5 Strategies for Deploying Python Modules on Heroku

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💡 Problem Formulation: You’ve developed a Python module that runs perfectly on your local machine and now you want to share it with the world by deploying it to a live server. Specifically, you’re looking at using Heroku, a popular platform as a service (PaaS) that enables developers to build, run, and operate applications entirely in the cloud. This article will guide you through the different methods to deploy Python modules on Heroku, from using Git to leveraging Docker containers.

Method 1: Deploy Using Git

Heroku integrates with Git, the popular version control system, for deployment. By creating a Heroku remote and pushing your code, Heroku automatically handles the deployment of your Python module. This method requires you have a ‘Procfile’, a ‘requirements.txt’ file listing your dependencies, and a Heroku account with the Heroku CLI installed.

Here’s an example:

git init
heroku create
echo "python app.py" > Procfile
pip freeze > requirements.txt
git add .
git commit -am "initial heroku commit"
git push heroku master

After running the last command, Heroku takes over, installs your dependencies, and starts your application as specified in your ‘Procfile’.

This process effectively pushes your local Git repository to the Heroku remote, triggering the Heroku platform to fetch all necessary Python dependencies listed in ‘requirements.txt’ and start a web process as outlined in the ‘Procfile’ to run your module.

Method 2: Heroku GitHub Integration

For developers who use GitHub for versioning their projects, Heroku offers a GitHub integration feature. This lets you connect your GitHub repository to your Heroku app and either manually deploy branches or set up automatic deploys whenever you push to a specific branch.

Here’s an example:

# Setup is done on the Heroku Dashboard under the "Deploy" tab of your app
# Choose GitHub as the deployment method
# Connect your GitHub repository
# Enable automatic deploys for your main branch

This method deploys your Python module hosted on GitHub to Heroku without requiring any commands to be executed locally. It simplifies the deployment process and keeps your deployed module up-to-date with your GitHub repository.

Method 3: Using Heroku Buildpacks

Heroku’s buildpacks are sets of scripts that prepare your code for execution on the Heroku platform. For Python applications, Heroku offers an official Python buildpack. You can specify which buildpack to use through the Heroku CLI when creating your app or via the app’s settings in the Heroku dashboard.

Here’s an example:

heroku create myapp --buildpack heroku/python
git push heroku master

Your app will be automatically detected as a Python app and the correct buildpack will be applied. The buildpack compiles your app, resolves dependencies with pip, and prepares it for execution.

Method 4: Container Deployment with Heroku

For applications with more complex dependencies, you can use Docker containers to deploy your Python modules on Heroku. This involves writing a ‘Dockerfile’ that specifies your environment, packaging your application as a container, and using the Heroku Container Registry to deploy.

Here’s an example:

heroku container:login
heroku create
heroku container:push web -a your-app-name
heroku container:release web -a your-app-name

This set of commands logs you into Heroku’s Container Registry, creates a new app, pushes your Docker container to your Heroku app, and then releases the container, making it accessible online.

Bonus One-Liner Method 5: Deploy with Heroku Button

If you want to share your Python module with others in the simplest way possible, you can use the Heroku Button. This requires you to create an ‘app.json’ file defining your module’s dependencies and configurations, but then users can deploy your module to their own Heroku account with a single click.

Here’s an example:

<a href="https://heroku.com/deploy?template=https://github.com/your-repository">
  <img src="https://www.herokucdn.com/deploy/button.svg" alt="Deploy">
</a>

This snippet creates a deploy button using Heroku’s CDN for the button image and links to the template on your GitHub repository.

Summary/Discussion

  • Method 1: Git Deployment. Most straightforward for individuals already using Git. Requires command line knowledge and manual deployment steps. Provides full control over the deployment process.
  • Method 2: GitHub Integration. Ideal for those with projects on GitHub. Enables automatic deployment upon committing, maintaining synchronization between the repository and the deployed application. It may be less flexible for custom deployment flows.
  • Method 3: Buildpacks. Built-in feature of Heroku’s platform. Simplifies deployment without custom configuration. Not suitable for applications with dependencies outside the scope of what the buildpack can handle.
  • Method 4: Container Deployment. Offers flexibility to define custom environments that aren’t possible with buildpacks. Requires Docker knowledge and is more complex than other methods.
  • Method 5: Heroku Button. The simplest method for sharing your app. Best suited when targeting non-technical users who want to deploy your module with minimal effort. It may lack the control needed for complex deployments.