;;; 8sync --- Asynchronous programming for Guile
-;;; Copyright (C) 2016 Christopher Allan Webber <cwebber@dustycloud.org>
+;;; Copyright © 2016, 2017 Christopher Allan Webber <cwebber@dustycloud.org>
;;;
;;; This file is part of 8sync.
;;;
#:use-module (ice-9 match)
#:use-module (ice-9 pretty-print)
#:use-module (8sync agenda)
- #:use-module (8sync repl)
#:export (;; utilities... ought to go in their own module
big-random-number
big-random-number-string
actor-id-hive
actor-id-string
+ actor-alive?
+
build-actions
- define-simple-actor
+ define-actor
<hive>
make-hive
;; There are more methods for the hive, but there's
;; no reason for the outside world to look at them maybe?
hive-id
- hive-create-actor hive-create-actor*
+ bootstrap-actor bootstrap-actor*
create-actor create-actor*
self-destruct
message-auto-reply?
- <- <-wait <-reply <-reply-wait
+ <- <-* <-wait <-wait* <-reply <-reply* <-reply-wait <-reply-wait*
- call-with-message msg-receive msg-val
+ call-with-message mbody-receive mbody-val
- ez-run-hive
+ run-hive
bootstrap-message
serialize-message write-message
;;; 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
- message-body-args)))
- (8sync (hive-process-message hive message))))
+;; This is the internal, generalized message sending method.
+;; Users shouldn't use it! Use the <-foo forms instead.
-(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"
+;; @@: Could we get rid of some of the conditional checks through
+;; some macro-foo?
+
+(define-inlinable (send-message send-options from-actor to-id action
+ replying-to-message wants-reply?
+ message-body-args)
+ (if replying-to-message
+ (set-message-replied! replying-to-message #t))
(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
- message-body-args
- #:wants-reply #t)))
- (abort-to-prompt abort-to from-actor message)))
+ (new-message
+ (make-message (hive-gen-message-id hive) to-id
+ (actor-id from-actor) action
+ message-body-args
+ #:wants-reply wants-reply?
+ #:in-reply-to
+ (if replying-to-message
+ (message-id replying-to-message)
+ #f))))
+ (if wants-reply?
+ (abort-to-prompt (hive-prompt (actor-hive from-actor))
+ from-actor new-message send-options)
+ ;; @@: It might be that eventually we pass in send-options
+ ;; here too. Since <-wait and <-reply-wait are the only ones
+ ;; that use it yet, for now it kind of just makes things
+ ;; confusing.
+ (8sync (hive-process-message hive new-message)))))
+
+(define (<- to-id action . message-body-args)
+ "Send a message from an actor to another actor"
+ (send-message '() (%current-actor) to-id action
+ #f #f message-body-args))
+
+(define (<-* send-options to-id action . message-body-args)
+ "Like <-*, but allows extra parameters via send-options"
+ (define* (really-send #:key (actor (%current-actor))
+ #:allow-other-keys)
+ (send-message send-options actor to-id action
+ #f #f message-body-args))
+ (apply really-send send-options))
+
+(define (<-wait to-id action . message-body-args)
+ "Send a message from an actor to another, but wait until we get a response"
+ (wait-maybe-handle-errors
+ (send-message '() (%current-actor) to-id action
+ #f #t message-body-args)))
+
+(define (<-wait* send-options to-id action . message-body-args)
+ "Like <-wait, but allows extra parameters, for example whether to
+#:accept-errors"
+ (define* (really-send #:key (actor (%current-actor))
+ #:allow-other-keys)
+ (apply wait-maybe-handle-errors
+ (send-message send-options actor to-id action
+ #f #t message-body-args)
+ send-options))
+ (apply really-send send-options))
;; TODO: Intelligently ~propagate(ish) errors on -wait functions.
;; We might have `send-message-wait-brazen' to allow callers to
;; not have an exception thrown and instead just have a message with
;; the appropriate '*error* message returned.
-(define (<-reply from-actor original-message . message-body-args)
+(define (<-reply 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*
- message-body-args
- #:in-reply-to (message-id original-message))))
- (8sync (hive-process-message hive new-message))))
-
-(define (<-auto-reply from-actor original-message)
+ (when (message-needs-reply? original-message)
+ (send-message '() (%current-actor) (message-from original-message) '*reply*
+ original-message #f message-body-args)))
+
+(define (<-reply* send-options original-message . message-body-args)
+ "Like <-reply, but allows extra parameters via send-options"
+ (define* (really-send #:key (actor (%current-actor))
+ #:allow-other-keys)
+ (send-message send-options actor
+ (message-from original-message) '*reply*
+ original-message #f message-body-args))
+ (when (message-needs-reply? original-message)
+ (apply really-send send-options)))
+
+(define (<-auto-reply 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))))
+ (send-message '() actor (message-from original-message) '*auto-reply*
+ original-message #f '()))
-(define (<-reply-wait from-actor original-message . message-body-args)
+(define (<-reply-wait 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))
- (abort-to (hive-prompt (actor-hive from-actor)))
- (new-message (make-message (hive-gen-message-id hive)
- (message-from original-message)
- (actor-id from-actor) '*reply*
- message-body-args
- #:wants-reply #t
- #:in-reply-to (message-id original-message))))
- (abort-to-prompt abort-to from-actor new-message)))
+ (if (message-needs-reply? original-message)
+ (wait-maybe-handle-errors
+ (send-message '() (%current-actor)
+ (message-from original-message) '*reply*
+ original-message #t message-body-args))
+ #f))
+
+(define (<-reply-wait* send-options original-message
+ . message-body-args)
+ "Like <-reply-wait, but allows extra parameters via send-options"
+ (define* (really-send #:key (actor (%current-actor))
+ #:allow-other-keys)
+ (apply wait-maybe-handle-errors
+ (send-message send-options actor
+ (message-from original-message) '*reply*
+ original-message #t message-body-args)
+ send-options))
+ (when (message-needs-reply? original-message)
+ (apply really-send send-options)))
+
+(define* (wait-maybe-handle-errors message
+ #:key accept-errors
+ #:allow-other-keys)
+ "Before returning a message to a waiting caller, see if we need to
+raise an exception if an error."
+ (define action (message-action message))
+ (cond ((and (eq? action '*error*)
+ (not accept-errors))
+ (throw 'hive-unresumable-coroutine
+ "Won't resume coroutine; got an *error* as a reply"
+ #:message message))
+ (else message)))
\f
(call/ec find-message-handler))
(apply method actor message (message-body message)))
+(define-syntax-rule (build-actions (symbol method) ...)
+ "Construct an alist of (symbol . method), where the method is wrapped
+with wrap-apply to facilitate live hacking and allow the method definition
+to come after class definition."
+ (list
+ (cons (quote symbol)
+ (wrap-apply method)) ...))
+
(define-class <actor> ()
;; An address object
(id #:init-keyword #:id
;; @@: There's no reason not to use #:class instead of
;; #:each-subclass anywhere in this file, except for
;; Guile bug #25211 (#:class is broken in Guile 2.2)
- #:allocation #:each-subclass)
+ #:allocation #:each-subclass
+ #:getter actor-message-handler)
+
+ ;; valid values are:
+ ;; - #t as in, send the init message, but don't wait (default)
+ ;; - 'wait, as in wait on the init message
+ ;; - #f as in don't bother to init
+ (should-init #:init-value #t
+ #:allocation #:each-subclass)
;; This is the default, "simple" way to inherit and process messages.
- (actions #:init-value '()
+ (actions #:init-value (build-actions
+ ;; Default init method is to do nothing.
+ (*init* (const #f))
+ ;; Default cleanup method is to do nothing.
+ (*cleanup* (const #f)))
#:allocation #:each-subclass))
-(define-method (actor-message-handler (actor <actor>))
- (slot-ref actor 'message-handler))
-
-;;; So these are the nicer representations of addresses.
-;;; However, they don't serialize so easily with scheme read/write, so we're
-;;; using the simpler cons cell version below for now.
-
-;; (define-record-type <address>
-;; (make-address actor-id hive-id) ; @@: Do we want the trailing -id?
-;; address?
-;; (actor-id address-actor-id)
-;; (hive-id address-hive-id))
-;;
-;; (set-record-type-printer!
-;; <address>
-;; (lambda (record port)
-;; (format port "<address: ~s@~s>"
-;; (address-actor-id record) (address-hive-id record))))
-;;
+;;; Addresses are vectors where the first part is the actor-id and
+;;; the second part is the hive-id. This works well enough... they
+;;; look decent being pretty-printed.
(define (make-address actor-id hive-id)
- (cons actor-id hive-id))
+ (vector actor-id hive-id))
(define (address-actor-id address)
- (car address))
+ (vector-ref address 0))
(define (address-hive-id address)
- (cdr address))
+ (vector-ref address 1))
(define (address->string address)
(string-append (address-actor-id address) "@"
(define %current-actor
(make-parameter #f))
+(define (actor-alive? actor)
+ (hive-resolve-local-actor (actor-hive actor) (actor-id actor)))
+
\f
;;; Actor utilities
;;; ===============
-(define-syntax-rule (build-actions (symbol method) ...)
- "Construct an alist of (symbol . method), where the method is wrapped
-with wrap-apply to facilitate live hacking and allow the method definition
-to come after class definition."
- (list
- (cons (quote symbol)
- (wrap-apply method)) ...))
-
-(define-syntax-rule (define-simple-actor class action ...)
- (define-class class (<actor>)
+(define-syntax-rule (define-actor class inherits
+ (action ...)
+ slots ...)
+ (define-class class inherits
(actions #:init-value (build-actions action ...)
- #:allocation #:each-subclass)))
+ #:allocation #:each-subclass)
+ slots ...))
\f
;;; The Hive
(build-actions
;; This is in the case of an ambassador failing to forward a
;; message... it reports it back to the hive
- (*failed-forward* hive-handle-failed-forward))))
+ (*failed-forward* hive-handle-failed-forward)
+ ;; These are called at start and end of run-hive
+ (*init-all* hive-handle-init-all)
+ (*cleanup-all* hive-handle-cleanup-all))))
+
+(define-method (hive-handle-init-all (hive <hive>) message)
+ "Run *init* method on all actors in registry"
+ ;; We have to do this hack and run over the list
+ ;; twice, because hash-for-each would result in an unrewindable
+ ;; continuation, and to avoid the hash-map changing during the
+ ;; middle of this.
+ (define actor-ids
+ (hash-map->list (lambda (actor-id actor) actor-id)
+ (hive-actor-registry hive)))
+ (for-each (lambda (actor-id)
+ (let* ((actor (hash-ref (hive-actor-registry hive)
+ actor-id)))
+ (match (slot-ref actor 'should-init)
+ (#f #f)
+ ('wait
+ (<-wait actor-id '*init*))
+ (_
+ (<- actor-id '*init*)))))
+ actor-ids))
(define-method (hive-handle-failed-forward (hive <hive>) message)
"Handle an ambassador failing to forward a message"
'TODO)
+(define-method (hive-handle-cleanup-all (hive <hive>) message)
+ "Send a message to all actors in our registry to clean themselves up."
+ ;; We have to do this hack and run over the list
+ ;; twice, because hash-for-each would result in an unrewindable
+ ;; continuation, and to avoid the hash-map changing during the
+ ;; middle of this.
+ (define actor-ids
+ (hash-map->list (lambda (actor-id actor) actor-id)
+ (hive-actor-registry hive)))
+ (for-each (lambda (actor-id)
+ (<- actor-id '*cleanup*))
+ actor-ids))
+
(define* (make-hive #:key hive-id)
(let ((hive (make <hive>
#:id (make-address
(big-random-number-string))))))
;; Set the hive's actor reference to itself
(set! (actor-hive hive) hive)
+ ;; Register the actor with itself
+ (hive-register-actor! hive hive)
hive))
(define-method (hive-id (hive <hive>))
(define-method (hive-gen-actor-id (hive <hive>) cookie)
(make-address (if cookie
- (string-append cookie "-" (big-random-number-string))
+ (string-append cookie ":" (big-random-number-string))
(big-random-number-string))
(hive-id hive)))
;; unresumable continuation.
(lambda () (hive-process-message hive new-message))))
+(define-record-type <waiting-on-reply>
+ (make-waiting-on-reply actor-id kont send-options)
+ waiting-on-reply?
+ (actor-id waiting-on-reply-actor-id)
+ (kont waiting-on-reply-kont)
+ (send-options waiting-on-reply-send-options))
+
+
(define-method (hive-process-message (hive <hive>) message)
"Handle one message, or forward it via an ambassador"
(define (maybe-autoreply actor)
(8sync (queued-error-handling-thunk))))
(call-with-prompt (hive-prompt hive)
call-catching-errors
- (lambda (kont actor message)
+ (lambda (kont actor message send-options)
;; Register the coroutine
(hash-set! (hive-waiting-coroutines hive)
(message-id message)
- (cons (actor-id actor) kont))
+ (make-waiting-on-reply
+ (actor-id actor) kont send-options))
;; Send off the message
(8sync (hive-process-message hive message)))))
result))))))
(define (resume-waiting-coroutine)
- (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)))))
+ (case (message-action message)
+ ;; standard reply / auto-reply
+ ((*reply* *auto-reply* *error*)
+ (call-catching-coroutine
+ (lambda ()
+ (match (hash-remove! (hive-waiting-coroutines hive)
+ (message-in-reply-to message))
+ ((_ . waiting)
+ (if (not (equal? (message-to message)
+ (waiting-on-reply-actor-id waiting)))
+ (throw 'resuming-to-wrong-actor
+ "Attempted to resume a coroutine to the wrong actor!"
+ #:expected-actor-id (message-to message)
+ #:got-actor-id (waiting-on-reply-actor-id waiting)
+ #:message message))
+ (let* (;; @@: How should we resolve resuming coroutines to actors who are
+ ;; now gone?
+ (actor (resolve-actor-to))
+ (kont (waiting-on-reply-kont waiting))
+ (result (kont message)))
+ (maybe-autoreply actor)
+ result))
+ (#f (throw 'no-waiting-coroutine
+ "message in-reply-to tries to resume nonexistent coroutine"
+ message))))))
+ ;; Unhandled action for a reply!
+ (else
+ (throw 'hive-unresumable-coroutine
+ "Won't resume coroutine, nonsense action on reply message"
+ #:action (message-action message)
+ #:message message))))
(define (process-remote-message)
;; Find the ambassador
(hash-set! (hive-actor-registry hive) (actor-id actor) actor))
(define-method (%hive-create-actor (hive <hive>) actor-class
- init id-cookie)
- "Actual method called by hive-create-actor.
+ init-args id-cookie send-init?)
+ "Actual method called by bootstrap-actor / create-actor.
Since this is a define-method it can't accept fancy define* arguments,
-so this gets called from the nicer hive-create-actor interface. See
+so this gets called from the nicer bootstrap-actor interface. See
that method for documentation."
(let* ((actor-id (hive-gen-actor-id hive id-cookie))
(actor (apply make actor-class
#:hive hive
#:id actor-id
- init)))
+ init-args))
+ (actor-should-init (slot-ref actor 'should-init)))
(hive-register-actor! hive actor)
+ ;; Maybe run actor init method
+ (when (and send-init? actor-should-init)
+ (let ((send-method
+ (if (eq? actor-should-init 'wait)
+ <-wait <-)))
+ (send-method actor-id '*init*)))
;; return the actor id
actor-id))
-(define* (hive-create-actor hive actor-class #:rest init)
+(define* (bootstrap-actor hive actor-class #:rest init-args)
+ "Create an actor on HIVE using ACTOR-CLASS passing in INIT-ARGS args"
(%hive-create-actor hive actor-class
- init #f))
+ init-args (symbol->string (class-name actor-class))
+ #f))
-(define* (hive-create-actor* hive actor-class id-cookie #:rest init)
+(define* (bootstrap-actor* hive actor-class id-cookie #:rest init-args)
+ "Create an actor, but also allow customizing a 'cookie' added to the id
+for debugging"
(%hive-create-actor hive actor-class
- init id-cookie))
+ init-args id-cookie
+ #f))
(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)
+;; (mbody-receive (<- bar baz)
;; (baz)
;; basil)
-;; Emacs: (put 'msg-receive 'scheme-indent-function 2)
+;; Emacs: (put 'mbody-receive 'scheme-indent-function 2)
;; @@: Or receive-msg or receieve-message or??
-(define-syntax-rule (msg-receive arglist message body ...)
+(define-syntax-rule (mbody-receive arglist message body ...)
"Call body with arglist (which can accept arguments like lambda*)
applied from the message-body of message."
(call-with-message message
(lambda* arglist
body ...)))
-(define (msg-val message)
+(define (mbody-val message)
"Retrieve the first value from the message-body of message.
Like single value return from a procedure call. Probably the most
common case when waiting on a reply from some action invocation."
;; TODO: move send-message and friends here...?
-(define* (create-actor from-actor actor-class #:rest init)
+(define* (create-actor from-actor actor-class #:rest init-args)
"Create an instance of actor-class. Return the new actor's id.
This is the method actors should call directly (unless they want
to supply an id-cookie, in which case they should use
create-actor*)."
(%hive-create-actor (actor-hive from-actor) actor-class
- init #f))
+ init-args #f #t))
-(define* (create-actor* from-actor actor-class id-cookie #:rest init)
+(define* (create-actor* from-actor actor-class id-cookie #:rest init-args)
"Create an instance of actor-class. Return the new actor's id.
Like create-actor, but permits supplying an id-cookie."
(%hive-create-actor (actor-hive from-actor) actor-class
- init id-cookie))
+ init-args id-cookie #t))
+
+(define* (self-destruct actor #:key (cleanup #t))
+ "Remove an actor from the hive.
-(define (self-destruct actor)
- "Remove an actor from the hive."
+Unless #:cleanup is set to #f, this will first have the actor handle
+its '*cleanup* action handler."
+ (when cleanup
+ (<-wait (actor-id actor) '*cleanup*))
(hash-remove! (hive-actor-registry (actor-hive actor))
(actor-id actor)))
;;; 8sync bootstrap utilities
;;; =========================
-(define* (ez-run-hive hive initial-tasks #:key repl-server)
+(define* (run-hive hive initial-tasks
+ #:key (cleanup #t)
+ (handle-signals (list SIGINT SIGTERM)))
"Start up an agenda and run HIVE in it with INITIAL-TASKS.
-Should we start up a cooperative REPL for live hacking? REPL-SERVER
-wants to know! You can pass it #t or #f, or if you want to specify a port,
-an integer."
- (let* ((queue (list->q initial-tasks))
- (agenda (make-agenda #:pre-unwind-handler print-error-and-continue
- #:queue queue)))
- (cond
- ;; If repl-server is an integer, we'll use that as the port
- ((integer? repl-server)
- (spawn-and-queue-repl-server! agenda repl-server))
- (repl-server
- (spawn-and-queue-repl-server! agenda)))
- (start-agenda agenda)))
+Keyword arguments:
+ - #:cleanup: Whether to run *cleanup* on all actors.
+ - #:handle-sigactions: a list of signals to set up interrupt
+ handlers for, so cleanup sill still happen as expected.
+ Defaults to a list of SIGINT and SIGTERM."
+ (dynamic-wind
+ (const #f)
+ (lambda ()
+ (define (run-it escape)
+ (define (handle-signal signum)
+ (restore-signals)
+ (escape signum))
+ (for-each (lambda (signum)
+ (sigaction signum handle-signal))
+ handle-signals)
+ (let* ((queue (list->q
+ (cons (bootstrap-message hive (actor-id hive) '*init-all*)
+ initial-tasks)))
+ (agenda (make-agenda #:pre-unwind-handler print-error-and-continue
+ #:queue queue)))
+ (run-agenda agenda)))
+ (call/ec run-it))
+ ;; Run cleanup
+ (lambda ()
+ (when cleanup
+ (run-hive-cleanup hive)))))
+
+(define (run-hive-cleanup hive)
+ (let ((queue (list->q (list (bootstrap-message hive (actor-id hive)
+ '*cleanup-all*)))))
+ (run-agenda
+ (make-agenda #:queue queue))))
(define (bootstrap-message hive to-id action . message-body-args)
(wrap
- (apply <- hive to-id action message-body-args)))
+ (apply <-* `(#:actor ,hive) to-id action message-body-args)))
\f
projects / 8sync.git / blobdiff