[bug#50326] [PATCH cuirass] Add systemd unit file for remote worker service.

[Thiago Jung Bauermann]

* etc/cuirass-remote-worker.service.in: New file.
* doc/cuirass.texi: Mention it.
* .gitignore: Ignore it.
* Makefile.am (noinst_SCRIPTS): Add ‘etc/cuirass-remote-worker.service’.
(EXTRA_DIST): Likewise.
(etc/cuirass-remote-worker.service): New target.
* configure.ac: Check for ‘(guix config)’ module.
Set ‘guix_localstatedir’ variable.
---

Hello,

This patch adds the systemd unit file I installed on guixp9. The
configure script finds out Guix’s localstatedir and substitutes it in
etc/cuirass-remote-worker.service.in. The service file isn’t installed
anywhere and the user is supposed to get it from the build directory if
they want to use it.

I did it this way because there’s no $PREFIX/doc/examples directory
or equivalent where it could be shipped, and I thought that it would
be excessive to add it to all Cuirass installations considering that
only a few of them would actually have a use for it. But I can send a
v2 making this change if people think it would be better.

 .gitignore                           |  1 +
 Makefile.am                          |  8 +++++++-
 configure.ac                         |  4 ++++
 doc/cuirass.texi                     | 13 +++++++++++++
 etc/cuirass-remote-worker.service.in | 15 +++++++++++++++
 5 files changed, 40 insertions(+), 1 deletion(-)
 create mode 100644 etc/cuirass-remote-worker.service.in

diff --git a/.gitignore b/.gitignore
index 95ed6cb3982c..0807874e9513 100644
--- a/.gitignore
+++ b/.gitignore
@@ -24,6 +24,7 @@
 /config.cache
 /configure
 /doc/version.texi
+/etc/cuirass-remote-worker.service
 /src/cuirass/config.scm
 /tests/cache
 Makefile
diff --git a/Makefile.am b/Makefile.am
index 1d754673f450..6c5dab26f105 100644
--- a/Makefile.am
+++ b/Makefile.am
@@ -25,7 +25,9 @@
 bin_SCRIPTS =                    \
   bin/cuirass
 
-noinst_SCRIPTS = pre-inst-env
+noinst_SCRIPTS =                               \
+  pre-inst-env                                 \
+  etc/cuirass-remote-worker.service
 
 guilesitedir = $(datarootdir)/guile/site/@GUILE_EFFECTIVE_VERSION@
 guileobjectdir = $(libdir)/guile/@GUILE_EFFECTIVE_VERSION@/site-ccache
@@ -188,6 +190,7 @@ EXTRA_DIST = \
   bootstrap \
   build-aux/guix.scm \
   src/cuirass/config.scm.in \
+  etc/cuirass-remote-worker.service.in \
   $(TESTS)
 
 dist-hook: gen-ChangeLog
@@ -247,6 +250,9 @@ $(bin_SCRIPTS): Makefile
        $(generate_file); chmod +x $@
 src/cuirass/config.scm: $(srcdir)/src/cuirass/config.scm.in Makefile
        $(generate_file)
+etc/cuirass-remote-worker.service: 
$(srcdir)/etc/cuirass-remote-worker.service.in \
+                                       Makefile
+       $(generate_file)
 
 # Guile modules require 'src/cuirass/config.scm' to exist before their
 # compilation.
diff --git a/configure.ac b/configure.ac
index 479e93a1cb8e..af294c16d025 100644
--- a/configure.ac
+++ b/configure.ac
@@ -47,6 +47,7 @@ GUILE_MODULE_REQUIRED([avahi])
 GUILE_MODULE_REQUIRED([fibers])
 GUILE_MODULE_REQUIRED([guix])
 GUILE_MODULE_REQUIRED([guix git])
+GUILE_MODULE_REQUIRED([guix config])
 GUILE_MODULE_REQUIRED([git])
 GUILE_MODULE_REQUIRED([json])
 GUILE_MODULE_REQUIRED([mailutils mailutils])
@@ -58,6 +59,9 @@ GUILE_MODULE_REQUIRED([zlib])
 # We depend on new Guile-Git errors.
 GUILE_MODULE_REQUIRED_EXPORT([(git)], git-error-message)
 
+guix_localstatedir="$($GUILE -c '(import (guix config)) (display 
%localstatedir)')"
+AC_SUBST(guix_localstatedir)
+
 AC_CONFIG_FILES([Makefile])
 AC_CONFIG_FILES([pre-inst-env:build-aux/pre-inst-env.in],
   [chmod +x pre-inst-env])
diff --git a/doc/cuirass.texi b/doc/cuirass.texi
index 72b0b5b0913a..e32ab29e5d5d 100644
--- a/doc/cuirass.texi
+++ b/doc/cuirass.texi
@@ -463,6 +463,19 @@ The easiest way to setup such an infrastructure is to rely 
on the GNU
 Guix Cuirass services definitions (@pxref{Continuous Integration,
 Continuous Integration,, guix, Guix}).
 
+Alternatively, there is a systemd service unit file at
+@code{etc/cuirass-remote-worker.service} to launch the
+@code{cuirass remote-worker} on systems which use systemd.  It can be
+installed and enabled as follows:
+
+@example
+sudo install -o root -g root -m 644 \
+     $CUIRASS_BUILD_DIR/etc/cuirass-remote-worker.service \
+     /etc/systemd/system
+sudo systemctl enable cuirass-remote-worker.service
+sudo systemctl start cuirass-remote-worker.service
+@end example
+
 @c *********************************************************************
 @node Invocation
 @chapter Invocation
diff --git a/etc/cuirass-remote-worker.service.in 
b/etc/cuirass-remote-worker.service.in
new file mode 100644
index 000000000000..2c334d74804f
--- /dev/null
+++ b/etc/cuirass-remote-worker.service.in
@@ -0,0 +1,15 @@
+# This is a "service unit file" for the systemd init system to launch
+# 'cuirass remote-worker'.  Drop it in /etc/systemd/system or similar
+# to have 'cuirass remote-worker' automatically started.
+
+[Unit]
+Description=Continuous integration remmote worker for GNU Guix
+
+[Service]
+ExecStart=@guix_localstatedir@/guix/profiles/per-user/root/guix-profile/bin/cuirass
 \
+    remote-worker --workers=2 --server=10.0.0.1:5555
+Environment= LC_ALL=en_US.UTF-8 \
+    
'GUIX_LOCPATH=@guix_localstatedir@/guix/profiles/per-user/root/guix-profile/lib/locale'
+
+[Install]
+WantedBy=multi-user.target