Megatest

(define *server-signature* #f)
;; These are called by the server on recipt of /api calls
;;    - keep it simple, only return the actual result of the call, i.e. no meta info here
;;
;;    - returns #( flag result )
;;
(define (api:execute-requests dbstruct dat)
  (db:open-no-sync-db) ;; sets *no-sync-db*
  ;;   (handle-exceptions
  ;;    exn
  ;;    (let ((call-chain (get-call-chain)))
  ;;      (debug:print 0 *default-log-port* "WARNING: api:execute-requests received an exception from peer, dat=" dat ", exn=" exn)
  ;;      (print-call-chain (current-error-port))
  ;;      (debug:print 0 *default-log-port* " message: "  ((condition-property-accessor 'exn 'message) exn))       
  ;;      (vector #f (vector exn call-chain dat))) ;; return some stuff for debug if an exception happens
  (if (> *api-process-request-count* 200)
      (begin
	(if (common:low-noise-print 30 "too many threads")
	    (debug:print 0 *default-log-port* "WARNING: "*api-process-request-count*" threads, potential overload, adding 0.5 sec delay."))
	(thread-sleep! 0.5) ;; take a nap
	))
  (cond
   ((not (vector? dat))                    ;; it is an error to not receive a vector
    (vector #f (vector #f "remote must be called with a vector")))
   #;((> *api-process-request-count* 200) ;; 20)
   (debug:print 0 *default-log-port* "WARNING: api:execute-requests received an overloaded message.")
   (set! *server-overloaded* #t)
   (vector #f (vector #f 'overloaded))) ;; the inner vector is what gets returned. nope, don't know why. please refactor!
   (else  
    (let* ((cmd-in            (vector-ref dat 0))
           (cmd               (if (symbol? cmd-in)
				  cmd-in
				  (string->symbol cmd-in)))
           (params            (vector-ref dat 1))
	   (run-id            (if (null? params)

	   (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)


  (db:open-no-sync-db)
  (case cmd
    ;;===============================================
    ;; READ/WRITE QUERIES
    ;;===============================================

    ((get-keys-write)                        (db:get-keys dbstruct)) ;; force a dummy "write" query to force server; for debug in -repl
    

(define *task-db*             #f) ;; (vector db path-to-db)
(define *db-access-allowed*   #t) ;; flag to allow access
;; (define *db-access-mutex*     (make-mutex)) ;; moved to dbfile
(define *db-transaction-mutex* (make-mutex))
(define *db-cache-path*       #f)
;; (define *db-with-db-mutex*    (make-mutex))
(define *db-api-call-time*    (make-hash-table)) ;; hash of command => (list of times)
;; no sync db
;; (define *no-sync-db*          #f)  ;; moved to dbfile

;; SERVER
(define *my-client-signature* #f)
(define *transport-type*    'http)             ;; override with [server] transport http|rpc|nmsg
(define *runremote*         #f)                ;; if set up for server communication this will hold <host port>
;; (define *max-cache-size*    0)
(define *logged-in-clients* (make-hash-table))

(define (db:get-dbsync-path)
  (case (rmt:transport-mode)
    ((http)(common:get-db-tmp-area))
    ((tcp) (conc *toppath*"/.megatest"))
    ((nfs) (conc *toppath*"/.megatest"))
    (else "/tmp/dunno-this-gonna-exist")))

 ;; (define (db:no-sync-db db-in)
 ;;   (if db-in
 ;;       db-in
 ;;       (if *no-sync-db*
 ;; 	  *no-sync-db*
 ;; 	  (begin
 ;; 	    (mutex-lock! *db-access-mutex*)
 ;; 	    (let ((dbpath (db:get-dbsync-path))
 ;; 		  (db     (dbfile:open-no-sync-db dbpath)))
 ;; 	      (assert (sqlite3:database? db) "FATAL: db:no-sync-db failed to open a database")
 ;; 	      (set! *no-sync-db* db)
 ;; 	      (mutex-unlock! *db-access-mutex*)
 ;; 	      db)))))

(define (with-no-sync-db proc)
  (let* ((db  (db:open-no-sync-db)))
    (proc db)))

(define (db:open-no-sync-db)
  (dbfile:open-no-sync-db (db:get-dbsync-path)))

(define (db:no-sync-close-db db stmt-cache)
  (db:safely-close-sqlite3-db db stmt-cache))


;; use a global for some primitive caching, it is just silly to
;; re-read the db over and over again for the keys since they never
;; change

;; why get the keys from the db? why not get from the *configdat*
;; using keys:config-get-fields?

(define (db:get-keys dbstruct)
  (keys:config-get-fields *configdat*)
)

;;  (if *db-keys* *db-keys* 
;;      (let ((res '()))
;;	(db:with-db dbstruct #f #f
;;		    (lambda (dbdat db)
;;		      (sqlite3:for-each-row 
;;		       (lambda (key)
;;			 (set! res (cons key res)))
;;		       db
;;		       "SELECT fieldname FROM keys ORDER BY id DESC;")))
;;	(set! *db-keys* res)
;;	res)))

;; extract index number given a header/data structure
(define (db:get-index-by-header header field)
  (list-index (lambda (x)(equal? x field)) header))

;; look up values in a header/data structure
(define (db:get-value-by-header row header field)

	(sync-stale-seconds (configf:lookup-number *configdat* "server" "sync-stale-seconds" default: 300))
 	(debug-mode         (debug:debug-mode 1))
 	(last-time          (current-seconds))     ;; last time through the sync loop
 	(no-sync-db         (db:open-no-sync-db))
 	(sync-duration      0)  ;; run time of the sync in milliseconds
	(tmp-area           (common:get-db-tmp-area)))
    ;; Sync moved to http-transport keep-running loop
    (set! *no-sync-db* no-sync-db) ;; make the no sync db available to api calls
    (debug:print-info 2 *default-log-port* "Periodic copy-based sync thread started. syncer is copy-sync, tmp-area is " tmp-area)
    (debug:print-info 3 *default-log-port* "watchdog starting. syncer is copy-sync pid="(current-process-id));;  " this-wd-num="this-wd-num)
    
    (if (and legacy-sync (not *time-to-exit*))
 	(begin
 	  (debug:print-info 0 *default-log-port* "Server running, periodic copy-based sync started.")
	  (let loop ()

       (sync-stale-seconds (configf:lookup-number *configdat* "server" "sync-stale-seconds" default: 300))
 	(debug-mode   (debug:debug-mode 1))
 	(last-time    (current-seconds))
 	(no-sync-db   (db:open-no-sync-db))
 	(stmt-cache   #f) ;; (dbr:dbstruct-stmt-cache dbstruct))
 	(sync-duration 0) ;; run time of the sync in milliseconds
       (subdbs       (hash-table-values (dbr:dbstruct-subdbs dbstruct))))
   (set! *no-sync-db* no-sync-db) ;; make the no sync db available to api calls
   (debug:print-info 2 *default-log-port* "Periodic sync thread started.")
   (debug:print-info 3 *default-log-port* "watchdog starting. legacy-sync is " legacy-sync" pid="(current-process-id)  );;  " this-wd-num="this-wd-num)
   
   (if (and legacy-sync (not *time-to-exit*))
 	(begin
 	  (debug:print-info 0 *default-log-port* "Server running, periodic sync started.")
	  (let loop ()

		    "cp "backupfname" "fname)))
    (dbfile:print-err "WARNING: attempting recovery of file "fname" by running commands:\n"
		      "  "cmd)
    (system cmd)))

;; opens and returns handle and nothing else
;;


(define (dbfile:raw-open-no-sync-db dbpath)
  (if (not (file-exists? dbpath))
      (create-directory dbpath #t))
  (debug:print-info 0 *default-log-port* "Opening "dbpath"/no-sync.db")
  (let* ((dbname    (conc dbpath "/no-sync.db"))
	 (db-exists (file-exists? dbname))
	 (init-proc (lambda (db)





		      (if (not db-exists)
			  (for-each
			   (lambda (stmt)
			     (sqlite3:execute db stmt))
			   (list
			    "CREATE TABLE IF NOT EXISTS no_sync_metadat
                                (var TEXT,
                                 val TEXT,
                                   CONSTRAINT no_sync_metadat_constraint UNIQUE (var));"
			    "CREATE TABLE IF NOT EXISTS no_sync_locks 
                                (key TEXT,
                                 val TEXT,
                                   CONSTRAINT no_sync_metadat_constraint UNIQUE (var));")))))
	 (on-tmp      (equal? (car (string-split dbpath "/")) "tmp"))
	 (db        (if on-tmp
			(dbfile:cautious-open-database dbname init-proc 0 "WAL")
			(dbfile:cautious-open-database dbname init-proc 0 #f)
			;; (sqlite3:open-database dbname)
			)))
    (if on-tmp	      ;; done in cautious-open-database
	(begin
	  (sqlite3:execute db "PRAGMA synchronous = 0;")
	  (sqlite3:set-busy-handler! db (sqlite3:make-busy-timeout 136000))))
    db))

(define (dbfile:with-no-sync-db dbpath proc)


  (let* ((db  (dbfile:raw-open-no-sync-db dbpath))
	 (res (proc db)))

    (sqlite3:finalize! db)

    res))

(define *no-sync-db-mutex* (make-mutex))

(define (dbfile:open-no-sync-db dbpath)
  (mutex-lock! *no-sync-db-mutex*)
  (let* ((res (if *no-sync-db*
		  *no-sync-db*
		  (let* ((db (dbfile:raw-open-no-sync-db dbpath)))
		    (set! *no-sync-db* db)
		    db))))

     ;; NOTE: This can fail when there is no mention of the host in /etc/hosts. FIXME
     (vector->list (hostinfo-addresses (hostname->hostinfo hostname))))
    (string-intersperse 
     (map number->string
	  (u8vector->list
	   (if res res (hostname->ip hostname)))) ".")))

;; (define server:sync-lock-token "SERVER_SYNC_LOCK")
;; (define (server:release-sync-lock)
;;   (db:no-sync-del! *no-sync-db* server:sync-lock-token))
;; (define (server:have-sync-lock?)
;;   (let* ((have-lock-pair (db:no-sync-get-lock *no-sync-db* server:sync-lock-token))
;;          (have-lock?     (car have-lock-pair))
;;          (lock-time      (cdr have-lock-pair))
;;          (lock-age       (- (current-seconds) lock-time)))
;;     (cond
;;      (have-lock? #t)
;;      ((>lock-age
;;        (* 3 (configf:lookup-number *configdat* "server" "minimum-intersync-delay" default: 180)))
;;       (server:release-sync-lock)
;;       (server:have-sync-lock?))
;;      (else #f))))

;; moving this here as it needs access to db and cannot be in common.
;;

(define (server:get-bruteforce-syncer dbstruct #!key (fork-to-background #f) (persist-until-sync #f))
  (debug:print "WARNING: bruteforce-syncer is called but has been disabled!")
  (lambda ()
    (debug:print "WARNING: bruteforce-syncer is called but has been disabled!"))
  #;(let* ((sqlite-exe   (or (get-environment-variable "MT_SQLITE3_EXE"))) ;; defined in cfg.sh
         (sync-log     (or (args:get-arg "-sync-log") (conc *toppath* "/logs/sync-" (current-process-id) "-" (get-host-name) ".log")))
	 (tmp-area     (common:get-db-tmp-area))
	 (tmp-db       (conc tmp-area "/megatest.db"))
	 (staging-file (conc *toppath* "/.megatest.db"))
	 (mtdbfile     (conc *toppath* "/megatest.db"))
	 (lockfile     (common:get-sync-lock-filepath))
         (sync-cmd-core     (conc sqlite-exe" " tmp-db " .dump | "sqlite-exe" " staging-file "&>"sync-log))
         (sync-cmd     (if fork-to-background 
                           (conc "/usr/bin/env NBFAKE_LOG="*toppath*"/logs/last-server-sync-"(current-process-id)".log nbfake \""sync-cmd-core" && /bin/mv -f " staging-file " " mtdbfile" \"")
                           sync-cmd-core))
         (default-min-intersync-delay 2)
	 (min-intersync-delay (configf:lookup-number *configdat* "server" "minimum-intersync-delay" default: default-min-intersync-delay))
         (default-duty-cycle 0.1)
         (duty-cycle   (configf:lookup-number *configdat* "server" "sync-duty-cycle" default: default-duty-cycle))
         (last-sync-seconds 10) ;; we will adjust this to a measurement and delay last-sync-seconds * (1 - duty-cycle)
         (calculate-off-time (lambda (work-duration duty-cycle)
                                  (* (/ (- 1 duty-cycle) duty-cycle) last-sync-seconds)))
         (off-time min-intersync-delay) ;; adjusted in closure below.
         (do-a-sync
          (lambda ()
            (BB> "Start do-a-sync with fork-to-background="fork-to-background" persist-until-sync="persist-until-sync)
            (let* ((finalres
                    (let retry-loop ((num-tries 0))
                         (if (common:simple-file-lock lockfile)
	                     (begin
                               (cond
                                ((not (or fork-to-background persist-until-sync))
                                 (debug:print 0 *default-log-port* "INFO: syncer thread sleeping for max of (server.minimum-intersync-delay="min-intersync-delay
                                              " , off-time="off-time" seconds ]")
                                 (thread-sleep! (max off-time min-intersync-delay)))
                                (else
                                 (debug:print 0 *default-log-port* "INFO: syncer thread NOT sleeping ; maybe time-to-exit...")))

                               (if (not (configf:lookup *configdat* "server" "disable-db-snapshot"))
                                   (common:snapshot-file mtdbfile subdir: ".db-snapshot"))
		               (delete-file* staging-file)
		               (let* ((start-time (current-milliseconds))
                                      (res (system sync-cmd))
                                      (dbbackupfile (conc mtdbfile ".backup"))
                                      (res2 
                                       (cond
                                        ((eq? 0 res )
                                         (handle-exceptions
                                            exn
                                            #f
                                         (if (file-exists? dbbackupfile)
		                           (delete-file* dbbackupfile)
                                         )
                                         (if (eq? 0 (file-size sync-log))
                                             (delete-file* sync-log))
		                         (system (conc "/bin/mv " staging-file " " mtdbfile))
                                         
                                         (set! last-sync-seconds (/ (- (current-milliseconds) start-time) 1000))
                                         (set! off-time (calculate-off-time
                                                         last-sync-seconds
                                                         (cond
                                                          ((and (number? duty-cycle) (> duty-cycle 0) (< duty-cycle 1))
                                                           duty-cycle)
                                                          (else
                                                           (debug:print 0 *default-log-port* "WARNING: ["(common:human-time)"] server.sync-duty-cycle is invalid.  Should be a number between 0 and 1, but "duty-cycle" was specified.  Using default value: "default-duty-cycle)
                                                           default-duty-cycle))))
                                         
                                         (debug:print 1 *default-log-port* "INFO: ["(common:human-time)"] pid="(current-process-id)" SYNC took "last-sync-seconds" sec")
                                         (debug:print 1 *default-log-port* "INFO: ["(common:human-time)"] pid="(current-process-id)" SYNC took "last-sync-seconds" sec ; with duty-cycle of "duty-cycle" off time is now "off-time)
                                         'sync-completed))
                                        (else
                                         (system (conc "/bin/cp "sync-log" "sync-log".fail"))
                                         (debug:print 0 *default-log-port* "ERROR: ["(common:human-time)"] Sync failed. See log at "sync-log".fail")
                                         (if (file-exists? (conc mtdbfile ".backup"))
                                             (system (conc "/bin/cp "mtdbfile ".backup " mtdbfile)))
                                         #f))))
                                 (common:simple-file-release-lock lockfile)
                                 (BB> "released lockfile: " lockfile)
                                 (when (common:file-exists? lockfile)
                                   (BB> "DID NOT ACTUALLY RELEASE LOCKFILE"))
                                 res2) ;; end let
                               );; end begin
                             ;; else
                             (cond
                              (persist-until-sync
                               (thread-sleep! 1)
                               (debug:print 1 *default-log-port* "INFO: ["(common:human-time)"] pid="(current-process-id)" other SYNC in progress; we're in a fork-to-background so we need to succeed.  Let's wait a jiffy and and try again. num-tries="num-tries" (waiting for lockfile="lockfile" to disappear)")
                               (retry-loop (add1 num-tries)))
                              (else
                               (thread-sleep! (max off-time (+ last-sync-seconds min-intersync-delay)))
                               (debug:print 1 *default-log-port* "INFO: ["(common:human-time)"] pid="(current-process-id)" other SYNC in progress; not syncing.")
                               'parallel-sync-in-progress))
                             ) ;; end if got lockfile
                         )
                    ))
              (BB> "End do-a-sync with fork-to-background="fork-to-background" persist-until-sync="persist-until-sync" and result="finalres)
              finalres)
            ) ;; end lambda
          ))
    do-a-sync))