Merge branch 'christian/railsdefaultenv'

docs/GettingStarted.md

@@ -65,7 +65,7 @@ of the Datadog tracer, you can override the following defaults:
       debug: false,
       trace_agent_hostname: 'localhost',
       trace_agent_port: 8126,
-      env: Rails.env,
+      env: nil,
       tags: {}
     }
 
@@ -88,7 +88,7 @@ Available settings are:
 * ``debug``: set to true to enable debug logging.
 * ``trace_agent_hostname``: set the hostname of the trace agent.
 * ``trace_agent_port``: set the port the trace agent is listening on.
-* ``env``: set the environment. Defaults to the Rails environment
+* ``env``: set the environment. Rails users may set it to ``Rails.env`` to use their application settings.
 * ``tags``: set global tags that should be applied to all spans. Defaults to an empty hash
 
 ### Sinatra

lib/ddtrace/contrib/rails/framework.rb

@@ -27,7 +27,7 @@ module Framework
           debug: false,
           trace_agent_hostname: Datadog::Writer::HOSTNAME,
           trace_agent_port: Datadog::Writer::PORT,
-          env: ::Rails.env,
+          env: nil,
           tags: {}
         }.freeze
 
@@ -51,6 +51,7 @@ def self.configure(config)
 
           # set default tracer tags
           datadog_config[:tracer].set_tags(datadog_config[:tags])
+
           datadog_config[:tracer].set_tags('env' => datadog_config[:env]) if datadog_config[:env]
 
           # set default service details

test/contrib/rails/tracer_test.rb

@@ -22,8 +22,8 @@ class TracerTest < ActionController::TestCase
     assert !Rails.configuration.datadog_trace[:debug]
     assert_equal(Rails.configuration.datadog_trace[:trace_agent_hostname], Datadog::Writer::HOSTNAME)
     assert_equal(Rails.configuration.datadog_trace[:trace_agent_port], Datadog::Writer::PORT)
-    assert_equal(Rails.configuration.datadog_trace[:env], 'test')
-    assert_equal(Rails.configuration.datadog_trace[:tags], {})
+    assert_nil(Rails.configuration.datadog_trace[:env], 'no env should be set by default')
+    assert_equal(Rails.configuration.datadog_trace[:tags], {}, 'no tags should be set by default')
   end
 
   test 'a default service and database should be properly set' do
@@ -133,19 +133,26 @@ class TracerTest < ActionController::TestCase
     assert_equal(tracer.tags['section'], 'users')
   end
 
-  test 'tracer env setting has precedence over tags setting' do
+  test 'tracer env and env tag setting precedence' do
     # default case
+    tracer = Rails.configuration.datadog_trace[:tracer]
+    assert_nil(tracer.tags['env'])
+
+    # use the Rails value
+    update_config(:env, ::Rails.env)
     update_config(:tags, 'env' => 'foo')
     tracer = Rails.configuration.datadog_trace[:tracer]
     assert_equal(tracer.tags['env'], 'test')
 
     # explicit set
+    update_config(:use_rails_env, false)
     update_config(:env, 'dev')
     update_config(:tags, 'env' => 'bar')
     tracer = Rails.configuration.datadog_trace[:tracer]
     assert_equal(tracer.tags['env'], 'dev')
 
     # env is not valid but tags is set
+    update_config(:use_rails_env, false)
     update_config(:env, nil)
     update_config(:tags, 'env' => 'bar')
     tracer = Rails.configuration.datadog_trace[:tracer]