adding class to create alerts (voxpupuli#24)

* adding class to create alerts

* fix puppet syntax in alert class

* fix puppet syntax in alert class

* fix name Value in Labels

README.md

@@ -21,6 +21,7 @@ This module automates the install and configuration of Prometheus monitoring too
 * Optionally installs a user to run it under
 * Installs a configuration file for prometheus daemon (/etc/prometheus/prometheus.yaml) or for alertmanager (/etc/prometheus/alert.rules)
 * Manages the services via upstart, sysv, or systemd
+* Optionally creates alert rules
 
 ## Usage
 
@@ -51,6 +52,32 @@ or simply:
 include ::prometheus
 ```
 
+To add alert rules, add the following to the class prometheus:
+```puppet
+    alerts => [{ 'name' => 'InstanceDown', 'condition' => 'up == 0', 'timeduration' => '5m', labels => [{ 'name' => 'severity', 'content' => 'page'}], 'annotations' => [{ 'name' => 'summary', content => 'Instance {{ $labels.instance }} down'}, {'name' => 'description', content => '{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 5 minutes.' }]}]
+```
+
+or in hiera:
+```yaml
+alertrules:
+    -
+        name: 'InstanceDown'
+        condition:  'up == 0'
+        timeduration: '5m'
+        labels:
+            -
+                name: 'severity'
+                content: 'critical'
+        annotations:
+            -
+                name: 'summary'
+                content: 'Instance {{ $labels.instance }} down'
+            -
+                name: 'description'
+                content: '{{ $labels.instance }} of job {{ $labels.job }} has been down for more than 5 minutes.'
+
+```
+
 On the monitored nodes:
 
 ```puppet

manifests/alerts.pp

@@ -0,0 +1,26 @@
+# Class: prometheus::alerts
+#
+# This module manages prometheus alerts for prometheus
+#
+#  [*location*]
+#  Whether to create the alert file for prometheus
+#
+#  [*alerts*]
+#  Array of alerts (see README)
+#
+class prometheus::alerts (
+  String $location,
+  Array  $alerts,
+  String $alertfile_name  = 'alert.rules'
+) inherits prometheus::params {
+
+    if $alerts != [] {
+        file{ "${location}/${alertfile_name}":
+                ensure  => 'file',
+                owner   => $prometheus::user,
+                group   => $prometheus::group,
+                content => epp("${module_name}/alerts.epp"),
+        }
+    }
+
+}

manifests/init.pp

@@ -136,6 +136,8 @@
   $global_config        = $::prometheus::params::global_config,
   $rule_files           = $::prometheus::params::rule_files,
   $scrape_configs       = $::prometheus::params::scrape_configs,
+  $alerts               = $::prometheus::params::alerts
+
 ) inherits prometheus::params {
   if( versioncmp($::prometheus::version, '1.0.0') == -1 ){
     $real_download_url    = pick($download_url,
@@ -172,6 +174,11 @@
     notify          => $notify_service,
     config_template => $config_template,
   } ->
+  class { '::prometheus::alerts':
+    location => $config_dir,
+    alerts   => $alerts,
+    notify   => $notify_service,
+  } ->
   class { '::prometheus::run_service': } ->
   anchor {'prometheus_last': }
 }

manifests/params.pp

@@ -39,6 +39,7 @@
   $global_config = { 'scrape_interval'=> '15s', 'evaluation_interval'=> '15s', 'external_labels'=> { 'monitor'=>'master'}}
   $rule_files = [ "${config_dir}/alert.rules" ]
   $scrape_configs = [ { 'job_name'=> 'prometheus', 'scrape_interval'=> '10s', 'scrape_timeout'=> '10s', 'static_configs'=> [ { 'targets'=> [ 'localhost:9090' ], 'labels'=> { 'alias'=> 'Prometheus'} } ] } ]
+  $alerts = []
   case $::architecture {
     'x86_64', 'amd64': { $arch = 'amd64' }
     'i386':            { $arch = '386'   }

templates/alerts.epp

@@ -0,0 +1,15 @@
+<% $prometheus::alerts::alerts.each |$alert| { -%>
+ALERT <%= $alert['name'] %>
+    IF <%= $alert['condition'] %>
+    FOR <%= $alert['timeduration'] %>
+    LABELS {
+    <% $alert['labels'].each |$label| { -%>
+        <%= $label['name'] %> = "<%= $label['content'] %>",
+    <% } -%>
+    }
+    ANNOTATIONS {
+    <% $alert['annotations'].each |$annotation| { -%>
+        <%= $annotation['name'] %> = "<%= $annotation['content'] %>",
+    <% } -%>
+    }
+<% } -%>

tests/init.pp

@@ -1,3 +1,4 @@
 include prometheus
 include prometheus::node_exporter
 include prometheus::alert_manager
+include prometheus::alerts