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Python Flask Server

Tutorial for deploying a Python Flask Server on Wasmer Edge

In this guide, you'll learn the process of deploying a python flask application on Wasmer Edge. We'll be deploying a basic flask server with default index endpoint.

Deploying a Python Application

Install Wasmer

Click here for instructions on how to install Wasmer if you haven't done it already!

Log in into Wasmer

Create a new account in Wasmer (opens in a new tab). Then, log in into the Wasmer CLI and follow the provided steps to provide the CLI access to your Wasmer account.

wasmer login

Initialize the Python Application Starter template

wasmer app create

Then follow the CLI and select some of the alternatives which creates a python flask app.

ℹ️

This is an interactive command. You can also use the --template flag to specify a template.

Further you will be prompted to enter your package name and app name. You can choose any name you like.

🚧

The app names should be globally unique across all apps on the registry.

You directory composition should look like this:

    • main.py
  • wasmer.toml
  • app.yaml

    • Configure the Python Virtual Environment

    python -m venv .env

    You directory composition should look like this with .env folder added:

    • main.py
  • wasmer.toml
  • app.yaml

    • Activate the Python Virtual Environment

    source .env/bin/activate

    Install the Python Flask package

    pip install flask

    Writing the Python Flask Application

    Modify the src/main.py file to look like this:

    src/main.py
    from flask import Flask
 
app = Flask(__name__)
 
@app.route("/")
def index():
    return "Hello, from Wasmer Edge 🚀"

    You can change the return string to anything you like.

    Test the flask application locally

    python -m flask --app src/main run --debug --no-reload

    Expect output similar to this:

    * Serving Flask app 'src/main'
* Debug mode: on
WARNING: This is a development server. Do not use it in a production deployment. Use a production WSGI server instead.
 * Running on http://127.0.0.1:5000
Press CTRL+C to quit
127.0.0.1 - - [13/Jan/2025 14:33:11] "GET / HTTP/1.1" 200 -

    Let's try to cURL the server:

    curl http://127.0.0.1:5000

    Expect to see:

    Hello, from Wasmer Edge 🚀

    Configure the wasmer.toml and app.yaml files

    In our wasmer.toml we need to set up some args and env variables.

    wasmer.toml
    [package]
name = "wasmer/python-flask-server"
version = "0.1.1"
description = "wasmer/python-flask-server python application"
readme = "README.md"
 
[dependencies]
"wasmer/python" = "^3.12.6"
 
[fs]
"/src" = "./src"
"/cpython/lib/python3.12" = "./.env/lib/python3.11"
 
[[command]]
name = "script"
module = "wasmer/python:python"
runner = "wasi"
 
[command.annotations.wasi]
main-args = [ # This is the command we want the python runner to run
    "-m",
    "flask",
    "--app",
    "/src/main",
    "run",
    "--debug",
    "--no-reload",
]
env = ["PYTHONEXECUTABLE: /bin/python"] # This is the path to the python executable

    In our app.yaml we want to provide the same args as we did in the wasmer.toml file.

    app.yaml
    ---
kind: wasmer.io/App.v0
name: wasmer-python-flask-server-myapp-example
package: wasmer/python-flask-server-myapp-example@0.1.0
cli_args: # This is the command we want the python runner to run on Wasmer Edge
  - -m
  - flask
  - --app
  - /src/main
  - run
  - --debug
  - --no-reload
env:
  PYTHONEXECUTABLE: /bin/python # This is the path to the python executable

    Now, we can test if our application runs with wasmer

    wasmer run .

    The above command will start a web server on http://127.0.0.1:5000.

    Let's try to cURL the server, running using wasmer:

    curl http://127.0.0.1:5000

    Expect to see:

    Hello, from Wasmer Edge 🚀

    Deploying your Python Application

    Deploying is the easiest part. Just run the following command:

    wasmer deploy

    Expect to see something like:

    Loaded app from: /.../wasmer-edge/python-flask/app.yaml
Deploying app wasmer-python-flask-server-myapp-example...

 ✅ App dynamite-bud/wasmer-python-flask-server-myapp-example was successfully deployed!

> App URL: https://wasmer-python-flask-server-myapp-example.wasmer.app
> Versioned URL: https://2mzhyi8cqzxr.id.wasmer.app
> Admin dashboard: https://wasmer.io/apps/wasmer-python-flask-server-myapp-example

Waiting for new deployment to become available...
(You can safely stop waiting now with CTRL-C)

    Now you can visit the URL and see your application running on Wasmer Edge.

    ℹ️

    You must be in the directory holding the wasmer.toml and app.yaml config files.

    💁

    You can view the above info again using wasmer app info.

    Conclusion

    Congratulations! You have successfully deployed your python flask application on Wasmer Edge.

    Resources

    wasmerio/python-flask-server-myapp-example
    React Static SiteUsing Wasmer Edge as a CDN