Create a Python app in the App Engine flexible environment
Region ID
The REGION_ID
is an abbreviated code that Google assigns
based on the region you select when you create your app. The code does not
correspond to a country or province, even though some region IDs may appear
similar to commonly used country and province codes. For apps created after
February 2020, REGION_ID.r
is included in
App Engine URLs. For existing apps created before this date, the
region ID is optional in the URL.
Learn more about region IDs.
This quickstart shows you how to create a small App Engine app that displays a short message.
Before you begin
- Sign in to your Google Cloud account. If you're new to Google Cloud, create an account to evaluate how our products perform in real-world scenarios. New customers also get $300 in free credits to run, test, and deploy workloads.
-
In the Google Cloud console, on the project selector page, select or create a Google Cloud project.
-
Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.
-
Enable the Cloud Build API.
- Install and initialize the Google Cloud CLI.
-
In the Google Cloud console, on the project selector page, select or create a Google Cloud project.
-
Make sure that billing is enabled for your Cloud project. Learn how to check if billing is enabled on a project.
-
Enable the Cloud Build API.
- Install and initialize the Google Cloud CLI.
Additional prerequisites
Initialize your App Engine app with your project and choose its region:
gcloud app create --project=[YOUR_PROJECT_ID]
When prompted, select the region where you want to locate your App Engine application.
Install the following prerequisites:
Run the following command to install the gcloud component that includes the App Engine extension for Python:
gcloud components install app-engine-python
Prepare your environment for Python development. It is recommended that you have the latest version of Python,
pip
, and other related tools installed on your system. For instructions, refer to the Python Development Environment Setup Guide.
App Engine locations
App Engine is regional, which means the infrastructure that runs your apps is located in a specific region, and Google manages it so that it is available redundantly across all of the zones within that region.
Meeting your latency, availability, or durability requirements are primary factors for selecting the region where your apps are run. You can generally select the region nearest to your app's users, but you should consider the locations where App Engine is available as well as the locations of the other Google Cloud products and services that your app uses. Using services across multiple locations can affect your app's latency as well as its pricing.
You cannot change an app's region after you set it.
If you already created an App Engine application, you can view its region by doing one of the following:
Run the
gcloud app describe
command.Open the App Engine Dashboard in the Cloud console. The region appears near the top of the page.
Download the Hello World app
We've created a simple Hello World app for Python so you can quickly get a feel for deploying an app to the Google Cloud.
Clone the Hello World sample app repository to your local machine.
git clone https://github.com/GoogleCloudPlatform/python-docs-samples
Alternatively, you can download the sample as a zip file and extract it.
Change to the directory that contains the sample code.
cd python-docs-samples/appengine/flexible/hello_world
Run Hello World on your local machine
To run the Hello World app on your local computer:
Mac OS / Linux
- Create an
isolated Python environment:
python3 -m venv env
source env/bin/activate
- If you're not in the directory that contains the sample code, navigate
to the directory that contains the
hello_world
sample code. Then install dependencies:cd YOUR_SAMPLE_CODE_DIR
pip install -r requirements.txt
- Run the application:
python main.py
- In your web browser, enter the following address:
http://localhost:8080
Windows
Use PowerShell to run your Python packages.
- Locate your installation of PowerShell.
- Right-click on the shortcut to PowerShell and start it as an administrator.
- Create an
isolated Python environment.
python -m venv env
.\env\Scripts\activate
- Navigate to your project directory and install dependencies. If you're not in the directory
that contains the sample code, navigate to the directory that contains the
hello_world
sample code. Then, install dependencies:cd YOUR_SAMPLE_CODE_DIR
pip install -r requirements.txt
- Run the application:
python main.py
- In your web browser, enter the following address:
http://localhost:8080
The Hello World message from the sample app displays on the page. In your terminal window, press Ctrl+C to exit the web server.
Deploy and run Hello World on App Engine
To deploy your app to the App Engine flexible environment:-
Deploy the Hello World app by running the following command from the
hello_world
directory:gcloud app deploy
Learn about the optional flags.
Common
gcloud
command flags-
Include the
--version
flag to specify an ID that uniquely identifies that version of your app, otherwise one is generated for you. Example:--version [YOUR_VERSION_ID]
-
Include the
--project
flag to specify an alternate Cloud project ID to what you initialized as the default in thegcloud
tool. Example:--project [YOUR_PROJECT_ID]
Example:
gcloud app deploy --version pre-prod-5 --project my-sample-app
To learn more about deploying your app from the command line, see Testing and Deploying Your App . For a list of all the command flags, see the
gcloud app deploy
reference. -
Include the
-
Launch your browser to view the app at
https://PROJECT_ID.REGION_ID.r.appspot.com
gcloud app browse
wherePROJECT_ID
represents your Google Cloud project ID.
This time, the page that displays the Hello World message is delivered by a web server running on an App Engine instance.
Congratulations! You've deployed your first Python app to App Engine flexible environment!
If you encountered any errors deploying your application, check the troubleshooting tips.See the following sections for information about cleaning up as well as links to possible next steps that you can take.
Clean up
To avoid incurring charges, you can delete your Cloud project to stop billing for all the resources used within that project.
- In the Cloud console, go to the Manage resources page.
- In the project list, select the project that you want to delete, and then click Delete.
- In the dialog, type the project ID, and then click Shut down to delete the project.
What's next
Learn the whole platform
Now that you know what it's like to develop and deploy App Engine apps, you can explore the rest of Google Cloud. You already have the Google Cloud CLI installed which gives you the tools to interact with products like Cloud SQL, Cloud Storage, Firestore, and more.
For a guided walkthrough that teaches you how to create an app that uses the entire platform, not just App Engine, check out our quickstart on creating the Bookshelf app.
Learn about the App Engine flexible environment
Here are some topics to help continue your learning about App Engine.
Hello World code review
Hello World is the simplest possible App Engine app, as it contains only one service, has only one version, and all of the code is located within the app's root directory. This section describes each of the app files in detail.
main.py
The Hello World app is a basic one-file Flask app.
app.yaml
The app.yaml
file describes an app's deployment configuration:
Here,
app.yaml
specifies the runtime used by
the app, and sets env: flex
, specifying that the app
uses the
flexible environment.
The entrypoint
tells App Engine how to start the app. This app uses
gunicorn
to serve
the Python app as an alternative to Flask's
development server
(used when running locally). The $PORT
variable is set by App Engine when it starts
the app. For more information about entrypoint
, see App
startup.
Additionally, the optional runtime_config
section sets python_version
to use
Python 3. If python_version
is not specified, then Python 2 is used by
default. You can also specify python_version: 2
explicitly.
For more information on how the Python runtime works, see The Python runtime.
For more details about how to design your app to take advantage of versions and services, see An overview of App Engine.
For more details about the configuration settings for App Engine, see Configuring your app with app.yaml.
requirements.txt
requirements.txt
and the Python package manager
pip
are used to declare and install application dependencies. Hello World requires
Flask, a web framework, and
Gunicorn, a WSGI server.
requirements.txt
defines the libraries that will be installed both locally
and when deploying to App Engine.