Add an App Engine Flexiable Python application. It is to demonstrate … (#9191)

* Add an App Engine Flexiable Python application. It is to demonstrate the newly released Python 3.10 runtime on Ubuntu 22. Documentation changes have been published to https://cloud.google.com/appengine/docs/flexible/python/runtime.

* Update copyright holder and license header.

* Attempt to fix nox tests.

* Add python type annotation.

* Update the license header.

Author: jinglundong

appengine/flexible_ubuntu/README.md

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+## Google App Engine Flexible Environment Python on Ubuntu Samples
+
+[![Open in Cloud Shell][shell_img]][shell_link]
+
+[shell_img]: http://gstatic.com/cloudssh/images/open-btn.png
+[shell_link]: https://console.cloud.google.com/cloudshell/open?git_repo=https://github.com/GoogleCloudPlatform/python-docs-samples&page=editor&open_in_editor=appengine/flexible_ubuntu/README.md
+
+These are samples for using Python on Google App Engine Flexible Environment on the Ubuntu 18 and Ubuntu 22 OS. These samples are typically referenced from the [docs](https://cloud.google.com/appengine/docs).
+
+See our other [Google Cloud Platform github repos](https://github.com/GoogleCloudPlatform) for sample applications and
+scaffolding for other frameworks and use cases.
+
+## Run Locally
+
+Some samples have specific instructions. If there is a README in the sample folder, please refer to it for any additional steps required to run the sample.
+
+In general, the samples typically require:
+
+1. Install the [Google Cloud SDK](https://cloud.google.com/sdk/), including the [gcloud tool](https://cloud.google.com/sdk/gcloud/), and [gcloud app component](https://cloud.google.com/sdk/gcloud-app).
+
+2. Setup the gcloud tool. This provides authentication to Google Cloud APIs and services.
+
+   ```
+   gcloud init
+   ```
+
+3. Clone this repo.
+
+   ```
+   git clone https://github.com/GoogleCloudPlatform/python-docs-samples.git
+   cd python-docs-samples/appengine/flexible
+   ```
+
+4. Open a sample folder, create a virtualenv, install dependencies, and run the sample:
+
+   ```
+   cd hello-world
+   virtualenv env
+   source env/bin/activate
+   pip install -r requirements.txt
+   python main.py
+   ```
+
+5. Visit the application at [http://localhost:8080](http://localhost:8080).
+
+
+## Deploying
+
+Some samples in this repositories may have special deployment instructions. Refer to the readme in the sample directory.
+
+1. Use the [Google Developers Console](https://console.developer.google.com)  to create a project/app id. (App id and project id are identical)
+
+2. Setup the gcloud tool, if you haven't already.
+
+   ```
+   gcloud init
+   ```
+
+3. Use gcloud to deploy your app. Your application must use a `gcloud` CLI
+   [version **420.0.0 or later**](/sdk/docs/install-sdk#installing_the_latest_version).
+   To view the current `gcloud` version, run the [`gcloud
+   version`](/sdk/gcloud/reference/version) command.
+
+   ```
+   gcloud app deploy
+   ```
+
+4. Congratulations!  Your application is now live at `your-app-id.appspot.com`
+
+## Contributing changes
+
+* See [CONTRIBUTING.md](../CONTRIBUTING.md)
+
+## Licensing
+
+* See [LICENSE](../LICENSE)

appengine/flexible_ubuntu/hello_world/app.yaml

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+# Copyright 2021 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.
+
+runtime: python
+env: flex
+entrypoint: gunicorn -b :$PORT main:app
+
+runtime_config:
+  operating_system: ubuntu22
+  # We also support 3.8, 3.9 and 3.11.
+  # See https://cloud.google.com/appengine/docs/flexible/python/runtime#interpreter for more info.
+  runtime_version: "3.10"
+
+# This sample incurs costs to run on the App Engine flexible environment. 
+# The settings below are to reduce costs during testing and are not appropriate
+# for production use. For more information, see:
+# https://cloud.google.com/appengine/docs/flexible/python/configuring-your-app-with-app-yaml
+manual_scaling:
+  instances: 1
+resources:
+  cpu: 1
+  memory_gb: 0.5
+  disk_size_gb: 10

appengine/flexible_ubuntu/hello_world/main.py

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+# Copyright 2023 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 gae_flex_quickstart]
+from flask import Flask
+
+
+app = Flask(__name__)
+
+
+@app.route('/')
+def hello() -> str:
+    """Return a friendly HTTP greeting."""
+    return 'Hello World!'
+
+
+if __name__ == '__main__':
+    # This is used when running locally only. When deploying to Google App
+    # Engine, a webserver process such as Gunicorn will serve the app.
+    app.run(host='127.0.0.1', port=8080, debug=True)
+# [END gae_flex_quickstart]

appengine/flexible_ubuntu/hello_world/main_test.py

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+# Copyright 2023 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.
+
+import main
+
+
+def test_index() -> str:
+    main.app.testing = True
+    client = main.app.test_client()
+
+    r = client.get('/')
+    assert r.status_code == 200
+    assert 'Hello World' in r.data.decode('utf-8')

appengine/flexible_ubuntu/hello_world/noxfile_config.py

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+# Copyright 2021 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.
+
+# Default TEST_CONFIG_OVERRIDE for python repos.
+
+# You can copy this file into your directory, then it will be imported from
+# the noxfile.py.
+
+# The source of truth:
+# https://github.com/GoogleCloudPlatform/python-docs-samples/blob/main/noxfile_config.py
+
+TEST_CONFIG_OVERRIDE = {
+    # You can opt out from the test for specific Python versions.
+    "ignored_versions": ["2.7", "3.6"],
+    # Old samples are opted out of enforcing Python type hints
+    # All new samples should feature them
+    "enforce_type_hints": True,
+    # An envvar key for determining the project id to use. Change it
+    # to 'BUILD_SPECIFIC_GCLOUD_PROJECT' if you want to opt in using a
+    # build specific Cloud project. You can also use your own string
+    # to use your own Cloud project.
+    "gcloud_project_env": "GOOGLE_CLOUD_PROJECT",
+    # 'gcloud_project_env': 'BUILD_SPECIFIC_GCLOUD_PROJECT',
+    # If you need to use a specific version of pip,
+    # change pip_version_override to the string representation
+    # of the version number, for example, "20.2.4"
+    "pip_version_override": None,
+    # A dictionary you want to inject into your test. Don't put any
+    # secrets here. These values will override predefined values.
+    "envs": {},
+}

appengine/flexible_ubuntu/hello_world/requirements-test.txt

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+pytest==6.2.4

appengine/flexible_ubuntu/hello_world/requirements.txt

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+Flask==2.1.1
+gunicorn==20.1.0