[elastic] Add config flags for shard level metrics

Tested with test-kitchen.

Closes #221

Signed-off-by: Mike Fiedler <miketheman@gmail.com>

.kitchen.yml

@@ -163,6 +163,8 @@ suites:
             username: someuser
             password: somepass
             is_external: false
+            pshard_stats: true
+            shard_level_metrics: true
             tags:
               - kitchen
               - sink

recipes/elasticsearch.rb

@@ -17,6 +17,43 @@
 #     :tags => ['env:prod']
 #   }
 # ]
+#
+# Additional flags:
+#
+# If you enable the "pshard_stats" flag, statistics over primary shards
+# will be collected by the check and sent to the backend with the
+# 'elasticsearch.primary' prefix. It is particularly useful if you want to
+# get certain metrics without taking replicas into account. For instance,
+# 'elasticsearch.primaries.docs.count` will give you the total number of
+# documents in your indexes WITHOUT counting duplicates due to the existence
+# of replica shards in your ES cluster
+#
+# The "shard_level_metrics" flag enables metrics and service checks on a per-
+# shard basis (all the information is fetched under the /_stats?level=shards
+# endpoint). The metrics and service check sent for each shard are named as
+# such: elasticsearch.shard.metric.name .
+# The shard name is computed according to elasticsearch's documentation. Each
+# primary shard is named Pi (ex: P0, P1, P2...) and every replica shards will
+# be named Ri (R0, R1, R2). In case the number of replicas is superior to 1,
+# we stick to the following convention for shard names : Rx_y where x is the
+# number of the associated primary shard while y is the replica number.
+#
+# Plase note that shard-level metrics will get the following extra tags:
+# es_node:<node_name>, es_shard:<shard_name>, es_index:<index_name> and
+# es_role:(primary|replica). They will also carry a "shard_specific" tag. It
+# should enable you to slice and dice as you please in your DatadogHQ.
+#
+# Example:
+#
+# node['datadog']['elasticsearch']['instances'] = [
+#   {
+#     :url => 'http://localhost:9200',
+#     :tags => ['env:test'],
+#     :pshard_stats => true,
+#     :shard_level_metrics: true
+#   }
+# ]
+#
 
 datadog_monitor 'elastic' do
   instances node['datadog']['elasticsearch']['instances']

templates/default/elastic.yaml.erb

@@ -1,6 +1,12 @@
 instances:
   <% @instances.each do |i| -%>
   - url: <%= i["url"] %>
+    <% unless i["shard_level_metrics"].nil? %>
+    shard_level_metrics: <%= i["shard_level_metrics"] %>
+    <% end %>
+    <% unless i["pshard_stats"].nil? %>
+    pshard_stats: <%= i["pshard_stats"] %>
+    <% end %>
     <% unless i["is_external"].nil? %>
     is_external: <%= i["is_external"] %>
     <% end %>

test/integration/datadog_elasticsearch/serverspec/elasticsearch_spec.rb

@@ -25,6 +25,8 @@
           'username' => 'someuser',
           'password' => 'somepass',
           'is_external' => false,
+          'pshard_stats' => true,
+          'shard_level_metrics' => true,
           'tags' => ['kitchen', 'sink']
         }
       ],