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Getting Started on Okteto Cloud with Python

Okteto Cloud gives instant access to secure Kubernetes namespaces to enable developers to code, build, and run Kubernetes applications entirely in the cloud.

This tutorial will show you how to develop and debug a Python sample application running in Okteto Cloud.

Prerequisites#

Step 1: Deploy the Python Sample App#

Get a local version of the Python Sample App by executing the following commands:

$ git clone https://github.com/okteto/python-getting-started
$ cd python-getting-started

The k8s.yml file contains the Kubernetes manifests of the Python Sample App. Deploy a dev version of the application by executing:

$ kubectl apply -f k8s.yml
deployment.apps "hello-world" created
service "hello-world" created

Log into Okteto Cloud and click on the URL of the application:

Okteto Cloud UI Python

Did you notice that you're accessing your application through an HTTPs endpoint? This is because Okteto Cloud will automatically create them for you when you deploy your application. Cool no ๐Ÿ˜Ž?

Step 2: Create your okteto manifest#

To start developing on the Python Sample App you first need to create an okteto manifest. With the Python Sample App deployed, run the following command to create your okteto manifest:

$ okteto init
This command walks you through creating an okteto manifest.
It only covers the most common items, and tries to guess sensible defaults.
See https://okteto.com/docs/reference/manifest for the official documentation about the okteto manifest.
Use the arrow keys to navigate: โ†“ โ†‘ โ†’ โ†
Select the deployment you want to develop:
โ–ธ hello-world
Use default values

The okteto init command will scan the available deployments in your Kubernetes namespace and ask you to pick one. Select the hello-world deployment. It's the one we deployed on the previous step.

โœ“ hello-world
โœ“ Deployment 'hello-world' successfully analyzed
โœ“ okteto manifest (okteto.yml) created
i Run 'okteto up' to activate your development container

The okteto init command creates the following okteto.yml file:

name: hello-world
command: bash
volumes:
- /root/.cache/pip
sync:
- .:/usr/src/app
forward:
- 8080:8080
reverse:
- 9000:9000

This file defines how to activate a development container for the Python Sample App:

  • name: the name of the Kubernetes deployment you want to put on development mode
  • command: the start command of the development container
  • volumes: a list of paths in your development container to be mounted as persistent volumes. This is useful to persist the pip cache.
  • sync: the folders that will be synchronized between your local machine and the development container
  • forward: a list of ports to forward from your development container
  • reverse: a list of ports to reverse forward from your development container to your local machine

Also, the okteto init command creates a .stignore file to indicate which files shouldn't be synchronized to your development container. This is useful to avoid virtual environments, build artifacts, or git metadata.

Step 3: Activate your development container#

Next, execute the following command to activate your development container:

$ okteto up
โœ“ Persistent volume successfully attached
โœ“ Images successfully pulled
โœ“ Files synchronized
Namespace: cindy
Name: hello-world
Forward: 8080 -> 8080
Reverse: 9000 <- 9000
Welcome to your development container. Happy coding!
cindy:hello-world app>

Working in your development container is the same as working on your local machine. Start the application in development mode by running the following command:

cindy:hello-world app> python app.py
Starting hello-world server...
* Serving Flask app "app" (lazy loading)
* Environment: development
* Debug mode: on
* Running on http://0.0.0.0:8080/ (Press CTRL+C to quit)

Go back to the browser and reload the page to test that your application is running.

Step 4: Develop directly on Okteto Cloud#

Open the app.py file in your favorite local IDE and modify the response message on line 7 to be Hello world from the cluster!. Save your changes.

@app.route('/')
def hello_world():
return 'Hello World from the cluster!'
}

Okteto will synchronize your changes to your development container in Kubernetes. Flask's auto-reloader will detect the changes automatically and restart the application with the new code.

* Detected change in '/usr/src/app/app.py', reloading
* Restarting with stat
Starting hello-world server...
* Debugger is active!
* Debugger PIN: 308-916-374

Go back to the browser and reload the page. Your code changes were instantly applied. No commit, build, or push required ๐Ÿ˜Ž!

Step 5: Debug directly in Okteto Cloud#

Okteto enables you to debug your applications directly from your favorite IDE. Let's take a look at how that works in one of python's most popular IDE's, PyCharm.

For VS Code users, this document explains how to configure the debugger with debugpy.

First, open the project in PyCharm and remove the comments on app.py line 20.

if __name__ == '__main__':
print('Starting hello-world server...')
# comment out to use Pycharm's remote debugger
attach()
app.run(host='0.0.0.0', port=8080)

Second, launch the Remote Debug Server by clicking on the Debug button on the top right. Ensure that the Debug Tool Window shows the Waiting for process connection... message. This message will be shown until you launch your app on the development container shell and it connects to the Debug Server.

Starting hello-world server...
* Serving Flask app "app" (lazy loading)
* Environment: development
* Debug mode: on
* Running on http://0.0.0.0:8080/ (Press CTRL+C to quit)
* Restarting with stat
Starting hello-world server...
Connecting to debugger...

On your local machine, switch to the Debug Tool Window. Once the app connects it will show the connection to the pydev debugger. Press the resume button to let the execution continue.

debugging with Python

Add a breakpoint on app.py, line 10. Go back to the browser and reload the page.

The execution will halt at your breakpoint. You can then inspect the request, the available variables, etc.

breakpoint in Python

Your code is executing in Okteto Cloud, but you can debug it from your local machine without any extra services or tools. Pretty cool no? ๐Ÿ˜‰

Next steps#

Congratulations, you just developed your first application in Okteto Cloud ๐Ÿš€.

Okteto lets you develop your applications directly on Kubernetes. This way you can:

  • Eliminate integration issues by developing in a realistic environment
  • Test your application end to end as fast as you type code
  • No more CPU cycles wasted in your machine. Develop at the speed of the cloud!

Ready to develop your application on Okteto Cloud? Read our step by step tutorial on how to configure an Okteto Pipeline to deploy realistic environments for your application in just one click.

Find more advanced samples with Okteto in this repository or join our #okteto channel in the Kubernetes community Slack to ask questions or share your feedback.