Send trace context with logs from web applications

logging/google/cloud/logging/handlers/_helpers.py

@@ -17,6 +17,17 @@
 import math
 import json
 
+try:
+ import flask
+except ImportError: # pragma: NO COVER
+ flask = None
+
+from google.cloud.logging.handlers.middleware.request import (
+ _get_django_request)
+
+_FLASK_TRACE_HEADER = 'X_CLOUD_TRACE_CONTEXT'
+_DJANGO_TRACE_HEADER = 'HTTP_X_CLOUD_TRACE_CONTEXT'
+
 
 def format_stackdriver_json(record, message):
  """Helper to format a LogRecord in in Stackdriver fluentd format.
@@ -37,3 +48,58 @@ def format_stackdriver_json(record, message):
  }
 
  return json.dumps(payload)
+
+
+def get_trace_id_from_flask():
+ """Get trace_id from flask request headers.
+
+ :rtype: str
+ :return: Trace_id in HTTP request headers.
+ """
+ if flask is None or not flask.request:
+ return None
+
+ header = flask.request.headers.get(_FLASK_TRACE_HEADER)
+
+ if header is None:
+ return None
+
+ trace_id = header.split('/', 1)[0]
+
+ return trace_id
+
+
+def get_trace_id_from_django():
+ """Get trace_id from django request headers.
+
+ :rtype: str
+ :return: Trace_id in HTTP request headers.
+ """
+ request = _get_django_request()
+
+ if request is None:
+ return None
+
+ header = request.META.get(_DJANGO_TRACE_HEADER)
+ if header is None:
+ return None
+
+ trace_id = header.split('/', 1)[0]
+
+ return trace_id
+
+
+def get_trace_id():
+ """Helper to get trace_id from web application request header.
+
+ :rtype: str
+ :returns: Trace_id in HTTP request headers.
+ """
+ checkers = (get_trace_id_from_django, get_trace_id_from_flask)
+
+ for checker in checkers:
+ trace_id = checker()
+ if trace_id is not None:
+ return trace_id
+
+ return None

logging/google/cloud/logging/handlers/app_engine.py

@@ -20,6 +20,7 @@
 
 import os
 
+from google.cloud.logging.handlers._helpers import get_trace_id
 from google.cloud.logging.handlers.handlers import CloudLoggingHandler
 from google.cloud.logging.handlers.transports import BackgroundThreadTransport
 from google.cloud.logging.resource import Resource
@@ -30,6 +31,8 @@
 _GAE_SERVICE_ENV = 'GAE_SERVICE'
 _GAE_VERSION_ENV = 'GAE_VERSION'
 
+_TRACE_ID_LABEL = 'appengine.googleapis.com/trace_id'
+
 
 class AppEngineHandler(CloudLoggingHandler):
  """A logging handler that sends App Engine-formatted logs to Stackdriver.
@@ -50,7 +53,8 @@ def __init__(self, client,
  client,
  name=_DEFAULT_GAE_LOGGER_NAME,
  transport=transport,
- resource=self.get_gae_resource())
+ resource=self.get_gae_resource(),
+ labels=self.get_gae_labels())
 
  def get_gae_resource(self):
  """Return the GAE resource using the environment variables.
@@ -67,3 +71,20 @@ def get_gae_resource(self):
  },
  )
  return gae_resource
+
+ def get_gae_labels(self):
+ """Return the labels for GAE app.
+
+ If the trace ID can be detected, it will be included as a label.
+ Currently, no other labels are included.
+
+ :rtype: dict
+ :returns: Labels for GAE app.
+ """
+ gae_labels = {}
+
+ trace_id = get_trace_id()
+ if trace_id is not None:
+ gae_labels[_TRACE_ID_LABEL] = trace_id
+
+ return gae_labels

logging/google/cloud/logging/handlers/handlers.py

@@ -57,6 +57,9 @@ class CloudLoggingHandler(logging.StreamHandler):
  :param resource: (Optional) Monitored resource of the entry, defaults
  to the global resource type.
 
+ :type labels: dict
+ :param labels: (Optional) Mapping of labels for the entry.
+
  Example:
 
  .. code-block:: python
@@ -79,12 +82,14 @@ class CloudLoggingHandler(logging.StreamHandler):
  def __init__(self, client,
  name=DEFAULT_LOGGER_NAME,
  transport=BackgroundThreadTransport,
- resource=_GLOBAL_RESOURCE):
+ resource=_GLOBAL_RESOURCE,
+ labels=None):
  super(CloudLoggingHandler, self).__init__()
  self.name = name
  self.client = client
  self.transport = transport(client, name)
  self.resource = resource
+ self.labels = labels
 
  def emit(self, record):
  """Actually log the specified logging record.
@@ -97,7 +102,11 @@ def emit(self, record):
  :param record: The record to be logged.
  """
  message = super(CloudLoggingHandler, self).format(record)
- self.transport.send(record, message, resource=self.resource)
+ self.transport.send(
+ record,
+ message,
+ resource=self.resource,
+ labels=self.labels)
 
 
 def setup_logging(handler, excluded_loggers=EXCLUDED_LOGGER_DEFAULTS,

logging/google/cloud/logging/handlers/middleware/__init__.py

@@ -0,0 +1,17 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+from google.cloud.logging.handlers.middleware.request import RequestMiddleware
+
+__all__ = ['RequestMiddleware']

logging/google/cloud/logging/handlers/middleware/request.py

@@ -0,0 +1,45 @@
+# Copyright 2017 Google Inc. All Rights Reserved.
+#
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+#
+# http://www.apache.org/licenses/LICENSE-2.0
+#
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+
+"""Django middleware helper to capture a request.
+
+The request is stored on a thread-local so that it can be
+inspected by other helpers.
+"""
+
+import threading
+
+
+_thread_locals = threading.local()
+
+
+def _get_django_request():
+ """Get Django request from thread local.
+
+ :rtype: str
+ :returns: Django request.
+ """
+ return getattr(_thread_locals, 'request', None)
+
+
+class RequestMiddleware(object):
+ """Saves the request in thread local"""
+
+ def process_request(self, request):
+ """Called on each request, before Django decides which view to execute.
+
+ :type request: :class:`~django.http.request.HttpRequest`
+ :param request: Django http request.
+ """
+ _thread_locals.request = request

logging/google/cloud/logging/handlers/transports/background_thread.py

@@ -203,7 +203,7 @@ def _main_thread_terminated(self):
  else:
  print('Failed to send %d pending logs.' % (self._queue.qsize(),))
 
- def enqueue(self, record, message, resource=None):
+ def enqueue(self, record, message, resource=None, labels=None):
  """Queues a log entry to be written by the background thread.
 
  :type record: :class:`logging.LogRecord`
@@ -215,6 +215,9 @@ def enqueue(self, record, message, resource=None):
 
  :type resource: :class:`~google.cloud.logging.resource.Resource`
  :param resource: (Optional) Monitored resource of the entry
+
+ :type labels: dict
+ :param labels: (Optional) Mapping of labels for the entry.
  """
  self._queue.put_nowait({
  'info': {
@@ -223,6 +226,7 @@ def enqueue(self, record, message, resource=None):
  },
  'severity': record.levelname,
  'resource': resource,
+ 'labels': labels,
  })
 
  def flush(self):
@@ -257,7 +261,7 @@ def __init__(self, client, name, grace_period=_DEFAULT_GRACE_PERIOD,
  self.worker = _Worker(logger)
  self.worker.start()
 
- def send(self, record, message, resource=None):
+ def send(self, record, message, resource=None, labels=None):
  """Overrides Transport.send().
 
  :type record: :class:`logging.LogRecord`
@@ -269,8 +273,11 @@ def send(self, record, message, resource=None):
 
  :type resource: :class:`~google.cloud.logging.resource.Resource`
  :param resource: (Optional) Monitored resource of the entry.
+
+ :type labels: dict
+ :param labels: (Optional) Mapping of labels for the entry.
  """
- self.worker.enqueue(record, message, resource=resource)
+ self.worker.enqueue(record, message, resource=resource, labels=labels)
 
  def flush(self):
  """Submit any pending log records."""

logging/google/cloud/logging/handlers/transports/base.py

@@ -22,7 +22,7 @@ class Transport(object):
  client and name object, and must override :meth:`send`.
  """
 
- def send(self, record, message, resource=None):
+ def send(self, record, message, resource=None, labels=None):
  """Transport send to be implemented by subclasses.
 
  :type record: :class:`logging.LogRecord`
@@ -34,6 +34,9 @@ def send(self, record, message, resource=None):
 
  :type resource: :class:`~google.cloud.logging.resource.Resource`
  :param resource: (Optional) Monitored resource of the entry.
+
+ :type labels: dict
+ :param labels: (Optional) Mapping of labels for the entry.
  """
  raise NotImplementedError
 

logging/google/cloud/logging/handlers/transports/sync.py

@@ -29,7 +29,7 @@ class SyncTransport(Transport):
  def __init__(self, client, name):
  self.logger = client.logger(name)
 
- def send(self, record, message, resource=None):
+ def send(self, record, message, resource=None, labels=None):
  """Overrides transport.send().
 
  :type record: :class:`logging.LogRecord`
@@ -38,8 +38,15 @@ def send(self, record, message, resource=None):
  :type message: str
  :param message: The message from the ``LogRecord`` after being
  formatted by the associated log formatters.
+
+ :type resource: :class:`~google.cloud.logging.resource.Resource`
+ :param resource: (Optional) Monitored resource of the entry.
+
+ :type labels: dict
+ :param labels: (Optional) Mapping of labels for the entry.
  """
  info = {'message': message, 'python_logger': record.name}
  self.logger.log_struct(info,
  severity=record.levelname,
- resource=resource)
+ resource=resource,
+ labels=labels)

logging/nox.py

@@ -31,7 +31,9 @@ def unit_tests(session, python_version):
  session.interpreter = 'python{}'.format(python_version)
 
  # Install all test dependencies, then install this package in-place.
- session.install('mock', 'pytest', 'pytest-cov', *LOCAL_DEPS)
+ session.install(
+ 'mock', 'pytest', 'pytest-cov',
+ 'flask', 'django', *LOCAL_DEPS)
  session.install('-e', '.')
 
  # Run py.test against the unit tests.