Getting Started on Okteto Cloud with Python

Okteto Cloud gives you free access to secure Kubernetes namespaces, fully integrated with remote development capabilities. Develop your Kubernetes applications in Okteto Cloud and forget about slow and tedious local development forever.

This tutorial will show you how to create an account in Okteto Cloud and how to develop a Python sample application.

Prerequisites

Step 1: Deploy the Python Sample App

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

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$ 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:

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

Open your browser and go to the URL of the application. You can get the URL by logging into Okteto Cloud and clicking on the application’s endpoint:

Did you notice that you are 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 😎?

Step 2: Start your remote development environment

We are going to use the dev version of the Python Sample App we just deployed as our remote development environment. To do that, run the following command:

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$ okteto up
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 ✓  Development environment activated
✓ Files synchronized
Namespace: cindy
Name: hello-world
Forward: 8080 -> 8080
5678 -> 22
Reverse: 3500 <- 3500

Welcome to your development environment. Happy coding!
okteto>

The okteto up command starts a remote development environment, which means:

  • The Python Sample App container is updated with the docker image okteto/python:3. This image contains the required dev tools to build, test, debug and run a Python application.
  • A file synchronization service is created to keep your changes up-to-date between your local filesystem and your application pods.
  • Container port 8080 (the application) is forward to localhost.
  • Container post 3500 (the debugger) is reverse forwarded to localhost.
  • A remote shell is started in your Kubernetes development environment. Build, test and run your application as if you were in your local machine.

All of this (and more) can be customized via the okteto.yml manifest file. You can also use the file .stignore to skip files from file synchronization. This is useful to avoid synchronizing virtual environments or git metadata.

Working in your remote development environment is the same as working on your local machine. You first create your virtual environment using the remote shell:

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okteto> python3 -m venv venv

Activate it:

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okteto> source venv/bin/activate

Install your pip dependencies:

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(venv)okteto> pip install -r requirements.txt

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Collecting Click==7.0 (from -r requirements.txt (line 1))
Downloading https://files.pythonhosted.org/packages/fa/37/45185cb5abbc30d7257104c434fe0b07e5a195a6847506c074527aa599ec/Click-7.0-py2.py3-none-any.whl (81kB)
...

Using a virtual environment in your development environment has two great benefits: You don’t need to rebuild your docker image every time you add new dependencies, and the virtual environment will be cached and restored automatically when you relaunch your development environment.

And then start the application:

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

Step 3: Develop directly in 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.

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

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

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 * Detected change in '/okteto/app.py', reloading
* Restarting with stat
Starting hello-world server...
* Debugger is active!
* Debugger PIN: 281-298-026

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

Step 4: 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.

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

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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 remote shell and it connects to the Debug Server.

Finally, stop and star the app again:

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(venv)okteto> python app.py

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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.

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.

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? 😉

Next steps

Congratulations, you just developed your first Kubernetes application in Okteto Cloud 🚀.

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

  • Reduce local setup and eliminate integration issues by developing the same way your application runs in production
  • Test your application as fast as you type code, without typing either docker or kubectl in your inner loop cycle
  • No more CPU cycles wasted in your machine. Hardware and network just limited by the power of the cloud

Okteto uses the okteto.yml file to determine the name of your development environment, the docker image to use and where to upload your code. Check the Okteto manifest docs to customize your development environments with your own dev tools, images, and dependencies to adapt Okteto to your own application.

Don’t forget to join our #okteto channel in the Kubernetes community Slack. Sign up here if you don’t have a Kubernetes slack account.