1 ;;; 8sync --- Asynchronous programming for Guile
2 ;;; Copyright (C) 2016 Christopher Allan Webber <cwebber@dustycloud.org>
4 ;;; This file is part of 8sync.
6 ;;; 8sync is free software: you can redistribute it and/or modify it
7 ;;; under the terms of the GNU Lesser General Public License as
8 ;;; published by the Free Software Foundation, either version 3 of the
9 ;;; License, or (at your option) any later version.
11 ;;; 8sync is distributed in the hope that it will be useful,
12 ;;; but WITHOUT ANY WARRANTY; without even the implied warranty of
13 ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 ;;; GNU Lesser General Public License for more details.
16 ;;; You should have received a copy of the GNU Lesser General Public
17 ;;; License along with 8sync. If not, see <http://www.gnu.org/licenses/>.
19 (define-module (8sync actors)
20 #:use-module (oop goops)
21 #:use-module (srfi srfi-9)
22 #:use-module (srfi srfi-9 gnu)
23 #:use-module (ice-9 control)
24 #:use-module (ice-9 format)
25 #:use-module (ice-9 match)
26 #:use-module (ice-9 pretty-print)
27 #:use-module (8sync agenda)
28 #:export (;; utilities... ought to go in their own module
30 big-random-number-string
31 simple-message-id-generator
39 ;;; Commenting out the <address> type for now;
40 ;;; it may be back when we have better serializers
43 address-actor-id address-hive-id
58 ;; There are more methods for the hive, but there's
59 ;; no reason for the outside world to look at them maybe?
61 bootstrap-actor bootstrap-actor*
63 create-actor create-actor*
68 message-to message-action message-from
69 message-id message-body message-in-reply-to
74 <- <-* <-wait <-wait* <-reply <-reply* <-reply-wait <-reply-wait*
76 call-with-message mbody-receive mbody-val
81 serialize-message write-message
82 serialize-message-pretty pprint-message
83 read-message read-message-from-string))
87 (make-parameter (random-state-from-platform)))
89 ;; Same size as a uuid4 I think...
90 (define random-number-size (expt 2 128))
92 (define (big-random-number)
93 (random random-number-size (%random-state)))
95 ;; Would be great to get this base64 encoded instead.
96 (define (big-random-number-string)
97 ;; @@: This is slow. Using format here is wasteful.
98 (format #f "~x" (big-random-number)))
100 ;; @@: This is slow. A mere ~275k / second on my (old) machine.
101 ;; The main cost seems to be in number->string.
102 (define (simple-message-id-generator)
103 ;; Prepending this cookie makes message ids unique per hive
104 (let ((prefix (format #f "~x:" (big-random-number)))
107 (set! counter (1+ counter))
108 (string-append prefix (number->string counter)))))
116 ;; @@: We may want to add a deferred-reply to the below, similar to
117 ;; what we had in XUDD, for actors which do their own response
118 ;; queueing.... ie, that might receive messages but need to shelve
119 ;; them to be acted upon after something else is taken care of.
121 (define-record-type <message>
122 (make-message-intern id to from action
123 body in-reply-to wants-reply
126 (id message-id) ; id of this message
127 (to message-to) ; actor id this is going to
128 (from message-from) ; actor id of sender
129 (action message-action) ; action (a symbol) to be handled
130 (body message-body) ; argument list "body" of message
131 (in-reply-to message-in-reply-to) ; message id this is in reply to, if any
132 (wants-reply message-wants-reply) ; whether caller is waiting for reply
133 (replied message-replied ; was this message replied to?
134 set-message-replied!))
137 (define* (make-message id to from action body
138 #:key in-reply-to wants-reply
140 (make-message-intern id to from action body
141 in-reply-to wants-reply replied))
143 (define (message-auto-reply? message)
144 (eq? (message-action message) '*auto-reply*))
146 (define (message-needs-reply? message)
147 "See if this message needs a reply still"
148 (and (message-wants-reply message)
149 (not (message-replied message))))
152 (define (kwarg-list-to-alist args)
153 (let loop ((remaining args)
156 (((? keyword? key) val rest ...)
158 (cons (cons (keyword->symbol key) val)
161 (_ (throw 'invalid-kwarg-list
162 "Invalid keyword argument list"
166 ;;; See: https://web.archive.org/web/20081223021934/http://mumble.net/~jar/articles/oo-moon-weinreb.html
167 ;;; (also worth seeing: http://mumble.net/~jar/articles/oo.html )
169 ;; This is the internal, generalized message sending method.
170 ;; Users shouldn't use it! Use the <-foo forms instead.
172 ;; @@: Could we get rid of some of the conditional checks through
175 (define-inlinable (send-message send-options from-actor to-id action
176 replying-to-message wants-reply?
178 (if replying-to-message
179 (set-message-replied! replying-to-message #t))
180 (let* ((hive (actor-hive from-actor))
182 (make-message (hive-gen-message-id hive) to-id
183 (actor-id from-actor) action
185 #:wants-reply wants-reply?
187 (if replying-to-message
188 (message-id replying-to-message)
191 (abort-to-prompt (hive-prompt (actor-hive from-actor))
192 from-actor new-message send-options)
193 ;; @@: It might be that eventually we pass in send-options
194 ;; here too. Since <-wait and <-reply-wait are the only ones
195 ;; that use it yet, for now it kind of just makes things
197 (8sync (hive-process-message hive new-message)))))
199 (define (<- to-id action . message-body-args)
200 "Send a message from an actor to another actor"
201 (send-message '() (%current-actor) to-id action
202 #f #f message-body-args))
204 (define (<-* send-options to-id action . message-body-args)
205 "Like <-*, but allows extra parameters via send-options"
206 (define* (really-send #:key (actor (%current-actor))
208 (send-message send-options actor to-id action
209 #f #f message-body-args))
210 (apply really-send send-options))
212 (define (<-wait to-id action . message-body-args)
213 "Send a message from an actor to another, but wait until we get a response"
214 (wait-maybe-handle-errors
215 (send-message '() (%current-actor) to-id action
216 #f #t message-body-args)))
218 (define (<-wait* send-options to-id action . message-body-args)
219 "Like <-wait, but allows extra parameters, for example whether to
221 (define* (really-send #:key (actor (%current-actor))
223 (apply wait-maybe-handle-errors
224 (send-message send-options actor to-id action
225 #f #t message-body-args)
227 (apply really-send send-options))
229 ;; TODO: Intelligently ~propagate(ish) errors on -wait functions.
230 ;; We might have `send-message-wait-brazen' to allow callers to
231 ;; not have an exception thrown and instead just have a message with
232 ;; the appropriate '*error* message returned.
234 (define (<-reply original-message . message-body-args)
236 (send-message '() (%current-actor) (message-from original-message) '*reply*
237 original-message #f message-body-args))
239 (define (<-reply* send-options original-message . message-body-args)
240 "Like <-reply, but allows extra parameters via send-options"
241 (define* (really-send #:key (actor (%current-actor))
243 (send-message send-options actor
244 (message-from original-message) '*reply*
245 original-message #f message-body-args))
246 (apply really-send send-options))
248 (define (<-auto-reply actor original-message)
249 "Auto-reply to a message. Internal use only!"
250 (send-message '() actor (message-from original-message) '*auto-reply*
251 original-message #f '()))
253 (define (<-reply-wait original-message . message-body-args)
254 "Reply to a messsage, but wait until we get a response"
255 (wait-maybe-handle-errors
256 (send-message '() (%current-actor)
257 (message-from original-message) '*reply*
258 original-message #t message-body-args)))
260 (define (<-reply-wait* send-options original-message
262 "Like <-reply-wait, but allows extra parameters via send-options"
263 (define* (really-send #:key (actor (%current-actor))
265 (apply wait-maybe-handle-errors
266 (send-message send-options actor
267 (message-from original-message) '*reply*
268 original-message #t message-body-args)
270 (apply really-send send-options))
272 (define* (wait-maybe-handle-errors message
275 "Before returning a message to a waiting caller, see if we need to
276 raise an exception if an error."
277 (define action (message-action message))
278 (cond ((and (eq? action '*error*)
280 (throw 'hive-unresumable-coroutine
281 "Won't resume coroutine; got an *error* as a reply"
287 ;;; Main actor implementation
288 ;;; =========================
290 (define (actor-inheritable-message-handler actor message)
291 (define action (message-action message))
292 (define (find-message-handler return)
293 (for-each (lambda (this-class)
295 (or (and (class-slot-definition this-class 'actions)
296 (class-slot-ref this-class 'actions))
298 (for-each (match-lambda
299 ((action-name . method)
300 (when (eq? action-name action)
303 (class-precedence-list (class-of actor)))
304 (throw 'action-not-found
305 "No appropriate action handler found for actor"
310 (call/ec find-message-handler))
311 (apply method actor message (message-body message)))
313 (define-syntax-rule (build-actions (symbol method) ...)
314 "Construct an alist of (symbol . method), where the method is wrapped
315 with wrap-apply to facilitate live hacking and allow the method definition
316 to come after class definition."
319 (wrap-apply method)) ...))
321 (define-class <actor> ()
323 (id #:init-keyword #:id
325 ;; The hive we're connected to.
326 ;; We need this to be able to send messages.
327 (hive #:init-keyword #:hive
328 #:accessor actor-hive)
329 ;; How we receive and process new messages
330 (message-handler #:init-value actor-inheritable-message-handler
331 ;; @@: There's no reason not to use #:class instead of
332 ;; #:each-subclass anywhere in this file, except for
333 ;; Guile bug #25211 (#:class is broken in Guile 2.2)
334 #:allocation #:each-subclass
335 #:getter actor-message-handler)
337 ;; This is the default, "simple" way to inherit and process messages.
338 (actions #:init-value (build-actions
339 ;; Default init method is to do nothing.
341 ;; Default cleanup method is to do nothing.
342 (*cleanup* (const #f)))
343 #:allocation #:each-subclass))
345 ;;; So these are the nicer representations of addresses.
346 ;;; However, they don't serialize so easily with scheme read/write, so we're
347 ;;; using the simpler cons cell version below for now.
349 ;; (define-record-type <address>
350 ;; (make-address actor-id hive-id) ; @@: Do we want the trailing -id?
352 ;; (actor-id address-actor-id)
353 ;; (hive-id address-hive-id))
355 ;; (set-record-type-printer!
357 ;; (lambda (record port)
358 ;; (format port "<address: ~s@~s>"
359 ;; (address-actor-id record) (address-hive-id record))))
362 (define (make-address actor-id hive-id)
363 (vector actor-id hive-id))
365 (define (address-actor-id address)
366 (vector-ref address 0))
368 (define (address-hive-id address)
369 (vector-ref address 1))
371 (define (address->string address)
372 (string-append (address-actor-id address) "@"
373 (address-hive-id address)))
375 (define-method (actor-id-actor (actor <actor>))
376 "Get the actor id component of the actor-id"
377 (address-actor-id (actor-id actor)))
379 (define-method (actor-id-hive (actor <actor>))
380 "Get the hive id component of the actor-id"
381 (address-hive-id (actor-id actor)))
383 (define-method (actor-id-string (actor <actor>))
384 "Render the full actor id as a human-readable string"
385 (address->string (actor-id actor)))
387 (define %current-actor
390 (define (actor-alive? actor)
391 (hive-resolve-local-actor (actor-hive actor) (actor-id actor)))
398 (define-syntax-rule (define-actor class inherits
401 (define-class class inherits
402 (actions #:init-value (build-actions action ...)
403 #:allocation #:each-subclass)
409 ;;; Every actor has a hive. The hive is a kind of "meta-actor"
410 ;;; which routes all the rest of the actors in a system.
412 (define-generic hive-handle-failed-forward)
414 (define-class <hive> (<actor>)
415 (actor-registry #:init-thunk make-hash-table
416 #:getter hive-actor-registry)
417 (msg-id-generator #:init-thunk simple-message-id-generator
418 #:getter hive-msg-id-generator)
419 ;; Ambassadors are used (or will be) for inter-hive communication.
420 ;; These are special actors that know how to route messages to other hives.
421 (ambassadors #:init-thunk make-weak-key-hash-table
422 #:getter hive-ambassadors)
423 ;; Waiting coroutines
424 ;; This is a map from cons cell of message-id
425 ;; to a cons cell of (actor-id . coroutine)
426 ;; @@: Should we have a <waiting-coroutine> record type?
427 ;; @@: Should there be any way to clear out "old" coroutines?
428 (waiting-coroutines #:init-thunk make-hash-table
429 #:getter hive-waiting-coroutines)
431 ;; When actors send messages to each other they abort to this prompt
432 ;; to send the message, then carry on their way
433 (prompt #:init-thunk make-prompt-tag
434 #:getter hive-prompt)
435 (actions #:allocation #:each-subclass
438 ;; This is in the case of an ambassador failing to forward a
439 ;; message... it reports it back to the hive
440 (*failed-forward* hive-handle-failed-forward)
441 ;; These are called at start and end of run-hive
442 (*init-all* hive-handle-init-all)
443 (*cleanup-all* hive-handle-cleanup-all))))
445 (define-method (hive-handle-init-all (hive <hive>) message)
446 "Run *init* method on all actors in registry"
447 ;; We have to do this hack and run over the list
448 ;; twice, because hash-for-each would result in an unrewindable
449 ;; continuation, and to avoid the hash-map changing during the
452 (hash-map->list (lambda (actor-id actor) actor-id)
453 (hive-actor-registry hive)))
454 (for-each (lambda (actor-id)
455 ;; @@: This could maybe just be <-, but we want actors
456 ;; to be used to the expectation in all circumstances
457 ;; that their init method is "waited on".
458 (<-wait actor-id '*init*))
461 (define-method (hive-handle-failed-forward (hive <hive>) message)
462 "Handle an ambassador failing to forward a message"
465 (define-method (hive-handle-cleanup-all (hive <hive>) message)
466 "Send a message to all actors in our registry to clean themselves up."
467 ;; We have to do this hack and run over the list
468 ;; twice, because hash-for-each would result in an unrewindable
469 ;; continuation, and to avoid the hash-map changing during the
472 (hash-map->list (lambda (actor-id actor) actor-id)
473 (hive-actor-registry hive)))
474 (for-each (lambda (actor-id)
475 (<- actor-id '*cleanup*))
478 (define* (make-hive #:key hive-id)
479 (let ((hive (make <hive>
482 (big-random-number-string))))))
483 ;; Set the hive's actor reference to itself
484 (set! (actor-hive hive) hive)
485 ;; Register the actor with itself
486 (hive-register-actor! hive hive)
489 (define-method (hive-id (hive <hive>))
490 (actor-id-hive hive))
492 (define-method (hive-gen-actor-id (hive <hive>) cookie)
493 (make-address (if cookie
494 (string-append cookie ":" (big-random-number-string))
495 (big-random-number-string))
498 (define-method (hive-gen-message-id (hive <hive>))
499 "Generate a message id using HIVE's message id generator"
500 ((hive-msg-id-generator hive)))
502 (define-method (hive-resolve-local-actor (hive <hive>) actor-address)
503 (hash-ref (hive-actor-registry hive) actor-address))
505 (define-method (hive-resolve-ambassador (hive <hive>) ambassador-address)
506 (hash-ref (hive-ambassadors hive) ambassador-address))
508 (define-method (make-forward-request (hive <hive>) (ambassador <actor>) message)
509 (make-message (hive-gen-message-id hive) (actor-id ambassador)
510 ;; If we make the hive not an actor, we could either switch this
511 ;; to #f or to the original actor...?
512 ;; Maybe some more thinking should be done on what should
513 ;; happen in case of failure to forward? Handling ambassador failures
514 ;; seems like the primary motivation for the hive remaining an actor.
517 `((original . ,message))))
519 (define-method (hive-reply-with-error (hive <hive>) original-message
520 error-key error-args)
521 ;; We only supply the error-args if the original sender is on the same hive
522 (define (orig-actor-on-same-hive?)
523 (equal? (hive-id hive)
524 (address-hive-id (message-from original-message))))
525 (set-message-replied! original-message #t)
526 (let* ((new-message-body
527 (if (orig-actor-on-same-hive?)
528 `(#:original-message ,original-message
529 #:error-key ,error-key
530 #:error-args ,error-args)
531 `(#:original-message ,original-message
532 #:error-key ,error-key)))
533 (new-message (make-message (hive-gen-message-id hive)
534 (message-from original-message)
535 (actor-id hive) '*error*
537 #:in-reply-to (message-id original-message))))
538 ;; We only return a thunk, rather than run 8sync here, because if
539 ;; we ran 8sync in the middle of a catch we'd end up with an
540 ;; unresumable continuation.
541 (lambda () (hive-process-message hive new-message))))
543 (define-record-type <waiting-on-reply>
544 (make-waiting-on-reply actor-id kont send-options)
546 (actor-id waiting-on-reply-actor-id)
547 (kont waiting-on-reply-kont)
548 (send-options waiting-on-reply-send-options))
551 (define-method (hive-process-message (hive <hive>) message)
552 "Handle one message, or forward it via an ambassador"
553 (define (maybe-autoreply actor)
554 ;; Possibly autoreply
555 (if (message-needs-reply? message)
556 (<-auto-reply actor message)))
558 (define (resolve-actor-to)
559 "Get the actor the message was aimed at"
560 (let ((actor (hive-resolve-local-actor hive (message-to message))))
562 (throw 'actor-not-found
563 (format #f "Message ~a from ~a directed to nonexistant actor ~a"
565 (address->string (message-from message))
566 (address->string (message-to message)))
570 (define (call-catching-coroutine thunk)
571 (define queued-error-handling-thunk #f)
572 (define (call-catching-errors)
573 ;; TODO: maybe parameterize (or attach to hive) and use
574 ;; maybe-catch-all from agenda.scm
575 ;; @@: Why not just use with-throw-handler and let the catch
576 ;; happen at the agenda? That's what we used to do, but
577 ;; it ended up with a SIGABRT. See:
578 ;; http://lists.gnu.org/archive/html/bug-guile/2016-05/msg00003.html
581 ;; In the actor model, we don't totally crash on errors.
583 ;; If an error happens, we raise it
585 (if (message-needs-reply? message)
586 ;; If the message is waiting on a reply, let them know
587 ;; something went wrong.
588 ;; However, we have to do it outside of this catch
589 ;; routine, or we'll end up in an unrewindable continuation
591 (set! queued-error-handling-thunk
592 (hive-reply-with-error hive message key args)))
593 ;; print error message
594 (apply print-error-and-continue key args)))
595 ;; @@: This is a kludge. See above for why.
596 (if queued-error-handling-thunk
597 (8sync (queued-error-handling-thunk))))
598 (call-with-prompt (hive-prompt hive)
600 (lambda (kont actor message send-options)
601 ;; Register the coroutine
602 (hash-set! (hive-waiting-coroutines hive)
604 (make-waiting-on-reply
605 (actor-id actor) kont send-options))
606 ;; Send off the message
607 (8sync (hive-process-message hive message)))))
609 (define (process-local-message)
610 (let ((actor (resolve-actor-to)))
611 (call-catching-coroutine
613 (define message-handler (actor-message-handler actor))
614 ;; @@: Should a more general error handling happen here?
615 (parameterize ((%current-actor actor))
617 (message-handler actor message)))
618 (maybe-autoreply actor)
619 ;; Returning result allows actors to possibly make a run-request
620 ;; at the end of handling a message.
621 ;; ... We do want that, right?
624 (define (resume-waiting-coroutine)
625 (case (message-action message)
626 ;; standard reply / auto-reply
627 ((*reply* *auto-reply* *error*)
628 (call-catching-coroutine
630 (match (hash-remove! (hive-waiting-coroutines hive)
631 (message-in-reply-to message))
633 (if (not (equal? (message-to message)
634 (waiting-on-reply-actor-id waiting)))
635 (throw 'resuming-to-wrong-actor
636 "Attempted to resume a coroutine to the wrong actor!"
637 #:expected-actor-id (message-to message)
638 #:got-actor-id (waiting-on-reply-actor-id waiting)
640 (let* (;; @@: How should we resolve resuming coroutines to actors who are
642 (actor (resolve-actor-to))
643 (kont (waiting-on-reply-kont waiting))
644 (result (kont message)))
645 (maybe-autoreply actor)
647 (#f (throw 'no-waiting-coroutine
648 "message in-reply-to tries to resume nonexistent coroutine"
650 ;; Unhandled action for a reply!
652 (throw 'hive-unresumable-coroutine
653 "Won't resume coroutine, nonsense action on reply message"
654 #:action (message-action message)
655 #:message message))))
657 (define (process-remote-message)
658 ;; Find the ambassador
659 (let* ((remote-hive-id (hive-id (message-to message)))
660 (ambassador (hive-resolve-ambassador remote-hive-id))
661 (message-handler (actor-message-handler ambassador))
662 (forward-request (make-forward-request hive ambassador message)))
663 (message-handler ambassador forward-request)))
665 (let ((to (message-to message)))
666 ;; This seems to be an easy mistake to make, so check that addressing
669 (throw 'missing-addressee
670 "`to' field is missing on message"
672 (if (hive-actor-local? hive to)
673 (if (message-in-reply-to message)
674 (resume-waiting-coroutine)
675 (process-local-message))
676 (process-remote-message))))
678 (define-method (hive-actor-local? (hive <hive>) address)
679 (equal? (hive-id hive) (address-hive-id address)))
681 (define-method (hive-register-actor! (hive <hive>) (actor <actor>))
682 (hash-set! (hive-actor-registry hive) (actor-id actor) actor))
684 (define-method (%hive-create-actor (hive <hive>) actor-class
685 init-args id-cookie send-init?)
686 "Actual method called by bootstrap-actor / create-actor.
688 Since this is a define-method it can't accept fancy define* arguments,
689 so this gets called from the nicer bootstrap-actor interface. See
690 that method for documentation."
691 (let* ((actor-id (hive-gen-actor-id hive id-cookie))
692 (actor (apply make actor-class
696 (hive-register-actor! hive actor)
697 ;; Wait on actor to init
699 (<-wait actor-id '*init*))
700 ;; return the actor id
703 (define* (bootstrap-actor hive actor-class #:rest init-args)
704 "Create an actor on HIVE using ACTOR-CLASS passing in INIT-ARGS args"
705 (%hive-create-actor hive actor-class
706 init-args (symbol->string (class-name actor-class))
709 (define* (bootstrap-actor* hive actor-class id-cookie #:rest init-args)
710 "Create an actor, but also allow customizing a 'cookie' added to the id
712 (%hive-create-actor hive actor-class
716 (define (call-with-message message proc)
717 "Applies message body arguments into procedure, with message as first
718 argument. Similar to call-with-values in concept."
719 (apply proc message (message-body message)))
721 ;; (mbody-receive (<- bar baz)
725 ;; Emacs: (put 'mbody-receive 'scheme-indent-function 2)
727 ;; @@: Or receive-msg or receieve-message or??
728 (define-syntax-rule (mbody-receive arglist message body ...)
729 "Call body with arglist (which can accept arguments like lambda*)
730 applied from the message-body of message."
731 (call-with-message message
735 (define (mbody-val message)
736 "Retrieve the first value from the message-body of message.
737 Like single value return from a procedure call. Probably the most
738 common case when waiting on a reply from some action invocation."
739 (call-with-message message
740 (lambda (_ val) val)))
743 ;;; Various API methods for actors to interact with the system
744 ;;; ==========================================================
746 ;; TODO: move send-message and friends here...?
748 (define* (create-actor from-actor actor-class #:rest init-args)
749 "Create an instance of actor-class. Return the new actor's id.
751 This is the method actors should call directly (unless they want
752 to supply an id-cookie, in which case they should use
754 (%hive-create-actor (actor-hive from-actor) actor-class
758 (define* (create-actor* from-actor actor-class id-cookie #:rest init-args)
759 "Create an instance of actor-class. Return the new actor's id.
761 Like create-actor, but permits supplying an id-cookie."
762 (%hive-create-actor (actor-hive from-actor) actor-class
763 init-args id-cookie #t))
766 (define* (self-destruct actor #:key (cleanup #t))
767 "Remove an actor from the hive.
769 Unless #:cleanup is set to #f, this will first have the actor handle
770 its '*cleanup* action handler."
772 (<-wait (actor-id actor) '*cleanup*))
773 (hash-remove! (hive-actor-registry (actor-hive actor))
778 ;;; 8sync bootstrap utilities
779 ;;; =========================
781 (define* (run-hive hive initial-tasks
783 (handle-signals (list SIGINT SIGTERM)))
784 "Start up an agenda and run HIVE in it with INITIAL-TASKS.
787 - #:cleanup: Whether to run *cleanup* on all actors.
788 - #:handle-sigactions: a list of signals to set up interrupt
789 handlers for, so cleanup sill still happen as expected.
790 Defaults to a list of SIGINT and SIGTERM."
794 (define (run-it escape)
795 (define (handle-signal signum)
798 (for-each (lambda (signum)
799 (sigaction signum handle-signal))
801 (let* ((queue (list->q
802 (cons (bootstrap-message hive (actor-id hive) '*init-all*)
804 (agenda (make-agenda #:pre-unwind-handler print-error-and-continue
806 (run-agenda agenda)))
811 (run-hive-cleanup hive)))))
813 (define (run-hive-cleanup hive)
814 (let ((queue (list->q (list (bootstrap-message hive (actor-id hive)
817 (make-agenda #:queue queue))))
819 (define (bootstrap-message hive to-id action . message-body-args)
821 (apply <-* `(#:actor ,hive) to-id action message-body-args)))
825 ;;; Basic readers / writers
826 ;;; =======================
828 (define (serialize-message message)
829 "Serialize a message for read/write"
833 (message-from message)
834 (message-action message)
835 (message-body message)
836 (message-in-reply-to message)
837 (message-wants-reply message)
838 (message-replied message)))
840 (define* (write-message message #:optional (port (current-output-port)))
841 "Write out a message to a port for easy reading later.
843 Note that if a sub-value can't be easily written to something
844 Guile's `read' procedure knows how to read, this doesn't do anything
845 to improve that. You'll need a better serializer for that.."
846 (write (serialize-message message) port))
848 (define (serialize-message-pretty message)
849 "Serialize a message in a way that's easy for humans to read."
851 (id ,(message-id message))
852 (to ,(message-to message))
853 (from ,(message-from message))
854 (action ,(message-action message))
855 (body ,(message-body message))
856 (in-reply-to ,(message-in-reply-to message))
857 (wants-reply ,(message-wants-reply message))
858 (replied ,(message-replied message))))
860 (define (pprint-message message)
861 "Pretty print a message."
862 (pretty-print (serialize-message-pretty message)))
864 (define* (read-message #:optional (port (current-input-port)))
865 "Read a message serialized via serialize-message from PORT"
867 ((id to from action body in-reply-to wants-reply replied)
869 id to from action body
870 in-reply-to wants-reply replied))
872 (throw 'message-read-bad-structure
873 "Could not read message from structure"
876 (define (read-message-from-string message-str)
877 "Read message from MESSAGE-STR"
878 (with-input-from-string message-str
880 (read-message (current-input-port)))))