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1 | ;;; GNU Guix --- Functional package management for GNU |
2 | ;;; Copyright © 2016 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 | ||
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43 | live-service? |
44 | live-service-provision | |
45 | live-service-requirement | |
46 | live-service-running | |
47 | ||
8bf92e39 | 48 | current-services |
240b57f0 LC |
49 | unload-services |
50 | unload-service | |
51 | load-services | |
52 | start-service)) | |
53 | ||
54 | ;;; Commentary: | |
55 | ;;; | |
56 | ;;; This module provides an interface to the GNU Shepherd, similar to the | |
57 | ;;; 'herd' command. Essentially it implements a subset of the (shepherd comm) | |
58 | ;;; module, but focusing only on the parts relevant to 'guix system | |
59 | ;;; reconfigure'. | |
60 | ;;; | |
61 | ;;; Code: | |
62 | ||
63 | (define %shepherd-socket-file | |
5e03b122 | 64 | (make-parameter "/var/run/shepherd/socket")) |
240b57f0 | 65 | |
5e03b122 | 66 | (define* (open-connection #:optional (file (%shepherd-socket-file))) |
240b57f0 LC |
67 | "Open a connection to the daemon, using the Unix-domain socket at FILE, and |
68 | return the socket." | |
69 | ;; The protocol is sexp-based and UTF-8-encoded. | |
70 | (with-fluids ((%default-port-encoding "UTF-8")) | |
71 | (let ((sock (socket PF_UNIX SOCK_STREAM 0)) | |
72 | (address (make-socket-address PF_UNIX file))) | |
73 | (catch 'system-error | |
74 | (lambda () | |
75 | (connect sock address) | |
76 | (setvbuf sock _IOFBF 1024) | |
77 | sock) | |
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78 | (lambda args |
79 | (close-port sock) | |
80 | (apply throw args)))))) | |
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81 | |
82 | (define-syntax-rule (with-shepherd connection body ...) | |
83 | "Evaluate BODY... with CONNECTION bound to an open socket to PID 1." | |
84 | (let ((connection (open-connection))) | |
1d6b7d58 | 85 | body ...)) |
240b57f0 | 86 | |
8bf92e39 LC |
87 | (define-condition-type &shepherd-error &error |
88 | shepherd-error?) | |
89 | ||
90 | (define-condition-type &service-not-found-error &shepherd-error | |
91 | service-not-found-error? | |
92 | (service service-not-found-error-service)) | |
93 | ||
94 | (define-condition-type &action-not-found-error &shepherd-error | |
95 | action-not-found-error? | |
96 | (service action-not-found-error-service) | |
97 | (action action-not-found-error-action)) | |
98 | ||
99 | (define-condition-type &action-exception-error &shepherd-error | |
100 | action-exception-error? | |
101 | (service action-exception-error-service) | |
102 | (action action-exception-error-action) | |
103 | (key action-exception-error-key) | |
104 | (args action-exception-error-arguments)) | |
105 | ||
106 | (define-condition-type &unknown-shepherd-error &shepherd-error | |
107 | unknown-shepherd-error? | |
108 | (sexp unknown-shepherd-error-sexp)) | |
109 | ||
110 | (define (raise-shepherd-error error) | |
111 | "Raise an error condition corresponding to ERROR, an sexp received by a | |
112 | shepherd client in reply to COMMAND, a command object. Return #t if ERROR | |
113 | does not denote an error." | |
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114 | (match error |
115 | (('error ('version 0 x ...) 'service-not-found service) | |
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116 | (raise (condition (&service-not-found-error |
117 | (service service))))) | |
240b57f0 | 118 | (('error ('version 0 x ...) 'action-not-found action service) |
8bf92e39 LC |
119 | (raise (condition (&action-not-found-error |
120 | (service service) | |
121 | (action action))))) | |
240b57f0 LC |
122 | (('error ('version 0 x ...) 'action-exception action service |
123 | key (args ...)) | |
8bf92e39 LC |
124 | (raise (condition (&action-exception-error |
125 | (service service) | |
126 | (action action) | |
127 | (key key) (args args))))) | |
240b57f0 | 128 | (('error . _) |
8bf92e39 | 129 | (raise (condition (&unknown-shepherd-error (sexp error))))) |
240b57f0 LC |
130 | (#f ;not an error |
131 | #t))) | |
132 | ||
133 | (define (display-message message) | |
8bf92e39 | 134 | (format (current-error-port) "shepherd: ~a~%" message)) |
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135 | |
136 | (define* (invoke-action service action arguments cont) | |
137 | "Invoke ACTION on SERVICE with ARGUMENTS. On success, call CONT with the | |
138 | result. Otherwise return #f." | |
139 | (with-shepherd sock | |
140 | (write `(shepherd-command (version 0) | |
141 | (action ,action) | |
142 | (service ,service) | |
143 | (arguments ,arguments) | |
144 | (directory ,(getcwd))) | |
145 | sock) | |
146 | (force-output sock) | |
147 | ||
148 | (match (read sock) | |
149 | (('reply ('version 0 _ ...) ('result (result)) ('error #f) | |
150 | ('messages messages)) | |
151 | (for-each display-message messages) | |
152 | (cont result)) | |
153 | (('reply ('version 0 x ...) ('result y) ('error error) | |
154 | ('messages messages)) | |
155 | (for-each display-message messages) | |
8bf92e39 | 156 | (raise-shepherd-error error) |
240b57f0 LC |
157 | #f) |
158 | (x | |
8bf92e39 | 159 | ;; invalid reply |
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160 | #f)))) |
161 | ||
162 | (define-syntax-rule (with-shepherd-action service (action args ...) | |
163 | result body ...) | |
164 | (invoke-action service action (list args ...) | |
165 | (lambda (result) body ...))) | |
166 | ||
167 | (define-syntax alist-let* | |
168 | (syntax-rules () | |
169 | "Bind the given KEYs in EXP to the corresponding items in ALIST. ALIST | |
170 | is assumed to be a list of two-element tuples rather than a traditional list | |
171 | of pairs." | |
172 | ((_ alist (key ...) exp ...) | |
173 | (let ((key (and=> (assoc-ref alist 'key) car)) ...) | |
174 | exp ...)))) | |
175 | ||
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176 | ;; Information about live Shepherd services. |
177 | (define-record-type <live-service> | |
178 | (live-service provision requirement running) | |
179 | live-service? | |
180 | (provision live-service-provision) ;list of symbols | |
181 | (requirement live-service-requirement) ;list of symbols | |
182 | (running live-service-running)) ;#f | object | |
183 | ||
240b57f0 | 184 | (define (current-services) |
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185 | "Return the list of currently defined Shepherd services, represented as |
186 | <live-service> objects. Return #f if the list of services could not be | |
187 | obtained." | |
240b57f0 LC |
188 | (with-shepherd-action 'root ('status) services |
189 | (match services | |
190 | ((('service ('version 0 _ ...) _ ...) ...) | |
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191 | (map (lambda (service) |
192 | (alist-let* service (provides requires running) | |
193 | (live-service provides requires running))) | |
194 | services)) | |
240b57f0 | 195 | (x |
183605c8 | 196 | #f)))) |
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197 | |
198 | (define (unload-service service) | |
199 | "Unload SERVICE, a symbol name; return #t on success." | |
200 | (with-shepherd-action 'root ('unload (symbol->string service)) result | |
201 | result)) | |
202 | ||
203 | (define (%load-file file) | |
204 | "Load FILE in the Shepherd." | |
205 | (with-shepherd-action 'root ('load file) result | |
206 | result)) | |
207 | ||
208 | (define (eval-there exp) | |
209 | "Eval EXP in the Shepherd." | |
210 | (with-shepherd-action 'root ('eval (object->string exp)) result | |
211 | result)) | |
212 | ||
213 | (define (load-services files) | |
214 | "Load and register the services from FILES, where FILES contain code that | |
215 | returns a shepherd <service> object." | |
216 | (eval-there `(register-services | |
217 | ,@(map (lambda (file) | |
218 | `(primitive-load ,file)) | |
219 | files)))) | |
220 | ||
221 | (define (start-service name) | |
222 | (with-shepherd-action name ('start) result | |
223 | result)) | |
224 | ||
225 | ;; Local Variables: | |
226 | ;; eval: (put 'alist-let* 'scheme-indent-function 2) | |
227 | ;; eval: (put 'with-shepherd 'scheme-indent-function 1) | |
228 | ;; eval: (put 'with-shepherd-action 'scheme-indent-function 3) | |
229 | ;; End: | |
230 | ||
231 | ;;; herd.scm ends here |