X-Git-Url: https://jxself.org/git/?p=8sync.git;a=blobdiff_plain;f=8sync%2Fsystems%2Factors.scm;h=ce46f63614fb7640eb3db3ee90450cffac999d92;hp=7e8d9576033587cff78537d956964cf2ff7e48bb;hb=ea14f5dc75cebaaf9cc21d96a6575b3738c43354;hpb=13cb6055e917635850e8f0e3eea5c6b0dc376e7a diff --git a/8sync/systems/actors.scm b/8sync/systems/actors.scm index 7e8d957..ce46f63 100644 --- a/8sync/systems/actors.scm +++ b/8sync/systems/actors.scm @@ -31,7 +31,6 @@ big-random-number big-random-number-string simple-message-id-generator - require-slot actor-id @@ -48,7 +47,7 @@ actor-id-hive actor-id-string - make-action-dispatch + simple-dispatcher build-actions make-action-dispatch define-simple-actor @@ -66,13 +65,15 @@ message-to message-action message-from message-id message-body message-in-reply-to message-wants-reply - message-ref - send-message send-message-wait - reply-message reply-message-wait + message-auto-reply? + + <- <-wait <-reply <-reply-wait + + call-with-message msg-receive => ez-run-hive - hive-bootstrap-message + bootstrap-message serialize-message write-message serialize-message-pretty pprint-message @@ -103,13 +104,6 @@ (set! counter (1+ counter)) (string-append prefix (number->string counter))))) -(define (require-slot slot-name) - "Generate something for #:init-thunk to complain about unfilled slot" - (lambda () - (throw 'required-slot - (format #f "Slot ~s not filled" slot-name) - slot-name))) - ;;; Messages @@ -119,10 +113,7 @@ (define-record-type (make-message-intern id to from action body in-reply-to wants-reply - replied - ;; @@: Not used yet. - ;; Will we ever find a real use case? - deferred-reply) + replied) message? (id message-id) (to message-to) @@ -131,55 +122,22 @@ (body message-body) (in-reply-to message-in-reply-to) (wants-reply message-wants-reply) - - ;; See XUDD source for these. Not use yet, maybe eventually will be? - ;; XUDD uses them for autoreply. - ;; Requiring mutation on message objects is clearly not great, - ;; but it may be worth it...? Investigate! - (replied message-replied set-message-replied!) - (deferred-reply message-deferred-reply set-message-deferred-reply!)) + (replied message-replied set-message-replied!)) (define* (make-message id to from action body #:key in-reply-to wants-reply - replied deferred-reply) + replied) (make-message-intern id to from action body - in-reply-to wants-reply replied - deferred-reply)) - -;; Note: the body of messages is currently an alist, but it's created -;; from a keyword based property list (see the following two functions). -;; But, that's an extra conversion step, and maybe totally unnecessary: -;; we already have message-ref, and this could just pull a keyword -;; from a property list. -;; The main ways this might be useful are error checking, -;; serialization across the wire (but even that might require some -;; change), and using existing tooling (though adding new tooling -;; would be negligible in implementation effort.) - -;; This cons cell is immutable and unique (for eq? tests) -(define %nothing-provided (cons 'nothing 'provided)) - -(define* (message-ref message key #:optional (dflt %nothing-provided)) - "Extract KEY from body of MESSAGE. - -Optionally set default with [DFLT] -If key not found and DFLT not provided, throw an error." - (let ((result (assoc key (message-body message)))) - (if result (cdr result) - (if (eq? dflt %nothing-provided) - (throw 'message-missing-key - "Message body does not contain key and no default provided" - #:key key - #:message message) - dflt)))) - - -(define (message-needs-reply message) + in-reply-to wants-reply replied)) + +(define (message-auto-reply? message) + (eq? (message-action message) '*auto-reply*)) + +(define (message-needs-reply? message) "See if this message needs a reply still" (and (message-wants-reply message) - (not (or (message-replied message) - (message-deferred-reply message))))) + (not (message-replied message)))) (define (kwarg-list-to-alist args) @@ -196,21 +154,24 @@ If key not found and DFLT not provided, throw an error." args))))) -(define (send-message from-actor to-id action . message-body-args) +;;; See: https://web.archive.org/web/20081223021934/http://mumble.net/~jar/articles/oo-moon-weinreb.html +;;; (also worth seeing: http://mumble.net/~jar/articles/oo.html ) + +(define (<- from-actor to-id action . message-body-args) "Send a message from an actor to another actor" (let* ((hive (actor-hive from-actor)) (message (make-message (hive-gen-message-id hive) to-id (actor-id from-actor) action - (kwarg-list-to-alist message-body-args)))) - (8sync-nowait (hive-process-message hive message)))) + message-body-args))) + (8sync (hive-process-message hive message)))) -(define (send-message-wait from-actor to-id action . message-body-args) +(define (<-wait from-actor to-id action . message-body-args) "Send a message from an actor to another, but wait until we get a response" (let* ((hive (actor-hive from-actor)) (abort-to (hive-prompt (actor-hive from-actor))) (message (make-message (hive-gen-message-id hive) to-id (actor-id from-actor) action - (kwarg-list-to-alist message-body-args) + message-body-args #:wants-reply #t))) (abort-to-prompt abort-to from-actor message))) @@ -219,20 +180,29 @@ If key not found and DFLT not provided, throw an error." ;; not have an exception thrown and instead just have a message with ;; the appropriate '*error* message returned. -(define (reply-message from-actor original-message - . message-body-args) +(define (<-reply from-actor original-message . message-body-args) "Reply to a message" (set-message-replied! original-message #t) (let* ((hive (actor-hive from-actor)) (new-message (make-message (hive-gen-message-id hive) (message-from original-message) (actor-id from-actor) '*reply* - (kwarg-list-to-alist message-body-args) + message-body-args #:in-reply-to (message-id original-message)))) - (8sync-nowait (hive-process-message hive new-message)))) + (8sync (hive-process-message hive new-message)))) -(define (reply-message-wait from-actor original-message - . message-body-args) +(define (<-auto-reply from-actor original-message) + "Auto-reply to a message. Internal use only!" + (set-message-replied! original-message #t) + (let* ((hive (actor-hive from-actor)) + (new-message (make-message (hive-gen-message-id hive) + (message-from original-message) + (actor-id from-actor) '*auto-reply* + '() + #:in-reply-to (message-id original-message)))) + (8sync (hive-process-message hive new-message)))) + +(define (<-reply-wait from-actor original-message . message-body-args) "Reply to a messsage, but wait until we get a response" (set-message-replied! original-message #t) (let* ((hive (actor-hive from-actor)) @@ -240,7 +210,7 @@ If key not found and DFLT not provided, throw an error." (new-message (make-message (hive-gen-message-id hive) (message-from original-message) (actor-id from-actor) '*reply* - (kwarg-list-to-alist message-body-args) + message-body-args #:wants-reply #t #:in-reply-to (message-id original-message)))) (abort-to-prompt abort-to from-actor new-message))) @@ -252,17 +222,14 @@ If key not found and DFLT not provided, throw an error." (define-class () ;; An address object - (id #:init-thunk (require-slot "id") - #:init-keyword #:id + (id #:init-keyword #:id #:getter actor-id) ;; The hive we're connected to. ;; We need this to be able to send messages. - (hive #:init-thunk (require-slot "hive") - #:init-keyword #:hive + (hive #:init-keyword #:hive #:accessor actor-hive) ;; How we receive and process new messages - (message-handler #:init-thunk (require-slot "message-handler") - #:allocation #:each-subclass)) + (message-handler #:allocation #:each-subclass)) (define-method (actor-message-handler (actor )) (slot-ref actor 'message-handler)) @@ -319,23 +286,30 @@ If key not found and DFLT not provided, throw an error." (let* ((action (message-action message)) (method (assoc-ref action-map action))) (if (not method) + ;; @@: There's every possibility this should be handled in + ;; hive-process-message instead. (throw 'action-not-found "No appropriate action handler found for actor" #:action action #:actor actor #:message message #:available-actions (map car action-map))) - (method actor message)))) + (apply method actor message (message-body message))))) (define-syntax %expand-action-item (syntax-rules () - ((_ ((action-name action-args ...) body ...)) - (cons (quote action-name) - (lambda (action-args ...) - body ...))) ((_ (action-name handler)) (cons (quote action-name) handler)))) +(define-syntax-rule (build-actions action-item ...) + "Build a mapping of actions. Same syntax as make-action-dispatch +but this doesn't build the dispatcher for you (you probably want to +pass it to simple-dispatcher). + +The advantage here is that since this simply builds an alist, you can +compose it with other action maps." + (list (%expand-action-item action-item) ...)) + (define-syntax make-action-dispatch (syntax-rules () "Expand a list of action names and actions into an alist @@ -357,8 +331,7 @@ more compact following syntax: ((party actor message) (display \"Life of the party!\")))" ((make-action-dispatch action-item ...) - (simple-dispatcher - (list (%expand-action-item action-item) ...))))) + (simple-dispatcher (build-actions action-item ...))))) (define-syntax-rule (define-simple-actor class actions ...) (define-class class () @@ -375,8 +348,6 @@ more compact following syntax: (define-generic hive-handle-failed-forward) (define-class () - ;; This gets set to itself immediately after being created - (hive #:init-value #f) (actor-registry #:init-thunk make-hash-table #:getter hive-actor-registry) (msg-id-generator #:init-thunk simple-message-id-generator @@ -447,14 +418,33 @@ more compact following syntax: '*forward* `((original . ,message)))) +(define-method (hive-reply-with-error (hive ) original-message + error-key error-args) + ;; We only supply the error-args if the original sender is on the same hive + (define (orig-actor-on-same-hive?) + (equal? (hive-id hive) + (address-hive-id (message-from original-message)))) + (set-message-replied! original-message #t) + (let* ((new-message-body + (if (orig-actor-on-same-hive?) + `(#:original-message ,original-message + #:error-key ,error-key + #:error-args ,error-args) + `(#:original-message ,original-message + #:error-key ,error-key))) + (new-message (make-message (hive-gen-message-id hive) + (message-from original-message) + (actor-id hive) '*error* + new-message-body + #:in-reply-to (message-id original-message)))) + (8sync (hive-process-message hive new-message)))) + (define-method (hive-process-message (hive ) message) "Handle one message, or forward it via an ambassador" (define (maybe-autoreply actor) ;; Possibly autoreply - (if (message-needs-reply message) - ;; @@: Should we give *autoreply* as the action instead of *reply*? - (reply-message actor message - #:*auto-reply* #t))) + (if (message-needs-reply? message) + (<-auto-reply actor message))) (define (resolve-actor-to) "Get the actor the message was aimed at" @@ -469,16 +459,34 @@ more compact following syntax: actor)) (define (call-catching-coroutine thunk) + (define (call-catching-errors) + ;; TODO: maybe parameterize (or attach to hive) and use + ;; maybe-catch-all from agenda.scm + ;; @@: Why not just use with-throw-handler and let the catch + ;; happen at the agenda? That's what we used to do, but + ;; it ended up with a SIGABRT. See: + ;; http://lists.gnu.org/archive/html/bug-guile/2016-05/msg00003.html + (catch #t + thunk + ;; In the actor model, we don't totally crash on errors. + (lambda _ #f) + ;; If an error happens, we raise it + (lambda (key . args) + (if (message-needs-reply? message) + ;; If the message is waiting on a reply, let them know + ;; something went wrong. + (hive-reply-with-error hive message key args)) + ;; print error message + (apply print-error-and-continue key args)))) (call-with-prompt (hive-prompt hive) - thunk + call-catching-errors (lambda (kont actor message) - (let ((hive (actor-hive actor))) - ;; Register the coroutine - (hash-set! (hive-waiting-coroutines hive) - (message-id message) - (cons (actor-id actor) kont)) - ;; Send off the message - (8sync (hive-process-message hive message)))))) + ;; Register the coroutine + (hash-set! (hive-waiting-coroutines hive) + (message-id message) + (cons (actor-id actor) kont)) + ;; Send off the message + (8sync (hive-process-message hive message))))) (define (process-local-message) (let ((actor (resolve-actor-to))) @@ -495,27 +503,45 @@ more compact following syntax: result))))) (define (resume-waiting-coroutine) - (call-catching-coroutine - (lambda () - (match (hash-remove! (hive-waiting-coroutines hive) - (message-in-reply-to message)) - ((_ . (resume-actor-id . kont)) - (if (not (equal? (message-to message) - resume-actor-id)) - (throw 'resuming-to-wrong-actor - "Attempted to resume a coroutine to the wrong actor!" - #:expected-actor-id (message-to message) - #:got-actor-id resume-actor-id - #:message message)) - (let (;; @@: How should we resolve resuming coroutines to actors who are - ;; now gone? - (actor (resolve-actor-to)) - (result (kont message))) - (maybe-autoreply actor) - result)) - (#f (throw 'no-waiting-coroutine - "message in-reply-to tries to resume nonexistent coroutine" - message)))))) + (cond + ((or (eq? (message-action message) '*reply*) + (eq? (message-action message) '*auto-reply*)) + (call-catching-coroutine + (lambda () + (match (hash-remove! (hive-waiting-coroutines hive) + (message-in-reply-to message)) + ((_ . (resume-actor-id . kont)) + (if (not (equal? (message-to message) + resume-actor-id)) + (throw 'resuming-to-wrong-actor + "Attempted to resume a coroutine to the wrong actor!" + #:expected-actor-id (message-to message) + #:got-actor-id resume-actor-id + #:message message)) + (let (;; @@: How should we resolve resuming coroutines to actors who are + ;; now gone? + (actor (resolve-actor-to)) + (result (kont message))) + (maybe-autoreply actor) + result)) + (#f (throw 'no-waiting-coroutine + "message in-reply-to tries to resume nonexistent coroutine" + message)))))) + ;; Yikes, we must have gotten an error or something back + (else + ;; @@: Not what we want in the long run? + ;; What we'd *prefer* to do is to resume this message + ;; and throw an error inside the message handler + ;; (say, from send-mesage-wait), but that causes a SIGABRT (??!!) + (hash-remove! (hive-waiting-coroutines hive) + (message-in-reply-to message)) + (let ((explaination + (if (eq? (message-action message) '*reply*) + "Won't resume coroutine; got an *error* as a reply" + "Won't resume coroutine because action is not *reply*"))) + (throw 'hive-unresumable-coroutine + explaination + #:message message))))) (define (process-remote-message) ;; Find the ambassador @@ -539,7 +565,7 @@ more compact following syntax: (process-remote-message)))) (define-method (hive-actor-local? (hive ) address) - (hash-ref (hive-actor-registry hive) address)) + (equal? (hive-id hive) (address-hive-id address))) (define-method (hive-register-actor! (hive ) (actor )) (hash-set! (hive-actor-registry hive) (actor-id actor) actor)) @@ -568,6 +594,28 @@ that method for documentation." (%hive-create-actor hive actor-class init id-cookie)) +(define (call-with-message message proc) + "Applies message body arguments into procedure, with message as first +argument. Similar to call-with-values in concept." + (apply proc message (message-body message))) + +;; (msg-receive (<- bar baz) +;; (baz) +;; basil) + +;; Emacs: (put 'msg-receive 'scheme-indent-function 2) + +;; @@: Or receive-msg or receieve-message or?? +(define-syntax-rule (msg-receive arglist the-message body ...) + (call-with-message the-message + (lambda* arglist + body ...))) + +;; Emacs: (put '=> 'scheme-indent-function 2) +;;; An experimental alias. +(define-syntax-rule (=> rest ...) + (msg-receive rest ...)) + ;;; Various API methods for actors to interact with the system @@ -581,16 +629,16 @@ that method for documentation." This is the method actors should call directly (unless they want to supply an id-cookie, in which case they should use create-actor*)." - (8sync (%hive-create-actor (actor-hive from-actor) actor-class - init #f))) + (%hive-create-actor (actor-hive from-actor) actor-class + init #f)) (define* (create-actor* from-actor actor-class id-cookie #:rest init) "Create an instance of actor-class. Return the new actor's id. Like create-actor, but permits supplying an id-cookie." - (8sync (%hive-create-actor (actor-hive from-actor) actor-class - init id-cookie))) + (%hive-create-actor (actor-hive from-actor) actor-class + init id-cookie)) (define (self-destruct actor) @@ -620,9 +668,9 @@ an integer." (spawn-and-queue-repl-server! agenda))) (start-agenda agenda))) -(define (hive-bootstrap-message hive to-id action . message-body-args) +(define (bootstrap-message hive to-id action . message-body-args) (wrap - (apply send-message hive to-id action message-body-args))) + (apply <- hive to-id action message-body-args))) @@ -639,8 +687,7 @@ an integer." (message-body message) (message-in-reply-to message) (message-wants-reply message) - (message-replied message) - (message-deferred-reply message))) + (message-replied message))) (define* (write-message message #:optional (port (current-output-port))) "Write out a message to a port for easy reading later. @@ -660,8 +707,7 @@ to improve that. You'll need a better serializer for that.." (body ,(message-body message)) (in-reply-to ,(message-in-reply-to message)) (wants-reply ,(message-wants-reply message)) - (replied ,(message-replied message)) - (deferred-reply ,(message-deferred-reply message)))) + (replied ,(message-replied message)))) (define (pprint-message message) "Pretty print a message." @@ -670,10 +716,10 @@ to improve that. You'll need a better serializer for that.." (define* (read-message #:optional (port (current-input-port))) "Read a message serialized via serialize-message from PORT" (match (read port) - ((id to from action body in-reply-to wants-reply replied deferred-reply) + ((id to from action body in-reply-to wants-reply replied) (make-message-intern id to from action body - in-reply-to wants-reply replied deferred-reply)) + in-reply-to wants-reply replied)) (anything-else (throw 'message-read-bad-structure "Could not read message from structure"