puppet: Add a redis exporter.

puppet/zulip/manifests/common.pp

@@ -123,6 +123,15 @@ class zulip::common {
       },
     },
 
+    # https://github.com/oliver006/redis_exporter/releases
+    'redis_exporter' => {
+      'version' => '1.37.0',
+      'sha256' => {
+        'amd64'   => 'c4d0554a378151eab3372235c40d3a9c8c40fd6f40d91d768830985df8a44744',
+        'aarch64' => '742047d938192894979c8370830891bb0fea3262b762e6c51c849a8e47ddfb7e',
+      },
+    },
+
     # https://github.com/timonwong/uwsgi_exporter/releases
     'uwsgi_exporter' => {
       'version' => '1.0.0',

puppet/zulip_ops/manifests/profile/chat_zulip_org.pp

@@ -4,6 +4,7 @@ class zulip_ops::profile::chat_zulip_org {
 
   include zulip_ops::profile::base
   include zulip_ops::app_frontend_monitoring
+  include zulip_ops::prometheus::redis
   zulip_ops::firewall_allow { 'http': }
   zulip_ops::firewall_allow { 'https': }
   zulip_ops::firewall_allow { 'smtp': }

puppet/zulip_ops/manifests/profile/redis.pp

@@ -1,5 +1,6 @@
 class zulip_ops::profile::redis inherits zulip_ops::profile::base {
   include zulip::profile::redis
+  include zulip_ops::prometheus::redis
 
   # Need redis_password in its own file for Nagios
   file { '/var/lib/nagios/redis_password':

puppet/zulip_ops/manifests/prometheus/redis.pp

@@ -0,0 +1,28 @@
+# @summary Prometheus monitoring of redis servers
+#
+class zulip_ops::prometheus::redis {
+  $version = $zulip::common::versions['redis_exporter']['version']
+  $dir = "/srv/zulip-redis_exporter-${version}"
+  $bin = "${dir}/redis_exporter"
+
+  zulip::external_dep { 'redis_exporter':
+    version        => $version,
+    url            => "https://github.com/oliver006/redis_exporter/releases/download/v${version}/redis_exporter-v${version}.linux-${zulip::common::goarch}.tar.gz",
+    tarball_prefix => "redis_exporter-v${version}.linux-${zulip::common::goarch}",
+  }
+
+  zulip_ops::firewall_allow { 'redis_exporter': port => '9121' }
+  file { "${zulip::common::supervisor_conf_dir}/prometheus_redis_exporter.conf":
+    ensure  => file,
+    require => [
+      User[zulip],
+      Package[supervisor],
+      Zulip::External_Dep['redis_exporter'],
+    ],
+    owner   => 'root',
+    group   => 'root',
+    mode    => '0644',
+    content => template('zulip_ops/supervisor/conf.d/prometheus_redis_exporter.conf.template.erb'),
+    notify  => Service[supervisor],
+  }
+}

puppet/zulip_ops/templates/supervisor/conf.d/prometheus_redis_exporter.conf.template.erb

@@ -0,0 +1,8 @@
+[program:prometheus_redis_exporter]
+command=/usr/local/bin/secret-env-wrapper REDIS_PASSWORD=redis_password <%= @bin %>
+priority=10
+autostart=true
+autorestart=true
+user=zulip
+redirect_stderr=true
+stdout_logfile=/var/log/zulip/redis_exporter.log