Merge pull request #1354 from DataDog/fix/metrics-statsd-init-flaky

[ART-380] Fix ArgumentError due to concurrent require and class use

Gemfile

@@ -24,6 +24,7 @@ gem 'redcarpet', '~> 3.4' if RUBY_PLATFORM != 'java'
 gem 'rspec', '~> 3.0'
 gem 'rspec-collection_matchers', '~> 1.1'
 gem 'rspec_junit_formatter', '>= 0.4.1'
+gem 'rspec_n', '~> 1.3' if RUBY_VERSION >= '2.3.0'
 gem 'rubocop', '= 0.50.0' if RUBY_VERSION >= '2.1.0'
 gem 'ruby-prof', '~> 1.4' if RUBY_PLATFORM != 'java' && RUBY_VERSION >= '2.4.0'
 gem 'simplecov', '~> 0.17'

lib/ddtrace/metrics.rb

@@ -41,7 +41,7 @@ def default_port
     end
 
     def default_statsd_client
-      require 'datadog/statsd' unless defined?(::Datadog::Statsd)
+      require 'datadog/statsd'
 
       # Create a StatsD client that points to the agent.
       Datadog::Statsd.new(default_hostname, default_port)

spec/ddtrace/tracer_integration_spec.rb

@@ -9,6 +9,10 @@
   subject(:tracer) { described_class.new(writer: FauxWriter.new) }
   let(:spans) { tracer.writer.spans(:keep) }
 
+  after do
+    tracer.shutdown! # Ensure no state gets left behind
+  end
+
   def sampling_priority_metric(span)
     span.get_metric(Datadog::Ext::DistributedTracing::SAMPLING_PRIORITY_KEY)
   end