Megatest

(declare (unit common))
(declare (uses commonmod))
(import commonmod)

(include "common_records.scm")

(define (remove-files filespec)
  (let ((files (glob filespec)))
    (for-each delete-file* files)))

(define (stop-the-train)
  (thread-start! (make-thread (lambda ()
				(let loop ()
				  (if (and *toppath*
					   (file-exists? (conc *toppath*"/stop-the-train")))
				      (begin
					(debug:print 0 *default-log-port* "ERROR: found file "*toppath*"/stop-the-train, exiting immediately")
                                        (remove-files (conc *toppath* "/logs/server*"))
                                        (remove-files (conc *toppath* "/.servinfo/*"))
                                        (remove-files (conc *toppath* "/.mtdb/*lock"))
					(exit 1)))
				  (thread-sleep! 5)
				  (loop))))))

;; execute thunk, return value.  If exception thrown, trap exception, return #f, and emit nonfatal condition note to *default-log-port* .
;; arguments - thunk, message
(define (common:fail-safe thunk warning-message-on-exception)

    (if dat
	dat
	""))))

(define (common:alist-ref/default key alist default)
  (or (alist-ref key alist) default))


;; The `common:low-noise-print` function is a utility that can be used to throttle the
;; frequency of certain operations. It does this by tracking the last time an operation was
;; performed and only allowing it again after a specified interval (`waitval`). This can be useful
;; for reducing noise in logs or limiting the rate of user notifications, among other use cases.

(define (common:low-noise-print waitval . keys)
  (let* ((key      (string-intersperse (map conc keys) "-" ))
	 (lasttime (hash-table-ref/default *common:denoise* key 0))
	 (currtime (current-seconds)))
    (if (> (- currtime lasttime) waitval)
	(begin
	  (hash-table-set! *common:denoise* key currtime)

					   (server:get-best-guess-address hostname)
					   #f)))
			    (if ipstr ipstr hostn))) ;; hostname))) 
	 (start-port      (portlogger:open-run-close portlogger:find-port))
	 (link-tree-path  (common:get-linktree))
	 (tmp-area        (common:get-db-tmp-area))
	 (start-file      (conc tmp-area "/.server-start")))

    ;; set some parameters for the server
    (root-path     (if link-tree-path 
		       link-tree-path
		       (current-directory))) ;; WARNING: SECURITY HOLE. FIX ASAP!
    (handle-directory spiffy-directory-listing)
    (handle-exception (lambda (exn chain)
			(signal (make-composite-condition

	 (server-log-file (args:get-arg "-log"))) ;; always set when we are a server

    (handle-exceptions
	exn
      (debug:print 0 *default-log-port* "Failed to create " started-file ", exn=" exn)
      (with-output-to-file started-file (lambda ()(print (current-process-id)))))

    (debug:print 0 *default-log-port* "Creating servinfo file for " (get-host-name) ":" (cadr *server-info*)) 
    (http:create-server-registration-file *toppath* (get-host-name) (cadr *server-info*))

    (let loop ((count         0)
	       (server-state 'available)
	       (bad-sync-count 0)
	       (start-time     (current-milliseconds)))

      ;; Use this opportunity to sync the tmp db to megatest.db
      (if (not server-going) ;; *dbstruct-dbs* 

	  (begin
             (if (not *server-id*)
		 (set! *server-id* (server:mk-signature)))
             (debug:print 0 *default-log-port* (current-seconds) (current-directory) (current-process-id) (argv))   
	     (debug:print 0 *default-log-port* "SERVER STARTED: " iface ":" port " AT " (current-seconds) " server-id: " *server-id*)
	     (flush-output *default-log-port*)))
      (if (common:low-noise-print 60 "dbstats")
	(begin
	    (debug:print 0 *default-log-port* "Server stats:")
	    (db:print-current-query-stats)))

        (let* ((hrs-since-start  (/ (- (current-seconds) server-start-time) 3600)))
	 (cond












         ((and *server-run*
	       (> (+ last-access server-timeout)
		  (current-seconds)))
          (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))
	      (let ((curr-time (current-seconds)))
		(handle-exceptions

                                    (args:get-arg "-server")
                                    "-")
                                )) "Server run"))
           (th3 (make-thread (lambda ()
                               (debug:print-info 0 *default-log-port* "Server monitor thread started")
                               (http-transport:keep-running)
                               "Keep running"))))

      (thread-start! th2)
      (thread-sleep! 0.25) ;; give the server time to settle before starting the keep-running monitor. 
      (thread-start! th3)
      (set! *didsomething* #t)
      (thread-join! th2)
      (exit))))

;; return servid
;; side-effects:
;;   ttdat-cleanup-proc is populated with function to remove the serverinfo file
(define (http:create-server-registration-file areapath host port)
  (let* (
         (servdir  (server:get-servinfo-dir areapath))
         (servinf (conc servdir"/"host":"port"-"(current-process-id)))
         (serv-id (server:mk-signature))
         (clean-proc (lambda ()
                       (delete-file* servinf)
                       )))
    (assert (and host port) "FATAL: tt:create-server-registration-file called with no conn")
    (with-output-to-file servinf
      (lambda ()
        (print "SERVER STARTED: "host":"port" AT "(current-seconds)" server-id: "serv-id" pid: "(current-process-id))))
      serv-id))


;; (define (http-transport:server-signal-handler signum)
;;   (signal-mask! signum)
;;   (handle-exceptions
;;    exn
;;    (debug:print 0 *default-log-port* " ... exiting ...")
;;    (let ((th1 (make-thread (lambda ()

;; a specific Megatest area. Detail are being hashed out and this may change.
;;
(if (args:get-arg "-adjutant")
    (begin
      (adjutant-run)
      (set! *didsomething* #t)))

(if (args:get-arg "-list-servers")

  (let* ((tl (launch:setup)) ;; need this to initialize *toppath*

        (servdir (server:get-servinfo-dir *toppath*))
        (servfiles (glob (conc servdir "/*:*.db")))
        (fmtstr  "~10a~22a~10a~25a~25a~8a\n")
        (dbfiles (append (glob (conc *toppath* "/.mtdb/main.db")) (glob (conc *toppath* "/.mtdb/?.db"))(glob (conc *toppath* "/.mtdb/??.db"))))
     )
     (format #t fmtstr "DB" "host:port" "PID" "age" "last mod" "state")
     (for-each
        (lambda (dbfile)
          (let* (
            (dbfname (conc (pathname-file dbfile) ".db"))
            )
                (let (
                  (sinfos (server:get-server-info-sorted *toppath* dbfname))
                  )
                  (for-each 
                     (lambda (sinfo)
                       (let* (

                         (db (list-ref sinfo 5))

                         (pid (list-ref sinfo 4))
                         (host (list-ref sinfo 0))
                         (port (list-ref sinfo 1))
                         (server-id (list-ref sinfo 3))
                         (age (seconds->hr-min-sec (- (current-seconds) (list-ref sinfo 2))))
                         (last-mod (seconds->string (list-ref sinfo 2)))
                         (status (system (conc "ssh " host " ps " pid " > /dev/null")))
                         (state (if (> status 0)
                                  "dead"
                                  (tt:ping host port server-id 0)
                                ))
                         )
                         (format #t fmtstr db (conc host ":" port) pid age last-mod state)
                       )
                     )
                     sinfos
                  )
                ) 
          )
       )
       dbfiles
     )
     (set! *didsomething* #t)
     (exit)  
  )
)


(if (args:get-arg "-kill-servers")

  (let* ((tl (launch:setup)) ;; need this to initialize *toppath*
        (servdir (server:get-servinfo-dir *toppath*))
        (servfiles (glob (conc servdir "/*:*.db")))
        (fmtstr  "~10a~22a~10a~25a~25a~8a\n")
        (dbfiles (append (glob (conc *toppath* "/.mtdb/main.db")) (glob (conc *toppath* "/.mtdb/?.db"))(glob (conc *toppath* "/.mtdb/??.db"))))

     )
     (format #t fmtstr "DB" "host:port" "PID" "age" "last mod" "state")
     (for-each

        (lambda (dbfile)

          (let* (

            (dbfname (conc (pathname-file dbfile) ".db"))
            (sfiles   (server:find-server *toppath* dbfname))
            )
            (for-each 
              (lambda (sfile)
                (let (
                  (sinfos (servert:get-server-info-sorted *toppath* dbfname))
                  )
                  (for-each 
                     (lambda (sinfo)
                       (let* (
                         (db (list-ref sinfo 5))
                         (pid (list-ref sinfo 4))
                         (host (list-ref sinfo 0))
                         (port (list-ref sinfo 1))
                         (server-id (list-ref sinfo 3))
                         (age (seconds->hr-min-sec (- (current-seconds) (list-ref sinfo 2))))
                         (last-mod (seconds->string (list-ref sinfo 2)))
                         (killed (system (conc "ssh " host " kill " pid " > /dev/null")))
                         (dummy2 (sleep 1))
                         (state (if (> (system (conc "ssh " host " ps " pid " > /dev/null")) 0) "dead" "alive"))
                            )
                         (format #t fmtstr db (conc host ":" port) pid age last-mod state)
                         (delete-file* sfile)
                       )
                     )
                     sinfos
                  )
                ) 
              )
              sfiles
            )
          )
       )
       dbfiles
     )
     ;; remove this db, because otherwise metadata contains records for old servers, and this causes a problem with db:no-sync-get-lock-with-id.
     (if (file-exists? (conc *toppath* "/.mtdb/no-sync.db"))
       (delete-file (conc *toppath* "/.mtdb/no-sync.db"))
     )
     (set! *didsomething* #t)
     (exit)  
  )
)



;;======================================================================
;; Weird special calls that need to run *after* the server has started?
;;======================================================================

(if (args:get-arg "-list-targets")
    (if (launch:setup)

	       (begin
		 (debug:print-info 2 *default-log-port* "Gating server start, last start: "
				   (seconds->time-string fmodtime) ", time since last start: " delta ", required idletime: " idletime ", gating reason:" (if old-enough "another job started a server" "too soon to start another server"))
		 
		 (thread-sleep! ( + 1 idletime))
		 (server:wait-for-server-start-last-flag areapath)))))))

(define (server:get-servinfo-dir areapath)
  (let* ((spath (conc areapath"/.servinfo")))
    (if (not (file-exists? spath))
	(create-directory spath #t))
    spath))

;; gets server info and appends path to server file
;; sorts by age, oldest first
;;
;; returns list of (host port startseconds server-id servinfofile)
;;
(define (server:get-server-info-sorted areapath dbfname)
  (let* (
	 (sfiles   (server:find-server areapath dbfname))
	 (sdats    (filter car (map server:server-get-info sfiles))) ;; first element is #f if the file disappeared while being read
	 (sorted   (sort sdats (lambda (a b)
				 (let* ((starta (list-ref a 2))
					(startb (list-ref b 2)))
				   (if (eq? starta startb)
				       (string>? (list-ref a 3)(list-ref b 3)) ;; if servers started at same time look at server-id
				       (< starta startb))))))
	 (count    0))
    (for-each
     (lambda (rec)
       (if (or (> (length sorted) 1)
	       (common:low-noise-print 120 "server info sorted"))
	   (debug:print 2 *default-log-port* "SERVER #"count": "(string-intersperse (map conc sorted) ", ")))
       (set! count (+ count 1)))
     sorted)
    sorted))

(define (server:clean-up-old areapath)
  ;; any server file that has not been touched in ten minutes is effectively dead
  (let* ((sfiles (glob (conc (server:get-servinfo-dir areapath)"/*"))))
    (for-each
     (lambda (sfile)
       (let* ((modtime (handle-exceptions
			   exn
			 (begin
			   (debug:print 0 *default-log-port* "WARNING: failed to get modification file for "sfile)
			   (current-seconds))
			 (file-modification-time sfile))))
	 (if (and (number? modtime)
		  (> (- (current-seconds) modtime)
		     600))
	     (begin
	       (debug:print 0 *default-log-port* "WARNING: found old server info file "sfile", removing it.")
	       (handle-exceptions
		   exn
		 (debug:print 0 *default-log-port* "WARNING: failed to delete old server info file "sfile)
		 (delete-file sfile))))))
     sfiles)))



(define server-last-start 0)

;; oldest server alive determines host then choose random of youngest
;; five servers on that host
;;
;; mode:
;;   best - get best server (random of newest five)
;;   home - get home host based on oldest server
;;   info - print info
(define (server:choose-server areapath #!optional (mode 'best))
  ;; age is current-starttime
  ;; find oldest alive
  ;;   1. sort by age ascending and ping until good
  ;; find alive rand from youngest
  ;;   1. sort by age descending
  ;;   2. take five
  ;;   3. check alive, discard if not and repeat
  ;; first we clean up old server files
  (assert (eq? (rmt:transport-mode) 'http) "FATAL: server:run called with rmt:transport-mode="(rmt:transport-mode))
  (server:clean-up-old areapath)
  (let* ((since-last (- (current-seconds) server-last-start))
        (server-start-delay 10))     
    (if ( < (- (current-seconds) server-last-start) 10 )
      (begin
        (debug:print 2 *default-log-port* "server:choose-server: seconds since last server start: " (- (current-seconds) server-last-start))
        (debug:print 2 *default-log-port* "server:choose-server: last server start less than " server-start-delay " seconds ago. Sleeping " server-start-delay " seconds")
        (thread-sleep! server-start-delay)
      )
      (debug:print 2 *default-log-port* "server:choose-server: seconds since last server start: " (- (current-seconds) server-last-start))
    )
  )
  (let* ((serversdat  (server:get-servers-info areapath))
	 (servkeys    (hash-table-keys serversdat))
	 (by-time-asc (if (not (null? servkeys)) ;; NOTE: Oldest is last
			  (sort servkeys ;; list of "host:port"
				(lambda (a b)
				  (>= (list-ref (hash-table-ref serversdat a) 2)
				      (list-ref (hash-table-ref serversdat b) 2))))
			  '())))
    (debug:print 2 *default-log-port* "server:choose-server: serversdat: " serversdat)
    (debug:print 2 *default-log-port* "server:choose-server: servkeys: " servkeys)
    (if (not (null? by-time-asc))
	(let* ((oldest     (last by-time-asc))
	       (oldest-dat (hash-table-ref serversdat oldest))
	       (host       (list-ref oldest-dat 0))
	       (all-valid  (filter (lambda (x)
				     (equal? host (list-ref (hash-table-ref serversdat x) 0)))
				   by-time-asc))
	       (best-ten  (lambda ()
			     (if (> (length all-valid) 11)
				 (take (drop-right all-valid 1) 10) ;; remove the oldest from consideration so it can age out
				 (if (> (length all-valid) 8)
				     (drop-right all-valid 1)
				     all-valid))))
	       (names->dats (lambda (names)
			      (map (lambda (x)
				     (hash-table-ref serversdat x))
				   names)))
	       (am-home?    (lambda ()
			      (let* ((currhost (get-host-name))
				     (bestadrs (server:get-best-guess-address currhost)))
				(or (equal? host currhost)
				    (equal? host bestadrs))))))
	  (case mode
	    ((info)
	     (debug:print 0 *default-log-port* "oldest: "oldest-dat", selected host: "host", all-valid: "all-valid)
	     (debug:print 0 *default-log-port* "youngest: "(hash-table-ref serversdat (car all-valid))))
	    ((home)     host)
	    ((homehost) (cons host (am-home?))) ;; shut up old code
	    ((home?)    (am-home?))
	    ((best-ten)(names->dats (best-ten)))
	    ((all-valid)(names->dats all-valid))
	    ((best)     (let* ((best-ten (best-ten))
			       (len       (length best-ten)))
			  (hash-table-ref serversdat (list-ref best-ten (random len)))))
	    ((count)(length all-valid))
	    (else
	     (debug:print 0 *default-log-port* "ERROR: invalid command "mode)
	     #f)))
	(begin
	  (server:run areapath)
          (set! server-last-start (current-seconds))
	  ;; (thread-sleep! 3)
	  (case mode
	    ((homehost) (cons #f #f))
	    (else	#f))))))




;; oldest server alive determines host then choose random of youngest
;; five servers on that host
;;
(define (server:get-servers-info areapath)
  ;; (assert *toppath* "FATAL: server:get-servers-info called before *toppath* has been set.")
  (let* ((servinfodir (server:get-servinfo-dir areapath))) ;; (conc *toppath*"/.servinfo")))
    (if (not (file-exists? servinfodir))
	(create-directory servinfodir))
    (let* ((allfiles    (glob (conc servinfodir"/*")))
	   (res         (make-hash-table)))
      (for-each
       (lambda (f)
	 (let* ((hostport  (pathname-strip-directory f))
		(serverdat (server:logf-get-start-info f)))
	   (match serverdat
	     ((host port start server-id pid)
	      (if (and host port start server-id pid)
		  (hash-table-set! res hostport serverdat)
		  (debug:print-info 2 *default-log-port* "bad server info for "f": "serverdat)))
	     (else
	      (debug:print-info 2 *default-log-port* "bad server info for "f": "serverdat)))))
       allfiles)
      res)))



;; given a path to a server info file return: host port startseconds server-id pid dbfname logf
;; 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 (server: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
	(bad-dat      (list #f #f #f #f #f #f logf)))
     (let ((fdat     (handle-exceptions
			 exn
		       (begin
			 ;; WARNING: this is potentially dangerous to blanket ignore the errors
			 (debug:print-info 0 *default-log-port* "Unable to get server info from "logf", exn="(condition->list exn))
			 '()) ;; no idea what went wrong, call it a bad server, return empty list
		       (with-input-from-file logf read-lines))))
       (if (null? fdat) ;; bad data, return bad-dat
	   bad-dat
	   (let loop ((inl  (car fdat))
		      (tail (cdr fdat))
		      (lnum 0))
	     (let ((mlst (string-match server-rx inl)))
	       (if (not mlst)
		   (if (> lnum 500) ;; give up if more than 500 lines of server log read
		       bad-dat
		       (if (null? tail)
			   bad-dat
			   (loop (car tail)(cdr tail)(+ lnum 1))))
		   (match mlst ;; have a not null list
		     ((_ host port start server-id pid dbfname)
		      (list host
			    (string->number port)
			    (string->number start)
			    server-id
			    (string->number pid)
			    dbfname
			    logf))
		     (else
		      (debug:print 0 *default-log-port* "ERROR: did not recognise SERVER line info "mlst)
		      bad-dat)))))))))



;; 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 (server:find-server areapath dbfname)
  (let* ((servdir  (server:get-servinfo-dir areapath))
	 (sfiles   (glob (conc servdir"/*:"dbfname)))
         (good-files '()))
         (for-each 
           (lambda (sfile)
             (let* ((sinfo (tt:server-get-info sfile))
                 (host (list-ref sinfo 0))
                 (port (list-ref sinfo 1))
                 (server-id (list-ref sinfo 3))
                 (pid (list-ref sinfo 4))
                 (status (system (conc "ssh " host " ps " pid " > /dev/null")))
                 )
                (if (= status 0)
                  (set! good-files (cons sfile good-files))
                  (delete-file* sfile)
                )
             )
           )
           sfiles
         )
    (debug:print-info 2 *default-log-port* "server:find-server: good-files: " good-files " sfiles: " sfiles)
    good-files))



        
;; kind start up of server, wait before allowing another server for a given
;; area to be launched
;;
(define (server:kind-run areapath)
  ;; look for $MT_RUN_AREA_HOME/logs/server-start-last
  ;; and wait for it to be at least <server idletime> seconds old
  (server:wait-for-server-start-last-flag areapath)
  (if (not (server:check-if-running areapath)) ;; why try if there is already a server running?
      (let* ((lock-file    (conc areapath "/logs/server-start.lock")))
	(let* ((start-flag (conc areapath "/logs/server-start-last")))
	  (common:simple-file-lock-and-wait lock-file expire-time: 25)
	  (debug:print-info  2 *default-log-port* "server:kind-run: touching " start-flag)
	  (system (conc "touch " start-flag)) ;; lazy but safe
	  (server:run areapath)
	  (thread-sleep! 20) ;; don't release the lock for at least a few seconds. And allow time for the server startup to get to "SERVER STARTED".
	  (common:simple-file-release-lock lock-file)))
      (debug:print-info 0 *default-log-port* "Found server already running. NOT trying to start another.")))

;; return servid
;; side-effects:
;;   ttdat-cleanup-proc is populated with function to remove the serverinfo file
(define (server:create-server-registration-file areapath host port)
  (let* (
	 (servdir  (server:get-servinfo-dir areapath))
	 (servinf (conc servdir"/"host":"port"-"(current-process-id)))
	 (serv-id (server:mk-signature areapath))
	 (clean-proc (lambda ()
		       (delete-file* servinf)
		       )))
    (assert (and host port) "FATAL: tt:create-server-registration-file called with no conn")
    (tt-cleanup-proc-set! ttdat clean-proc)
    (tt-servinf-file-set! ttdat servinf)
    (with-output-to-file servinf
      (lambda ()
	(print "SERVER STARTED: "host":"port" AT "(current-seconds)" server-id: "serv-id" pid: "(current-process-id))))
      serv-id))



;; this one seems to be the general entry point
;;
(define (server:start-and-wait areapath #!key (timeout 60))
  (let ((give-up-time (+ (current-seconds) timeout)))
    (let loop ((server-info (server:check-if-running areapath))
	       (try-num    0))