Merge pull request #11 from andrewsg/health_checks

handle health checks in middleware

Author: andrewsg

multicore_runtime/dev/Dockerfile

@@ -5,7 +5,7 @@ RUN apt-get -q update && \
     python2.7 python-pip python-gevent python-greenlet && \
   apt-get clean && rm /var/lib/apt/lists/*_*
 
-COPY python-runtime-0.1.tar.gz /home/vmagent/python-runtime.tar.gz
+COPY appengine-python-vm-runtime-0.1.tar.gz /home/vmagent/python-runtime.tar.gz
 
 RUN pip install --upgrade pip>=6.1.1 gunicorn==19.1.1
 RUN pip install /home/vmagent/python-runtime.tar.gz

multicore_runtime/middleware.py

@@ -17,6 +17,9 @@
 import logging
 import os
 
+from werkzeug.wrappers import Request
+from werkzeug.wrappers import Response
+
 
 RESERVED_ENV_KEYS = {
     'AUTH_DOMAIN': 'gmail.com',  # Default auth domain must be set.
@@ -160,3 +163,23 @@ def get_env_to_hide_service_bridge(wsgi_env):
                     'SERVER_PORT', https)
 
   return output
+
+
+def health_check_middleware(app):
+  """Intercept requests to /_ah/health and respond healthy (200 OK).
+
+  Args:
+    app: The WSGI app to wrap.
+
+  Returns:
+    The wrapped app, also a WSGI app.
+  """
+
+  def health_check_intercept_wrapper(wsgi_env, start_response):  # pylint: disable=missing-docstring
+    request = Request(wsgi_env)
+    if request.path == '/_ah/health':  # Only intercept exact matches.
+      return Response('healthy', status=200)(wsgi_env, start_response)
+    else:
+      return app(wsgi_env, start_response)
+
+  return health_check_intercept_wrapper

multicore_runtime/wsgi.py

@@ -25,6 +25,7 @@
 
 from dispatcher import dispatcher
 from middleware import reset_environment_middleware
+from middleware import health_check_middleware
 from wsgi_config import env_vars_from_env_config
 from wsgi_config import get_module_config
 from wsgi_config import get_module_config_filename
@@ -83,7 +84,11 @@
 # layer (the middleware code that will process a request first). Inside the
 # innermost layer is the actual dispatcher, above.
 
+# Intercept health check requests on /_ah/health. This is a temporary measure
+# until container-level health check handlers are in place and turned on.
+meta_app = health_check_middleware(meta_app)
+
 # Reset os.environ to the frozen state and add request-specific data.
 meta_app = reset_environment_middleware(meta_app, frozen_environment,
                                         frozen_user_env,
-                                        frozen_env_config_env)
+                                        frozen_env_config_env)

setup.py

@@ -1,6 +1,23 @@
-from setuptools import setup, find_packages
+# Copyright 2015 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.
+#
+"""Configure and install the runtime package."""
 
-setup(name='python-runtime',
+from setuptools import find_packages
+from setuptools import setup
+
+setup(name='appengine-python-vm-runtime',
       version='0.1',
       description='Google App Engine-compatible Python runtime for Managed VMs',
       url='https://github.com/GoogleCloudPlatform/appengine-python-vm-runtime',
@@ -9,19 +26,15 @@
       classifiers=[
           'Development Status :: 3 - Alpha',
           'Intended Audience :: Developers',
-          'License :: OSI Approved :: MIT License',
+          'License :: OSI Approved :: Apache Software License',
           'Programming Language :: Python :: 2',
           'Programming Language :: Python :: 2.7',
       ],
       package_dir={'': 'python_vm_runtime',
                    'google.appengine.vmruntime': 'multicore_runtime',},
       include_package_data=True,
-      packages=find_packages('python_vm_runtime') + ['google.appengine.vmruntime'],
-      # namespace_packages=['google'], # While google is a namespace, marking
-                                       # it as such makes the installer skip
-                                       # __init__.py, which breaks some
-                                       # packages expecting google to have
-                                       # a __file__ attribute.
+      packages=find_packages('python_vm_runtime') + ['google.appengine.vmruntime'],  # pylint: disable=line-too-long
+      # namespace_packages=['google'],  # This skips google/__init__.py
       install_requires=['requests>=2.5.0',
                         'webapp2>=2.5.2',
                         'WebOb>=1.4',