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db4fdc04 | 1 | ;;; GNU Guix --- Functional package management for GNU |
94af9daa | 2 | ;;; Copyright © 2015, 2016 Ludovic Courtès <ludo@gnu.org> |
4d343a14 | 3 | ;;; Copyright © 2016 Chris Marusich <cmmarusich@gmail.com> |
db4fdc04 LC |
4 | ;;; |
5 | ;;; This file is part of GNU Guix. | |
6 | ;;; | |
7 | ;;; GNU Guix is free software; you can redistribute it and/or modify it | |
8 | ;;; under the terms of the GNU General Public License as published by | |
9 | ;;; the Free Software Foundation; either version 3 of the License, or (at | |
10 | ;;; your option) any later version. | |
11 | ;;; | |
12 | ;;; GNU Guix is distributed in the hope that it will be useful, but | |
13 | ;;; WITHOUT ANY WARRANTY; without even the implied warranty of | |
14 | ;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
15 | ;;; GNU General Public License for more details. | |
16 | ;;; | |
17 | ;;; You should have received a copy of the GNU General Public License | |
18 | ;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>. | |
19 | ||
20 | (define-module (gnu services) | |
bebc8681 | 21 | #:use-module (guix gexp) |
0adfe95a LC |
22 | #:use-module (guix monads) |
23 | #:use-module (guix store) | |
db4fdc04 | 24 | #:use-module (guix records) |
af4c3fd5 | 25 | #:use-module (guix profiles) |
0adfe95a LC |
26 | #:use-module (guix sets) |
27 | #:use-module (guix ui) | |
28 | #:use-module (gnu packages base) | |
29 | #:use-module (gnu packages bash) | |
30 | #:use-module (srfi srfi-1) | |
31 | #:use-module (srfi srfi-9) | |
32 | #:use-module (srfi srfi-9 gnu) | |
33 | #:use-module (srfi srfi-26) | |
34 | #:use-module (srfi srfi-34) | |
35 | #:use-module (srfi srfi-35) | |
36 | #:use-module (ice-9 vlist) | |
37 | #:use-module (ice-9 match) | |
38 | #:export (service-extension | |
39 | service-extension? | |
40 | ||
41 | service-type | |
42 | service-type? | |
5152d13b LC |
43 | service-type-name |
44 | service-type-extensions | |
45 | service-type-compose | |
46 | service-type-extend | |
0adfe95a | 47 | |
db4fdc04 | 48 | service |
0adfe95a LC |
49 | service? |
50 | service-kind | |
51 | service-parameters | |
52 | ||
cd6f6c22 | 53 | modify-services |
5152d13b | 54 | service-back-edges |
0adfe95a LC |
55 | fold-services |
56 | ||
57 | service-error? | |
58 | missing-target-service-error? | |
59 | missing-target-service-error-service | |
60 | missing-target-service-error-target-type | |
61 | ambiguous-target-service-error? | |
62 | ambiguous-target-service-error-service | |
63 | ambiguous-target-service-error-target-type | |
64 | ||
d62e201c | 65 | system-service-type |
0adfe95a | 66 | boot-service-type |
be7be9e8 | 67 | cleanup-service-type |
0adfe95a LC |
68 | activation-service-type |
69 | activation-service->script | |
a241a7ac | 70 | %linux-bare-metal-service |
0adfe95a LC |
71 | etc-service-type |
72 | etc-directory | |
73 | setuid-program-service-type | |
af4c3fd5 | 74 | profile-service-type |
0adfe95a LC |
75 | firmware-service-type |
76 | ||
77 | %boot-service | |
78 | %activation-service | |
79 | etc-service | |
80 | ||
81 | file-union)) ;XXX: for lack of a better place | |
82 | ||
83 | ;;; Comment: | |
84 | ;;; | |
85 | ;;; This module defines a broad notion of "service types" and "services." | |
db4fdc04 | 86 | ;;; |
0adfe95a LC |
87 | ;;; A service type describe how its instances extend instances of other |
88 | ;;; service types. For instance, some services extend the instance of | |
89 | ;;; ACCOUNT-SERVICE-TYPE by providing it with accounts and groups to create; | |
d4053c71 AK |
90 | ;;; others extend SHEPHERD-ROOT-SERVICE-TYPE by passing it instances of |
91 | ;;; <shepherd-service>. | |
0adfe95a LC |
92 | ;;; |
93 | ;;; When applicable, the service type defines how it can itself be extended, | |
94 | ;;; by providing one procedure to compose extensions, and one procedure to | |
95 | ;;; extend itself. | |
96 | ;;; | |
d62e201c LC |
97 | ;;; A notable service type is SYSTEM-SERVICE-TYPE, which has a single |
98 | ;;; instance, which is the root of the service DAG. Its value is the | |
99 | ;;; derivation that produces the 'system' directory as returned by | |
100 | ;;; 'operating-system-derivation'. | |
0adfe95a LC |
101 | ;;; |
102 | ;;; The 'fold-services' procedure can be passed a list of procedures, which it | |
103 | ;;; "folds" by propagating extensions down the graph; it returns the root | |
104 | ;;; service after the applying all its extensions. | |
db4fdc04 LC |
105 | ;;; |
106 | ;;; Code: | |
107 | ||
0adfe95a LC |
108 | (define-record-type <service-extension> |
109 | (service-extension target compute) | |
110 | service-extension? | |
111 | (target service-extension-target) ;<service-type> | |
112 | (compute service-extension-compute)) ;params -> params | |
113 | ||
114 | (define-record-type* <service-type> service-type make-service-type | |
115 | service-type? | |
116 | (name service-type-name) ;symbol (for debugging) | |
117 | ||
118 | ;; Things extended by services of this type. | |
119 | (extensions service-type-extensions) ;list of <service-extensions> | |
120 | ||
121 | ;; Given a list of extensions, "compose" them. | |
122 | (compose service-type-compose ;list of Any -> Any | |
123 | (default #f)) | |
124 | ||
125 | ;; Extend the services' own parameters with the extension composition. | |
126 | (extend service-type-extend ;list of Any -> parameters | |
127 | (default #f))) | |
128 | ||
129 | (define (write-service-type type port) | |
130 | (format port "#<service-type ~a ~a>" | |
131 | (service-type-name type) | |
132 | (number->string (object-address type) 16))) | |
133 | ||
134 | (set-record-type-printer! <service-type> write-service-type) | |
135 | ||
136 | ;; Services of a given type. | |
137 | (define-record-type <service> | |
138 | (service type parameters) | |
db4fdc04 | 139 | service? |
0adfe95a LC |
140 | (type service-kind) |
141 | (parameters service-parameters)) | |
142 | ||
143 | ||
cd6f6c22 LC |
144 | (define-syntax %modify-service |
145 | (syntax-rules (=>) | |
146 | ((_ service) | |
147 | service) | |
148 | ((_ svc (kind param => exp ...) clauses ...) | |
149 | (if (eq? (service-kind svc) kind) | |
150 | (let ((param (service-parameters svc))) | |
151 | (service (service-kind svc) | |
152 | (begin exp ...))) | |
153 | (%modify-service svc clauses ...))))) | |
154 | ||
155 | (define-syntax modify-services | |
156 | (syntax-rules () | |
4d343a14 CM |
157 | "Modify the services listed in SERVICES according to CLAUSES and return |
158 | the resulting list of services. Each clause must have the form: | |
cd6f6c22 LC |
159 | |
160 | (TYPE VARIABLE => BODY) | |
161 | ||
162 | where TYPE is a service type, such as 'guix-service-type', and VARIABLE is an | |
163 | identifier that is bound within BODY to the value of the service of that | |
164 | TYPE. Consider this example: | |
165 | ||
166 | (modify-services %base-services | |
167 | (guix-service-type config => | |
168 | (guix-configuration | |
169 | (inherit config) | |
170 | (use-substitutes? #f) | |
171 | (extra-options '(\"--gc-keep-derivations\")))) | |
172 | (mingetty-service-type config => | |
173 | (mingetty-configuration | |
174 | (inherit config) | |
175 | (motd (plain-file \"motd\" \"Hi there!\"))))) | |
176 | ||
177 | It changes the configuration of the GUIX-SERVICE-TYPE instance, and that of | |
178 | all the MINGETTY-SERVICE-TYPE instances. | |
179 | ||
180 | This is a shorthand for (map (lambda (svc) ...) %base-services)." | |
181 | ((_ services clauses ...) | |
182 | (map (lambda (service) | |
183 | (%modify-service service clauses ...)) | |
184 | services)))) | |
0adfe95a LC |
185 | |
186 | \f | |
187 | ;;; | |
188 | ;;; Core services. | |
189 | ;;; | |
190 | ||
d62e201c LC |
191 | (define (system-derivation mentries mextensions) |
192 | "Return as a monadic value the derivation of the 'system' directory | |
193 | containing the given entries." | |
194 | (mlet %store-monad ((entries mentries) | |
195 | (extensions (sequence %store-monad mextensions))) | |
196 | (lower-object | |
197 | (file-union "system" | |
198 | (append entries (concatenate extensions)))))) | |
199 | ||
200 | (define system-service-type | |
201 | ;; This is the ultimate service type, the root of the service DAG. The | |
202 | ;; service of this type is extended by monadic name/item pairs. These items | |
203 | ;; end up in the "system directory" as returned by | |
204 | ;; 'operating-system-derivation'. | |
205 | (service-type (name 'system) | |
206 | (extensions '()) | |
207 | (compose identity) | |
208 | (extend system-derivation))) | |
209 | ||
3a391e68 | 210 | (define (compute-boot-script _ mexps) |
be7be9e8 | 211 | (mlet %store-monad ((gexps (sequence %store-monad mexps))) |
0adfe95a | 212 | (gexp->file "boot" |
d4053c71 | 213 | ;; Clean up and activate the system, then spawn shepherd. |
be7be9e8 | 214 | #~(begin #$@gexps)))) |
0adfe95a | 215 | |
d62e201c LC |
216 | (define (boot-script-entry mboot) |
217 | "Return, as a monadic value, an entry for the boot script in the system | |
218 | directory." | |
219 | (mlet %store-monad ((boot mboot)) | |
220 | (return `(("boot" ,boot))))) | |
221 | ||
0adfe95a LC |
222 | (define boot-service-type |
223 | ;; The service of this type is extended by being passed gexps as monadic | |
224 | ;; values. It aggregates them in a single script, as a monadic value, which | |
225 | ;; becomes its 'parameters'. It is the only service that extends nothing. | |
226 | (service-type (name 'boot) | |
d62e201c LC |
227 | (extensions |
228 | (list (service-extension system-service-type | |
229 | boot-script-entry))) | |
3a391e68 LC |
230 | (compose append) |
231 | (extend compute-boot-script))) | |
0adfe95a LC |
232 | |
233 | (define %boot-service | |
d62e201c | 234 | ;; The service that produces the boot script. |
0adfe95a | 235 | (service boot-service-type #t)) |
be7be9e8 LC |
236 | |
237 | (define (cleanup-gexp _) | |
238 | "Return as a monadic value a gexp to clean up /tmp and similar places upon | |
239 | boot." | |
240 | (define %modules | |
241 | '((guix build utils))) | |
242 | ||
243 | (mlet %store-monad ((modules (imported-modules %modules)) | |
244 | (compiled (compiled-modules %modules))) | |
245 | (return #~(begin | |
246 | (eval-when (expand load eval) | |
247 | ;; Make sure 'use-modules' below succeeds. | |
248 | (set! %load-path (cons #$modules %load-path)) | |
249 | (set! %load-compiled-path | |
250 | (cons #$compiled %load-compiled-path))) | |
251 | ||
252 | (use-modules (guix build utils)) | |
253 | ||
254 | ;; Clean out /tmp and /var/run. | |
255 | ;; | |
256 | ;; XXX This needs to happen before service activations, so it | |
257 | ;; has to be here, but this also implicitly assumes that /tmp | |
258 | ;; and /var/run are on the root partition. | |
3c4c8c3e LC |
259 | (letrec-syntax ((fail-safe (syntax-rules () |
260 | ((_ exp rest ...) | |
261 | (begin | |
262 | (catch 'system-error | |
263 | (lambda () exp) | |
264 | (const #f)) | |
265 | (fail-safe rest ...))) | |
266 | ((_) | |
267 | #t)))) | |
268 | ;; Ignore I/O errors so the system can boot. | |
269 | (fail-safe | |
270 | (delete-file-recursively "/tmp") | |
271 | (delete-file-recursively "/var/run") | |
272 | (mkdir "/tmp") | |
273 | (chmod "/tmp" #o1777) | |
274 | (mkdir "/var/run") | |
275 | (chmod "/var/run" #o755))))))) | |
be7be9e8 LC |
276 | |
277 | (define cleanup-service-type | |
278 | ;; Service that cleans things up in /tmp and similar. | |
279 | (service-type (name 'cleanup) | |
280 | (extensions | |
281 | (list (service-extension boot-service-type | |
282 | cleanup-gexp))))) | |
0adfe95a LC |
283 | |
284 | (define* (file-union name files) ;FIXME: Factorize. | |
285 | "Return a <computed-file> that builds a directory containing all of FILES. | |
286 | Each item in FILES must be a list where the first element is the file name to | |
287 | use in the new directory, and the second element is a gexp denoting the target | |
288 | file." | |
289 | (computed-file name | |
290 | #~(begin | |
291 | (mkdir #$output) | |
292 | (chdir #$output) | |
293 | #$@(map (match-lambda | |
294 | ((target source) | |
37dd1e6a LC |
295 | #~(begin |
296 | ;; Stat the source to abort early if it | |
297 | ;; does not exist. | |
298 | (stat #$source) | |
299 | ||
300 | (symlink #$source #$target)))) | |
0adfe95a LC |
301 | files)))) |
302 | ||
303 | (define (directory-union name things) | |
304 | "Return a directory that is the union of THINGS." | |
305 | (match things | |
306 | ((one) | |
307 | ;; Only one thing; return it. | |
308 | one) | |
309 | (_ | |
310 | (computed-file name | |
311 | #~(begin | |
312 | (use-modules (guix build union)) | |
313 | (union-build #$output '#$things)) | |
314 | #:modules '((guix build union)))))) | |
315 | ||
0adfe95a LC |
316 | (define* (activation-service->script service) |
317 | "Return as a monadic value the activation script for SERVICE, a service of | |
318 | ACTIVATION-SCRIPT-TYPE." | |
319 | (activation-script (service-parameters service))) | |
320 | ||
321 | (define (activation-script gexps) | |
322 | "Return the system's activation script, which evaluates GEXPS." | |
323 | (define %modules | |
324 | '((gnu build activation) | |
325 | (gnu build linux-boot) | |
326 | (gnu build linux-modules) | |
327 | (gnu build file-systems) | |
328 | (guix build utils) | |
329 | (guix build syscalls) | |
6eb43907 | 330 | (guix build bournish) |
0adfe95a LC |
331 | (guix elf))) |
332 | ||
333 | (define (service-activations) | |
334 | ;; Return the activation scripts for SERVICES. | |
335 | (mapm %store-monad | |
336 | (cut gexp->file "activate-service" <>) | |
337 | gexps)) | |
338 | ||
339 | (mlet* %store-monad ((actions (service-activations)) | |
340 | (modules (imported-modules %modules)) | |
a241a7ac | 341 | (compiled (compiled-modules %modules))) |
0adfe95a LC |
342 | (gexp->file "activate" |
343 | #~(begin | |
344 | (eval-when (expand load eval) | |
345 | ;; Make sure 'use-modules' below succeeds. | |
346 | (set! %load-path (cons #$modules %load-path)) | |
347 | (set! %load-compiled-path | |
348 | (cons #$compiled %load-compiled-path))) | |
349 | ||
350 | (use-modules (gnu build activation)) | |
351 | ||
352 | ;; Make sure /bin/sh is valid and current. | |
353 | (activate-/bin/sh | |
354 | (string-append #$(canonical-package bash) "/bin/sh")) | |
355 | ||
0adfe95a LC |
356 | ;; Run the services' activation snippets. |
357 | ;; TODO: Use 'load-compiled'. | |
358 | (for-each primitive-load '#$actions) | |
359 | ||
360 | ;; Set up /run/current-system. | |
361 | (activate-current-system))))) | |
362 | ||
363 | (define (gexps->activation-gexp gexps) | |
364 | "Return a gexp that runs the activation script containing GEXPS." | |
365 | (mlet %store-monad ((script (activation-script gexps))) | |
366 | (return #~(primitive-load #$script)))) | |
367 | ||
3a391e68 LC |
368 | (define (second-argument a b) b) |
369 | ||
0adfe95a LC |
370 | (define activation-service-type |
371 | (service-type (name 'activate) | |
372 | (extensions | |
373 | (list (service-extension boot-service-type | |
374 | gexps->activation-gexp))) | |
375 | (compose append) | |
376 | (extend second-argument))) | |
377 | ||
378 | (define %activation-service | |
379 | ;; The activation service produces the activation script from the gexps it | |
380 | ;; receives. | |
381 | (service activation-service-type #t)) | |
382 | ||
a241a7ac LC |
383 | (define %modprobe-wrapper |
384 | ;; Wrapper for the 'modprobe' command that knows where modules live. | |
385 | ;; | |
386 | ;; This wrapper is typically invoked by the Linux kernel ('call_modprobe', | |
387 | ;; in kernel/kmod.c), a situation where the 'LINUX_MODULE_DIRECTORY' | |
388 | ;; environment variable is not set---hence the need for this wrapper. | |
389 | (let ((modprobe "/run/current-system/profile/bin/modprobe")) | |
390 | (program-file "modprobe" | |
391 | #~(begin | |
392 | (setenv "LINUX_MODULE_DIRECTORY" | |
393 | "/run/booted-system/kernel/lib/modules") | |
394 | (apply execl #$modprobe | |
395 | (cons #$modprobe (cdr (command-line)))))))) | |
396 | ||
397 | (define %linux-kernel-activation | |
398 | ;; Activation of the Linux kernel running on the bare metal (as opposed to | |
399 | ;; running in a container.) | |
400 | #~(begin | |
401 | ;; Tell the kernel to use our 'modprobe' command. | |
402 | (activate-modprobe #$%modprobe-wrapper) | |
403 | ||
404 | ;; Let users debug their own processes! | |
405 | (activate-ptrace-attach))) | |
406 | ||
407 | (define linux-bare-metal-service-type | |
408 | (service-type (name 'linux-bare-metal) | |
409 | (extensions | |
410 | (list (service-extension activation-service-type | |
411 | (const %linux-kernel-activation)))))) | |
412 | ||
413 | (define %linux-bare-metal-service | |
414 | ;; The service that does things that are needed on the "bare metal", but not | |
415 | ;; necessary or impossible in a container. | |
416 | (service linux-bare-metal-service-type #f)) | |
417 | ||
0adfe95a LC |
418 | (define (etc-directory service) |
419 | "Return the directory for SERVICE, a service of type ETC-SERVICE-TYPE." | |
420 | (files->etc-directory (service-parameters service))) | |
421 | ||
422 | (define (files->etc-directory files) | |
423 | (file-union "etc" files)) | |
424 | ||
d62e201c LC |
425 | (define (etc-entry files) |
426 | "Return an entry for the /etc directory consisting of FILES in the system | |
427 | directory." | |
428 | (with-monad %store-monad | |
429 | (return `(("etc" ,(files->etc-directory files)))))) | |
430 | ||
0adfe95a LC |
431 | (define etc-service-type |
432 | (service-type (name 'etc) | |
433 | (extensions | |
434 | (list | |
435 | (service-extension activation-service-type | |
436 | (lambda (files) | |
437 | (let ((etc | |
438 | (files->etc-directory files))) | |
d62e201c LC |
439 | #~(activate-etc #$etc)))) |
440 | (service-extension system-service-type etc-entry))) | |
0adfe95a LC |
441 | (compose concatenate) |
442 | (extend append))) | |
443 | ||
444 | (define (etc-service files) | |
445 | "Return a new service of ETC-SERVICE-TYPE that populates /etc with FILES. | |
446 | FILES must be a list of name/file-like object pairs." | |
447 | (service etc-service-type files)) | |
448 | ||
449 | (define setuid-program-service-type | |
450 | (service-type (name 'setuid-program) | |
451 | (extensions | |
452 | (list (service-extension activation-service-type | |
453 | (lambda (programs) | |
454 | #~(activate-setuid-programs | |
455 | (list #$@programs)))))) | |
456 | (compose concatenate) | |
457 | (extend append))) | |
458 | ||
af4c3fd5 LC |
459 | (define (packages->profile-entry packages) |
460 | "Return a system entry for the profile containing PACKAGES." | |
461 | (mlet %store-monad ((profile (profile-derivation | |
60a0886d SB |
462 | (packages->manifest |
463 | (delete-duplicates packages eq?))))) | |
af4c3fd5 LC |
464 | (return `(("profile" ,profile))))) |
465 | ||
466 | (define profile-service-type | |
467 | ;; The service that populates the system's profile---i.e., | |
468 | ;; /run/current-system/profile. It is extended by package lists. | |
469 | (service-type (name 'profile) | |
470 | (extensions | |
471 | (list (service-extension system-service-type | |
472 | packages->profile-entry))) | |
473 | (compose concatenate) | |
474 | (extend append))) | |
475 | ||
0adfe95a LC |
476 | (define (firmware->activation-gexp firmware) |
477 | "Return a gexp to make the packages listed in FIRMWARE loadable by the | |
478 | kernel." | |
479 | (let ((directory (directory-union "firmware" firmware))) | |
480 | ;; Tell the kernel where firmware is. | |
481 | #~(activate-firmware (string-append #$directory "/lib/firmware")))) | |
482 | ||
483 | (define firmware-service-type | |
484 | ;; The service that collects firmware. | |
485 | (service-type (name 'firmware) | |
486 | (extensions | |
487 | (list (service-extension activation-service-type | |
488 | firmware->activation-gexp))) | |
489 | (compose concatenate) | |
490 | (extend append))) | |
491 | ||
492 | \f | |
493 | ;;; | |
494 | ;;; Service folding. | |
495 | ;;; | |
496 | ||
497 | (define-condition-type &service-error &error | |
498 | service-error?) | |
499 | ||
500 | (define-condition-type &missing-target-service-error &service-error | |
501 | missing-target-service-error? | |
502 | (service missing-target-service-error-service) | |
503 | (target-type missing-target-service-error-target-type)) | |
504 | ||
505 | (define-condition-type &ambiguous-target-service-error &service-error | |
506 | ambiguous-target-service-error? | |
507 | (service ambiguous-target-service-error-service) | |
508 | (target-type ambiguous-target-service-error-target-type)) | |
509 | ||
510 | (define (service-back-edges services) | |
511 | "Return a procedure that, when passed a <service>, returns the list of | |
512 | <service> objects that depend on it." | |
513 | (define (add-edges service edges) | |
514 | (define (add-edge extension edges) | |
515 | (let ((target-type (service-extension-target extension))) | |
516 | (match (filter (lambda (service) | |
517 | (eq? (service-kind service) target-type)) | |
518 | services) | |
519 | ((target) | |
520 | (vhash-consq target service edges)) | |
521 | (() | |
522 | (raise | |
523 | (condition (&missing-target-service-error | |
524 | (service service) | |
525 | (target-type target-type)) | |
526 | (&message | |
527 | (message | |
528 | (format #f (_ "no target of type '~a' for service ~s") | |
529 | (service-type-name target-type) | |
530 | service)))))) | |
531 | (x | |
532 | (raise | |
533 | (condition (&ambiguous-target-service-error | |
534 | (service service) | |
535 | (target-type target-type)) | |
536 | (&message | |
537 | (message | |
538 | (format #f | |
539 | (_ "more than one target service of type '~a'") | |
540 | (service-type-name target-type)))))))))) | |
541 | ||
542 | (fold add-edge edges (service-type-extensions (service-kind service)))) | |
543 | ||
544 | (let ((edges (fold add-edges vlist-null services))) | |
545 | (lambda (node) | |
546 | (reverse (vhash-foldq* cons '() node edges))))) | |
547 | ||
d62e201c LC |
548 | (define* (fold-services services |
549 | #:key (target-type system-service-type)) | |
0adfe95a LC |
550 | "Fold SERVICES by propagating their extensions down to the root of type |
551 | TARGET-TYPE; return the root service adjusted accordingly." | |
552 | (define dependents | |
553 | (service-back-edges services)) | |
554 | ||
555 | (define (matching-extension target) | |
556 | (let ((target (service-kind target))) | |
557 | (match-lambda | |
558 | (($ <service-extension> type) | |
559 | (eq? type target))))) | |
560 | ||
561 | (define (apply-extension target) | |
562 | (lambda (service) | |
563 | (match (find (matching-extension target) | |
564 | (service-type-extensions (service-kind service))) | |
565 | (($ <service-extension> _ compute) | |
566 | (compute (service-parameters service)))))) | |
567 | ||
568 | (match (filter (lambda (service) | |
569 | (eq? (service-kind service) target-type)) | |
570 | services) | |
571 | ((sink) | |
572 | (let loop ((sink sink)) | |
573 | (let* ((dependents (map loop (dependents sink))) | |
574 | (extensions (map (apply-extension sink) dependents)) | |
575 | (extend (service-type-extend (service-kind sink))) | |
576 | (compose (service-type-compose (service-kind sink))) | |
577 | (params (service-parameters sink))) | |
578 | ;; We distinguish COMPOSE and EXTEND because PARAMS typically has a | |
579 | ;; different type than the elements of EXTENSIONS. | |
580 | (if extend | |
581 | (service (service-kind sink) | |
582 | (extend params (compose extensions))) | |
583 | sink)))) | |
584 | (() | |
585 | (raise | |
586 | (condition (&missing-target-service-error | |
587 | (service #f) | |
588 | (target-type target-type)) | |
589 | (&message | |
590 | (message (format #f (_ "service of type '~a' not found") | |
591 | (service-type-name target-type))))))) | |
592 | (x | |
593 | (raise | |
594 | (condition (&ambiguous-target-service-error | |
595 | (service #f) | |
596 | (target-type target-type)) | |
597 | (&message | |
598 | (message | |
599 | (format #f | |
600 | (_ "more than one target service of type '~a'") | |
601 | (service-type-name target-type))))))))) | |
db4fdc04 LC |
602 | |
603 | ;;; services.scm ends here. |