Add language and extra metadata as headers (#289)

Author: gabsn

ddtrace/api.py

@@ -1,10 +1,11 @@
 # stdlib
 import logging
 import time
+import ddtrace
 
 # project
 from .encoding import get_encoder, JSONEncoder
-from .compat import httplib
+from .compat import httplib, PYTHON_VERSION, PYTHON_INTERPRETER
 
 
 log = logging.getLogger(__name__)
@@ -25,7 +26,13 @@ def __init__(self, hostname, port, headers=None, encoder=None):
 
         # overwrite the Content-type with the one chosen in the Encoder
         self._headers = headers or {}
-        self._headers.update({'Content-Type': self._encoder.content_type})
+        self._headers.update({
+            'Content-Type': self._encoder.content_type,
+            'Datadog-Meta-Lang': 'python',
+            'Datadog-Meta-Lang-Version': PYTHON_VERSION,
+            'Datadog-Meta-Lang-Interpreter': PYTHON_INTERPRETER,
+            'Datadog-Meta-Tracer-Version': ddtrace.__version__,
+        })
 
     def _downgrade(self):
         """

ddtrace/compat.py

@@ -1,8 +1,13 @@
 import sys
+import platform
 
-PYTHON_VERSION = sys.version_info
+PYTHON_VERSION_INFO = sys.version_info
 PY2 = sys.version_info[0] == 2
 
+# Infos about python passed to the trace agent through the header
+PYTHON_VERSION = platform.python_version()
+PYTHON_INTERPRETER = platform.python_implementation()
+
 stringify = str
 
 if PY2:

ddtrace/contrib/aiobotocore/patch.py

@@ -8,7 +8,7 @@
 from aiobotocore.endpoint import ClientResponseContentProxy
 
 from ...ext import http, aws
-from ...compat import PYTHON_VERSION
+from ...compat import PYTHON_VERSION_INFO
 
 
 ARGS_NAME = ('action', 'params', 'path', 'verb')
@@ -53,7 +53,7 @@ def read(self, *args, **kwargs):
         return result
 
     # wrapt doesn't proxy `async with` context managers
-    if PYTHON_VERSION >= (3, 5, 0):
+    if PYTHON_VERSION_INFO >= (3, 5, 0):
         @asyncio.coroutine
         def __aenter__(self):
             # call the wrapped method but return the object proxy

tests/test_integration.py

@@ -4,6 +4,7 @@
 import msgpack
 import logging
 import mock
+import ddtrace
 
 from unittest import TestCase, skipUnless
 from nose.tools import eq_, ok_
@@ -15,11 +16,10 @@
 from ddtrace.span import Span
 from ddtrace.tracer import Tracer
 from ddtrace.encoding import JSONEncoder, MsgpackEncoder, get_encoder
-from ddtrace.compat import httplib
+from ddtrace.compat import httplib, PYTHON_INTERPRETER, PYTHON_VERSION
 from tests.test_tracer import get_dummy_tracer
 
 
-
 class MockedLogHandler(logging.Handler):
     """Record log messages to verify error logging logic"""
 
@@ -257,10 +257,19 @@ def test_send_presampler_headers(self, mocked_http):
         eq_(request_call.call_count, 1)
 
         # retrieve the headers from the mocked request call
+        expected_headers = {
+                'Datadog-Meta-Lang': 'python',
+                'Datadog-Meta-Lang-Interpreter': PYTHON_INTERPRETER,
+                'Datadog-Meta-Lang-Version': PYTHON_VERSION,
+                'Datadog-Meta-Tracer-Version': ddtrace.__version__,
+                'X-Datadog-Trace-Count': '1',
+                'Content-Type': 'application/msgpack'
+        }
         params, _ = request_call.call_args_list[0]
         headers = params[3]
-        ok_('X-Datadog-Trace-Count' in headers.keys())
-        eq_(headers['X-Datadog-Trace-Count'], '1')
+        eq_(len(expected_headers), len(headers))
+        for k, v in expected_headers.items():
+            eq_(v, headers[k])
 
     @mock.patch('ddtrace.api.httplib.HTTPConnection')
     def test_send_presampler_headers_not_in_services(self, mocked_http):
@@ -277,6 +286,20 @@ def test_send_presampler_headers_not_in_services(self, mocked_http):
         request_call = mocked_http.return_value.request
         eq_(request_call.call_count, 1)
 
+        # retrieve the headers from the mocked request call
+        expected_headers = {
+                'Datadog-Meta-Lang': 'python',
+                'Datadog-Meta-Lang-Interpreter': PYTHON_INTERPRETER,
+                'Datadog-Meta-Lang-Version': PYTHON_VERSION,
+                'Datadog-Meta-Tracer-Version': ddtrace.__version__,
+                'Content-Type': 'application/msgpack'
+        }
+        params, _ = request_call.call_args_list[0]
+        headers = params[3]
+        eq_(len(expected_headers), len(headers))
+        for k, v in expected_headers.items():
+            eq_(v, headers[k])
+
         # retrieve the headers from the mocked request call
         params, _ = request_call.call_args_list[0]
         headers = params[3]