Merge pull request #2151 from dhermes/fix-2102

Merging logging-stdlib-handler-feature branch back into master

CONTRIBUTING.rst

@@ -160,7 +160,8 @@ Running System Tests
     can be downloaded directly from the developer's console by clicking
     "Generate new JSON key". See private key
     `docs <https://cloud.google.com/storage/docs/authentication#generating-a-private-key>`__
-    for more details.
+    for more details. In order for Logging system tests to work, the Service Account
+    will also have to be made a project Owner. This can be changed under "IAM & Admin".
 
 - Examples of these can be found in ``system_tests/local_test_setup.sample``. We
   recommend copying this to ``system_tests/local_test_setup``, editing the

docs/index.rst

@@ -106,6 +106,10 @@
   logging-entries
   logging-metric
   logging-sink
+  logging-handlers
+  logging-transports-sync
+  logging-transports-thread
+  logging-transports-base
 
 .. toctree::
   :maxdepth: 0

docs/logging-handlers.rst

@@ -0,0 +1,6 @@
+Python Logging Module Handler
+==============================
+
+.. automodule:: gcloud.logging.handlers.handlers
+  :members:
+  :show-inheritance:

docs/logging-transports-base.rst

@@ -0,0 +1,6 @@
+Python Logging Handler Sync Transport
+======================================
+
+.. automodule:: gcloud.logging.handlers.transports.base
+  :members:
+  :show-inheritance:

docs/logging-transports-sync.rst

@@ -0,0 +1,6 @@
+Python Logging Handler Sync Transport
+======================================
+
+.. automodule:: gcloud.logging.handlers.transports.sync
+  :members:
+  :show-inheritance:

docs/logging-transports-thread.rst

@@ -0,0 +1,7 @@
+Python Logging Handler Threaded Transport
+=========================================
+
+
+.. automodule:: gcloud.logging.handlers.transports.background_thread
+  :members:
+  :show-inheritance:

docs/logging-usage.rst

@@ -383,3 +383,74 @@ Delete a sink:
    >>> sink.delete()  # API call
    >>> sink.exists()  # API call
    False
+
+Integration with Python logging module
+---------------------------------------------
+
+
+It's possible to tie the Python :mod:`logging` module directly into Google Cloud Logging. To use it,
+create a :class:`CloudLoggingHandler <gcloud.logging.CloudLoggingHandler>` instance from your
+Logging client.
+
+.. doctest::
+
+    >>> import logging
+    >>> import gcloud.logging # Don't conflict with standard logging
+    >>> from gcloud.logging.handlers import CloudLoggingHandler
+    >>> client = gcloud.logging.Client()
+    >>> handler = CloudLoggingHandler(client)
+    >>> cloud_logger = logging.getLogger('cloudLogger')
+    >>> cloud_logger.setLevel(logging.INFO) # defaults to WARN
+    >>> cloud_logger.addHandler(handler)
+    >>> cloud_logger.error('bad news')
+
+.. note::
+
+    This handler by default uses an asynchronous transport that sends log entries on a background
+     thread. However, the API call will still be made in the same process. For other transport
+     options, see the transports section.
+
+All logs will go to a single custom log, which defaults to "python". The name of the Python
+logger will be included in the structured log entry under the "python_logger" field. You can
+change it by providing a name to the handler:
+
+.. doctest::
+
+    >>> handler = CloudLoggingHandler(client, name="mycustomlog")
+
+It is also possible to attach the handler to the root Python logger, so that for example a plain
+`logging.warn` call would be sent to Cloud Logging, as well as any other loggers created. However,
+you must avoid infinite recursion from the logging calls the client itself makes. A helper
+method :meth:`setup_logging <gcloud.logging.handlers.setup_logging>` is provided to configure
+this automatically:
+
+.. doctest::
+
+    >>> import logging
+    >>> import gcloud.logging # Don't conflict with standard logging
+    >>> from gcloud.logging.handlers import CloudLoggingHandler, setup_logging
+    >>> client = gcloud.logging.Client()
+    >>> handler = CloudLoggingHandler(client)
+    >>> logging.getLogger().setLevel(logging.INFO) # defaults to WARN
+    >>> setup_logging(handler)
+    >>> logging.error('bad news')
+
+You can also exclude certain loggers:
+
+.. doctest::
+
+   >>> setup_logging(handler, excluded_loggers=('werkzeug',)))
+
+
+
+Python logging handler transports
+==================================
+
+The Python logging handler can use different transports. The default is
+:class:`gcloud.logging.handlers.BackgroundThreadTransport`.
+
+ 1. :class:`gcloud.logging.handlers.BackgroundThreadTransport` this is the default. It writes
+ entries on a background :class:`python.threading.Thread`.
+
+ 1. :class:`gcloud.logging.handlers.SyncTransport` this handler does a direct API call on each
+ logging statement to write the entry.

gcloud/logging/handlers/__init__.py

@@ -0,0 +1,18 @@
+# Copyright 2016 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.
+
+"""Python :mod:`logging` handlers for Google Cloud Logging."""
+
+from gcloud.logging.handlers.handlers import CloudLoggingHandler
+from gcloud.logging.handlers.handlers import setup_logging

gcloud/logging/handlers/handlers.py

@@ -0,0 +1,133 @@
+# Copyright 2016 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.
+
+"""Python :mod:`logging` handlers for Google Cloud Logging."""
+
+import logging
+
+from gcloud.logging.handlers.transports import BackgroundThreadTransport
+
+
+EXCLUDE_LOGGER_DEFAULTS = (
+    'gcloud',
+    'oauth2client'
+)
+
+DEFAULT_LOGGER_NAME = 'python'
+
+
+class CloudLoggingHandler(logging.StreamHandler):
+    """Python standard ``logging`` handler.
+
+    This handler can be used to route Python standard logging messages
+    directly to the Google Cloud Logging API.
+
+    Note that this handler currently only supports a synchronous API call,
+    which means each logging statement that uses this handler will require
+    an API call.
+
+    :type client: :class:`gcloud.logging.client`
+    :param client: the authenticated gcloud logging client for this handler
+                   to use
+
+    :type name: str
+    :param name: the name of the custom log in Stackdriver Logging. Defaults
+                 to 'python'. The name of the Python logger will be represented
+                 in the ``python_logger`` field.
+
+    :type transport: type
+    :param transport: Class for creating new transport objects. It should
+                      extend from the base :class:`.Transport` type and
+                      implement :meth`.Transport.send`. Defaults to
+                      :class:`.BackgroundThreadTransport`. The other
+                      option is :class:`.SyncTransport`.
+
+    Example:
+
+    .. doctest::
+
+        import gcloud.logging
+        from gcloud.logging.handlers import CloudLoggingHandler
+
+        client = gcloud.logging.Client()
+        handler = CloudLoggingHandler(client)
+
+        cloud_logger = logging.getLogger('cloudLogger')
+        cloud_logger.setLevel(logging.INFO)
+        cloud_logger.addHandler(handler)
+
+        cloud.logger.error('bad news')  # API call
+
+    """
+
+    def __init__(self, client,
+                 name=DEFAULT_LOGGER_NAME,
+                 transport=BackgroundThreadTransport):
+        super(CloudLoggingHandler, self).__init__()
+        self.name = name
+        self.client = client
+        self.transport = transport(client, name)
+
+    def emit(self, record):
+        """Actually log the specified logging record.
+
+        Overrides the default emit behavior of ``StreamHandler``.
+
+        See: https://docs.python.org/2/library/logging.html#handler-objects
+
+        :type record: :class:`logging.LogRecord`
+        :param record: The record to be logged.
+        """
+        message = super(CloudLoggingHandler, self).format(record)
+        self.transport.send(record, message)
+
+
+def setup_logging(handler, excluded_loggers=EXCLUDE_LOGGER_DEFAULTS):
+    """Attach the ``CloudLogging`` handler to the Python root logger
+
+    Excludes loggers that this library itself uses to avoid
+    infinite recursion.
+
+    :type handler: :class:`logging.handler`
+    :param handler: the handler to attach to the global handler
+
+    :type excluded_loggers: tuple
+    :param excluded_loggers: The loggers to not attach the handler to. This
+                             will always include the loggers in the path of
+                             the logging client itself.
+
+    Example:
+
+    .. doctest::
+
+        import logging
+        import gcloud.logging
+        from gcloud.logging.handlers import CloudLoggingHandler
+
+        client = gcloud.logging.Client()
+        handler = CloudLoggingHandler(client)
+        gcloud.logging.setup_logging(handler)
+        logging.getLogger().setLevel(logging.DEBUG)
+
+        logging.error('bad news')  # API call
+
+    """
+    all_excluded_loggers = set(excluded_loggers + EXCLUDE_LOGGER_DEFAULTS)
+    logger = logging.getLogger()
+    logger.addHandler(handler)
+    logger.addHandler(logging.StreamHandler())
+    for logger_name in all_excluded_loggers:
+        logger = logging.getLogger(logger_name)
+        logger.propagate = False
+        logger.addHandler(logging.StreamHandler())