refactor - move header name to propagator (part 2) (#219)

* refactor - move header name to propagator (part 1)

* update the Trace Parent header name to reflect the latest W3C draft

* fix lint error

* add unit tests for GoogleCloudFormat and TraceContext propagators

* refactor - move header name to propagator (part 2)

* refactor pyramid_middleware

* fix system test cases

* change X_CLOUD_TRACE_CONTEXT to X-Cloud-Trace-Context and add Django specific conversion

* fix typo

* fix unit test for Django

Author: reyang

opencensus/trace/ext/django/middleware.py

@@ -33,8 +33,6 @@
 
 REQUEST_THREAD_LOCAL_KEY = 'django_request'
 
-_DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
-
 BLACKLIST_PATHS = 'BLACKLIST_PATHS'
 GCP_EXPORTER_PROJECT = 'GCP_EXPORTER_PROJECT'
 SAMPLING_RATE = 'SAMPLING_RATE'
@@ -47,6 +45,19 @@
 log = logging.getLogger(__name__)
 
 
+class _DjangoMetaWrapper(object):
+    """
+    Wrapper class which takes HTTP header name and retrieve the value from
+    Django request.META
+    """
+
+    def __init__(self, meta=None):
+        self.meta = meta or _get_django_request().META
+
+    def get(self, key):
+        return self.meta.get('HTTP_' + key.upper().replace('-', '_'))
+
+
 def _get_django_request():
     """Get Django request from thread local.
 
@@ -79,19 +90,6 @@ def _set_django_attributes(tracer, request):
         tracer.add_attribute_to_current_span('/django/user/name', user_name)
 
 
-def get_django_header():
-    """Get trace context header from django request headers.
-
-    :rtype: str
-    :returns: Trace context header in HTTP request headers.
-    """
-    request = _get_django_request()
-
-    header = request.META.get(_DJANGO_TRACE_HEADER)
-
-    return header
-
-
 class OpencensusMiddleware(MiddlewareMixin):
     """Saves the request in thread local"""
 
@@ -155,8 +153,8 @@ def process_request(self, request):
 
         try:
             # Start tracing this request
-            header = get_django_header()
-            span_context = self.propagator.from_header(header)
+            span_context = self.propagator.from_headers(
+                _DjangoMetaWrapper(_get_django_request().META))
 
             # Reload the tracer with the new span context
             tracer = tracer_module.Tracer(

opencensus/trace/ext/flask/flask_middleware.py

@@ -30,9 +30,6 @@
 from opencensus.trace.propagation import google_cloud_format
 from opencensus.trace.samplers import always_on, probability
 
-
-_FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-
 HTTP_METHOD = attributes_helper.COMMON_ATTRIBUTES['HTTP_METHOD']
 HTTP_URL = attributes_helper.COMMON_ATTRIBUTES['HTTP_URL']
 HTTP_STATUS_CODE = attributes_helper.COMMON_ATTRIBUTES['HTTP_STATUS_CODE']
@@ -169,8 +166,7 @@ def _before_request(self):
             return
 
         try:
-            header = get_flask_header()
-            span_context = self.propagator.from_header(header)
+            span_context = self.propagator.from_headers(flask.request.headers)
 
             tracer = tracer_module.Tracer(
                 span_context=span_context,
@@ -236,18 +232,3 @@ def _teardown_request(self, exception):
             tracer.finish()
         except Exception:  # pragma: NO COVER
             log.error('Failed to trace request', exc_info=True)
-
-
-def get_flask_header():
-    """Get trace context header from flask request headers.
-
-    :rtype: str
-    :returns: Trace context header in HTTP request headers.
-    """
-    header = flask.request.headers.get(_FLASK_TRACE_HEADER)
-
-    # In case the header is unicode, convert it to string.
-    if header is not None:
-        header = str(header.encode('utf-8'))
-
-    return header

opencensus/trace/ext/pyramid/pyramid_middleware.py

@@ -26,8 +26,6 @@
 HTTP_URL = attributes_helper.COMMON_ATTRIBUTES['HTTP_URL']
 HTTP_STATUS_CODE = attributes_helper.COMMON_ATTRIBUTES['HTTP_STATUS_CODE']
 
-_PYRAMID_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
-
 BLACKLIST_PATHS = 'BLACKLIST_PATHS'
 
 
@@ -78,8 +76,7 @@ def _before_request(self, request):
             return
 
         try:
-            header = get_context_header(request)
-            span_context = self.propagator.from_header(header)
+            span_context = self.propagator.from_headers(request.headers)
 
             tracer = tracer_module.Tracer(
                 span_context=span_context,
@@ -117,8 +114,3 @@ def _after_request(self, request, response):
             tracer.finish()
         except Exception:  # pragma: NO COVER
             log.error('Failed to trace request', exc_info=True)
-
-
-def get_context_header(request):
-    """Get trace context header from pyramid request headers."""
-    return request.headers.get(_PYRAMID_TRACE_HEADER)

opencensus/trace/propagation/google_cloud_format.py

@@ -18,7 +18,7 @@
 from opencensus.trace.span_context import SpanContext
 from opencensus.trace.trace_options import TraceOptions
 
-_TRACE_CONTEXT_HEADER_NAME = 'X_CLOUD_TRACE_CONTEXT'
+_TRACE_CONTEXT_HEADER_NAME = 'X-Cloud-Trace-Context'
 _TRACE_CONTEXT_HEADER_FORMAT = '([0-9a-f]{32})(\/([0-9a-f]{16}))?(;o=(\d+))?'
 _TRACE_CONTEXT_HEADER_RE = re.compile(_TRACE_CONTEXT_HEADER_FORMAT)
 _TRACE_ID_DELIMETER = '/'
@@ -85,9 +85,11 @@ def from_headers(self, headers):
         """
         if headers is None:
             return SpanContext()
-        if _TRACE_CONTEXT_HEADER_NAME not in headers:
+        header = headers.get(_TRACE_CONTEXT_HEADER_NAME)
+        if header is None:
             return SpanContext()
-        return self.from_header(headers[_TRACE_CONTEXT_HEADER_NAME])
+        header = str(header.encode('utf-8'))
+        return self.from_header(header)
 
     def to_header(self, span_context):
         """Convert a SpanContext object to header string.

opencensus/trace/propagation/trace_context_http_header_format.py

@@ -88,9 +88,11 @@ def from_headers(self, headers):
         """
         if headers is None:
             return SpanContext()
-        if _TRACE_PARENT_HEADER_NAME not in headers:
+        header = headers.get(_TRACE_PARENT_HEADER_NAME)
+        if header is None:
             return SpanContext()
-        return self.from_header(headers[_TRACE_PARENT_HEADER_NAME])
+        header = str(header.encode('utf-8'))
+        return self.from_header(header)
 
     def to_header(self, span_context):
         """Convert a SpanContext object to header string, using version 0.

tests/system/trace/flask/flask_system_test.py

@@ -78,7 +78,7 @@ def setUp(self):
         self.process = run_application()
 
         self.headers_trace = {
-            'X_CLOUD_TRACE_CONTEXT': '{}/{};o={}'.format(
+            'X-Cloud-Trace-Context': '{}/{};o={}'.format(
                 self.trace_id, self.span_id, 1)
         }
 

tests/unit/trace/ext/django/test_middleware.py

@@ -177,7 +177,7 @@ def test_process_request(self):
         django_trace_id = '{}/{}'.format(trace_id, span_id)
 
         django_request = RequestFactory().get('/', **{
-            middleware._DJANGO_TRACE_HEADER: django_trace_id})
+            'HTTP_X_CLOUD_TRACE_CONTEXT': django_trace_id})
 
         middleware_obj = middleware.OpencensusMiddleware()
 
@@ -260,7 +260,7 @@ def test_process_response(self):
         django_trace_id = '{}/{}'.format(trace_id, span_id)
 
         django_request = RequestFactory().get('/', **{
-            middleware._DJANGO_TRACE_HEADER: django_trace_id})
+            google_cloud_format._TRACE_CONTEXT_HEADER_NAME: django_trace_id})
 
         middleware_obj = middleware.OpencensusMiddleware()
 

tests/unit/trace/ext/flask/test_flask_middleware.py

@@ -157,7 +157,7 @@ def test_init_app_config_zipkin_exporter(self):
     def test__before_request(self):
         from opencensus.trace import execution_context
 
-        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         flask_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -187,7 +187,7 @@ def test__before_request(self):
             self.assertEqual(span_context.trace_id, trace_id)
 
     def test__before_request_blacklist(self):
-        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         flask_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -214,7 +214,7 @@ def test_header_encoding(self):
         # in SpanContext because it cannot match the pattern for trace_id,
         # And a new trace_id will generate for the context.
 
-        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_header = 'X-Cloud-Trace-Context'
         trace_id = "你好"
         span_id = '6e0c63257de34c92'
         flask_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -265,7 +265,7 @@ def test_header_is_none(self):
             assert isinstance(span.parent_span, base.NullContextManager)
 
     def test__after_request_not_sampled(self):
-        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         flask_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -281,7 +281,7 @@ def test__after_request_not_sampled(self):
         self.assertEqual(response.status_code, 200)
 
     def test__after_request_sampled(self):
-        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         flask_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -296,7 +296,7 @@ def test__after_request_sampled(self):
         self.assertEqual(response.status_code, 200)
 
     def test__after_request_blacklist(self):
-        flask_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        flask_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         flask_trace_id = '{}/{}'.format(trace_id, span_id)

tests/unit/trace/ext/pyramid/test_pyramid_middleware.py

@@ -40,7 +40,7 @@ def tearDown(self):
         execution_context.clear()
 
     def test_constructor(self):
-        pyramid_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        pyramid_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         pyramid_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -116,7 +116,7 @@ def dummy_handler(request):
         self.assertEqual(middleware.exporter.port, port)
 
     def test__before_request(self):
-        pyramid_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        pyramid_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         pyramid_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -158,7 +158,7 @@ def dummy_handler(request):
         self.assertEqual(span_context.trace_id, trace_id)
 
     def test__before_request_blacklist(self):
-        pyramid_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        pyramid_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         pyramid_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -192,7 +192,7 @@ def dummy_handler(request):
         assert isinstance(span, base.NullContextManager)
 
     def test__after_request(self):
-        pyramid_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        pyramid_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         pyramid_trace_id = '{}/{}'.format(trace_id, span_id)
@@ -236,7 +236,7 @@ def dummy_handler(request):
         self.assertEqual(span.attributes, expected_attributes)
 
     def test__after_request_blacklist(self):
-        pyramid_trace_header = 'X_CLOUD_TRACE_CONTEXT'
+        pyramid_trace_header = 'X-Cloud-Trace-Context'
         trace_id = '2dd43a1d6b2549c6bc2a1a54c2fc0b05'
         span_id = '6e0c63257de34c92'
         pyramid_trace_id = '{}/{}'.format(trace_id, span_id)

tests/unit/trace/propagation/test_google_cloud_format.py

@@ -100,7 +100,7 @@ def test_header_not_match(self):
     def test_headers_match(self):
         # Trace option is enabled.
         headers = {
-            'X_CLOUD_TRACE_CONTEXT':
+            'X-Cloud-Trace-Context':
                 '6e0c63257de34c92bf9efcd03927272e/00f067aa0ba902b7;o=1',
         }
         expected_trace_id = '6e0c63257de34c92bf9efcd03927272e'
@@ -147,7 +147,7 @@ def test_to_headers(self):
 
         headers = propagator.to_headers(span_context)
         expected_headers = {
-            'X_CLOUD_TRACE_CONTEXT': '{}/{};o={}'.format(trace_id, span_id, 1),
+            'X-Cloud-Trace-Context': '{}/{};o={}'.format(trace_id, span_id, 1),
         }
 
         self.assertEqual(headers, expected_headers)