Run logging manual (GoogleCloudPlatform#2513)

* Adding cloud run manual logging sample

* Updating test file

* Cleaning up

* Fixing nits

Author: dinagraves

run/logging-manual/.dockerignore

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+Dockerfile
+.dockerignore
+__pycache__
+.pytest_cache

run/logging-manual/Dockerfile

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+# Copyright 2019 Google, LLC.
+#
+# 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.
+
+# Use the official Python image.
+# https://hub.docker.com/_/python
+FROM python:3.7
+
+# Copy application dependency manifests to the container image.
+# Copying this separately prevents re-running pip install on every code change.
+COPY requirements.txt .
+
+# Install production dependencies.
+RUN pip install -r requirements.txt
+
+# Copy local code to the container image.
+ENV APP_HOME /app
+WORKDIR $APP_HOME
+COPY . .
+
+# Run the web service on container startup. 
+# Use gunicorn webserver with one worker process and 8 threads.
+# For environments with multiple CPU cores, increase the number of workers
+# to be equal to the cores available.
+CMD exec gunicorn --bind :$PORT --workers 1 --threads 8 main:app

run/logging-manual/README.md

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+# Cloud Run Manual Logging Sample
+
+This sample shows how to send structured logs to Stackdriver Logging.
+
+[![Run in Google Cloud][run_img]][run_link]
+
+[run_img]: https://storage.googleapis.com/cloudrun/button.svg
+[run_link]: https://console.cloud.google.com/cloudshell/editor?shellonly=true&cloudshell_image=gcr.io/cloudrun/button&cloudshell_git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&cloudshell_working_dir=run/logging-manual
+
+## Build
+
+```
+docker build --tag logging-manual:python .
+```
+
+## Run Locally
+
+```
+docker run --rm -p 9090:8080 logging-manual:python
+```
+
+## Test
+
+```
+pytest
+```
+
+_Note: you may need to install `pytest` using `pip install pytest`._
+
+## Deploy
+
+```sh
+# Set an environment variable with your GCP Project ID
+export GOOGLE_CLOUD_PROJECT=<PROJECT_ID>
+
+# Submit a build using Google Cloud Build
+gcloud builds submit --tag gcr.io/${GOOGLE_CLOUD_PROJECT}/logging-manual
+
+# Deploy to Cloud Run
+gcloud beta run deploy logging-manual \
+--image gcr.io/${GOOGLE_CLOUD_PROJECT}/logging-manual \
+--set-env-vars GOOGLE_CLOUD_PROJECT=${GOOGLE_CLOUD_PROJECT}
+```
+
+Read more about Cloud Run logging in the [Logging How-to Guide](http://cloud.google.com/run/docs/logging).
+
+For more details on how to work with this sample read the [Python Cloud Run Samples README](https://github.com/GoogleCloudPlatform/python-docs-samples/tree/master/run)

run/logging-manual/main.py

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+# Copyright 2019 Google, LLC.
+#
+# 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 flask import Flask, request
+import json
+import os
+import sys
+
+app = Flask(__name__)
+
+
+@app.route('/', methods=['GET'])
+def index():
+    PROJECT = os.environ['GOOGLE_CLOUD_PROJECT']
+
+    # [START run_manual_logging]
+    # Uncomment and populate this variable in your code:
+    # PROJECT = 'The project ID of your Cloud Run service';
+
+    # Build structured log messages as an object.
+    global_log_fields = {}
+
+    # Add log correlation to nest all log messages
+    # beneath request log in Log Viewer.
+    trace_header = request.headers.get('X-Cloud-Trace-Context')
+
+    if trace_header and PROJECT:
+        trace = trace_header.split('/')
+        global_log_fields['logging.googleapis.com/trace'] = (
+            f"projects/{PROJECT}/traces/{trace[0]}")
+
+    # Complete a structured log entry.
+    entry = dict(severity='NOTICE',
+                 message='This is the default display field.',
+                 # Log viewer accesses 'component' as jsonPayload.component'.
+                 component='arbitrary-property',
+                 **global_log_fields)
+
+    print(json.dumps(entry))
+    # [END run_manual_logging]
+
+    # Flush the stdout to avoid log buffering.
+    sys.stdout.flush()
+
+    return 'Hello Logger!'
+
+
+if __name__ == '__main__':
+    PORT = int(os.getenv('PORT')) if os.getenv('PORT') else 8080
+
+    # This is used when running locally. Gunicorn is used to run the
+    # application on Cloud Run. See entrypoint in Dockerfile.
+    app.run(host='127.0.0.1', port=PORT, debug=True)

run/logging-manual/main_test.py

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+# Copyright 2019 Google, LLC.
+#
+# 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.
+
+# NOTE:
+# These unit tests mock logging.
+
+
+import pytest
+import main
+
+
+@pytest.fixture
+def client():
+    main.app.testing = True
+    return main.app.test_client()
+
+
+def test_no_trace_in_headers(client, capsys):
+    r = client.get('/')
+    assert r.status_code == 200
+
+    out, _ = capsys.readouterr()
+    print(out)
+    assert 'trace' not in out
+
+
+def test_with_cloud_headers(client, capsys):
+    r = client.get('/', headers={'X-Cloud-Trace-Context': 'foo/bar'})
+    assert r.status_code == 200
+
+    out, _ = capsys.readouterr()
+    print(out)
+    assert 'trace' in out

run/logging-manual/requirements.txt

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+Flask==1.1.1
+pytest==5.1.3
+gunicorn==19.9.0