Megatest

;;     GNU General Public License for more details.
;; 
;;     You should have received a copy of the GNU General Public License
;;     along with Megatest.  If not, see <http://www.gnu.org/licenses/>.
;;
;;======================================================================



(declare (unit api))
(declare (uses rmt))
(declare (uses db))
(declare (uses dbmod))
(declare (uses dbfile))
(declare (uses tasks))
(declare (uses tcp-transportmod))

(import dbmod)
(import dbfile)
(import tcp-transportmod)

(use srfi-69
     posix
     matchable
     s11n)

;; allow these queries through without starting a server
;;
(define api:read-only-queries
  '(get-key-val-pairs
    get-var
    get-keys

             (begin
               #;(common:telemetry-log (conc "api-out:"(->string cmd))
               payload: `((params . ,params)
               (ok-res . #f)))
               (vector #t res))))))))

;; indat is (cmd run-id params meta)
(define (api:tcp-dispatch-request-make-handler dbstruct) ;; cmd run-id params)
  (lambda ()
    (let* ((indat (deserialize)))
      (set! *api-process-request-count* (+ *api-process-request-count* 1))
      (match indat
	((cmd run-id params meta)
	 (let* ((status  (cond
			  ((> *api-process-request-count* 50) 'busy)
			  ((> *api-process-request-count* 25) 'loaded)
			  (else 'ok)))
		(errmsg  (case status
			   ((busy)   (conc "Server overloaded, "*api-process-request-count*" threads in flight"))
			   ((loaded) (conc "Server loaded, "*api-process-request-count*" threads in flight"))
			   (else     #f)))
		(result  (case status
			   ((busy) #f)
			   (else
			    (case cmd
			      ((ping) (tt:mk-signature *toppath*))
			      (else
			       (api:dispatch-request dbstruct cmd run-id params))))))
		(payload (list status errmsg result '())))

	   (set! *api-process-request-count* (- *api-process-request-count* 1))
	   (serialize payload)))
	(else

	 (assert #f "FATAL: failed to deserialize indat "indat))))))
       

(define (api:dispatch-request dbstruct cmd run-id params)
  (case cmd
    ;;===============================================
    ;; READ/WRITE QUERIES
    ;;===============================================

	   (dbfname    (args:get-arg "-db"))
	   (tl         (launch:setup)))
      (case (rmt:transport-mode)
	((http)(http-transport:launch))
	((tcp)
	 (debug:print 0 *default-log-port* "INFO: Running using tcp method.")
	 (if run-id
	     (tt:start-server tl run-id dbfname api:tcp-dispatch-request-make-handler)
	     (begin
	       (debug:print 0 *default-log-port* "ERROR: transport mode is tcp - -run-id is required.")
	       (exit 1))))
	(else (debug:print 0 *default-log-port* "ERROR: rmt:transport-mode value not recognised "(rmt:transport-mode))))
      (set! *didsomething* #t)))

;; The adjutant is a bit different, it does NOT run (launch:setup) as it is not necessarily tied to

  (thread       #f)
  (host-port    #f)
  (cmd-thread   #f)
  (last-access  (current-seconds))
  )

(define (tt:make-remote areapath)
  (make-tt areapath: areapath))

;; do all the busy work of finding and setting up conn for
;; connecting to a server
;; 
(define (tt:client-connect-to-server ttdat dbfname run-id )
  (let* ((conn (hash-table-ref/default (tt-conns ttdat) dbfname #f))
	 (server-start-proc (lambda ()
			      (tt:server-process-run
			       (tt-areapath ttdat)
			       (dbfile:testsuite-name)
			       (common:find-local-megatest)
			       run-id))))
    (if conn
	conn ;; we are already connected to the server
	(let* ((sdat (tt:get-current-server-info ttdat dbfname run-id)))
	  (match sdat
	    ((host port start-time server-id pid dbfname2)
	     (assert (equal? dbfname dbfname2) "FATAL: read server info from wrong file.")
	     (let* ((host-port (conc host":"port))
		    (conn (make-tt-conn
			   host: host
			   port: port
			   host-port: host-port
			   dbfname: dbfname
			   server-id: server-id
			   server-start: start-time
			   pid: pid)))
	       (hash-table-set! (tt-conns ttdat) dbfname conn)
	       ;; verify we can talk to this server
	       (if (tt:ping host port server-id)
		   conn
		   (begin
		     ;; rm the (last server) would go here
		     (server-start-proc)
		     (thread-sleep! 1)
		     (tt:client-connect-to-server ttdat dbfname run-id)))))
	    (else
	     (server-start-proc)




	     (thread-sleep! 1)
	     (tt:client-connect-to-server ttdat dbfname run-id)))))))
    
(define (tt:ping host port server-id)
  (let*  ((res (tt:send-receive-direct host port `(ping #f #f #f)))) ;; please send me your server-id
    ;;
    ;; need two threads, one a 5 second timer
    ;;
    (match res
      ((status errmsg result meta)
       (if (equal? result server-id)
	   #t ;; then we are good
	   (begin
	     (debug:print 0 *default-log-port* "WARNING: server-id does not match, expected: "server-id", got: "result)
	     #f)))
      (else
       (debug:print 0 *default-log-port* "res not in form (status errmsg resutl meta), got: "res)
       #f))))

;; client side handler
;;
(define (tt:handler ttdat cmd run-id params attemptnum area-dat areapath readonly-mode dbfname testsuite mtexe)
  ;; NOTE: areapath is passed in and in tt struct. We'll use passed in value for now.
  (let* ((conn (tt:client-connect-to-server ttdat dbfname run-id))) ;; (hash-table-ref/default (tt-conns ttdat) dbfname #f)))
    (if conn

		(thread-sleep! 2)
		(tt:handler  ttdat cmd run-id params attemptnum area-dat areapath readonly-mode dbfname testsuite mtexe))
	       ((loaded)
		(debug:print 0 *default-log-port* "WARNING: server is loaded, will try again in a second.")
		(thread-sleep! 1)
		(tt:handler  ttdat cmd run-id params attemptnum area-dat areapath readonly-mode dbfname testsuite mtexe))
	       (else
		result)))
	    (else
	     (assert #f "FATAL: tt:handler received bad data "res))))
	(begin
	  (thread-sleep! 1) ;; give it a rest and try again
	  (tt:handler ttdat cmd run-id params attemptnum area-dat areapath readonly-mode dbfname testsuite mtexe)))))

	;; no conn yet, find and or start and find a server
;; 	(let* ((server (tt:find-server ttdat dbfname)))
;; 	  (if server

;; 		(tt:handler  ttdat cmd run-id params attemptnum area-dat areapath
;; 			     readonly-mode dbfname testsuite mtexe)))))))

(define (tt:bid-for-servership run-id)
  #f)

(define (tt:get-current-server-info ttdat dbfname run-id)
  (assert (tt-areapath ttdat) "FATAL: areapath not set in ttdat.")
  (let* ((areapath (tt-areapath ttdat))

	 (sfiles   (tt:find-server areapath dbfname))
	 (sdats    (filter car (map tt:server-get-info sfiles))) ;; first element is #f if the file disappeared while being read
	 (sorted   (sort sdats (lambda (a b)
				 (< (list-ref a 2)(list-ref b 2))))))
    (if (null? sorted)
	#f  ;; we'll want to wait until extra servers have exited
	(car sorted))))

(define (tt:send-receive ttdat conn cmd run-id params)
  (let* ((host-port (tt-conn-host-port conn)) ;; (conc (tt-conn-host conn)":"(tt-conn-port conn)))
	 (host      (tt-conn-host conn))
	 (port      (tt-conn-port conn))
	 (dat       (list cmd run-id params #f))) ;; no meta data yet
    (tt:send-receive-direct host port dat)))

(define (tt:send-receive-direct host port dat)
  (assert (number? port) "FATAL: tt:send-receive-direct called with port not a number "port)
  (handle-exceptions
      exn
    #f ;; Add condition-case or better handling here
    (let-values (((inp oup)(tcp-connect host port)))
      (let ((res (if (and inp oup)
		     (begin
		       (serialize dat oup)
		       (close-output-port oup)
		       (deserialize inp))


		     )))
	(close-input-port inp)

	res))))



;;======================================================================
;; server
;;======================================================================

(define (tt:sync-dbs ttdat)
  #f)

;; start the listener and start responding to requests
;;
;; NOTE: organise by dbfname, not run-id so we don't need
;;       to pull in more modules
;;
;; This is the routine called in megatest.scm to start a server
;;
(define (tt:start-server areapath run-id dbfname handler)
  (assert areapath "FATAL: areapath not provided for tt:start-server")
  ;; is there already a server for this dbfile? Then exit.
  (let* ((ttdat   (make-tt areapath: areapath))
	 (servers (tt:find-server areapath dbfname))) ;; should use tt:get-current-server-info instead

    (if (null? servers)
	(let* ((dbstruct   (dbmod:open-dbmoddb areapath run-id (dbfile:db-init-proc))))
	  (tt-handler-set! ttdat (handler dbstruct))
	  (let* ((tcp-thread (make-thread
			      (lambda ()
				(tt:start-tcp-server ttdat)) ;; start the tcp-server which applies handler to incoming data
			      "tcp-server-thread"))
		 (run-thread (make-thread
			      (lambda ()
				(tt:keep-running ttdat dbfname)))))
	    (thread-start! tcp-thread)
	    (thread-start! run-thread)
	    (thread-join! run-thread) ;; run thread will exit on timeout or other conditions
	    ;;
	    ;; set a flag here to tell tcp-thread to stop running
	    ;;
	    ;; (thread-join! tcp-thread) ;; can't wait 
	    ;;
	    ;; remove the servinfo file
	    ;;
	    ;; close the database, remove lock in on-disk db
	    ;;
	    ;; close the listener ports
	    ;;
	    (exit)))
	(begin
	  (debug:print 0 *default-log-port* "INFO: found server(s) already running for db "dbfname", "(string-intersperse servers ",")" Exiting.")
	  (exit)))))

(define (tt:keep-running ttdat dbfname)
  ;; verfiy conn for ready
  ;; listener socket has been started by this stage

	      (thread-sleep! 1)
	      (loop (+ count 1))))))
  
  (tt:create-server-registration-file ttdat dbfname)
  ;; now start watching the last-access, if it hasn't been touched
  ;; in over ten seconds we exit
  (let loop ()
    (if (< (- (current-seconds) (tt-last-access ttdat)) 60)
	(begin
	  (thread-sleep! 2)
	  (loop))))
  (if (tt-cleanup-proc ttdat)
      ((tt-cleanup-proc ttdat)))
  (debug:print 0 *default-log-port* "INFO: Server timed out, exiting."))

      serv-id))

;; find valid server
;; get servers listed, last part of name must match :<dbfname>
;; if more than one, wait one second and look again
;; future: ping oldest, if alive remove other :<dbfname> files
;;
(define (tt:find-server areapath dbfname)

  (let* ((servdir  (tt:get-servinfo-dir areapath))
	 (sfiles   (glob (conc servdir"/*:"dbfname))))
    sfiles))

;; given a path to a server info file return: host port startseconds server-id
;; example of what it's looking for in the log file:
;;     SERVER STARTED: 10.38.175.67:50216 AT 1616502350.0 server-id: 4907e90fc55c7a09694e3f658c639cf4 
;;
(define (tt:server-get-info logf)
  (let ((server-rx    (regexp "^SERVER STARTED: (\\S+):(\\d+) AT ([\\d\\.]+) server-id: (\\S+) pid: (\\d+) dbfname: (\\S+)")) ;; SERVER STARTED: host:port AT timesecs server id
        (dbprep-rx    (regexp "^SERVER: dbprep"))
        (dbprep-found 0)
	(bad-dat      (list #f #f #f #f #f #f)))
    (handle-exceptions
     exn
     (begin
       ;; WARNING: this is potentially dangerous to blanket ignore the errors
       (if (file-exists? logf)
	   (debug:print-info 2 *default-log-port* "Unable to get server info from "logf", exn=" exn))
       bad-dat) ;; no idea what went wrong, call it a bad server

		 (if (not mlst)
		     (if (< lnum 500) ;; give up if more than 500 lines of server log read
			 (loop (read-line)(+ lnum 1))
			 (begin 
                           (debug:print-info 0 *default-log-port* "Unable to get server info from first 500 lines of " logf )
                           bad-dat))
		     (match mlst
			    ((_ host port start server-id pid dbfname)
			     (list host
				   (string->number port)
				   (string->number start)
				   server-id
				   (string->number pid)
				   dbfname))
			    (else
			     (debug:print 0 *default-log-port* "ERROR: did not recognise SERVER line info "mlst)
			     bad-dat))))
	       (begin 
		 (if dbprep-found
		     (begin
		       (debug:print-info 2 *default-log-port* "Server is in dbprep at " (common:human-time))