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240b57f0 | 1 | ;;; GNU Guix --- Functional package management for GNU |
bb64b2e7 | 2 | ;;; Copyright © 2016, 2017, 2018, 2019 Ludovic Courtès <ludo@gnu.org> |
5e03b122 | 3 | ;;; Copyright © 2017 Mathieu Othacehe <m.othacehe@gmail.com> |
240b57f0 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 herd) | |
240b57f0 | 21 | #:use-module (srfi srfi-1) |
183605c8 | 22 | #:use-module (srfi srfi-9) |
240b57f0 | 23 | #:use-module (srfi srfi-11) |
8bf92e39 LC |
24 | #:use-module (srfi srfi-34) |
25 | #:use-module (srfi srfi-35) | |
240b57f0 | 26 | #:use-module (ice-9 match) |
5e03b122 MO |
27 | #:export (%shepherd-socket-file |
28 | ||
29 | shepherd-error? | |
8bf92e39 LC |
30 | service-not-found-error? |
31 | service-not-found-error-service | |
32 | action-not-found-error? | |
33 | action-not-found-error-service | |
34 | action-not-found-error-action | |
35 | action-exception-error? | |
36 | action-exception-error-service | |
37 | action-exception-error-action | |
38 | action-exception-error-key | |
39 | action-exception-error-arguments | |
40 | unknown-shepherd-error? | |
41 | unknown-shepherd-error-sexp | |
42 | ||
183605c8 LC |
43 | live-service? |
44 | live-service-provision | |
45 | live-service-requirement | |
46 | live-service-running | |
47 | ||
147c5aa5 | 48 | with-shepherd-action |
8bf92e39 | 49 | current-services |
240b57f0 LC |
50 | unload-services |
51 | unload-service | |
52 | load-services | |
4245ddcb | 53 | load-services/safe |
0642838b CB |
54 | start-service |
55 | stop-service)) | |
240b57f0 LC |
56 | |
57 | ;;; Commentary: | |
58 | ;;; | |
59 | ;;; This module provides an interface to the GNU Shepherd, similar to the | |
60 | ;;; 'herd' command. Essentially it implements a subset of the (shepherd comm) | |
61 | ;;; module, but focusing only on the parts relevant to 'guix system | |
62 | ;;; reconfigure'. | |
63 | ;;; | |
64 | ;;; Code: | |
65 | ||
66 | (define %shepherd-socket-file | |
5e03b122 | 67 | (make-parameter "/var/run/shepherd/socket")) |
240b57f0 | 68 | |
5e03b122 | 69 | (define* (open-connection #:optional (file (%shepherd-socket-file))) |
240b57f0 LC |
70 | "Open a connection to the daemon, using the Unix-domain socket at FILE, and |
71 | return the socket." | |
72 | ;; The protocol is sexp-based and UTF-8-encoded. | |
73 | (with-fluids ((%default-port-encoding "UTF-8")) | |
74 | (let ((sock (socket PF_UNIX SOCK_STREAM 0)) | |
75 | (address (make-socket-address PF_UNIX file))) | |
76 | (catch 'system-error | |
77 | (lambda () | |
78 | (connect sock address) | |
bb64b2e7 | 79 | (setvbuf sock 'block 1024) |
240b57f0 | 80 | sock) |
1d6b7d58 LC |
81 | (lambda args |
82 | (close-port sock) | |
83 | (apply throw args)))))) | |
240b57f0 LC |
84 | |
85 | (define-syntax-rule (with-shepherd connection body ...) | |
86 | "Evaluate BODY... with CONNECTION bound to an open socket to PID 1." | |
87 | (let ((connection (open-connection))) | |
89a26478 LC |
88 | (dynamic-wind |
89 | (const #t) | |
90 | (lambda () | |
91 | body ...) | |
92 | (lambda () | |
93 | (close-port connection))))) | |
240b57f0 | 94 | |
8bf92e39 LC |
95 | (define-condition-type &shepherd-error &error |
96 | shepherd-error?) | |
97 | ||
98 | (define-condition-type &service-not-found-error &shepherd-error | |
99 | service-not-found-error? | |
100 | (service service-not-found-error-service)) | |
101 | ||
102 | (define-condition-type &action-not-found-error &shepherd-error | |
103 | action-not-found-error? | |
104 | (service action-not-found-error-service) | |
105 | (action action-not-found-error-action)) | |
106 | ||
107 | (define-condition-type &action-exception-error &shepherd-error | |
108 | action-exception-error? | |
109 | (service action-exception-error-service) | |
110 | (action action-exception-error-action) | |
111 | (key action-exception-error-key) | |
112 | (args action-exception-error-arguments)) | |
113 | ||
114 | (define-condition-type &unknown-shepherd-error &shepherd-error | |
115 | unknown-shepherd-error? | |
116 | (sexp unknown-shepherd-error-sexp)) | |
117 | ||
118 | (define (raise-shepherd-error error) | |
119 | "Raise an error condition corresponding to ERROR, an sexp received by a | |
120 | shepherd client in reply to COMMAND, a command object. Return #t if ERROR | |
121 | does not denote an error." | |
240b57f0 LC |
122 | (match error |
123 | (('error ('version 0 x ...) 'service-not-found service) | |
8bf92e39 LC |
124 | (raise (condition (&service-not-found-error |
125 | (service service))))) | |
240b57f0 | 126 | (('error ('version 0 x ...) 'action-not-found action service) |
8bf92e39 LC |
127 | (raise (condition (&action-not-found-error |
128 | (service service) | |
129 | (action action))))) | |
240b57f0 LC |
130 | (('error ('version 0 x ...) 'action-exception action service |
131 | key (args ...)) | |
8bf92e39 LC |
132 | (raise (condition (&action-exception-error |
133 | (service service) | |
134 | (action action) | |
135 | (key key) (args args))))) | |
240b57f0 | 136 | (('error . _) |
8bf92e39 | 137 | (raise (condition (&unknown-shepherd-error (sexp error))))) |
240b57f0 LC |
138 | (#f ;not an error |
139 | #t))) | |
140 | ||
141 | (define (display-message message) | |
8bf92e39 | 142 | (format (current-error-port) "shepherd: ~a~%" message)) |
240b57f0 LC |
143 | |
144 | (define* (invoke-action service action arguments cont) | |
145 | "Invoke ACTION on SERVICE with ARGUMENTS. On success, call CONT with the | |
7d14082d LC |
146 | list of results (one result per instance with the name SERVICE). Otherwise |
147 | return #f." | |
240b57f0 LC |
148 | (with-shepherd sock |
149 | (write `(shepherd-command (version 0) | |
150 | (action ,action) | |
151 | (service ,service) | |
152 | (arguments ,arguments) | |
153 | (directory ,(getcwd))) | |
154 | sock) | |
155 | (force-output sock) | |
156 | ||
157 | (match (read sock) | |
dc7b3e56 | 158 | (('reply ('version 0 _ ...) ('result result) ('error #f) |
240b57f0 LC |
159 | ('messages messages)) |
160 | (for-each display-message messages) | |
161 | (cont result)) | |
162 | (('reply ('version 0 x ...) ('result y) ('error error) | |
163 | ('messages messages)) | |
164 | (for-each display-message messages) | |
8bf92e39 | 165 | (raise-shepherd-error error) |
240b57f0 LC |
166 | #f) |
167 | (x | |
8bf92e39 | 168 | ;; invalid reply |
240b57f0 LC |
169 | #f)))) |
170 | ||
171 | (define-syntax-rule (with-shepherd-action service (action args ...) | |
172 | result body ...) | |
147c5aa5 LC |
173 | "Invoke ACTION on SERVICE with the given ARGS, and evaluate BODY with RESULT |
174 | bound to the action's result." | |
240b57f0 LC |
175 | (invoke-action service action (list args ...) |
176 | (lambda (result) body ...))) | |
177 | ||
178 | (define-syntax alist-let* | |
179 | (syntax-rules () | |
180 | "Bind the given KEYs in EXP to the corresponding items in ALIST. ALIST | |
181 | is assumed to be a list of two-element tuples rather than a traditional list | |
182 | of pairs." | |
183 | ((_ alist (key ...) exp ...) | |
184 | (let ((key (and=> (assoc-ref alist 'key) car)) ...) | |
185 | exp ...)))) | |
186 | ||
183605c8 LC |
187 | ;; Information about live Shepherd services. |
188 | (define-record-type <live-service> | |
189 | (live-service provision requirement running) | |
190 | live-service? | |
191 | (provision live-service-provision) ;list of symbols | |
192 | (requirement live-service-requirement) ;list of symbols | |
193 | (running live-service-running)) ;#f | object | |
194 | ||
240b57f0 | 195 | (define (current-services) |
183605c8 LC |
196 | "Return the list of currently defined Shepherd services, represented as |
197 | <live-service> objects. Return #f if the list of services could not be | |
198 | obtained." | |
7d14082d LC |
199 | (with-shepherd-action 'root ('status) results |
200 | ;; We get a list of results, one for each service with the name 'root'. | |
201 | ;; In practice there's only one such service though. | |
202 | (match results | |
203 | ((services _ ...) | |
204 | (match services | |
205 | ((('service ('version 0 _ ...) _ ...) ...) | |
206 | (map (lambda (service) | |
207 | (alist-let* service (provides requires running) | |
208 | (live-service provides requires running))) | |
209 | services)) | |
210 | (x | |
211 | #f)))))) | |
240b57f0 LC |
212 | |
213 | (define (unload-service service) | |
214 | "Unload SERVICE, a symbol name; return #t on success." | |
215 | (with-shepherd-action 'root ('unload (symbol->string service)) result | |
7d14082d | 216 | (first result))) |
240b57f0 LC |
217 | |
218 | (define (%load-file file) | |
219 | "Load FILE in the Shepherd." | |
220 | (with-shepherd-action 'root ('load file) result | |
7d14082d | 221 | (first result))) |
240b57f0 LC |
222 | |
223 | (define (eval-there exp) | |
224 | "Eval EXP in the Shepherd." | |
225 | (with-shepherd-action 'root ('eval (object->string exp)) result | |
7d14082d | 226 | (first result))) |
240b57f0 LC |
227 | |
228 | (define (load-services files) | |
229 | "Load and register the services from FILES, where FILES contain code that | |
230 | returns a shepherd <service> object." | |
231 | (eval-there `(register-services | |
232 | ,@(map (lambda (file) | |
233 | `(primitive-load ,file)) | |
234 | files)))) | |
235 | ||
4245ddcb CZ |
236 | (define (load-services/safe files) |
237 | "This is like 'load-services', but make sure only the subset of FILES that | |
238 | can be safely reloaded is actually reloaded. | |
239 | ||
240 | This is done to accommodate the Shepherd < 0.15.0 where services lacked the | |
241 | 'replacement' slot, and where 'register-services' would throw an exception | |
242 | when passed a service with an already-registered name." | |
243 | (eval-there `(let* ((services (map primitive-load ',files)) | |
244 | (slots (map slot-definition-name | |
245 | (class-slots <service>))) | |
246 | (can-replace? (memq 'replacement slots))) | |
247 | (define (registered? service) | |
248 | (not (null? (lookup-services (canonical-name service))))) | |
249 | ||
250 | (apply register-services | |
251 | (if can-replace? | |
252 | services | |
253 | (remove registered? services)))))) | |
254 | ||
ca0c43ec MO |
255 | (define* (start-service name #:optional (arguments '())) |
256 | (invoke-action name 'start arguments | |
257 | (lambda (result) | |
258 | result))) | |
240b57f0 | 259 | |
0642838b CB |
260 | (define (stop-service name) |
261 | (with-shepherd-action name ('stop) result | |
262 | result)) | |
263 | ||
240b57f0 LC |
264 | ;; Local Variables: |
265 | ;; eval: (put 'alist-let* 'scheme-indent-function 2) | |
266 | ;; eval: (put 'with-shepherd 'scheme-indent-function 1) | |
267 | ;; eval: (put 'with-shepherd-action 'scheme-indent-function 3) | |
268 | ;; End: | |
269 | ||
270 | ;;; herd.scm ends here |