services: Introduce extensible services.

This patch rewrites GuixSD services to make them extensible.

* gnu-system.am (GNU_SYSTEM_MODULES): Add gnu/services/dbus.scm.
* gnu/services.scm (<service>): Replace with new record type.
  (<service-extension>, <service-type>): New record types.
  (write-service-type, compute-boot-script, second-argument): New
  procedures.
  (%boot-service, boot-service-type): New variables.
  (file-union, directory-union, modprobe-wrapper,
  activation-service->script, activation-script,
  gexps->activation-gexp): New procedures.
  (activation-service-type, %activation-service): New variables.
  (etc-directory, files->etc-directory, etc-service): New procedures.
  (etc-service-type, setuid-program-service, firmware-service-type): New
  variables.
  (firmware->activation-gexp): New procedure.
  (&service-error, &missing-target-service-error,
  &ambiguous-target-service-error): New condition types.
  (service-back-edges, fold-services): New procedures.
* gnu/services/avahi.scm (<avahi-configuration>): New record type.
  (configuration-file): Replace keyword parameters with a single
  'config' parameter.
  (%avahi-accounts, %avahi-activation, avahi-service-type): New
  variables.
  (avahi-dmd-service): New procedure.
  (avahi-service): Rewrite using 'service' and 'avahi-configuration'.
* gnu/services/base.scm (%root-file-system-dmd-service,
  root-file-system-service-type): New variables.
  (root-file-system-service): Use them.
  (file-system->dmd-service-name): New procedure.
  (file-system-service-type): New variable.
  (file-system-service): Use it.  Replace keyword parameters with a
  single 'file-system' object.
  (user-unmount-service-type): New variable.
  (user-unmount-service): Use it.
  (user-processes-service-type): New variable.
  (user-processes-service): Use it.
  (host-name-service-type): New variable.
  (host-name-service): Use it.
  (console-keymap-service-type): New variable.
  (console-keymap-service): Use it.
  (console-font-service-type): New variable.
  (console-font-service): Use it.
  (mingetty-pam-service, mingetty-dmd-service): New procedures.
  (mingetty-service-type): New variable.
  (mingetty-service): Use it.
  (nscd-dmd-service): New procedure.
  (nscd-activation, nscd-service-type): New variables.
  (nscd-service): Use the latter.
  (syslog-service-type): New variable.
  (syslog-service): Use it.
  (<guix-configuration>): New record type.
  (%default-guix-configuration): New variable.
  (guix-dmd-service, guix-accounts, guix-activation): New procedures.
  (guix-service-type): New variable.
  (guix-service): Replace list of keyword parameters with a single
  'config' parameter.  Rewrite using 'service'.
  (<udev-configuration>): New record type.
  (udev-dmd-service): New procedure.
  (udev-service-type): New variable.
  (udev-service): Use it.
  (device-mapping-service-type): New variable.
  (device-mapping-service): Use it.
  (swap-service-type): New variable.
  (swap-service): Use it.
* gnu/services/databases.scm (<postgresql-configuration>): New record
  type.
  (%postgresql-accounts, postgresql-activation): New variables.
  (postgresql-dmd-service): New procedure.
  (postgresql-service): Rewrite using 'service' and
  'postgresql-configuration'.
* gnu/services/dbus.scm: New file.
* gnu/services/desktop.scm (dbus-configuration-directory, dbus-service):
  Remove.
  (wrapped-dbus-service): New procedure.
  (<upower-configuration>): New record type.
  (upower-configuration-file): Replace keyword parameters with single
  <upower-configuration> parameter.
  (%upower-accounts, %upower-activation): New variables.
  (upower-dbus-service, upower-dmd-service): New procedures.
  (upower-service-type): New variable.
  (upower-service): Rewrite using 'service' and 'upower-configuration'.
  (%colord-activation, %colord-accounts): New variables.
  (colord-dmd-service): New procedure.
  (colord-service-type): New variable.
  (colord-service): Rewrite using 'service'.
  (<geoclue-configuration>): New record type.
  (geoclue-configuration-file): Replace keyword parameters with a single
  'config' parameter.
  (geoclue-dbus-service, geoclue-dmd-service): New procedures.
  (%geoclue-accounts, geoclue-service-type): New variables.
  (geoclue-service): Rewrite using 'service' and
  'geoclue-configuration'.
  (%polkit-accounts, %polkit-pam-services, polkit-service-type): New
  variables.
  (polkit-dmd-service): New procedure.
  (polkit-service): Rewrite using 'service'.
  (<elogind-configuration>)[elogind]: New field.
  (elogind-dmd-service): New procedure.
  (elogind-service-type): New variable.
  (elogind-service): Rewrite using 'service'.
  (%desktop-services): Remove argument to 'dbus-service'.  Remove 'map'
  over %BASE-SERVICES.
* gnu/services/dmd.scm (dmd-boot-gexp): New procedure.
  (dmd-root-service-type, %dmd-root-service): New variables.
  (dmd-service-type): New macro.
  (<dmd-service>): New record type.
* gnu/services/lirc.scm (<lirc-configuration>): New record type.
  (%lirc-activation): New variable.
  (lirc-dmd-service): New procedure.
  (lirc-service-type): New variable.
  (lirc-service): Rewrite using 'service' and 'lirc-configuration'.
* gnu/services/networking.scm (<static-networking>): New record type.
  (static-networking-service-type): New variable.
  (static-networking-service): Rewrite using 'service' and
  'static-networking'.
  (dhcp-client-service-type): New variable.
  (dhcp-client-service): Rewrite using 'service'.
  (<ntp-configuration>): New record type.
  (ntp-dmd-service): New procedure.
  (ntp-service-type): New variable.
  (ntp-service): New procedure.
  (%tor-accounts, tor-service-type): New variable.
  (tor-dmd-service): New procedure.
  (tor-service): Rewrite using 'service'.
  (<bitlbee-configuration>): New record type.
  (bitlbee-dmd-service): New procedure.
  (%bitlbee-accounts, %bitlbee-activation, bitlbee-service-type): New
  variables.
  (bitlbee-service): Rewrite using 'service'.
  (%wicd-activation): New variable.
  (wicd-dmd-service): New procedure.
  (wicd-service-type): New variable.
  (wicd-service): Rewrite using 'service'.
* gnu/services/ssh.scm (<lsh-configuration>): New record type.
  (activation): Rename to...
  (lsh-initialization): ... this.
  (lsh-activation, lsh-dmd-service, lsh-pam-services): New procedures.
  (lsh-service-type): New variable.
  (lsh-service): Rewrite using 'service' and 'lsh-configuration'.
* gnu/services/web.scm (<nginx-configuration>): New record type.
  (%nginx-accounts): New variable.
  (nginx-activation, nginx-dmd-service): New procedures.
  (nginx-service-type): New variable.
  (nginx-service): Rewrite using 'service' and 'nginx-configuration'.
* gnu/services/xorg.scm (<slim-configuration>): New record type.
  (slim-pam-service, slim-dmd-service): New procedures.
  (slim-service-type): New variable.
  (slim-service): Rewrite using 'service' and 'slim-configuration'.
* gnu/system.scm (file-union): Remove.
  (other-file-system-services): Adjust to new 'file-system-service'
  signature.
  (essential-services): Add #:container? parameter.  Add
  %DMD-ROOT-SERVICE, %ACTIVATION-SERVICE, and calls to
  'pam-root-service', 'account-service', 'operating-system-etc-service',
  and a SETUID-PROGRAM-SERVICE instance.
  (operating-system-services): Pass #:container? to 'essential-services.
  (etc-directory): Remove.
  (operating-system-etc-service): New procedure.  Rewrite as a call to
  'etc-service'.
  (operating-system-accounts): Change to not return accounts required by
  services.
  (operating-system-etc-directory): Rewrite as a call to 'fold-services'
  and 'etc-directory'.
  (user-group->gexp, user-account->gexp, modprobe-wrapper): Remove.
  (operating-system-activation-script): Rewrite as a call to
  'fold-services' and 'activation-service->script'.
  (operating-system-boot-script): Likewise.
  (operating-system-derivation): Add call to 'lower-object'.
  (emacs-site-file, emacs-site-directory, shells-file): Change to use
  'computed-file' and 'scheme-file' instead of the monadic procedures.
* gnu/system/install.scm (cow-store-service-type): New variable.
  (cow-store-service): Rewrite using 'service'.
  (/etc/configuration-files): New procedure.
  (configuration-template-service-type,
  %configuration-template-service): New variables.
  (configuration-template-service): Remove.
  (installation-services): Adjust accordingly.  Adjust argument to
  'guix-service'.
* gnu/system/linux.scm (/etc-entry, pam-root-service): New procedures.
  (pam-root-service-type): New variable.
* gnu/system/shadow.scm (user-group->gexp, user-account->gexp,
  account-activation, etc-skel, account-service): New procedures.
  (account-service-type): New variable.
* tests/services.scm: New file.
* doc/guix.texi (Base Services, Desktop Services): Adjust accordingly.
  (Defining Services): Rewrite.
* doc/images/service-graph.dot: New file.
* doc.am (DOT_FILES): Add it.
* po/guix/POTFILES.in: Add gnu/services.scm.

1 files changed, 82 insertions, 40 deletions

diff --git a/gnu/services/avahi.scm b/gnu/services/avahi.scm
index 929ac2fbb6..b576c395ff 100644
--- a/gnu/services/avahi.scm
+++ b/gnu/services/avahi.scm
@@ -18,10 +18,13 @@
 
 (define-module (gnu services avahi)
   #:use-module (gnu services)
+  #:use-module (gnu services base)
+  #:use-module (gnu services dmd)
+  #:use-module (gnu services dbus)
   #:use-module (gnu system shadow)
   #:use-module (gnu packages avahi)
   #:use-module (gnu packages admin)
-  #:use-module (guix store)
+  #:use-module (guix records)
   #:use-module (guix gexp)
   #:export (avahi-service))
 
@@ -32,12 +35,27 @@
 ;;;
 ;;; Code:
 
-(define* (configuration-file #:key host-name publish?
-                             ipv4? ipv6? wide-area? domains-to-browse)
-  "Return an avahi-daemon configuration file."
+  ;; TODO: Export.
+(define-record-type* <avahi-configuration>
+  avahi-configuration make-avahi-configuration
+  avahi-configuration?
+  (avahi             avahi-configuration-avahi    ;<package>
+                     (default avahi))
+  (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"
@@ -45,14 +63,63 @@
                    (string-append "host-name=" host-name "\n")
                    "")
 
-               "browse-domains=" (string-join domains-to-browse)
+               "browse-domains=" (string-join
+                                  (avahi-configuration-domains-to-browse
+                                   config))
                "\n"
-               "use-ipv4=" (bool ipv4?)
-               "use-ipv6=" (bool ipv6?)
+               "use-ipv4=" (bool (avahi-configuration-ipv4? config))
+               "use-ipv6=" (bool (avahi-configuration-ipv6? config))
                "[wide-area]\n"
-               "enable-wide-area=" (bool wide-area?)
+               "enable-wide-area=" (bool (avahi-configuration-wide-area? config))
                "[publish]\n"
-               "disable-publishing=" (bool (not publish?)))))
+               "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 #~(string-append #$shadow "/sbin/nologin")))))
+
+(define %avahi-activation
+  ;; Activation gexp.
+  #~(begin
+      (use-modules (guix build utils))
+      (mkdir-p "/var/run/avahi-daemon")))
+
+(define (avahi-dmd-service config)
+  "Return a list of <dmd-service> for CONFIG."
+  (let ((config (configuration-file config))
+        (avahi  (avahi-configuration-avahi config)))
+    (list (dmd-service
+           (documentation "Run the Avahi mDNS/DNS-SD responder.")
+           (provision '(avahi-daemon))
+           (requirement '(dbus-system networking))
+
+           (start #~(make-forkexec-constructor
+                     (list (string-append #$avahi "/sbin/avahi-daemon")
+                           "--syslog" "-f" #$config)))
+           (stop #~(make-kill-destructor))))))
+
+(define avahi-service-type
+  (service-type (name 'avahi)
+                (extensions
+                 (list (service-extension dmd-root-service-type
+                                          avahi-dmd-service)
+                       (service-extension dbus-root-service-type
+                                          (compose list
+                                                   avahi-configuration-avahi))
+                       (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)))))))
 
 (define* (avahi-service #:key (avahi avahi)
                         host-name
@@ -75,36 +142,11 @@ 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."
-  (let ((config (configuration-file #:host-name host-name
-                                    #:publish? publish?
-                                    #:ipv4? ipv4?
-                                    #:ipv6? ipv6?
-                                    #:wide-area? wide-area?
-                                    #:domains-to-browse
-                                    domains-to-browse)))
-    (service
-     (documentation "Run the Avahi mDNS/DNS-SD responder.")
-     (provision '(avahi-daemon))
-     (requirement '(dbus-system networking))
-
-     (start #~(make-forkexec-constructor
-               (list (string-append #$avahi "/sbin/avahi-daemon")
-                     "--syslog" "-f" #$config)))
-     (stop #~(make-kill-destructor))
-     (activate #~(begin
-                   (use-modules (guix build utils))
-                   (mkdir-p "/var/run/avahi-daemon")))
-
-     (user-groups (list (user-group
-                         (name "avahi")
-                         (system? #t))))
-     (user-accounts (list (user-account
-                           (name "avahi")
-                           (group "avahi")
-                           (system? #t)
-                           (comment "Avahi daemon user")
-                           (home-directory "/var/empty")
-                           (shell
-                            #~(string-append #$shadow "/sbin/nologin"))))))))
+  (service avahi-service-type
+           (avahi-configuration
+            (avahi avahi) (host-name host-name)
+            (publish? publish?) (ipv4? ipv4?) (ipv6? ipv6?)
+            (wide-area? wide-area?)
+            (domains-to-browse domains-to-browse))))
 
 ;;; avahi.scm ends here