configure service for embedded prometheus exporter

REFERENCE.md

@@ -15,6 +15,7 @@
 * `solr::config`: Setup and configure Solr.
 * `solr::customplugins`: Manages custom plugins for Solr.
 * `solr::install`: Installs and prepares the Solr application.
+* `solr::prometheus_exporter`: Configure the embedded prometheus exporter as a service.
 * `solr::service`: Installs and configures the Solr service.
 
 ### Defined types
@@ -35,16 +36,24 @@ The following parameters are available in the `solr` class:
 * [`custom_plugins`](#custom_plugins)
 * [`custom_plugins_dir`](#custom_plugins_dir)
 * [`custom_plugins_id`](#custom_plugins_id)
+* [`enable_prometheus_exporter`](#enable_prometheus_exporter)
 * [`enable_remote_jmx`](#enable_remote_jmx)
 * [`extract_dir`](#extract_dir)
 * [`gc_log_opts`](#gc_log_opts)
 * [`gc_tune`](#gc_tune)
 * [`java_home`](#java_home)
 * [`java_mem`](#java_mem)
+* [`limit_file_max`](#limit_file_max)
+* [`limit_proc_max`](#limit_proc_max)
 * [`log_dir`](#log_dir)
 * [`manage_custom_plugins`](#manage_custom_plugins)
+* [`manage_service_limits`](#manage_service_limits)
 * [`mirror`](#mirror)
 * [`service_name`](#service_name)
+* [`prometheus_exporter_user`](#prometheus_exporter_user)
+* [`prometheus_exporter_env_vars`](#prometheus_exporter_env_vars)
+* [`prometheus_exporter_extra_options`](#prometheus_exporter_extra_options)
+* [`prometheus_exporter_service_name`](#prometheus_exporter_service_name)
 * [`solr_base`](#solr_base)
 * [`solr_home`](#solr_home)
 * [`solr_host`](#solr_host)
@@ -84,6 +93,12 @@ Data type: `String`
 
 Sets the Solr config option that is used to configure custom plugins.
 
+##### <a name="enable_prometheus_exporter"></a>`enable_prometheus_exporter`
+
+Data type: `Boolean`
+
+Determines whether to enable embedded prometheus exporter as a service.
+
 ##### <a name="enable_remote_jmx"></a>`enable_remote_jmx`
 
 Data type: `Boolean`
@@ -148,7 +163,8 @@ Determines whether to enable support for custom plugins.
 
 Data type: `Boolean`
 
-Determines whether to set resource limits for the Solr service. The service is NOT restarted when limits are changed.
+Determines whether to set resource limits for the Solr service. The service
+is NOT restarted when limits are changed.
 
 ##### <a name="mirror"></a>`mirror`
 
@@ -162,6 +178,30 @@ Data type: `String`
 
 Sets the name of the system service that should be setup.
 
+##### <a name="prometheus_exporter_user"></a>`prometheus_exporter_user`
+
+Data type: `String`
+
+Sets the user running the solr-exporter binary.
+
+##### <a name="prometheus_exporter_env_vars"></a>`prometheus_exporter_env_vars`
+
+Data type: `Optional[Hash]`
+
+Sets solr-exporter environment variables in service file (see https://solr.apache.org/guide/solr/latest/deployment-guide/monitoring-with-prometheus-and-grafana.html#environment-variable-options).
+
+##### <a name="prometheus_exporter_extra_options"></a>`prometheus_exporter_extra_options`
+
+Data type: `Optional[String]`
+
+Sets solr-exporter custom command line options (see https://solr.apache.org/guide/solr/latest/deployment-guide/monitoring-with-prometheus-and-grafana.html#command-line-parameters).
+
+##### <a name="prometheus_exporter_service_name"></a>`prometheus_exporter_service_name`
+
+Data type: `String`
+
+Sets the name of the prometheus exporter system service that should be setup.
+
 ##### <a name="solr_base"></a>`solr_base`
 
 Data type: `Stdlib::Compat::Absolute_path`

data/common.yaml

@@ -3,6 +3,7 @@ solr::cloud: false
 solr::custom_plugins: []
 solr::custom_plugins_dir: "%{lookup('solr::var_dir')}/libs"
 solr::custom_plugins_id: 'solr.custom_plugins.dir'
+solr::enable_prometheus_exporter: false
 solr::enable_remote_jmx: false
 solr::extract_dir: '/opt'
 solr::gc_log_opts:
@@ -31,6 +32,10 @@ solr::log_dir: '/var/log/solr'
 solr::manage_custom_plugins: false
 solr::manage_service_limits: true
 solr::mirror: 'https://dlcdn.apache.org/solr/solr'
+solr::prometheus_exporter_env_vars: {}
+solr::prometheus_exporter_extra_options: ~
+solr::prometheus_exporter_user: "%{lookup('solr::solr_user')}"
+solr::prometheus_exporter_service_name: 'solr-exporter'
 solr::service_name: 'solr'
 solr::solr_base: "%{lookup('solr::extract_dir')}/%{lookup('solr::service_name')}"
 solr::solr_home: "%{lookup('solr::var_dir')}/data"

manifests/init.pp

@@ -13,6 +13,9 @@
 # @param custom_plugins_id
 #   Sets the Solr config option that is used to configure custom plugins.
 #
+# @param enable_prometheus_exporter
+#   Determines whether to enable embedded prometheus exporter as a service.
+#
 # @param enable_remote_jmx
 #   Determines whether to enable remote JMX support.
 #
@@ -53,6 +56,18 @@
 # @param service_name
 #   Sets the name of the system service that should be setup.
 #
+# @param prometheus_exporter_user
+#   Sets the user running the solr-exporter binary.
+#
+# @param prometheus_exporter_env_vars
+#   Sets solr-exporter environment variables in service file (see https://solr.apache.org/guide/solr/latest/deployment-guide/monitoring-with-prometheus-and-grafana.html#environment-variable-options).
+#
+# @param prometheus_exporter_extra_options
+#   Sets solr-exporter custom command line options (see https://solr.apache.org/guide/solr/latest/deployment-guide/monitoring-with-prometheus-and-grafana.html#command-line-parameters).
+#
+# @param prometheus_exporter_service_name
+#   Sets the name of the prometheus exporter system service that should be setup.
+#
 # @param solr_base
 #   Internal module parameter, SHOULD NOT BE CHANGED! Specifies a symlink that is created by the Solr installer.
 #
@@ -112,6 +127,7 @@
   Integer $zk_timeout,
   String $solr_host,
   String $solr_time,
+  Boolean $enable_prometheus_exporter,
   Boolean $enable_remote_jmx,
   String $service_name,
   Stdlib::Compat::Absolute_path $solr_base,
@@ -123,6 +139,10 @@
   Boolean $manage_service_limits,
   Integer $limit_file_max,
   Integer $limit_proc_max,
+  String $prometheus_exporter_service_name,
+  String $prometheus_exporter_user,
+  Optional[Hash] $prometheus_exporter_env_vars,
+  Optional[String] $prometheus_exporter_extra_options,
   Optional[Array] $gc_log_opts,
   Optional[Array] $gc_tune,
   Optional[Stdlib::Compat::Absolute_path] $java_home,
@@ -133,4 +153,10 @@
   -> Class { 'solr::customplugins': }
   -> Class { 'solr::service': }
   -> Class['solr']
+
+  if $enable_prometheus_exporter {
+    Class { 'solr::prometheus_exporter':
+      require => Class['solr'],
+    }
+  }
 }

manifests/prometheus_exporter.pp

@@ -0,0 +1,48 @@
+# @summary
+#   Configure the embedded prometheus exporter as a service.
+#
+# @api private
+class solr::prometheus_exporter {
+  assert_private()
+
+  $solr_dir = "${solr::extract_dir}/${solr::service_name}"
+  if versioncmp($solr::version, '9.0.0') >= 0 {
+    $exporter_dir = "${solr_dir}/prometheus-exporter"
+  } elsif versioncmp($solr::version, '7.3.0') >= 0 {
+    $exporter_dir = "${solr_dir}/contrib/prometheus-exporter"
+  } else {
+    fail("The provided version ${solr::version} does not contain the embedded exporter (min 7.3.0)")
+  }
+
+  $bin_path = "${exporter_dir}/bin/solr-exporter"
+  # File mode is 0644 by default, set it to executable
+  file { $bin_path:
+    ensure => 'file',
+    mode   => '0755',
+  }
+
+  if $solr::prometheus_exporter_extra_options {
+    $command = "${bin_path} ${solr::prometheus_exporter_extra_options}"
+  } else {
+    $command = $bin_path
+  }
+
+  include 'systemd'
+
+  systemd::unit_file { "${solr::prometheus_exporter_service_name}.service":
+    content => epp('solr/solr-exporter.systemd.epp', {
+        'exporter_dir' => $exporter_dir,
+        'user'         => $solr::prometheus_exporter_user,
+        'env_vars'     => $solr::prometheus_exporter_env_vars,
+        'command'      => $command,
+    }),
+    require => File[$bin_path],
+    notify  => Service[$solr::prometheus_exporter_service_name],
+  }
+
+  service { $solr::prometheus_exporter_service_name:
+    ensure   => 'running',
+    enable   => true,
+    provider => 'systemd',
+  }
+}

spec/acceptance/class_spec.rb

@@ -65,4 +65,44 @@ class { 'solr':
       }
     end
   end
+  context 'with exporter' do
+    describe 'work idempotently with no errors' do
+      let(:pp) do
+        <<-MANIFEST
+        class { 'solr':
+          version                    => '9.0.0',
+          # Use 'localhost' for acceptance tests.
+          solr_host                  => 'localhost',
+          # Use Apache Archive, because "old" releases get removed
+          # very quickly from the official mirrors.
+          # mirror    => 'https://archive.apache.org/dist/lucene/solr',
+          enable_prometheus_exporter => true,
+        }
+        MANIFEST
+      end
+
+      it 'runs successfully' do
+        apply_manifest(pp, catch_failures: true)
+      end
+
+      it 'is idempotent' do
+        apply_manifest(pp, catch_changes: true)
+      end
+    end
+
+    describe service('solr-exporter') do
+      it { is_expected.to be_enabled }
+      it { is_expected.to be_running }
+    end
+
+    describe port(8989) do
+      it {
+        # Solr-exporter may take a while to start up
+        sleep(10)
+        # Depending on the host system, this may be either IPv4-
+        # or IPv6-only, so both needs to work.
+        is_expected.to be_listening
+      }
+    end
+  end
 end

spec/classes/solr_spec.rb

@@ -116,6 +116,70 @@
           it { is_expected.not_to contain_limits__limits('solr/nofile') }
           it { is_expected.not_to contain_limits__limits('solr/nproc') }
         end
+
+        context 'solr class when enable_prometheus_exporter is set to true' do
+          let(:params) do
+            {
+              enable_prometheus_exporter: true,
+              version: '9.0.0',
+            }
+          end
+
+          it { is_expected.to compile.with_all_deps }
+
+          it { is_expected.to contain_class('solr::prometheus_exporter').that_requires('Class[solr]') }
+
+          it { is_expected.to contain_file('/opt/solr/prometheus-exporter/bin/solr-exporter').with('mode' => '0755') }
+          it { is_expected.to contain_systemd__unit_file('solr-exporter.service').that_requires('File[/opt/solr/prometheus-exporter/bin/solr-exporter]').that_notifies('Service[solr-exporter]') }
+          it { is_expected.to contain_service('solr-exporter').with('ensure' => 'running', 'enable' => true) }
+        end
+
+        context 'solr class when enable_prometheus_exporter is set to true with version < 9.0.0' do
+          let(:params) do
+            {
+              enable_prometheus_exporter: true,
+              version: '8.11.2',
+            }
+          end
+
+          it { is_expected.to compile.with_all_deps }
+
+          it { is_expected.to contain_class('solr::prometheus_exporter').that_requires('Class[solr]') }
+
+          it { is_expected.to contain_file('/opt/solr/contrib/prometheus-exporter/bin/solr-exporter').with('mode' => '0755') }
+          it {
+            is_expected.to contain_systemd__unit_file('solr-exporter.service')
+              .that_requires('File[/opt/solr/contrib/prometheus-exporter/bin/solr-exporter]')
+              .that_notifies('Service[solr-exporter]')
+          }
+          it { is_expected.to contain_service('solr-exporter').with('ensure' => 'running', 'enable' => true) }
+        end
+
+        context 'solr class fails when enable_prometheus_exporter is set to true with version < 7.3.0' do
+          let(:params) do
+            {
+              enable_prometheus_exporter: true,
+              version: '7.2.1',
+              mirror: 'https://archive.apache.org/dist/lucene/solr/',
+            }
+          end
+
+          it { is_expected.to compile.with_all_deps.and_raise_error(%r{The provided version 7\.2\.1 does not contain the embedded exporter \(min 7\.3\.0\)}) }
+        end
+
+        context 'solr class when enable_prometheus_exporter is set to true and env_vars are provided' do
+          let(:params) do
+            {
+              enable_prometheus_exporter: true,
+              prometheus_exporter_env_vars: { 'JAVA_HEAP': '128m' },
+              version: '9.0.0',
+            }
+          end
+
+          it { is_expected.to compile.with_all_deps }
+
+          it { is_expected.to contain_systemd__unit_file('solr-exporter.service').with_content(%r{Environment="JAVA_HEAP=128m"}) }
+        end
       end
     end
   end

templates/solr-exporter.systemd.epp

@@ -0,0 +1,26 @@
+<%- | String $exporter_dir,
+      String $user,
+      String $command,
+      Hash   $env_vars
+| -%>
+# THIS FILE IS MANAGED BY PUPPET
+[Unit]
+Description=Solr Prometheus Exporter
+Wants=network-online.target
+After=network-online.target
+
+[Service]
+WorkingDirectory=<%= $exporter_dir %>
+User=<%= $user %>
+<% $env_vars.each |$key, $value| { -%>
+Environment="<%= $key %>=<%= $value %>"
+<% } -%>
+ExecStart=<%= $command %>
+
+Type=simple
+ExecReload=/bin/kill -HUP $MAINPID
+KillMode=process
+Restart=always
+
+[Install]
+WantedBy=multi-user.target