guix-devel/gnu/services/avahi.scm

176 lines
7.2 KiB
Scheme

;;; GNU Guix --- Functional package management for GNU
;;; Copyright © 2014, 2015, 2016, 2017, 2018 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 avahi)
#:use-module (gnu services)
#:use-module (gnu services base)
#:use-module (gnu services shepherd)
#:use-module (gnu services dbus)
#:use-module (gnu system shadow)
#:use-module (gnu packages avahi)
#:use-module (gnu packages admin)
#:use-module (guix records)
#:use-module (guix gexp)
#:export (avahi-configuration
avahi-service
avahi-service-type))
;;; Commentary:
;;;
;;; This module provides service definitions for the Avahi
;;; "zero-configuration" tool set.
;;;
;;; Code:
;; TODO: Export.
(define-record-type* <avahi-configuration>
avahi-configuration make-avahi-configuration
avahi-configuration?
(avahi avahi-configuration-avahi ;<package>
(default avahi))
(debug? avahi-configuration-debug? ;Boolean
(default #f))
(host-name avahi-configuration-host-name) ;string
(publish? avahi-configuration-publish?) ;Boolean
(ipv4? avahi-configuration-ipv4?) ;Boolean
(ipv6? avahi-configuration-ipv6?) ;Boolean
(wide-area? avahi-configuration-wide-area?) ;Boolean
(domains-to-browse avahi-configuration-domains-to-browse)) ;list of strings
(define* (configuration-file config)
"Return an avahi-daemon configuration file based on CONFIG, an
<avahi-configuration>."
(define (bool value)
(if value "yes\n" "no\n"))
(define host-name (avahi-configuration-host-name config))
(plain-file "avahi-daemon.conf"
(string-append
"[server]\n"
(if host-name
(string-append "host-name=" host-name "\n")
"")
"browse-domains=" (string-join
(avahi-configuration-domains-to-browse
config))
"\n"
"use-ipv4=" (bool (avahi-configuration-ipv4? config))
"use-ipv6=" (bool (avahi-configuration-ipv6? config))
"[wide-area]\n"
"enable-wide-area=" (bool (avahi-configuration-wide-area? config))
"[publish]\n"
"disable-publishing="
(bool (not (avahi-configuration-publish? config))))))
(define %avahi-accounts
;; Account and group for the Avahi daemon.
(list (user-group (name "avahi") (system? #t))
(user-account
(name "avahi")
(group "avahi")
(system? #t)
(comment "Avahi daemon user")
(home-directory "/var/empty")
(shell (file-append shadow "/sbin/nologin")))))
(define %avahi-activation
;; Activation gexp.
#~(begin
(use-modules (guix build utils))
(mkdir-p "/var/run/avahi-daemon")))
(define (avahi-shepherd-service config)
"Return a list of <shepherd-service> for CONFIG."
(let ((config (configuration-file config))
(debug? (avahi-configuration-debug? config))
(avahi (avahi-configuration-avahi config)))
(list (shepherd-service
(documentation "Run the Avahi mDNS/DNS-SD responder.")
(provision '(avahi-daemon))
(requirement '(dbus-system networking))
(start #~(make-forkexec-constructor
(list #$(file-append avahi "/sbin/avahi-daemon")
"--daemonize"
#$@(if debug? #~("--debug") #~())
"-f" #$config)
#:pid-file "/var/run/avahi-daemon/pid"))
(stop #~(make-kill-destructor))))))
(define avahi-service-type
(let ((avahi-package (compose list avahi-configuration-avahi)))
(service-type (name 'avahi)
(description
"Run @command{avahi-daemon}, a host and service discovery
daemon that implements the multicast DNS (mDNS) and DNS service
discovery (DNS-SD) protocols. Additionally, extend the C library's name
service switch (NSS) with support for @code{.local} host name resolution.")
(extensions
(list (service-extension shepherd-root-service-type
avahi-shepherd-service)
(service-extension dbus-root-service-type
avahi-package)
(service-extension account-service-type
(const %avahi-accounts))
(service-extension activation-service-type
(const %avahi-activation))
(service-extension nscd-service-type
(const (list nss-mdns)))
;; Provide 'avahi-browse', 'avahi-resolve', etc. in
;; the system profile.
(service-extension profile-service-type
avahi-package))))))
(define* (avahi-service #:key (avahi avahi) debug?
host-name
(publish? #t)
(ipv4? #t) (ipv6? #t)
wide-area?
(domains-to-browse '()))
"Return a service that runs @command{avahi-daemon}, a system-wide
mDNS/DNS-SD responder that allows for service discovery and
\"zero-configuration\" host name lookups (see @uref{http://avahi.org/}), and
extends the name service cache daemon (nscd) so that it can resolve
@code{.local} host names using
@uref{http://0pointer.de/lennart/projects/nss-mdns/, nss-mdns}. Additionally,
add the @var{avahi} package to the system profile so that commands such as
@command{avahi-browse} are directly usable.
If @var{host-name} is different from @code{#f}, use that as the host name to
publish for this machine; otherwise, use the machine's actual host name.
When @var{publish?} is true, publishing of host names and services is allowed;
in particular, avahi-daemon will publish the machine's host name and IP
address via mDNS on the local network.
When @var{wide-area?} is true, DNS-SD over unicast DNS is enabled.
Boolean values @var{ipv4?} and @var{ipv6?} determine whether to use IPv4/IPv6
sockets."
(service avahi-service-type
(avahi-configuration
(avahi avahi) (debug? debug?) (host-name host-name)
(publish? publish?) (ipv4? ipv4?) (ipv6? ipv6?)
(wide-area? wide-area?)
(domains-to-browse domains-to-browse))))
;;; avahi.scm ends here