- Added custom metrics example and specs

Author: Seth Cleveland

manifests/integrations/postgres.pp

@@ -33,6 +33,18 @@
 #    dbname   => 'postgres'
 #    username => 'datadog',
 #    password => 'some_pass',
+#    custom_metrics => {
+#      a_custom_query => {
+#        query => "select tag_column, %s from table",
+#        relation => false,
+#        metrics => {
+#          value_column => ["value_column.datadog.tag", "GAUGE"]
+#        },
+#        descriptors => [
+#          ["tag_column", "tag_column.datadog.tag"]
+#        ]
+#      }
+#    }
 #  }
 #
 #

manifests/integrations/postgres_custom_metric.pp

@@ -21,7 +21,7 @@
   $relation = false,
   $descriptors = [],
 ) {
-  validate_re($query, '^.*%s.*$')
+  validate_re($query, '^.*%s.*$', 'custom_metrics require %s for metric substitution')
   validate_hash($metrics)
   validate_array($descriptors)
 }

spec/classes/datadog_agent_integrations_postgres_spec.rb

@@ -55,6 +55,53 @@
       it { should contain_file(conf_file).with_content(%r{username: monitoring}) }
       it { should contain_file(conf_file).with_content(%r{^[^#]*tags:\s+- foo\s+- bar\s+- baz}) }
       it { should contain_file(conf_file).with_content(%r{^[^#]*relations:\s+- furry\s+- fuzzy\s+- funky}) }
+
+      context 'with custom metric query missing %s' do
+        let(:params) {{
+          host: 'postgres1',
+          dbname: 'cats',
+          port: 4142,
+          username: 'monitoring',
+          password: 'abc123',
+          custom_metrics: {
+            'query_is_missing_%s' => {
+              'query' => 'select * from fuzz',
+              'metrics' => { },
+            }
+          }
+        }}
+        it do
+          expect {
+            is_expected.to compile
+          }.to raise_error(/custom_metrics require %s for metric substitution/)
+        end
+      end
+
+      context 'with custom metric query' do
+        let(:params) {{
+          host: 'postgres1',
+          dbname: 'cats',
+          port: 4142,
+          username: 'monitoring',
+          password: 'abc123',
+          custom_metrics: {
+            'foo_gooo_bar_query' => {
+              'query' => 'select foo, %s from bar',
+              'metrics' => {
+                "gooo" => ["custom_metric.tag.gooo", "GAUGE"]
+              },
+              'descriptors' => [["foo", "custom_metric.tag.foo"]]
+            }
+          }
+        }}
+        it { is_expected.to compile }
+        it { should contain_file(conf_file).with_content(%r{^[^#]*custom_metrics:}) }
+        it { should contain_file(conf_file).with_content(%r{\s+query:\s*['"]?select foo, %s from bar['"]?}) }
+        it { should contain_file(conf_file).with_content(%r{\s+metrics:}) }
+        it { should contain_file(conf_file).with_content(%r{\s+"gooo":\s+\[custom_metric.tag.gooo, GAUGE\]}) }
+        it { should contain_file(conf_file).with_content(%r{\s+query.*\n\s+relation:\s*false}) }
+        it { should contain_file(conf_file).with_content(%r{\s+descriptors.*\n\s+-\s+\[foo, custom_metric.tag.foo\]}) }
+      end
     end
   end
 

templates/agent-conf.d/postgres.yaml.erb

@@ -55,9 +55,9 @@ instances:
 #
 <% if @custom_metrics and ! @custom_metrics.empty? -%>
     custom_metrics:
-  <%- Array(@custom_metrics).each do |custom_metric| -%>
+  <%- Array(@custom_metrics).each do |n, custom_metric| -%>
       - query: <%= custom_metric["query"] %>
-        relation: <%= custom_metric["relation"] %>
+        relation: <%= custom_metric["relation"]? "true" : "false" %>
         metrics:
     <%- Array(custom_metric["metrics"]).each do |metric_name, metric_descriptor| -%>
           "<%= metric_name %>": [<%= metric_descriptor[0] %>, <%= metric_descriptor[1] %>]