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;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2013, 2014, 2015 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 dmd)
#: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-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 dmd.
(execl (string-append #$dmd "/bin/dmd")
"dmd" "--config" #$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)))))
(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-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)))
(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-configuration-file services)
"Return the dmd configuration file for SERVICES."
(define modules
;; Extra modules visible to dmd.conf.
'((guix build syscalls)
(gnu build file-systems)
(guix build utils)))
(assert-valid-graph services)
(mlet %store-monad ((modules (imported-modules modules))
(compiled (compiled-modules modules)))
(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 (ice-9 ftw)
(guix build syscalls)
(guix build utils)
((gnu build file-systems)
#:select (check-file-system canonicalize-device-spec)))
(register-services
#$@(map (lambda (service)
#~(make <service>
#:docstring '#$(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 #$(dmd-service-stop service)))
services))
;; guix-daemon 0.6 aborts if 'PATH' is undefined, so work around it.
(setenv "PATH" "/run/current-system/profile/bin")
(format #t "starting services...~%")
(for-each start
'#$(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)))
;;; dmd.scm ends here
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