add support for remote_read

manifests/config.pp

@@ -4,19 +4,27 @@
   $global_config,
   $rule_files,
   $scrape_configs,
+  $remote_read_configs,
   $purge = true,
   $config_template = $::prometheus::params::config_template,
 ) {
 
   if $prometheus::init_style {
     if( versioncmp($::prometheus::version, '2.0.0') < 0 ){
+      # helper variable indicating prometheus version, so we can use on this information in the template
+      $prometheus_v2 = false
+      if $remote_read_configs != [] {
+        fail('remote_read_configs requires prometheus 2.X')
+      }
       $daemon_flags = [
         "-config.file=${::prometheus::config_dir}/prometheus.yaml",
         "-storage.local.path=${::prometheus::localstorage}",
         "-web.console.templates=${::prometheus::shared_dir}/consoles",
         "-web.console.libraries=${::prometheus::shared_dir}/console_libraries",
       ]
     } else {
+      # helper variable indicating prometheus version, so we can use on this information in the template
+      $prometheus_v2 = true
       $daemon_flags = [
         "--config.file=${::prometheus::config_dir}/prometheus.yaml",
         "--storage.tsdb.path=${::prometheus::localstorage}",

manifests/init.pp

@@ -99,6 +99,9 @@
 #  [*scrape_configs*]
 #  Prometheus scrape configs
 #
+#  [*remote_read_configs*]
+#  Prometheus remote_read config to scrape prometheus 1.8+ instances
+#
 #  [*alert_relabel_config*]
 #  Prometheus alert relabel config under alerting
 #
@@ -144,6 +147,7 @@
   Hash $global_config         = $::prometheus::params::global_config,
   Array $rule_files           = $::prometheus::params::rule_files,
   Array $scrape_configs       = $::prometheus::params::scrape_configs,
+  Array $remote_read_configs  = $::prometheus::params::remote_read_configs,
   $alerts                     = $::prometheus::params::alerts,
   Array $alert_relabel_config = $::prometheus::params::alert_relabel_config,
   Array $alertmanagers_config = $::prometheus::params::alertmanagers_config,
@@ -167,11 +171,12 @@
   anchor {'prometheus_first': }
   -> class { '::prometheus::install': }
   -> class { '::prometheus::config':
-    global_config   => $global_config,
-    rule_files      => $rule_files,
-    scrape_configs  => $scrape_configs,
-    purge           => $purge_config_dir,
-    config_template => $config_template,
+    global_config       => $global_config,
+    rule_files          => $rule_files,
+    scrape_configs      => $scrape_configs,
+    remote_read_configs => $remote_read_configs,
+    purge               => $purge_config_dir,
+    config_template     => $config_template,
   }
   -> class { '::prometheus::alerts':
     location => $config_dir,

manifests/params.pp

@@ -132,6 +132,7 @@
   $package_name = 'prometheus'
   $rule_files = [ "${config_dir}/alert.rules" ]
   $scrape_configs = [ { 'job_name'=> 'prometheus', 'scrape_interval'=> '10s', 'scrape_timeout'=> '10s', 'static_configs'=> [ { 'targets'=> [ 'localhost:9090' ], 'labels'=> { 'alias'=> 'Prometheus'} } ] } ]
+  $remote_read_configs = []
   $shared_dir = '/usr/local/share/prometheus'
   $statsd_exporter_download_extension = 'tar.gz'
   $statsd_exporter_download_url_base = 'https://github.com/prometheus/statsd_exporter/releases'

spec/classes/prometheus_spec.rb

@@ -170,7 +170,7 @@
               'owner'   => 'prometheus',
               'group'   => 'prometheus',
               'mode'    => '0660',
-              'content' => File.read(fixtures('files', 'prometheus.yaml'))
+              'content' => File.read(fixtures('files', "prometheus#{prom_major}.yaml"))
             ).that_notifies('Class[prometheus::service_reload]')
           }
 

spec/fixtures/files/prometheus2.yaml

@@ -0,0 +1,21 @@
+---
+global:
+  scrape_interval: 15s
+  evaluation_interval: 15s
+  external_labels:
+    monitor: master
+rule_files:
+- "/etc/prometheus/alert.rules"
+scrape_configs:
+- job_name: prometheus
+  scrape_interval: 10s
+  scrape_timeout: 10s
+  static_configs:
+  - targets:
+    - localhost:9090
+    labels:
+      alias: Prometheus
+alerting:
+  alert_relabel_configs: []
+  alertmanagers: []
+remote_read: []

templates/prometheus.yaml.erb

@@ -2,13 +2,19 @@
 <% global_config = scope.lookupvar('::prometheus::global_config') -%>
 <% rule_files = scope.lookupvar('::prometheus::rule_files') -%>
 <% scrape_configs = scope.lookupvar('::prometheus::scrape_configs') -%>
+<% remote_read_configs = scope.lookupvar('::prometheus::remote_read_configs') -%>
 <% full_config = {
   'global'=>global_config,
   'rule_files'=>rule_files,
   'scrape_configs'=>scrape_configs,
   'alerting'=>{
     'alert_relabel_configs'=>scope.lookupvar('::prometheus::alert_relabel_config'),
     'alertmanagers'=>scope.lookupvar('::prometheus::alertmanagers_config'),
-  }
-} -%>
+  },
+}
+if @prometheus_v2
+    # this variable has to be absent on 1.X, so we filter using the helper variable
+    full_config['remote_read'] = remote_read_configs
+end
+ -%>
 <%= full_config.to_yaml(options = {:line_width => -1}).gsub(/source_labels: ".+?"/) { |x| x.gsub('"', '') } -%>