Merge pull request #977 from DataDog/feature/add_environment_env_var

Add DD_ENV environment variable

lib/ddtrace/correlation.rb

@@ -1,17 +1,22 @@
+require 'ddtrace/ext/environment'
+
 module Datadog
   # Contains behavior for managing correlations with tracing
   # e.g. Retrieve a correlation to the current trace for logging, etc.
   module Correlation
     # Struct representing correlation
-    Identifier = Struct.new(:trace_id, :span_id) do
+    Identifier = Struct.new(:trace_id, :span_id, :env) do
       def initialize(*args)
         super
         self.trace_id = trace_id || 0
         self.span_id = span_id || 0
+        self.env = env || ENV[Datadog::Ext::Environment::ENV_ENVIRONMENT]
       end
 
       def to_s
-        "dd.trace_id=#{trace_id} dd.span_id=#{span_id}"
+        str = "dd.trace_id=#{trace_id} dd.span_id=#{span_id}"
+        str += " dd.env=#{env}" unless env.nil?
+        str
       end
     end.freeze
 

lib/ddtrace/ext/environment.rb

@@ -0,0 +1,7 @@
+module Datadog
+  module Ext
+    module Environment
+      ENV_ENVIRONMENT = 'DD_ENV'.freeze
+    end
+  end
+end

lib/ddtrace/metrics.rb

@@ -1,4 +1,5 @@
 require 'ddtrace/ext/metrics'
+require 'ddtrace/ext/environment'
 
 require 'set'
 require 'logger'
@@ -151,6 +152,7 @@ def default_metric_options
         # and defaults are unfrozen for mutation in Statsd.
         DEFAULT.dup.tap do |options|
           options[:tags] = options[:tags].dup
+          options[:tags] << "env:#{ENV[Ext::Environment::ENV_ENVIRONMENT]}" if ENV.key?(Ext::Environment::ENV_ENVIRONMENT)
         end
       end
     end

lib/ddtrace/tracer.rb

@@ -3,6 +3,8 @@
 require 'logger'
 require 'pathname'
 
+require 'ddtrace/ext/environment'
+
 require 'ddtrace/span'
 require 'ddtrace/context'
 require 'ddtrace/logger'
@@ -83,7 +85,9 @@ def initialize(options = {})
                        end
 
       @mutex = Mutex.new
-      @tags = {}
+      @tags = {}.tap do |tags|
+        tags[:env] = ENV[Ext::Environment::ENV_ENVIRONMENT] if ENV.key?(Ext::Environment::ENV_ENVIRONMENT)
+      end
 
       # Enable priority sampling by default
       activate_priority_sampling!(@sampler)

spec/ddtrace/correlation_spec.rb

@@ -36,6 +36,32 @@
         expect(correlation_ids.span_id).to eq(span_id)
         expect(correlation_ids.to_s).to eq("dd.trace_id=#{trace_id} dd.span_id=#{span_id}")
       end
+
+      context "when #{Datadog::Ext::Environment::ENV_ENVIRONMENT}" do
+        context 'is not defined' do
+          around do |example|
+            ClimateControl.modify(Datadog::Ext::Environment::ENV_ENVIRONMENT => nil) do
+              example.run
+            end
+          end
+
+          it { expect(correlation_ids.env).to be nil }
+          it { expect(correlation_ids.to_s).to eq("dd.trace_id=#{trace_id} dd.span_id=#{span_id}") }
+        end
+
+        context 'is defined' do
+          let(:environment) { 'my-env' }
+
+          around do |example|
+            ClimateControl.modify(Datadog::Ext::Environment::ENV_ENVIRONMENT => environment) do
+              example.run
+            end
+          end
+
+          it { expect(correlation_ids.env).to eq environment }
+          it { expect(correlation_ids.to_s).to eq("dd.trace_id=#{trace_id} dd.span_id=#{span_id} dd.env=#{environment}") }
+        end
+      end
     end
   end
 end

spec/ddtrace/metrics_spec.rb

@@ -613,6 +613,59 @@
   end
 end
 
+RSpec.describe Datadog::Metrics::Options do
+  context 'when included into a class' do
+    subject(:instance) { options_class.new }
+    let(:options_class) { stub_const('OptionsClass', Class.new { include Datadog::Metrics::Options }) }
+
+    describe '#default_metric_options' do
+      subject(:default_metric_options) { instance.default_metric_options }
+
+      it { is_expected.to be_a_kind_of(Hash) }
+      it { expect(default_metric_options.frozen?).to be false }
+
+      describe ':tags' do
+        subject(:default_tags) { default_metric_options[:tags] }
+
+        it { is_expected.to be_a_kind_of(Array) }
+        it { expect(default_tags.frozen?).to be false }
+        it 'includes default tags' do
+          is_expected.to include(
+            "#{Datadog::Ext::Metrics::TAG_LANG}:#{Datadog::Runtime::Identity.lang}",
+            "#{Datadog::Ext::Metrics::TAG_LANG_INTERPRETER}:#{Datadog::Runtime::Identity.lang_interpreter}",
+            "#{Datadog::Ext::Metrics::TAG_LANG_VERSION}:#{Datadog::Runtime::Identity.lang_version}",
+            "#{Datadog::Ext::Metrics::TAG_TRACER_VERSION}:#{Datadog::Runtime::Identity.tracer_version}"
+          )
+        end
+
+        context "when #{Datadog::Ext::Environment::ENV_ENVIRONMENT}" do
+          context 'is not defined' do
+            around do |example|
+              ClimateControl.modify(Datadog::Ext::Environment::ENV_ENVIRONMENT => nil) do
+                example.run
+              end
+            end
+
+            it { is_expected.to_not include(/env:/) }
+          end
+
+          context 'is defined' do
+            let(:environment) { 'my-env' }
+
+            around do |example|
+              ClimateControl.modify(Datadog::Ext::Environment::ENV_ENVIRONMENT => environment) do
+                example.run
+              end
+            end
+
+            it { is_expected.to include("env:#{environment}") }
+          end
+        end
+      end
+    end
+  end
+end
+
 RSpec.describe Datadog::Metrics::Logging::Adapter do
   subject(:adapter) { described_class.new(logger) }
   let(:logger) { instance_double(Logger) }

spec/ddtrace/tracer_spec.rb

@@ -19,6 +19,36 @@
     end
   end
 
+  describe '#tags' do
+    subject(:tags) { tracer.tags }
+
+    it { is_expected.to be_a_kind_of(Hash) }
+
+    context "when #{Datadog::Ext::Environment::ENV_ENVIRONMENT}" do
+      context 'is not defined' do
+        around do |example|
+          ClimateControl.modify(Datadog::Ext::Environment::ENV_ENVIRONMENT => nil) do
+            example.run
+          end
+        end
+
+        it { is_expected.to_not include(:env) }
+      end
+
+      context 'is defined' do
+        let(:environment) { 'my-env' }
+
+        around do |example|
+          ClimateControl.modify(Datadog::Ext::Environment::ENV_ENVIRONMENT => environment) do
+            example.run
+          end
+        end
+
+        it { is_expected.to include(env: environment) }
+      end
+    end
+  end
+
   describe '#trace' do
     let(:name) { 'span.name' }
     let(:options) { {} }