th2)
	      (thread-start! th3)
	      (set! *didsomething* #t)
	      ;; (thread-join! th3)
	      (thread-join! th2)
	      )
	    (debug:print 0 "ERROR: Failed to setup for megatest")))
    (exit)))

(define (server:client-signal-handler signum)
  (handle-exceptions
   exn
   (debug:print " ... exiting ...")
   (let ((th1 (make-thread (lambda ()
			     (if (not *received-response*)
				 (receive-message* *runremote*))) ;; flush out last call if applicable
			   "eat response"))
	 (th2 (make-thread (lambda ()
			     (debug:print 0 "ERROR: Received ^C, attempting clean exit. Please be patient and wait a few seconds before hitting ^C again.")
			     (thread-sleep! 3) ;; give the flush three seconds to do it's stuff
			     (debug:print 0 "       Done.")
			     (exit 4))
			   "exit on ^C timer")))
     (thread-start! th2)
     (thread-start! th1)
     (thread-join! th2))))

(define (server:client-launch)
  (set-signal-handler! signal/int server:client-signal-handler)
   (if (server:client-setup)
       (debug:print-info 2 "connected as client")
       (begin
	 (debug:print 0 "ERROR: Failed to connect as client")
	 (exit))))

;;======================================================================
;; Defunct functions
;;======================================================================

;; ping a server and return number of clients or #f (if no response)
;; NOT IN USE!
(define (server:ping host port #!key (secs 10)(return-socket #f))
  (cdb:use-non-blocking-mode
   (lambda ()
     (let* ((res #f)
	    (th1 (make-thread
		  (lambda ()
		    (let* ((zmq-context (make-context 1))
			   (zmq-socket  (server:client-connect host port context: zmq-context)))
		      (if zmq-socket
			  (if (server:client-login zmq-socket)
			      (let ((numclients (cdb:num-clients zmq-socket)))
				(if (not return-socket)
				    (begin
				      (server:client-logout zmq-socket)
				      (close-socket  zmq-socket)))
				(set! res (list #t numclients (if return-socket zmq-socket #f))))
			      (begin
				;; (close-socket zmq-socket)
				(set! res (list #f "CAN'T LOGIN" #f))))
			  (set! res (list #f "CAN'T CONNECT" #f)))))
		  "Ping: th1"))
	    (th2 (make-thread
		  (lambda ()
		    (let loop ((count 1))
		      (debug:print-info 1 "Ping " count " server on " host " at port " port)
		      (thread-sleep! 2)
		      (if (< count (/ secs 2))
			  (loop (+ count 1))))
		    ;; (thread-terminate! th1)
		    (set! res (list #f "TIMED OUT" #f)))
		  "Ping: th2")))
       (thread-start! th2)
       (thread-start! th1)
       (handle-exceptions
	exn
	(set! res (list #f "TIMED OUT" #f))
	(thread-join! th1 secs))
       res))))

;; (define (server:self-ping server-info)
;;   ;; server-info: server-id interface pullport pubport
;;   (let ((iface    (list-ref server-info 1))
;; 	(pullport (list-ref server-info 2))
;; 	(pubport  (list-ref server-info 3)))
;;     (server:client-connect iface pullport pubport)
;;     (let loop ()
;;       (thread-sleep! 2)
;;       (cdb:client-call *runremote* 'ping #t)
;;       (debug:print 4 "server:self-ping - I'm alive on " iface ":" pullport "/" pubport "!")
;;       (mutex-lock! *heartbeat-mutex*)
;;       (set! *server-loop-heart-beat* (current-seconds))
;;       (mutex-unlock! *heartbeat-mutex*)
;;       (loop))))
    
(define (server:reply pubsock target query-sig success/fail result)
  (debug:print-info 11 "server:reply target=" target ", result=" result)
  (send-message pubsock target send-more: #t)
  (send-message pubsock (db:obj->string (vector success/fail query-sig result))))