Introduce config option to disable statsd metrics

config/cloud_controller.yml

@@ -354,6 +354,7 @@ staging:
 
 statsd_host: "127.0.0.1"
 statsd_port: 8125
+enable_statsd_metrics: true
 
 perform_blob_cleanup: false
 

lib/cloud_controller/config_schemas/base/api_schema.rb

@@ -322,6 +322,7 @@ class ApiSchema < VCAP::Config
 
             statsd_host: String,
             statsd_port: Integer,
+            optional(:enable_statsd_metrics) => bool,
             system_hostnames: [String],
             default_app_ssh_access: bool,
 

lib/cloud_controller/config_schemas/base/clock_schema.rb

@@ -177,6 +177,7 @@ class ClockSchema < VCAP::Config
 
             statsd_host: String,
             statsd_port: Integer,
+            optional(:enable_statsd_metrics) => bool,
 
             max_labels_per_resource: Integer,
             max_annotations_per_resource: Integer,

lib/cloud_controller/config_schemas/base/deployment_updater_schema.rb

@@ -130,6 +130,7 @@ class DeploymentUpdaterSchema < VCAP::Config
 
             statsd_host: String,
             statsd_port: Integer,
+            optional(:enable_statsd_metrics) => bool,
 
             max_labels_per_resource: Integer,
             max_annotations_per_resource: Integer,

lib/cloud_controller/dependency_locator.rb

@@ -350,8 +350,13 @@ def statsd_client
       if @dependencies[:statsd_client]
         @dependencies[:statsd_client]
       else
-        Statsd.logger = Steno.logger('statsd.client')
-        register(:statsd_client, Statsd.new(config.get(:statsd_host), config.get(:statsd_port)))
+        config = CloudController::DependencyLocator.instance.config
+        if config.get(:enable_statsd_metrics) == true
+          Statsd.logger = Steno.logger('statsd.client')
+          register(:statsd_client, Statsd.new(config.get(:statsd_host), config.get(:statsd_port)))
+        else
+          register(:statsd_client, NullStatsdClient.new)
+        end
       end
     end
 
@@ -441,4 +446,22 @@ def create_paginated_collection_renderer(opts={})
                                                                              })
     end
   end
+
+  class NullStatsdClient
+    def timing(_key, _value)
+      # Null implementation
+    end
+
+    def increment(_key)
+      # Null implementation
+    end
+
+    def gauge(_stat, _value, _sample_rate=1)
+      # Null implementation
+    end
+
+    def batch
+      # Null implementation
+    end
+  end
 end

spec/fixtures/config/port_8181_config.yml

@@ -206,6 +206,7 @@ droplets:
 
 statsd_host: "127.0.0.1"
 statsd_port: 8125
+enable_statsd_metrics: true
 
 perform_blob_cleanup: false
 

spec/unit/lib/cloud_controller/dependency_locator_spec.rb

@@ -484,6 +484,41 @@
 
       expect(locator.statsd_client).to eq(expected_client)
     end
+
+    it 'returns the null statsd client' do
+      host = 'test-host'
+      port = 1234
+
+      TestConfig.override(
+        statsd_host: host,
+        statsd_port: port,
+        enable_statsd_metrics: false
+      )
+
+      expected_client = double(CloudController::NullStatsdClient)
+
+      allow(CloudController::NullStatsdClient).to receive(:new).
+        and_return(expected_client)
+
+      expect(locator.statsd_client).to eq(expected_client)
+    end
+
+    it 'returns the statsd client for other than api vms' do
+      host = 'test-host'
+      port = 1234
+      TestConfig.context = :deployment_updater
+      TestConfig.override(
+        statsd_host: host,
+        statsd_port: port
+      )
+
+      expected_client = double(Statsd)
+
+      allow(Statsd).to receive(:new).with(host, port).
+        and_return(expected_client)
+
+      expect(locator.statsd_client).to eq(expected_client)
+    end
   end
 
   describe '#bbs_stager_client' do