Megatest

;;======================================================================
;; Copyright 2006-2013, 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.
;;======================================================================

(use json format) ;; RADT => purpose of json format??

(declare (unit rmt))
(declare (uses api))
(declare (uses tdb))
(declare (uses http-transport))
;;(declare (uses nmsg-transport))

;;
;; THESE ARE ALL CALLED ON THE CLIENT SIDE!!!
;;

;; ;; For debugging add the following to ~/.megatestrc
;;
;; (require-library trace)

    (if cinfo
	cinfo
	;; NB// can cache the answer for server running for 10 seconds ...
	;;  ;; (and (not (rmt:write-frequency-over-limit? cmd run-id))
	(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

;; RA => e.g. usage (rmt:send-receive 'get-var #f (list varname))
;;
(define (rmt:send-receive cmd rid params #!key (attemptnum 1)) ;; start attemptnum at 1 so the modulo below works as expected
  ;; clean out old connections
  ;; (mutex-lock! *db-multi-sync-mutex*)
  (let ((expire-time (- (current-seconds) (server:get-timeout) 10))) ;; don't forget the 10 second margin
    (for-each 
     (lambda (run-id)
       (let ((connection (hash-table-ref/default *runremote* run-id #f)))
         (if (and (vector? connection)
        	  (< (http-transport:server-dat-get-last-access connection) expire-time))
             (begin
               (debug:print-info 0 *default-log-port* "Discarding connection to server for run-id " run-id ", too long between accesses")
               ;; bb- disabling nanomsg
               ;; SHOULD CLOSE THE CONNECTION HERE 
	       ;; (case *transport-type*
	       ;;   ((nmsg)(nn-close (http-transport:server-dat-get-socket 
	       ;;  		   (hash-table-ref *runremote* run-id)))))
               (hash-table-delete! *runremote* run-id)))))
     (hash-table-keys *runremote*)))
  ;; (mutex-unlock! *db-multi-sync-mutex*)
  ;; (mutex-lock! *send-receive-mutex*)
  (let* ((run-id          (if rid rid 0))
	 (connection-info (rmt:get-connection-info run-id)))
    ;; the nmsg method does the encoding under the hood (the http method should be changed to do this also)
    (if connection-info
	;; use the server if have connection info

	(let* ((dat     (case *transport-type*




			  ((http)(condition-case
				  (http-transport:client-api-send-receive run-id connection-info cmd params)
				  ((commfail)(vector #f "communications fail"))
				  ((exn)(vector #f "other fail"))))
			  ;; ((nmsg)(condition-case
			  ;;         (nmsg-transport:client-api-send-receive run-id connection-info cmd params)





			  ;;         ((timeout)(vector #f "timeout talking to server"))))
			  (else  (exit))))
	       (success (if (vector? dat) (vector-ref dat 0) #f))
	       (res     (if (vector? dat) (vector-ref dat 1) #f)))
	  (if (vector? connection-info)(http-transport:server-dat-update-last-access connection-info))
	  (if success
	      (begin
		;; (mutex-unlock! *send-receive-mutex*)
		(case *transport-type* 
		  ((http) res) ;; (db:string->obj res))
		  ;; ((nmsg) res)




                  )) ;; (vector-ref res 1)))


	      (begin ;; let ((new-connection-info (client:setup run-id)))
		(debug:print 0 *default-log-port* "WARNING: Communication failed, trying call to rmt:send-receive again.")
		;; (case *transport-type*
		;;   ((nmsg)(nn-close (http-transport:server-dat-get-socket connection-info))))

		(hash-table-delete! *runremote* run-id) ;; don't keep using the same connection
		;; NOTE: killing server causes this process to block forever. No idea why. Dec 2. 
		;; (if (eq? (modulo attemptnum 5) 0)
		;;     (tasks:kill-server-run-id run-id tag: "api-send-receive-failed"))
		;; (mutex-unlock! *send-receive-mutex*) ;; close the mutex here to allow other threads access to communications
		(tasks:start-and-wait-for-server (tasks:open-db) run-id 15)
		;; (nmsg-transport:client-api-send-receive run-id connection-info cmd param remtries: (- remtries 1))))))

		;; no longer killing the server in http-transport:client-api-send-receive
		;; may kill it here but what are the criteria?
		;; start with three calls then kill server
		;; (if (eq? attemptnum 3)(tasks:kill-server-run-id run-id))
		;; (thread-sleep! 2)
		(rmt:send-receive cmd run-id params attemptnum: (+ attemptnum 1)))))






	;; no connection info? try to start a server, or access locally if no
	;; server and the query is read-only
	;;
	;; Note: The tasks db was checked for a server in starting mode in the rmt:get-connection-info call
	;;
	(if (and (< attemptnum 15)
		 (member cmd api:write-queries))
	    (let ((faststart (configf:lookup *configdat* "server" "faststart")))
	      (hash-table-delete! *runremote* run-id)
	      ;; (mutex-unlock! *send-receive-mutex*)
	      (if (and faststart (equal? faststart "no"))
		  (begin
		    (tasks:start-and-wait-for-server (db:delay-if-busy (tasks:open-db)) run-id 10)
		    (thread-sleep! (random 5)) ;; give some time to settle and minimize collison?
		    (rmt:send-receive cmd rid params attemptnum: (+ attemptnum 1)))
		  (let ((start-time (current-milliseconds))
			(max-query  (string->number (or (configf:lookup *configdat* "server" "server-query-threshold")
							"300")))
			(newres     (rmt:open-qry-close-locally cmd run-id params)))
		    (let ((delta (- (current-milliseconds) start-time)))
		      (if (> delta max-query)
			  (begin
			    (debug:print-info 0 *default-log-port* "Starting server as query time " delta " is over the limit of " max-query)
			    (server:kind-run run-id)))
		      ;; return the result!
		      newres)
		    )))
	    (begin
	      ;; (debug:print-error 0 *default-log-port* "Communication failed!")
	      ;; (mutex-unlock! *send-receive-mutex*)
	      ;; (exit)
	      (rmt:open-qry-close-locally cmd run-id params)
	      )))))

(define (rmt:update-db-stats run-id rawcmd params duration)
  (mutex-lock! *db-stats-mutex*)
  (handle-exceptions
   exn
   (begin
     (debug:print 0 *default-log-port* "WARNING: stats collection failed in update-db-stats")

			     (if (> tot 10)
				 (cons newmax-cmd currmax)
				 (cons 'none 0))
			     (loop (car tal)(cdr tal) newmax-cmd currmax)))))))
    (mutex-unlock! *db-stats-mutex*)
    res))
	  
(define (rmt:open-qry-close-locally cmd run-id params #!key (remretries 5))
  (let* ((dbstruct-local (if *dbstruct-db*
			     *dbstruct-db*
			     (let* ((dbdir (db:dbfile-path #f)) ;;  (conc    (configf:lookup *configdat* "setup" "linktree") "/.db"))
				    (db (make-dbr:dbstruct path:  dbdir local: #t)))
			       (set! *dbstruct-db* db)
			       db)))
	 (db-file-path   (db:dbfile-path 0))
	 ;; (read-only      (not (file-read-access? db-file-path)))
	 (start          (current-milliseconds))
	 (resdat         (api:execute-requests dbstruct-local (vector (symbol->string cmd) params)))
	 (success        (vector-ref resdat 0))
	 (res            (vector-ref resdat 1))
	 (duration       (- (current-milliseconds) start)))
    (if (not success)
	(if (> remretries 0)
	    (begin
	      (debug:print-error 0 *default-log-port* "local query failed. Trying again.")
	      (thread-sleep! (/ (random 5000) 1000)) ;; some random delay 
	      (rmt:open-qry-close-locally cmd run-id params remretries: (- remretries 1)))
	    (begin
	      (debug:print-error 0 *default-log-port* "too many retries in rmt:open-qry-close-locally, giving up")
	      #f))
	(begin
	  ;; (rmt:update-db-stats run-id cmd params duration)
	  ;; mark this run as dirty if this was a write
	  (if (not (member cmd api:read-only-queries))
	      (let ((start-time (current-seconds)))
		(mutex-lock! *db-multi-sync-mutex*)
		;; (if (not (hash-table-ref/default *db-local-sync* run-id #f))
		;; just set it every time. Is a write more expensive than a read and does it matter?
		(hash-table-set! *db-local-sync* (or run-id 0) start-time) ;; the oldest "write"
		(mutex-unlock! *db-multi-sync-mutex*)))
	  res))))

(define (rmt:send-receive-no-auto-client-setup connection-info cmd run-id params)
  (let* ((run-id   (if run-id run-id 0))
	 ;; (jparams  (db:obj->string params)) ;; (rmt:dat->json-str params))
	 (res  	   (handle-exceptions
		    exn
		    #f
		    (http-transport:client-api-send-receive run-id connection-info cmd params))))

(define (rmt:login run-id)
  (rmt:send-receive 'login run-id (list *toppath* megatest-version run-id *my-client-signature*)))

;; This login does no retries under the hood - it acts a bit like a ping.
;; Deprecated for nmsg-transport.
;;
(define (rmt:login-no-auto-client-setup connection-info run-id)
  (case *transport-type*
    ((http)(rmt:send-receive-no-auto-client-setup connection-info 'login run-id (list *toppath* megatest-version run-id *my-client-signature*)))
    ;;((nmsg)(nmsg-transport:client-api-send-receive run-id connection-info 'login (list *toppath* megatest-version run-id *my-client-signature*)))



    ))

;; hand off a call to one of the db:queries statements
;; added run-id to make looking up the correct db possible 
;;
(define (rmt:general-call stmtname run-id . params)
  (rmt:send-receive 'general-call run-id (append (list stmtname run-id) params)))