feat: add eventarc generic sample and other eventarc (GoogleCloudPlatform#4845)

## Description

- Adds running locally instructions like Run
- Simplifies Eventarc samples. Does not use CE SDK – blocked by cloudevents/sdk-python#126
- Adds `eventarc/generic` sample

Fixes GoogleCloudPlatform#4834

Ran `nox -s lint`

Author: grant

eventarc/README.md

@@ -30,9 +30,33 @@ For more Cloud Run samples beyond Python, see the main list in the [Cloud Run Sa
 
     Note: Some samples in the list above are hosted in other repositories. They are noted with the symbol "➥".
 
-
 ## How to run a sample locally
 
+Install [`pip`][pip] and [`virtualenv`][virtualenv] if you do not already have them.
+
+You may want to refer to the [`Python Development Environment Setup Guide`][setup] for Google Cloud Platform for instructions.   
+
+1. Create a virtualenv. Samples are compatible with Python 2.7 and 3.4+.
+
+    ```sh
+    virtualenv env
+    source env/bin/activate
+    ```
+
+1. Install the dependencies needed to run the samples.
+
+    ```sh
+    pip install -r requirements.txt
+    ```
+
+1. Start the application
+
+    ```sh
+    python main.py
+    ```
+
+## How to run a sample in a container
+
 1. [Install docker locally](https://docs.docker.com/install/)
 
 2. [Build the sample container](https://cloud.google.com/run/docs/building/containers#building_locally_and_pushing_using_docker):
@@ -112,3 +136,6 @@ for more information.
 [events_storage]: audit-storage/README.md
 [anthos_events_storage]: audit-storage/anthos.md
 [testing]: https://cloud.google.com/run/docs/testing/local#running_locally_using_docker_with_access_to_services
+[setup]: https://cloud.google.com/python/setup
+[pip]: https://pip.pypa.io/
+[virtualenv]: https://virtualenv.pypa.io/

eventarc/audit-storage/main.py

@@ -15,43 +15,22 @@
 # [START eventarc_gcs_server]
 import os
 
-import cloudevents.exceptions as cloud_exceptions
-from cloudevents.http import from_http
-
 from flask import Flask, request
 
 
-required_fields = ['Ce-Id', 'Ce-Source', 'Ce-Type', 'Ce-Specversion']
 app = Flask(__name__)
 # [END eventarc_gcs_server]
 
 
 # [START eventarc_gcs_handler]
 @app.route('/', methods=['POST'])
 def index():
-    # Create CloudEvent from HTTP headers and body
-    try:
-        event = from_http(request.headers, request.get_data())
-
-    except cloud_exceptions.MissingRequiredFields as e:
-        print(f"cloudevents.exceptions.MissingRequiredFields: {e}")
-        return "Failed to find all required cloudevent fields. ", 400
-
-    except cloud_exceptions.InvalidStructuredJSON as e:
-        print(f"cloudevents.exceptions.InvalidStructuredJSON: {e}")
-        return "Could not deserialize the payload as JSON. ", 400
-
-    except cloud_exceptions.InvalidRequiredFields as e:
-        print(f"cloudevents.exceptions.InvalidRequiredFields: {e}")
-        return "Request contained invalid required cloudevent fields. ", 400
-
-    if 'subject' not in event:
-        errmsg = 'Bad Request: expected header ce-subject'
-        print(errmsg)
-        return errmsg, 400
+    # Gets the GCS bucket name from the CloudEvent header
+    # Example: "storage.googleapis.com/projects/_/buckets/my-bucket"
+    bucket = request.headers.get('ce-subject')
 
-    print(f"Detected change in GCS bucket: {event['subject']}")
-    return (f"Detected change in GCS bucket: {event['subject']}", 200)
+    print(f"Detected change in GCS bucket: {bucket}")
+    return (f"Detected change in GCS bucket: {bucket}", 200)
 # [END eventarc_gcs_handler]
 
 

eventarc/audit-storage/main_test.py

@@ -43,23 +43,3 @@ def test_endpoint(client, capsys):
 
     out, _ = capsys.readouterr()
     assert f"Detected change in GCS bucket: {test_headers['Ce-Subject']}" in out
-
-
-def test_missing_subject(client, capsys):
-    r = client.post('/', headers=binary_headers)
-    assert r.status_code == 400
-
-    out, _ = capsys.readouterr()
-    assert 'Bad Request: expected header ce-subject' in out
-
-
-def test_missing_required_fields(client, capsys):
-    for field in binary_headers:
-        test_headers = copy.copy(binary_headers)
-        test_headers.pop(field)
-
-        r = client.post('/', headers=test_headers)
-        assert r.status_code == 400
-
-        out, _ = capsys.readouterr()
-        assert 'MissingRequiredFields' in out

eventarc/audit-storage/requirements.txt

@@ -1,3 +1,2 @@
 Flask==1.1.2
 gunicorn==20.0.4
-cloudevents==1.2.0

eventarc/generic/.dockerignore

@@ -0,0 +1,6 @@
+Dockerfile
+README.md
+*.pyc
+*.pyo
+*.pyd
+__pycache__

eventarc/generic/Dockerfile

@@ -0,0 +1,41 @@
+# Copyright 2020 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.
+
+# [START eventarc_generic_dockerfile]
+
+# Use the official Python image.
+# https://hub.docker.com/_/python
+FROM python:3.8-slim
+
+# Allow statements and log messages to immediately appear in the Cloud Run logs
+ENV PYTHONUNBUFFERED True
+
+# 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 --timeout 0 main:app
+# [END eventarc_generic_dockerfile]

eventarc/generic/main.py

@@ -0,0 +1,50 @@
+# Copyright 2020 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.
+
+# [START eventarc_generic_server]
+import os
+
+from flask import Flask, request
+
+
+app = Flask(__name__)
+# [END eventarc_generic_server]
+
+
+# [START eventarc_generic_handler]
+@app.route('/', methods=['POST'])
+def index():
+    print('Event received!')
+
+    print('HEADERS:')
+    headers = dict(request.headers)
+    headers.pop('Authorization', None)  # do not log authorization header if exists
+    print(headers)
+
+    print('BODY:')
+    body = dict(request.json)
+    print(body)
+
+    resp = {
+        "headers": headers,
+        "body": body
+    }
+    return (resp, 200)
+# [END eventarc_generic_handler]
+
+
+# [START eventarc_generic_server]
+if __name__ == "__main__":
+    app.run(debug=True, host='0.0.0.0', port=int(os.environ.get('PORT', 8080)))
+# [END eventarc_generic_server]

eventarc/generic/main_test.py

@@ -0,0 +1,51 @@
+# Copyright 2020 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 uuid import uuid4
+
+import pytest
+
+import main
+
+
+binary_headers = {
+    "ce-id": str(uuid4),
+    "ce-type": "com.pytest.sample.event",
+    "ce-source": "<my-test-source>",
+    "ce-specversion": "1.0"
+}
+
+
+@pytest.fixture
+def client():
+
+    main.app.testing = True
+    return main.app.test_client()
+
+
+def test_relay(client, capsys):
+
+    r = client.post('/', json={'message': {'data': 'Hello'}}, headers=binary_headers)
+    assert r.status_code == 200
+
+    out, _ = capsys.readouterr()
+
+    # Assert print
+    assert 'Event received!' in out
+
+    # Ensure output relays HTTP headers
+    assert '"Ce-Specversion":"1.0"' in r.data.decode('utf-8')
+
+    # Ensure output relays HTTP body
+    assert binary_headers['ce-id'] in out
+    assert "{'message': {'data': 'Hello'}}" in out

eventarc/generic/requirements-test.txt

@@ -0,0 +1 @@
+pytest==6.0.1

eventarc/generic/requirements.txt

@@ -0,0 +1,2 @@
+Flask==1.1.2
+gunicorn==20.0.4