Add package to provide gevent compatibiliy (#628)

README.rst

@@ -185,6 +185,7 @@ OpenCensus supports integration with popular web frameworks, client libraries an
 
 -  `Django`_
 -  `Flask`_
+-  `gevent`_
 -  `Google Cloud Client Libraries`_
 -  `gRPC`_
 -  `httplib`_
@@ -216,6 +217,7 @@ Stats Exporter
 .. _Azure: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-azure
 .. _Django: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-django
 .. _Flask: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-flask
+.. _gevent: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-gevent
 .. _Google Cloud Client Libraries: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-google-cloud-clientlibs
 .. _gRPC: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-grpc
 .. _httplib: https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-httplib

contrib/opencensus-ext-gevent/CHANGELOG.md

@@ -0,0 +1,5 @@
+# Changelog
+
+## Unreleased
+
+- Initial version

contrib/opencensus-ext-gevent/README.rst

@@ -0,0 +1,41 @@
+OpenCensus gevent helper
+============================================================================
+
+|pypi|
+
+.. |pypi| image:: https://badge.fury.io/py/opencensus-ext-gevent.svg
+   :target: https://pypi.org/project/opencensus-ext-gevent/
+
+Installation
+------------
+
+::
+
+    pip install opencensus-ext-gevent
+
+Usage
+-----
+
+As gevent is to date `incompatible <https://github.com/gevent/gevent/issues/1407>`_ with
+the new context variables the **OpenCensus gevent helper** configures OpenCensus to use
+a compatible thread based runtime context implementation.
+
+No action apart from installing the package is needed as it listens to events
+`emitted by gevent  <http://www.gevent.org/api/gevent.monkey.html#plugins>`_ once
+patching via ``patch_all`` is complete.
+
+
+Warning
+-------
+
+OpenCensus itself is completely compatible with gevent. Be aware though that not all
+available OpenCensus integrations are compatible.
+
+You should  check this on a case by case basis.
+
+
+References
+----------
+
+* `OpenCensus Project <https://opencensus.io/>`_
+* `gevent <https://www.gevent.org/>`_

contrib/opencensus-ext-gevent/opencensus/__init__.py

@@ -0,0 +1 @@
+__path__ = __import__('pkgutil').extend_path(__path__, __name__)

contrib/opencensus-ext-gevent/opencensus/ext/__init__.py

@@ -0,0 +1 @@
+__path__ = __import__('pkgutil').extend_path(__path__, __name__)

contrib/opencensus-ext-gevent/opencensus/ext/gevent/__init__.py

@@ -0,0 +1 @@
+__path__ = __import__('pkgutil').extend_path(__path__, __name__)

contrib/opencensus-ext-gevent/opencensus/ext/gevent/geventcompatibility.py

@@ -0,0 +1,21 @@
+import logging
+import gevent.monkey
+
+
+def patch_opencensus(event):
+    # Switch from the default runtime context using ContextVar to one
+    # using thread locals. Needed until gevent supports ContextVar.
+    # See https://github.com/gevent/gevent/issues/1407
+    import opencensus.common.runtime_context as runtime_context
+
+    if not gevent.monkey.is_module_patched("contextvars"):
+        runtime_context.RuntimeContext = (
+            runtime_context._ThreadLocalRuntimeContext()
+        )
+
+        logging.warning("OpenCensus patched for gevent compatibility")
+    else:
+        logging.warning(
+            "OpenCensus is already compatible with your gevent version. "
+            "Feel free to uninstall the opencensus-ext-gevent package."
+        )

contrib/opencensus-ext-gevent/setup.cfg

@@ -0,0 +1,2 @@
+[bdist_wheel]
+universal = 1

contrib/opencensus-ext-gevent/setup.py

@@ -0,0 +1,56 @@
+# Copyright 2019, OpenCensus Authors
+#
+# 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 setuptools import find_packages
+from setuptools import setup
+from version import __version__
+
+setup(
+    name='opencensus-ext-gevent',
+    version=__version__,  # noqa
+    author='OpenCensus Authors',
+    author_email='census-developers@googlegroups.com',
+    classifiers=[
+        'Intended Audience :: Developers',
+        'Development Status :: 3 - Alpha',
+        'Intended Audience :: Developers',
+        'License :: OSI Approved :: Apache Software License',
+        'Programming Language :: Python',
+        'Programming Language :: Python :: 2',
+        'Programming Language :: Python :: 2.7',
+        'Programming Language :: Python :: 3',
+        'Programming Language :: Python :: 3.4',
+        'Programming Language :: Python :: 3.5',
+        'Programming Language :: Python :: 3.6',
+        'Programming Language :: Python :: 3.7',
+    ],
+    description='OpenCensus gevent compatibility helper',
+    include_package_data=True,
+    long_description=open('README.rst').read(),
+    install_requires=[
+        'opencensus >= 0.6.dev0, < 1.0.0',
+        'gevent >= 1.3'
+    ],
+    extras_require={},
+    license='Apache-2.0',
+    packages=find_packages(exclude=('tests',)),
+    namespace_packages=[],
+    url='https://github.com/census-instrumentation/opencensus-python/tree/master/contrib/opencensus-ext-gevent',  # noqa: E501
+    zip_safe=False,
+    entry_points={
+        "gevent.plugins.monkey.did_patch_builtins": [
+            "opencensus = opencensus.ext.gevent.geventcompatibility:patch_opencensus"  # noqa: E501
+        ]
+    },
+)

contrib/opencensus-ext-gevent/tests/test_patching.py

@@ -0,0 +1,96 @@
+# Copyright 2019, OpenCensus Authors
+#
+# 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.
+
+import unittest
+
+import opencensus.common.runtime_context as runtime_context
+import gevent.monkey
+
+import mock
+
+
+class TestPatching(unittest.TestCase):
+    def setUp(self):
+        self.original_context = runtime_context.RuntimeContext
+
+    def tearDown(self):
+        runtime_context.RuntimeContext = self.original_context
+
+    @mock.patch("gevent.monkey.is_module_patched", return_value=False)
+    def test_context_is_switched_without_contextvar_support(
+        self, patched_is_module_patched
+    ):
+        # patched_is_module_patched.return_value = False
+
+        # Trick gevent into thinking it is run for the first time.
+        # Allows to run multiple tests.
+        gevent.monkey.saved = {}
+
+        # All module patching is disabled to avoid the need of "unpatching".
+        # The needed events are emitted nevertheless.
+        gevent.monkey.patch_all(
+            contextvar=False,
+            socket=False,
+            dns=False,
+            time=False,
+            select=False,
+            thread=False,
+            os=False,
+            ssl=False,
+            httplib=False,
+            subprocess=False,
+            sys=False,
+            aggressive=False,
+            Event=False,
+            builtins=False,
+            signal=False,
+            queue=False
+        )
+
+        assert isinstance(
+            runtime_context.RuntimeContext,
+            runtime_context._ThreadLocalRuntimeContext,
+        )
+
+    @mock.patch("gevent.monkey.is_module_patched", return_value=True)
+    def test_context_is_switched_with_contextvar_support(
+        self, patched_is_module_patched
+    ):
+
+        # Trick gevent into thinking it is run for the first time.
+        # Allows to run multiple tests.
+        gevent.monkey.saved = {}
+
+        # All module patching is disabled to avoid the need of "unpatching".
+        # The needed events are emitted nevertheless.
+        gevent.monkey.patch_all(
+            contextvar=False,
+            socket=False,
+            dns=False,
+            time=False,
+            select=False,
+            thread=False,
+            os=False,
+            ssl=False,
+            httplib=False,
+            subprocess=False,
+            sys=False,
+            aggressive=False,
+            Event=False,
+            builtins=False,
+            signal=False,
+            queue=False
+        )
+
+        assert runtime_context.RuntimeContext is self.original_context

contrib/opencensus-ext-gevent/version.py

@@ -0,0 +1,15 @@
+# Copyright 2019, OpenCensus Authors
+#
+# 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.
+
+__version__ = '0.1.dev0'

nox.py

@@ -27,6 +27,7 @@ def _install_dev_packages(session):
     session.install('-e', 'contrib/opencensus-ext-dbapi')
     session.install('-e', 'contrib/opencensus-ext-django')
     session.install('-e', 'contrib/opencensus-ext-flask')
+    session.install('-e', 'contrib/opencensus-ext-gevent')
     session.install('-e', 'contrib/opencensus-ext-grpc')
     session.install('-e', 'contrib/opencensus-ext-httplib')
     session.install('-e', 'contrib/opencensus-ext-jaeger')