[__systemd_service] new type to manage the state of systemd services

cdist/conf/type/__systemd_service/explorer/state

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+#!/bin/sh -e
+# explorer/state
+#
+# 2020 Matthias Stecher <matthiasstecher at gmx.de>
+#
+# This file is part of cdist.
+#
+# cdist 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.
+#
+# cdist 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 cdist. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# Check if the service is running or stopped.
+#
+# The explorer must check before if the service exist, because 'systemctl is-active'
+# will return "inactive" even if there is no service there:
+#   systemctl cat foo        # does not exist
+#   systemctl is-active foo  # is "inactive"
+
+
+# get name of the service
+if [ -f "$__object/parameter/name" ]; then
+    name="$(cat "$__object/parameter/name")"
+else
+    name="$__object_id"
+fi
+
+
+# check if the service exist, else exit without output (also if systemd doesn't exist)
+# do not exit here with an error code, will be done in the gencode-remote script
+systemctl cat "$name" > /dev/null 2>&1 || exit 0
+
+# print if the service is running or not
+systemctl is-active -q "$name" && printf "running" || printf "stopped"

cdist/conf/type/__systemd_service/gencode-remote

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+#!/bin/sh -e
+# gencode-remote
+#
+# 2020 Matthias Stecher <matthiasstecher at gmx.de>
+#
+# This file is part of cdist.
+#
+# cdist 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.
+#
+# cdist 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 cdist. If not, see <http://www.gnu.org/licenses/>.
+#
+
+# Checks the given state of the service and set it to the given
+# state. Optionally, it executes the action if service running.
+
+
+# get name of the service
+name="$__object/parameter/name"
+if [ -f "$name" ]; then
+    name="$(cat "$name")"
+else
+    name="$__object_id"
+fi
+
+
+# read current status and parameters
+state="$(cat "$__object/explorer/state")"
+should="$(cat "$__object/parameter/state")"
+
+# if systemd/service does not exist
+if [ -z "$state" ]; then
+    printf "systemd or service '%s' does not exist!\n" "$name" >&2
+    exit 1
+fi
+
+
+# save the action required
+required_action=""
+
+# check the state of the service that should be
+if [ "$state" != "$should" ]; then
+    # select what to do to get the $should state
+    case "$should" in
+        running)
+            if [ "$state" = "stopped" ]; then required_action="start"; fi
+            ;;
+
+        stopped)
+            if [ "$state" = "running" ]; then required_action="stop"; fi
+            ;;
+    esac
+fi
+
+# check if the action can be achieved if given
+if [ -f "$__object/parameter/action" ] \
+    && [ -z "$required_action" ] && [ "$state" = "running" ]; then
+
+    # there must be an action
+    action="$(cat "$__object/parameter/action")"
+
+    # select the action to the required element
+    case "$action" in
+        restart)
+            required_action="restart"
+            ;;
+
+        reload)
+            required_action="reload"
+            ;;
+
+        *)
+            printf "action '%s' does not exist!" "$action" >&2
+            exit 2
+    esac
+
+    # Make a special check: only do this action if a dependency did something
+    # it is required that the dependencies write there action to $__messages_in
+    if [ -f "$__object/parameter/if-required" ]; then
+        # exit here if there are no changes from the dependencies affected (nothing to do)
+        if ! grep -q -f "$__object/require" "$__messages_in"; then exit 0; fi
+    fi
+fi
+
+# print the execution command if a action given
+if [ -n "$required_action" ]; then
+    # also print it as message
+    echo "$required_action" >> "$__messages_out"
+    echo "systemctl $required_action '$name'"
+fi

cdist/conf/type/__systemd_service/man.rst

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+cdist-type__systemd-service(7)
+==============================
+
+NAME
+----
+cdist-type__systemd-service - Controls a systemd service state
+
+DESCRIPTION
+-----------
+This type controls systemd services to define a state of the service,
+or an action like reloading or restarting. It is useful to reload a
+service after configuration applied or shutdown one service.
+
+The activation or deactivation is out of scope. Look for the
+:strong:`cdist-type__systemd_util`\ (7) type instead.
+
+REQUIRED PARAMETERS
+-------------------
+
+None.
+
+OPTIONAL PARAMETERS
+-------------------
+
+name
+    String which will used as name instead of the object id.
+
+state
+    The state which the service should be in:
+
+    running
+        Service should run (default)
+
+    stoppend
+        Service should stopped
+
+action
+    Executes an action on on the service. It will only execute it if the
+    service keeps the state **running**. There are following actions, where:
+
+    reload
+        Reloads the service
+
+    restart
+        Restarts the service
+
+BOOLEAN PARAMETERS
+-----------------
+
+if-required
+    Only execute the action if minimum one required type outputs a message to
+    **$__messages_out**. Through this, the action should only executed if a
+    dependency did something. The action will not executed if no dependencies
+    given.
+
+MESSAGES
+--------
+
+start
+    Started the service
+
+stop
+    Stopped the service
+
+restart
+    Restarted the service
+
+reload
+    Reloaded the service
+
+ABORTS
+------
+Aborts in following cases:
+
+systemd or the service does not exist
+
+EXAMPLES
+--------
+.. code-block:: sh
+
+    # service must run
+    __systemd_service nginx
+
+    # service must stopped
+    __systemd_service sshd \
+        --state stopped
+
+    # restart the service
+    __systemd_service apache2 \
+        --action restart
+
+    # makes sure the service exist with an alternative name
+    __systemd_service foo \
+        --name sshd
+
+    # reload the service for a modified configuration file
+    # only reloads the service if the file really changed
+    require="__config_file/etc/foo.conf" __systemd_service foo \
+        --action reload --if-required
+
+AUTHORS
+-------
+Matthias Stecher <matthiasstecher at gmx.de>
+
+COPYRIGHT
+---------
+Copyright \(C) 2020 Matthias Stecher. 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.

cdist/conf/type/__systemd_service/parameter/boolean

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+if-required

cdist/conf/type/__systemd_service/parameter/default/state

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+running

cdist/conf/type/__systemd_service/parameter/optional

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+name
+state
+action