summaryrefslogtreecommitdiff
path: root/gnu/services/shepherd.scm
diff options
context:
space:
mode:
Diffstat (limited to 'gnu/services/shepherd.scm')
-rw-r--r--gnu/services/shepherd.scm275
1 files changed, 275 insertions, 0 deletions
diff --git a/gnu/services/shepherd.scm b/gnu/services/shepherd.scm
new file mode 100644
index 0000000000..a33985efa1
--- /dev/null
+++ b/gnu/services/shepherd.scm
@@ -0,0 +1,275 @@
+;;; GNU Guix --- Functional package management for GNU
+;;; Copyright © 2013, 2014, 2015, 2016 Ludovic Courtès <ludo@gnu.org>
+;;;
+;;; This file is part of GNU Guix.
+;;;
+;;; GNU Guix is free software; you can redistribute it and/or modify it
+;;; under the terms of the GNU General Public License as published by
+;;; the Free Software Foundation; either version 3 of the License, or (at
+;;; your option) any later version.
+;;;
+;;; GNU Guix is distributed in the hope that it will be useful, but
+;;; WITHOUT ANY WARRANTY; without even the implied warranty of
+;;; MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+;;; GNU General Public License for more details.
+;;;
+;;; You should have received a copy of the GNU General Public License
+;;; along with GNU Guix. If not, see <http://www.gnu.org/licenses/>.
+
+(define-module (gnu services shepherd)
+ #:use-module (guix ui)
+ #:use-module (guix sets)
+ #:use-module (guix gexp)
+ #:use-module (guix store)
+ #:use-module (guix monads)
+ #:use-module (guix records)
+ #:use-module (guix derivations) ;imported-modules, etc.
+ #:use-module (gnu services)
+ #:use-module (gnu packages admin)
+ #:use-module (ice-9 match)
+ #:use-module (ice-9 vlist)
+ #:use-module (srfi srfi-1)
+ #:use-module (srfi srfi-26)
+ #:use-module (srfi srfi-34)
+ #:use-module (srfi srfi-35)
+ #:export (dmd-root-service-type
+ %dmd-root-service
+ dmd-service-type
+
+ dmd-service
+ dmd-service?
+ dmd-service-documentation
+ dmd-service-provision
+ dmd-service-requirement
+ dmd-service-respawn?
+ dmd-service-start
+ dmd-service-stop
+ dmd-service-auto-start?
+ dmd-service-modules
+ dmd-service-imported-modules
+
+ %default-imported-modules
+ %default-modules
+
+ dmd-service-back-edges))
+
+;;; Commentary:
+;;;
+;;; Instantiating system services as a dmd configuration file.
+;;;
+;;; Code:
+
+
+(define (dmd-boot-gexp services)
+ (mlet %store-monad ((dmd-conf (dmd-configuration-file services)))
+ (return #~(begin
+ ;; Keep track of the booted system.
+ (false-if-exception (delete-file "/run/booted-system"))
+ (symlink (readlink "/run/current-system")
+ "/run/booted-system")
+
+ ;; Close any remaining open file descriptors to be on the safe
+ ;; side. This must be the very last thing we do, because
+ ;; Guile has internal FDs such as 'sleep_pipe' that need to be
+ ;; alive.
+ (let loop ((fd 3))
+ (when (< fd 1024)
+ (false-if-exception (close-fdes fd))
+ (loop (+ 1 fd))))
+
+ ;; Start shepherd.
+ (execl (string-append #$shepherd "/bin/shepherd")
+ "shepherd" "--config" #$dmd-conf)))))
+
+(define dmd-root-service-type
+ (service-type
+ (name 'dmd-root)
+ ;; Extending the root dmd service (aka. PID 1) happens by concatenating the
+ ;; list of services provided by the extensions.
+ (compose concatenate)
+ (extend append)
+ (extensions (list (service-extension boot-service-type dmd-boot-gexp)
+ (service-extension profile-service-type
+ (const (list shepherd)))))))
+
+(define %dmd-root-service
+ ;; The root dmd service, aka. PID 1. Its parameter is a list of
+ ;; <dmd-service> objects.
+ (service dmd-root-service-type '()))
+
+(define-syntax-rule (dmd-service-type service-name proc)
+ "Return a <service-type> denoting a simple dmd service--i.e., the type for a
+service that extends DMD-ROOT-SERVICE-TYPE and nothing else."
+ (service-type
+ (name service-name)
+ (extensions
+ (list (service-extension dmd-root-service-type
+ (compose list proc))))))
+
+(define %default-imported-modules
+ ;; Default set of modules imported for a service's consumption.
+ '((guix build utils)
+ (guix build syscalls)))
+
+(define %default-modules
+ ;; Default set of modules visible in a service's file.
+ `((shepherd service)
+ (oop goops)
+ (guix build utils)
+ (guix build syscalls)))
+
+(define-record-type* <dmd-service>
+ dmd-service make-dmd-service
+ dmd-service?
+ (documentation dmd-service-documentation ;string
+ (default "[No documentation.]"))
+ (provision dmd-service-provision) ;list of symbols
+ (requirement dmd-service-requirement ;list of symbols
+ (default '()))
+ (respawn? dmd-service-respawn? ;Boolean
+ (default #t))
+ (start dmd-service-start) ;g-expression (procedure)
+ (stop dmd-service-stop ;g-expression (procedure)
+ (default #~(const #f)))
+ (auto-start? dmd-service-auto-start? ;Boolean
+ (default #t))
+ (modules dmd-service-modules ;list of module names
+ (default %default-modules))
+ (imported-modules dmd-service-imported-modules ;list of module names
+ (default %default-imported-modules)))
+
+
+(define (assert-valid-graph services)
+ "Raise an error if SERVICES does not define a valid dmd service graph, for
+instance if a service requires a nonexistent service, or if more than one
+service uses a given name.
+
+These are constraints that dmd's 'register-service' verifies but we'd better
+verify them here statically than wait until PID 1 halts with an assertion
+failure."
+ (define provisions
+ ;; The set of provisions (symbols). Bail out if a symbol is given more
+ ;; than once.
+ (fold (lambda (service set)
+ (define (assert-unique symbol)
+ (when (set-contains? set symbol)
+ (raise (condition
+ (&message
+ (message
+ (format #f (_ "service '~a' provided more than once")
+ symbol)))))))
+
+ (for-each assert-unique (dmd-service-provision service))
+ (fold set-insert set (dmd-service-provision service)))
+ (setq 'dmd)
+ services))
+
+ (define (assert-satisfied-requirements service)
+ ;; Bail out if the requirements of SERVICE aren't satisfied.
+ (for-each (lambda (requirement)
+ (unless (set-contains? provisions requirement)
+ (raise (condition
+ (&message
+ (message
+ (format #f (_ "service '~a' requires '~a', \
+which is undefined")
+ (match (dmd-service-provision service)
+ ((head . _) head)
+ (_ service))
+ requirement)))))))
+ (dmd-service-requirement service)))
+
+ (for-each assert-satisfied-requirements services))
+
+(define (dmd-service-file-name service)
+ "Return the file name where the initialization code for SERVICE is to be
+stored."
+ (let ((provisions (string-join (map symbol->string
+ (dmd-service-provision service)))))
+ (string-append "dmd-"
+ (string-map (match-lambda
+ (#\/ #\-)
+ (chr chr))
+ provisions)
+ ".scm")))
+
+(define (dmd-service-file service)
+ "Return a file defining SERVICE."
+ (gexp->file (dmd-service-file-name service)
+ #~(begin
+ (use-modules #$@(dmd-service-modules service))
+
+ (make <service>
+ #:docstring '#$(dmd-service-documentation service)
+ #:provides '#$(dmd-service-provision service)
+ #:requires '#$(dmd-service-requirement service)
+ #:respawn? '#$(dmd-service-respawn? service)
+ #:start #$(dmd-service-start service)
+ #:stop #$(dmd-service-stop service)))))
+
+(define (dmd-configuration-file services)
+ "Return the dmd configuration file for SERVICES."
+ (define modules
+ (delete-duplicates
+ (append-map dmd-service-imported-modules services)))
+
+ (assert-valid-graph services)
+
+ (mlet %store-monad ((modules (imported-modules modules))
+ (compiled (compiled-modules modules))
+ (files (mapm %store-monad dmd-service-file services)))
+ (define config
+ #~(begin
+ (eval-when (expand load eval)
+ (set! %load-path (cons #$modules %load-path))
+ (set! %load-compiled-path
+ (cons #$compiled %load-compiled-path)))
+
+ (use-modules (system repl error-handling))
+
+ ;; Arrange to spawn a REPL if loading one of FILES fails. This is
+ ;; better than a kernel panic.
+ (call-with-error-handling
+ (lambda ()
+ (apply register-services (map primitive-load '#$files))))
+
+ ;; guix-daemon 0.6 aborts if 'PATH' is undefined, so work around it.
+ (setenv "PATH" "/run/current-system/profile/bin")
+
+ (format #t "starting services...~%")
+ (for-each start
+ '#$(append-map dmd-service-provision
+ (filter dmd-service-auto-start?
+ services)))))
+
+ (gexp->file "dmd.conf" config)))
+
+(define (dmd-service-back-edges services)
+ "Return a procedure that, when given a <dmd-service> from SERVICES, returns
+the list of <dmd-service> that depend on it."
+ (define provision->service
+ (let ((services (fold (lambda (service result)
+ (fold (cut vhash-consq <> service <>)
+ result
+ (dmd-service-provision service)))
+ vlist-null
+ services)))
+ (lambda (name)
+ (match (vhash-assq name services)
+ ((_ . service) service)
+ (#f #f)))))
+
+ (define edges
+ (fold (lambda (service edges)
+ (fold (lambda (requirement edges)
+ (vhash-consq (provision->service requirement) service
+ edges))
+ edges
+ (dmd-service-requirement service)))
+ vlist-null
+ services))
+
+ (lambda (service)
+ (vhash-foldq* cons '() service edges)))
+
+;;; shepherd.scm ends here
generated by cgit v1.2.3 (git 2.46.2) at 2024-11-11 14:24:05 +0000