Megatest

     
     ;; needed to get the interface:port that was automatically found
     udat-port
     udat-host-port
     
     ;; for testing only
     ;; pp-uconn
     work-method ;; parameter; 'threads, 'mailbox, 'limited, 'direct
     )

(import scheme
	chicken.base
	chicken.file
	chicken.time
	chicken.condition

  (cnum       0)                 ;; cookie number
  (mboxes     (make-hash-table)) ;; for the replies
  (avail-cmboxes '())            ;; list of (<cookie> . <mbox>) for re-use
  ;; threads
  (numthreads 10)
  (cmd-thread #f)
  (work-queue-thread #f)
  (num-threads-running 0)
  ) 

;; Parameters

;; work-method:
;;    mailbox - all rdat goes through mailbox
;;    threads - all rdat immediately executed in new thread
;;    limited - run rdats in immediately executed threads until NthreadsMax
;;              reached, then put in mailbox
;;    direct  - no queuing
;;
(define work-method (make-parameter 'threads)) 
;; ;; struct for keeping track of others we are talking to
;; ;;
;; (defstruct pdat
;;   (host-port  #f)
;;   (conns      '()) ;; list of pcon structs, pop one off when calling the peer
;;   )
;; 

;; it then returns control
;;
(define (run-listener handler-proc #!optional (port-suggestion 4242))
  (let* ((uconn (make-udat)))
    (udat-work-proc-set! uconn handler-proc)
    (if (setup-listener uconn port-suggestion)
	(let* ((th1 (make-thread (lambda ()(ulex-cmd-loop uconn)) "Ulex command loop"))
	       (th2 (make-thread (lambda ()
				   (case (work-method)
				     ((mailbox limited)
				      (process-work-queue uconn))))
				 "Ulex work queue processor")))
	  (tcp-buffer-size 2048)
	  ;; (max-connections 2048) 
	  (thread-start! th1)
	  (thread-start! th2)
	  (udat-cmd-thread-set! uconn th1)
	  (udat-work-queue-thread-set! uconn th2)
	  (print "cmd loop and process workers started, listening on "(udat-host-port uconn)".")
	  uconn)
	(assert #f "ERROR: run-listener called without proper setup."))))

(define (wait-and-close uconn)
  (thread-join! (udat-cmd-thread uconn))
  (tcp-close (udat-socket uconn)))

		 (mbox-timeout-result 'MBOX_TIMEOUT)
		 (res                  (mailbox-receive! mbox mbox-timeout-secs mbox-timeout-result))
		 (mbox-receive-time    (current-milliseconds)))
	    ;; (put-cmbox uconn cmbox) ;; reuse mbox and cookie. is it worth it?
	    (hash-table-delete! (udat-mboxes uconn) qrykey)
	    (if (eq? res 'MBOX_TIMEOUT)
		(begin
		  (print "WARNING: mbox timed out for query "cmd", with data "data", waiting for response from "host-port".")

		  ;; here it might make sense to clean up connection records and force clean start?
		  ;; NO. The progam using ulex needs to do the reset. Right thing here is exception
		  
		  #f)  ;; convert to raising exception?
		res))
	  (begin
	    (print "ERROR: Communication failed? Got "sres)
	    #f))))))

;;======================================================================
;; responder side
;;======================================================================

;; take a request, rdat, and if not immediate put it in the work queue

     (print "BAD DATA? controldat=" rdat)
     'ack) ;; send ack anyway?
    ))

;; given an already set up uconn start the cmd-loop
;;
(define (ulex-cmd-loop uconn)
  (let* ((serv-listener (udat-socket uconn))
	 (listener      (lambda ()
			  (let loop ((state 'start))
			    (let-values (((inp oup)(tcp-accept serv-listener)))
			      (let* ((rdat  (deserialize inp)) ;; '(my-host-port qrykey cmd params)
				     (resp  (ulex-handler uconn rdat)))
				(if resp (serialize resp oup))
				(close-input-port inp)
				(close-output-port oup))
			      (loop state))))))
    ;; start N of them
    (let loop ((thnum   0)
	       (threads '()))
      (if (< thnum 100)
	  (let* ((th (make-thread listener (conc "listener" thnum))))
	    (thread-start! th)
	    (loop (+ thnum 1)
		  (cons th threads)))
	  (map thread-join! threads)))))

;; add a proc to the cmd list, these are done symetrically (i.e. in all instances)
;; so that the proc can be dereferenced remotely
;;
(define (set-work-handler uconn proc)
  (udat-work-proc-set! uconn proc))

;;======================================================================
;; work queues - this is all happening on the listener side
;;======================================================================

;; rdat is (rem-host-port qrykey cmd params)
					     
(define (add-to-work-queue uconn rdat)
  #;(queue-add! (udat-work-queue uconn) rdat)
  (case (work-method)
    ((threads)
     (thread-start! (make-thread (lambda ()
				   (do-work uconn rdat))
				 "worker thread")))
    ((mailbox)
     (mailbox-send! (udat-work-queue uconn) rdat))
    ((direct)
     (do-work uconn rdat))
    (else
     (print "ULEX ERROR: work-method "(work-method)" not recognised, using mailbox.")
     (mailbox-send! (udat-work-queue uconn) rdat))))
     

(define (do-work uconn rdat)
  (let* ((proc (udat-work-proc uconn))) ;; get it each time - conceivebly it could change
    ;; put this following into a do-work procedure
    (match rdat
      ((rem-host-port qrykey cmd params)
       (let* ((start-time (current-milliseconds))
	      (result (proc rem-host-port qrykey cmd params))
	      (end-time (current-milliseconds))
	      (run-time (- end-time start-time)))
	 (print "ULEX: work "cmd", "params" done in "run-time" ms")
	 ;; send 'response as cmd and result as params
	 (send uconn rem-host-port qrykey 'response result) ;; could check for ack
	 (print "ULEX: response sent back to "rem-host-port" in "(- (current-milliseconds) end-time))))
      (MBOX_TIMEOUT #f)
      (else
       (print "ERROR: rdat "rdat", did not match rem-host-port qrykey cmd params")))))

;; NEW APPROACH:
;;   
(define (process-work-queue uconn) 
  (let ((wqueue (udat-work-queue uconn))
	(proc   (udat-work-proc  uconn))
	(numthr (udat-numthreads uconn)))
    (let loop ((thnum    1)
	       (threads '()))
      (let ((thlst (cons (make-thread (lambda ()