Don't hijack statsd

lib/kubernetes-deploy.rb

@@ -23,5 +23,5 @@
 
 module KubernetesDeploy
   MIN_KUBE_VERSION = '1.9.0'
-  KubernetesDeploy::StatsD.build
+  StatsD.build
 end

lib/kubernetes-deploy/deploy_task.rb

@@ -159,25 +159,25 @@ def run!(verify_result: true, allow_protected_ns: false, prune: true)
         MSG
         @logger.summary.add_paragraph(ColorizedString.new(warning).yellow)
       end
-      ::StatsD.event("Deployment of #{@namespace} succeeded",
+      StatsD.event("Deployment of #{@namespace} succeeded",
         "Successfully deployed all #{@namespace} resources to #{@context}",
         alert_type: "success", tags: statsd_tags << "status:success")
-      ::StatsD.measure('all_resources.duration', StatsD.duration(start), tags: statsd_tags << "status:success")
+      StatsD.distribution('all_resources.duration', StatsD.duration(start), tags: statsd_tags << "status:success")
       @logger.print_summary(:success)
     rescue DeploymentTimeoutError
       @logger.print_summary(:timed_out)
-      ::StatsD.event("Deployment of #{@namespace} timed out",
+      StatsD.event("Deployment of #{@namespace} timed out",
         "One or more #{@namespace} resources failed to deploy to #{@context} in time",
         alert_type: "error", tags: statsd_tags << "status:timeout")
-      ::StatsD.measure('all_resources.duration', StatsD.duration(start), tags: statsd_tags << "status:timeout")
+      StatsD.distribution('all_resources.duration', StatsD.duration(start), tags: statsd_tags << "status:timeout")
       raise
     rescue FatalDeploymentError => error
       @logger.summary.add_action(error.message) if error.message != error.class.to_s
       @logger.print_summary(:failure)
-      ::StatsD.event("Deployment of #{@namespace} failed",
+      StatsD.event("Deployment of #{@namespace} failed",
         "One or more #{@namespace} resources failed to deploy to #{@context}",
         alert_type: "error", tags: statsd_tags << "status:failed")
-      ::StatsD.measure('all_resources.duration', StatsD.duration(start), tags: statsd_tags << "status:failed")
+      StatsD.distribution('all_resources.duration', StatsD.duration(start), tags: statsd_tags << "status:failed")
       raise
     end
 

lib/kubernetes-deploy/kubectl.rb

@@ -45,7 +45,7 @@ def run(*args, log_failure: nil, use_context: true, use_namespace: true, raise_i
           raise(ResourceNotFoundError, err) if raise_if_not_found
         else
           @logger.debug("Kubectl err: #{err}") unless output_is_sensitive?
-          ::StatsD.increment('kubectl.error', 1, tags: { context: @context, namespace: @namespace, cmd: args[1] })
+          StatsD.increment('kubectl.error', 1, tags: { context: @context, namespace: @namespace, cmd: args[1] })
         end
         sleep retry_delay(attempt) unless attempt == attempts
       end

lib/kubernetes-deploy/kubernetes_resource.rb

@@ -293,7 +293,7 @@ def pretty_status
 
     def report_status_to_statsd(watch_time)
       unless @statsd_report_done
-        ::StatsD.measure('resource.duration', watch_time, tags: statsd_tags)
+        StatsD.distribution('resource.duration', watch_time, tags: statsd_tags)
         @statsd_report_done = true
       end
     end

lib/kubernetes-deploy/restart_task.rb

@@ -57,14 +57,14 @@ def perform!(deployments_names = nil)
         raise DeploymentTimeoutError
       end
       raise FatalDeploymentError unless success
-      ::StatsD.distribution('restart.duration', StatsD.duration(start), tags: tags('success', deployments))
+      StatsD.distribution('restart.duration', StatsD.duration(start), tags: tags('success', deployments))
       @logger.print_summary(:success)
     rescue DeploymentTimeoutError
-      ::StatsD.distribution('restart.duration', StatsD.duration(start), tags: tags('timeout', deployments))
+      StatsD.distribution('restart.duration', StatsD.duration(start), tags: tags('timeout', deployments))
       @logger.print_summary(:timed_out)
       raise
     rescue FatalDeploymentError => error
-      ::StatsD.distribution('restart.duration', StatsD.duration(start), tags: tags('failure', deployments))
+      StatsD.distribution('restart.duration', StatsD.duration(start), tags: tags('failure', deployments))
       @logger.summary.add_action(error.message) if error.message != error.class.to_s
       @logger.print_summary(:failure)
       raise

lib/kubernetes-deploy/runner_task.rb

@@ -45,14 +45,14 @@ def run!(task_template:, entrypoint:, args:, env_vars: [], verify_result: true)
       else
         record_status_once(pod)
       end
-      ::StatsD.distribution('task_runner.duration', StatsD.duration(start), tags: statsd_tags('success'))
+      StatsD.distribution('task_runner.duration', StatsD.duration(start), tags: statsd_tags('success'))
       @logger.print_summary(:success)
     rescue DeploymentTimeoutError
-      ::StatsD.distribution('task_runner.duration', StatsD.duration(start), tags: statsd_tags('timeout'))
+      StatsD.distribution('task_runner.duration', StatsD.duration(start), tags: statsd_tags('timeout'))
       @logger.print_summary(:timed_out)
       raise
     rescue FatalDeploymentError
-      ::StatsD.distribution('task_runner.duration', StatsD.duration(start), tags: statsd_tags('failure'))
+      StatsD.distribution('task_runner.duration', StatsD.duration(start), tags: statsd_tags('failure'))
       @logger.print_summary(:failure)
       raise
     end

lib/kubernetes-deploy/statsd.rb

@@ -4,23 +4,37 @@
 
 module KubernetesDeploy
   class StatsD
+    extend ::StatsD
+
+    PREFIX = "KubernetesDeploy"
+
     def self.duration(start_time)
       (Time.now.utc - start_time).round(1)
     end
 
     def self.build
-      ::StatsD.default_sample_rate = 1.0
-      ::StatsD.prefix = "KubernetesDeploy"
-
       if ENV['STATSD_DEV'].present?
-        ::StatsD.backend = ::StatsD::Instrument::Backends::LoggerBackend.new(Logger.new($stderr))
+        self.backend = ::StatsD::Instrument::Backends::LoggerBackend.new(Logger.new($stderr))
       elsif ENV['STATSD_ADDR'].present?
         statsd_impl = ENV['STATSD_IMPLEMENTATION'].present? ? ENV['STATSD_IMPLEMENTATION'] : "datadog"
-        ::StatsD.backend = ::StatsD::Instrument::Backends::UDPBackend.new(ENV['STATSD_ADDR'], statsd_impl)
+        self.backend = ::StatsD::Instrument::Backends::UDPBackend.new(ENV['STATSD_ADDR'], statsd_impl)
       else
-        ::StatsD.backend = ::StatsD::Instrument::Backends::NullBackend.new
+        self.backend = ::StatsD::Instrument::Backends::NullBackend.new
       end
-      ::StatsD.backend
+    end
+
+    # It is not sufficient to set the prefix field on the KubernetesDeploy::StatsD singleton itself, since its value
+    # is overridden in the underlying calls to the ::StatsD library, hence the need to pass it in as a custom prefix
+    # via the metric_options hash. This is done since KubernetesDeploy may be included as a library and should not
+    # change the global StatsD configuration of the importing application.
+    def self.increment(key, value = 1, **metric_options)
+      metric_options[:prefix] = PREFIX
+      super
+    end
+
+    def self.distribution(key, value = nil, **metric_options, &block)
+      metric_options[:prefix] = PREFIX
+      super
     end
 
     module MeasureMethods
@@ -49,7 +63,12 @@ def measure_method(method_name, metric = nil)
               dynamic_tags[:error] = error if dynamic_tags.is_a?(Hash)
               dynamic_tags << "error:#{error}" if dynamic_tags.is_a?(Array)
             end
-            ::StatsD.distribution(metric, KubernetesDeploy::StatsD.duration(start_time), tags: dynamic_tags)
+
+            StatsD.distribution(
+              metric,
+              KubernetesDeploy::StatsD.duration(start_time),
+              tags: dynamic_tags
+            )
           end
         end
 

test/helpers/statsd_helper.rb

@@ -0,0 +1,17 @@
+# frozen_string_literal: true
+module StatsDHelper
+  def capture_statsd_calls
+    mock_backend = ::StatsD::Instrument::Backends::CaptureBackend.new
+    old_backend = KubernetesDeploy::StatsD.backend
+    KubernetesDeploy::StatsD.backend = mock_backend
+
+    yield if block_given?
+
+    mock_backend.collected_metrics
+  ensure
+    if old_backend.is_a?(::StatsD::Instrument::Backends::CaptureBackend)
+      old_backend.collected_metrics.concat(mock_backend.collected_metrics)
+    end
+    KubernetesDeploy::StatsD.backend = old_backend
+  end
+end

test/integration-serial/serial_deploy_test.rb

@@ -2,6 +2,7 @@
 require 'integration_test_helper'
 
 class SerialDeployTest < KubernetesDeploy::IntegrationTest
+  include StatsDHelper
   # This cannot be run in parallel because it either stubs a constant or operates in a non-exclusive namespace
   def test_deploying_to_protected_namespace_with_override_does_not_prune
     KubernetesDeploy::DeployTask.stub_const(:PROTECTED_NAMESPACES, [@namespace]) do

test/integration-serial/serial_task_run_test.rb

@@ -3,6 +3,7 @@
 
 class SerialTaskRunTest < KubernetesDeploy::IntegrationTest
   include TaskRunnerTestHelper
+  include StatsDHelper
 
   # Mocha is not thread-safe: https://github.com/freerange/mocha#thread-safety
   def test_run_without_verify_result_fails_if_pod_was_not_created

test/unit/kubernetes-deploy/kubectl_test.rb

@@ -2,6 +2,7 @@
 require 'test_helper'
 
 class KubectlTest < KubernetesDeploy::TestCase
+  include StatsDHelper
   def setup
     super
     KubernetesDeploy::Kubectl.any_instance.unstub(:run)

test/unit/kubernetes-deploy/statsd_test.rb

@@ -3,6 +3,7 @@
 require 'test_helper'
 
 class StatsDTest < KubernetesDeploy::TestCase
+  include StatsDHelper
   class TestMeasureClass
     extend(KubernetesDeploy::StatsD::MeasureMethods)
 
@@ -40,14 +41,29 @@ def test_build_when_statsd_addr_env_present_but_statsd_implementation_is_not
 
     KubernetesDeploy::StatsD.build
 
-    assert_equal :datadog, StatsD.backend.implementation
+    assert_equal(:datadog, KubernetesDeploy::StatsD.backend.implementation)
   ensure
     ENV['STATSD_ADDR'] = original_addr
     ENV['STATSD_IMPLEMENTATION'] = original_impl
     ENV['STATSD_DEV'] = original_dev
     KubernetesDeploy::StatsD.build
   end
 
+  def test_kubernetes_statsd_does_not_override_global_config
+    old_prefix = ::StatsD.prefix
+    old_sample_rate = ::StatsD.default_sample_rate
+
+    ::StatsD.prefix = "test"
+    ::StatsD.default_sample_rate = 2.0
+    KubernetesDeploy::StatsD.build
+    refute_equal(KubernetesDeploy::StatsD.prefix, ::StatsD.prefix)
+    refute_equal(KubernetesDeploy::StatsD.default_sample_rate, ::StatsD.default_sample_rate)
+    refute_equal(KubernetesDeploy::StatsD.backend, ::StatsD.backend)
+  ensure
+    ::StatsD.prefix = old_prefix
+    ::StatsD.default_sample_rate = old_sample_rate
+  end
+
   def test_measuring_non_existent_method_raises
     assert_raises_message(NotImplementedError, "Cannot instrument undefined method bogus_method") do
       TestMeasureClass.measure_method(:bogus_method)