services: ntp: Use the NTP pool via the 'guix' zone.

* gnu/services/networking.scm (%ntp-servers): Use *.guix.pool.ntp.org.

services: openssh: Extensions provide extra authorized keys.

* gnu/services/ssh.scm (extend-openssh-authorized-keys): New procedure.
(openssh-service-type)[compose, extend]: New fields.
* doc/guix.texi (Networking Services): Document the extension.

services: openssh: Add 'authorized-keys' field.

* gnu/services/ssh.scm (<openssh-configuration>)[authorized-keys]: New
field.
(authorized-key-directory): New procedure.
(openssh-config-file): Honor 'authorized-keys'.
(openssh-activation): Use 'with-imported-modules'.  Make /etc/ssh
755.  Create /etc/ssh/authorized_keys.d.
* doc/guix.texi (Networking Services): Document it.

services: cuirass: Set 'GIT_SSL_CAINFO' and 'GIT_EXEC_PATH'.

Reported by Ricardo Wurmus.

* gnu/services/cuirass.scm (cuirass-shepherd-service): Pass
 #:environment-variables.

services: Add memcached.

* gnu/services/databases.scm (memcached-service-type, %memcached-accounts):
  New variables.
  (<memcached-configuration>): New record type.
  (memcached-service-type): New procedures.
* gnu/tests/databases.scm: New file.
* doc/guix.texi (Database Services): Document the new memcached service.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add entry for tests/databases.scm.

gnu: services: admin: Add tailon.

* gnu/services/admin.scm
  (<tailon-configuration>, <tailon-configuration-file>): New record types.
  (tailon-configuration-files-string, tailon-shepherd-service): New
  procedures.
  (%tailon-accounts, tailon-service-type: New variables.
* doc/guix.texi (Monitoring Services: Document the Tailon service.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add gnu/tests/admin.scm.
* gnu/tests/admin.scm: New file.

services: guix-publish: Run in a UTF-8 locale.

Works around <https://bugs.gnu.org/26948>.

* gnu/services/base.scm (guix-publish-shepherd-service): Pass
  #:environment-variables to 'make-forkexec-constructor'.

gnu: Add fcgiwrap service.

* doc/guix.texi (Web Services): Add documentation.
* gnu/services/web.scm (<fcgiwrap-configuration>): New record type.
(fcgiwrap-accounts, fcgiwrap-shepherd-service): New service extensions.
(fcgiwrap-service-type): New service type.

Signed-off-by: Ludovic Courtès <ludo@gnu.org>

services: cuirass: Add fallback parameter.

* gnu/services/cuirass.scm (<cuirass-configuration>)[fallback?]: New field.
(cuirass-shepherd-service): Take it into account.
* doc/guix.texi (Continuous Integration): Document it.

services: sysctl: Fix typo.

* gnu/services/sysctl.scm: Fix typo of 'make-sysctl-configuration'.

services: elogind: Start from the Shepherd.

Fixes <http://bugs.gnu.org/27580>.
Reported by William <w@vieta.uk>.

* gnu/services/desktop.scm (elogind-shepherd-service): New procedure.
(elogind-service-type): Extend SHEPHERD-ROOT-SERVICE-TYPE.

services: dbus, polkit: Add default value.

* gnu/services/dbus.scm (dbus-root-service-type)[default-value]: New
field.
(polkit-service-type)[default-value]: New field.

services: Add 'sysctl-service-type'.

* gnu/services/sysctl.scm: New file.
* doc/guix.texi (Miscellaneous Services): Document it.
* gnu/local.mk (GNU_SYSTEM_MODULES): Add it.

gnu: services: use seconds instead of duration strings.

* gnu/services/dns.scm (zone-file, knot-policy-configuration): Use numbers
instead of duration strings.
(verify-knot-policy-configuration): Fix typo.
* doc/guix.texi (DNS Services): Update documentation.

services: network-manager: Specify a default value.

* gnu/services/networking.scm (network-manager-service-type)[default-value]:
New field.

services: cuirass: Extend rottlog with log rotations.

* gnu/services/cuirass.scm (cuirass-log-rotations): New procedure.
(cuirass-service-type): Use it to extend ROTTLOG-SERVICE-TYPE.

services: rottlog: Make extensible.

* gnu/services/admin.scm (rottlog-service-type)[compose, extend]: New
fields.
* doc/guix.texi (Log Rotation): Mention extension.

services: rottlog: Define <log-rotation> objects.

* gnu/services/admin.scm (<log-rotation>): New record type.
(syslog-rotation-config, simple-rotation-config): Remove.
(%default-rotations): Define as a list of <log-rotation> objects.
(log-rotation->config, log-rotations->/etc-entries): New procedures.
(<rottlog-configuration>)[periodic-rotations]: Remove.
[rotations]: New field.
(rottlog-etc): Use 'log-rotations->/etc-entries'.
* doc/guix.texi (Log Rotation): Update accordingly.

services: guix: Add 'max-silent-time' and 'timeout'.

* gnu/services/base.scm (<guix-configuration>)[max-silent-time]
[timeout]: New fields.
(guix-shepherd-service): Honor them.
* doc/guix.texi (Base Services): Document them.

Merge branch 'master' into staging