Adding support for custom MySQL queries (#259)

Already supported by the agent, but not exposed in the Chef cookbook

Adding a kitchen test on MySQL as well

.kitchen.yml

@@ -316,6 +316,32 @@ suites:
           - host: localhost
             port: 27017
 
+- name: datadog_mysql
+  run_list:
+    - recipe[datadog::mysql]
+  attributes:
+    datadog:
+      <<: *DATADOG
+      mysql:
+        instances:
+          - server: 1.1.1.1
+            port: 3307
+            user: my_username
+            pass: my_password
+            sock: /path/to/mysql.sock
+            tags: ['prod', 'my_app']
+            options:
+              - 'replication: 0'
+            queries:
+              - type: gauge
+                field: users_count
+                metric: my_app.my_users.count
+                query: SELECT COUNT(1) AS users_count FROM users
+              - type: gauge
+                field: max_query_time
+                metric: mysql.performance.max_query_time
+                query: SELECT IFNULL(MAX(TIME), 0) AS max_query_time FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND != 'Sleep'
+
 - name: datadog_ntp
   run_list:
     - recipe[datadog::ntp]

recipes/mysql.rb

@@ -17,6 +17,14 @@
 #     'options' => [
 #       "replication: 0",
 #       "galera_cluster: 1"
+#     ],
+#     'queries' => [
+#       {
+#         'type' => 'gauge',
+#         'field' => 'users_count'
+#         'metric' => 'my_app.my_users.count',
+#         'query' => 'SELECT COUNT(1) AS users_count FROM users'
+#       },
 #     ]
 #   },
 # ]

templates/default/mysql.yaml.erb

@@ -21,6 +21,15 @@ instances:
       <%= o %>
     <% end -%>
   <% end -%>
+  <% if i.key?('queries') -%>
+    queries:
+    <% i['queries'].each do |q| -%>
+      - type: <%= q['type'] %>
+        field: <%= q['field'] %>
+        metric: <%= q['metric'] %>
+        query: <%= q['query'] %>
+    <% end -%>
+  <% end -%>
 <% end -%>
 
 # Nothing to configure here

test/integration/datadog_mysql/serverspec/Gemfile

@@ -0,0 +1 @@
+../../helpers/serverspec/Gemfile

test/integration/datadog_mysql/serverspec/mysql_spec.rb

@@ -0,0 +1,54 @@
+# Encoding: utf-8
+require 'json_spec'
+require 'serverspec'
+require 'yaml'
+
+set :backend, :exec
+set :path, '/sbin:/usr/local/sbin:$PATH'
+
+AGENT_CONFIG = '/etc/dd-agent/conf.d/mysql.yaml'
+
+describe service('datadog-agent') do
+  it { should be_running }
+end
+
+describe file(AGENT_CONFIG) do
+  it { should be_a_file }
+
+  it 'is valid yaml matching input values' do
+    generated = YAML.load_file(AGENT_CONFIG)
+
+    expected = {
+      'instances' => [
+        {
+          'server' => '1.1.1.1',
+          'port' => 3307,
+          'user' => 'my_username',
+          'pass' => 'my_password',
+          'sock' => '/path/to/mysql.sock',
+          'tags' => ['prod', 'my_app'],
+          'options' => {
+            'replication' => 0
+          },
+          'queries' => [
+            {
+              'type' => 'gauge',
+              'field' => 'users_count',
+              'metric' => 'my_app.my_users.count',
+              'query' => 'SELECT COUNT(1) AS users_count FROM users'
+            },
+            {
+              'type' => 'gauge',
+              'field' => 'max_query_time',
+              'metric' => 'mysql.performance.max_query_time',
+              'query' => "SELECT IFNULL(MAX(TIME), 0) AS max_query_time FROM INFORMATION_SCHEMA.PROCESSLIST WHERE COMMAND != 'Sleep'"
+            }
+          ]
+        }
+      ],
+      'init_config' => nil
+    }
+
+    expect(generated.to_json).to be_json_eql expected.to_json
+  end
+end