Merge pull request #77 from palazzem/django-configure

[django] users can configure HOSTNAME and PORT in their settings

Author: Emanuele Palazzetti

ddtrace/contrib/django/__init__.py

@@ -42,12 +42,18 @@
   tracer is used.
 * ``DEFAULT_SERVICE`` (default: ``django``): set the service name used by the
   tracer. Usually this configuration must be updated with a meaningful name.
-* ``ENABLED``: (default: ``not django_settings.DEBUG``): set if the tracer
-  is enabled or not. When a tracer is disabled, Django internals are not
-  automatically instrumented and the requests are not traced even if the
-  ``TraceMiddleware`` is properly installed. This setting cannot be changed
-  at runtime and a restart is required. By default the tracer is disabled
-  when in ``DEBUG`` mode, enabled otherwise.
+* ``ENABLED`` (default: ``not django_settings.DEBUG``): defines if the tracer is
+  enabled or not. If set to false, the code is still instrumented but no spans
+  are sent to the trace agent. This setting cannot be changed at runtime
+  and a restart is required. By default the tracer is disabled when in ``DEBUG``
+  mode, enabled otherwise.
+* ``AUTO_INSTRUMENT`` (default: ``True``): if set to false the code will not be
+  instrumented, while the tracer may be active for your internal usage. This could
+  be useful if you want to use the Django integration, but you want to trace only
+  particular functions or views. If set to False, the request middleware will be
+  disabled even if present.
+* ``AGENT_HOSTNAME`` (default: ``localhost``): define the hostname of the trace agent.
+* ``AGENT_PORT`` (default: ``7777``): define the port of the trace agent.
 """
 from ..util import require_modules
 

ddtrace/contrib/django/apps.py

@@ -24,16 +24,24 @@ def ready(self):
         Tracing capabilities must be enabled in this function so that
         all Django internals are properly configured.
         """
-        if settings.ENABLED:
-            tracer = settings.TRACER
-
-            # define the service details
-            tracer.set_service_info(
-                app='django',
-                app_type=AppTypes.web,
-                service=settings.DEFAULT_SERVICE,
-            )
-
+        tracer = settings.TRACER
+
+        # define the service details
+        tracer.set_service_info(
+            app='django',
+            app_type=AppTypes.web,
+            service=settings.DEFAULT_SERVICE,
+        )
+
+        # configure the tracer instance
+        # TODO[manu]: we may use configure() but because it creates a new
+        # AgentWriter, it breaks all tests. The configure() behavior must
+        # be changed to use it in this integration
+        tracer.enabled = settings.ENABLED
+        tracer.writer._reporter.transport.hostname = settings.AGENT_HOSTNAME
+        tracer.writer._reporter.transport.port = settings.AGENT_PORT
+
+        if settings.AUTO_INSTRUMENT:
             # trace Django internals
             try:
                 patch_db(tracer)

ddtrace/contrib/django/conf.py

@@ -24,6 +24,9 @@
     'TRACER': 'ddtrace.tracer',
     'DEFAULT_SERVICE': 'django',
     'ENABLED': True,
+    'AUTO_INSTRUMENT': True,
+    'AGENT_HOSTNAME': 'localhost',
+    'AGENT_PORT': '7777',
 }
 
 # List of settings that may be in string import notation.

ddtrace/contrib/django/middleware.py

@@ -20,7 +20,8 @@ class TraceMiddleware(object):
     """
     def __init__(self):
         # disable the middleware if the tracer is not enabled
-        if not settings.ENABLED:
+        # or if the auto instrumentation is disabled
+        if not settings.AUTO_INSTRUMENT:
             raise MiddlewareNotUsed
 
     def process_request(self, request):

tests/contrib/django/app/settings.py

@@ -96,4 +96,6 @@
     # tracer with a DummyWriter
     'TRACER': 'tests.contrib.django.utils.tracer',
     'ENABLED': True,
+    'AGENT_HOSTNAME': 'agent.service.consul',
+    'AGENT_PORT': '8777',
 }

tests/contrib/django/test_instrumentation.py

@@ -0,0 +1,18 @@
+import time
+
+# 3rd party
+from nose.tools import eq_, ok_
+from django.test import override_settings
+
+# testing
+from .utils import DjangoTraceTestCase
+
+
+class DjangoInstrumentationTest(DjangoTraceTestCase):
+    """
+    Ensures that Django is correctly configured according to
+    users settings
+    """
+    def test_enabled_flag(self):
+        eq_(self.tracer.writer._reporter.transport.hostname, 'agent.service.consul')
+        eq_(self.tracer.writer._reporter.transport.port, '8777')