Megatest

    (if (member cmd '(blah))
      (begin
	(mutex-lock! *send-receive-mutex*)
	(if (not *runremote*)(set! *runremote* (make-remote)))
	(let ((ulex:conn (remote-ulex:conn *runremote*)))
	  (if (not ulex:conn)(remote-ulex:conn-set! *runremote* (rmtmod:setup-ulex *toppath*)))
	  (rmtmod:send-receive-ulex ulex:conn cmd rid params attemptnum area-dat)))
      (rmt:send-receive-orig *default-log-port* runremote *rmt-mutex* areapath *db-multi-sync-mutex* cmd rid params attemptnum: attemptnum area-dat: area-dat ro-queries: api:read-only-queries))))

;; RA => e.g. usage (rmt:send-receive 'get-var #f (list varname))
;;
;;  add multi-sync-mutex 
;;
(define (rmt:send-receive-orig log-port runremote rmt-mutex toppath multi-sync-mutex cmd rid params #!key (attemptnum 1)(area-dat #f)) ;; start attemptnum at 1 so the modulo below works as expected

  #;(common:telemetry-log (conc "rmt:"(->string cmd))
                        payload: `((rid . ,rid)
                                   (params . ,params)))
                          
  
  ;; do all the prep locked under the rmt-mutex
  ;;(mutex-lock! rmt-mutex)
  
  ;; 1. check if server is started IFF cmd is a write OR if we are not on the homehost, store in runremote
  ;; 2. check the age of the connections. refresh the connection if it is older than timeout-20 seconds.
  ;; 3. do the query, if on homehost use local access
  ;;
  (let* ((start-time    (current-seconds)) ;; snapshot time so all use cases get same value

     ((> attemptnum 15)
      (debug:print 0 log-port "ERROR: 15 tries to start/connect to server. Giving up.")
      (exit 1))

     ;; readonly mode, read request-  handle it - case 2
     ((and readonly-mode
           (member cmd api:read-only-queries)) 
      ;; (mutex-unlock! rmt-mutex)
      (debug:print-info 12 log-port "rmt:send-receive, case 2")
      (rmt:open-qry-close-locally log-port multi-sync-mutex cmd 0 params ro-queries: api:read-only-queries)
      )

     ;; readonly mode, write request.  Do nothing, return #f
     (readonly-mode (extras-readonly-mode rmt-mutex log-port cmd params))

     ;; This block was for pre-emptively resetting the connection if there had been no communication for some time.
     ;; I don't think it adds any value. If the server is not there, just fail and start a new connection.
     ;; also, the expire-time calculation might not be correct. We want, time-since-last-server-access > (server:get-timeout)
     ;;
     ;; reset the connection if it has been unused too long
     ((and runremote
           (remote-conndat runremote)
	   (> (current-seconds) ;; if it has been more than server-timeout seconds since last contact, close this connection and start a new on
	      (+ (http-transport:server-dat-get-last-access (remote-conndat runremote))
		 (remote-server-timeout runremote))))
      (debug:print-info 0 log-port "Connection to " (remote-server-url runremote) " expired due to no accesses, forcing new connection.")
      (http-transport:close-connections area-dat: runremote)
      (remote-conndat-set! runremote #f) ;; invalidate the connection, thus forcing a new connection.
      ;; (mutex-unlock! rmt-mutex)
      (rmt:send-receive-orig log-port runremote rmt-mutex toppath multi-sync-mutex cmd rid params attemptnum: attemptnum))
     

     ;; on homehost and this is a read
     ((and (not (remote-force-server runremote)) ;; honor forced use of server, i.e. server NOT required
	   (cdr (remote-hh-dat runremote))       ;; on homehost
           (member cmd api:read-only-queries))   ;; this is a read
      ;; (mutex-unlock! rmt-mutex)
      (debug:print-info 12 log-port "rmt:send-receive, case  5")
      (rmt:open-qry-close-locally log-port multi-sync-mutex cmd 0 params ro-queries: api:read-only-queries))

     ;; on homehost and this is a write, we already have a server, but server has died
     ((and (cdr (remote-hh-dat runremote))           ;; on homehost
           (not (member cmd api:read-only-queries))  ;; this is a write
           (remote-server-url runremote)             ;; have a server
           (not (server:ping (remote-server-url runremote))))  ;; server has died. NOTE: this is not a cheap call! Need better approach.
      (set! *runremote* (make-remote))
      (remote-force-server-set! runremote (common:force-server?))
      ;; (mutex-unlock! rmt-mutex)
      (debug:print-info 12 log-port "rmt:send-receive, case  6")
      (rmt:send-receive-orig log-port runremote rmt-mutex toppath  multi-sync-mutex cmd rid params attemptnum: attemptnum))

     ;; on homehost and this is a write, we already have a server
     ((and (not (remote-force-server runremote))     ;; honor forced use of server, i.e. server NOT required
	   (cdr (remote-hh-dat runremote))           ;; on homehost
           (not (member cmd api:read-only-queries))  ;; this is a write
           (remote-server-url runremote))            ;; have a server
      ;;(mutex-unlock! rmt-mutex)
      (debug:print-info 12 log-port "rmt:send-receive, case  4.1")
      (rmt:open-qry-close-locally  log-port multi-sync-mutex cmd 0 params ro-queries: api:read-only-queries))

     ;;  on homehost, no server contact made and this is a write, passively start a server 
     ((and (not (remote-force-server runremote))     ;; honor forced use of server, i.e. server NOT required
	   (cdr (remote-hh-dat runremote))           ;; have homehost
           (not (remote-server-url runremote))       ;; no connection yet
	   (not (member cmd api:read-only-queries))) ;; not a read-only query
      (debug:print-info 12 log-port "rmt:send-receive, case  8")
      (let ((server-url  (server:check-if-running toppath))) ;; (server:read-dotserver->url toppath))) ;; (server:check-if-running toppath))) ;; Do NOT want to run server:check-if-running - very expensive to do for every write call
	(if server-url
	    (remote-server-url-set! runremote server-url) ;; the string can be consumed by the client setup if needed
	    (if (common:force-server?)
		(server:start-and-wait toppath)
		(server:kind-run toppath))))
      (remote-force-server-set! runremote (common:force-server?))
      ;; (mutex-unlock! rmt-mutex)
      (debug:print-info 12 log-port "rmt:send-receive, case  8.1")
      (rmt:open-qry-close-locally  log-port multi-sync-mutex cmd 0 params ro-queries: api:read-only-queries))

     ((or (and (remote-force-server runremote)              ;; we are forcing a server and don't yet have a connection to one
	       (not (remote-conndat runremote)))
	  (and (not (cdr (remote-hh-dat runremote)))        ;; not on a homehost 
	       (not (remote-conndat runremote))))           ;; and no connection
      (debug:print-info 12 log-port "rmt:send-receive, case 9, hh-dat: " (remote-hh-dat runremote) " conndat: " (remote-conndat runremote))
      ;;(mutex-unlock! rmt-mutex)
      (if (not (server:check-if-running toppath)) ;; who knows, maybe one has started up?
	  (server:start-and-wait toppath))
      (remote-conndat-set! runremote (rmt:get-connection-info toppath)) ;; calls client:setup which calls client:setup-http
      (rmt:send-receive-orig log-port runremote rmt-mutex toppath multi-sync-mutex cmd rid params attemptnum: attemptnum)) ;; TODO: add back-off timeout as

     ;; all set up if get this far, dispatch the query
     ((and (not (remote-force-server runremote))
	   (cdr (remote-hh-dat runremote))) ;; we are on homehost
      ;;(mutex-unlock! rmt-mutex)
      (debug:print-info 12 log-port "rmt:send-receive, case 10")
      (rmt:open-qry-close-locally  log-port multi-sync-mutex cmd (if rid rid 0) params ro-queries: api:read-only-queries))

     ;; not on homehost, do server query
     (else (extras-case-11 log-port runremote cmd params attemptnum rid)))))

;; bunch of small functions factored out of send-receive to make debug easier
;;

  ;; db stuff for local db access
  (set! db:dbfile-path                   dbfile-path)
  (set! db:setup                         dbsetup)
  (set! apt:execute-requests             exec-req)
  (set! api:read-only-queries	         read-only-queries)
  )

(define (rmt:open-qry-close-locally log-port multi-sync-mutex cmd run-id params #!key (ro-queries '())(remretries 5))
  (let* ((qry-is-write   (not (member cmd ro-queries)))
	 (db-file-path   (db:dbfile-path)) ;;  0))
	 (dbstruct-local (db:setup #t))  ;; make-dbr:dbstruct path:  dbdir local: #t)))
	 (read-only      (not (file-write-access? db-file-path)))
	 (start          (current-milliseconds))
	 (resdat         (if (not (and read-only qry-is-write))
			     (let ((v (api:execute-requests dbstruct-local (vector (symbol->string cmd) params))))
			       (handle-exceptions ;; there has been a long history of receiving strange errors from values returned by the client when things go wrong..

    (if (and read-only qry-is-write)
        (debug:print 0 log-port "ERROR: attempt to write to read-only database ignored. cmd=" cmd))
    (if (not success)
	(if (> remretries 0)
	    (begin
	      (debug:print-error 0 log-port "local query failed. Trying again.")
	      (thread-sleep! (/ (random 5000) 1000)) ;; some random delay 
	      (rmt:open-qry-close-locally log-port multi-sync-mutex cmd run-id params ro-queries: ro-queries remretries: (- remretries 1)))
	    (begin
	      (debug:print-error 0 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, the watchdog is responsible for syncing it
	  #;(if qry-is-write

	    (begin
	      (remote-ro-mode-set! runremote ro-mode)
	      (remote-ro-mode-checked-set! runremote #t)
	      ro-mode)
	    ro-mode))))

(define (extras-readonly-mode rmt-mutex log-port cmd params)
  ;;(mutex-unlock! rmt-mutex)
  (debug:print-info 12 log-port "rmt:send-receive, case 3")
  (debug:print 0 log-port "WARNING: write transaction requested on a readonly area.  cmd="cmd" params="params)
  #f)

(define (extras-transport-failed *default-log-port* *rmt-mutex* attemptnum runremote cmd rid params)
  (debug:print 0 *default-log-port* "WARNING: communication failed. Trying again, try num: " attemptnum)
  ;;(mutex-lock! *rmt-mutex*)
  (remote-conndat-set!    runremote #f)
  (http-transport:close-connections area-dat: runremote)
  (remote-server-url-set! runremote #f)
  ;;(mutex-unlock! *rmt-mutex*)
  (debug:print-info 12 *default-log-port* "rmt:send-receive, case  9.1")
  (rmt:send-receive cmd rid params attemptnum: (+ attemptnum 1)))
  
(define (extras-transport-succeded *default-log-port* *rmt-mutex* attemptnum runremote res params rid cmd)
  (if (and (vector? res)
	   (eq? (vector-length res) 2)
	   (eq? (vector-ref res 1) 'overloaded)) ;; since we are

						 ;; is bad or the
						 ;; server is
						 ;; overloaded and we
						 ;; want to ease off
						 ;; the queries
      (let ((wait-delay (+ attemptnum (* attemptnum 10))))
	(debug:print 0 *default-log-port* "WARNING: server is overloaded. Delaying " wait-delay " seconds and trying call again.")
	;;(mutex-lock! *rmt-mutex*)
	(http-transport:close-connections area-dat: runremote)
	(set! *runremote* #f) ;; force starting over
	;;(mutex-unlock! *rmt-mutex*)
	(thread-sleep! wait-delay)
	(rmt:send-receive cmd rid params attemptnum: (+ attemptnum 1)))
      res)) ;; All good, return res

;;======================================================================
;; ulex and steps stuff
;;======================================================================