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Leonardo Montini
Leonardo Montini

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Use Custom Inputs in your GitHub Action

GitHub Actions are a powerful tool to automate your workflow. They can be used to run tests, deploy your code, publish a package, and much more.

The cool thing is, there's a GitHub Actions Marketplace where you can find a lot of actions created by... the community.

But what if you can't find the action you need? You can create your own and publish it there!

How to use this tutorial


In this tutorial we're going to see in detail how to:

  • Create a GitHub Action in Typescript
  • Expand our Action to support custom inputs
  • Integrate with GitHub's API to add labels to Pull Requests
  • Unit testing our action
  • Debugging in Visual Studio Code
  • Publishing our action to the GitHub Marketplace
  • Using our action in another repository
  • Some final touches to make our project more robust

The articles will be split into separate bite-sized chapters as technically each one can be a little tutorial by itself.

If you're interested in the full text all at once, you can find it here:

One more great piece of advice is to create a new repository and follow along with the steps. This way you'll have a working action at the end of the post and you'll be able to play with it and experiment, rather than just reading a long tutorial and forgetting about 90% of it.

The full code of this tutorial is available on GitHub on this repo, so you can always refer to it if you get stuck.

The full tutorial (all chapters at once) is also available as a video, which you can find here:

Chapter 3: Reading inputs

Let's make our action a bit more interesting by reading an input from the workflow.

Add inputs to the action definition

As usual, the first step is to define the input in the action.yml file.

    description: 'The name of the person to greet'
    required: true
    default: 'World'
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Read the input in the action code

Then we can read the input in the action code.

const name = getInput('name');

console.log(`Hello ${name}!`);
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But where does the getInput function come from? It's defined in the @actions/core package, which we need to install.

npm install @actions/core
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And then add the import on top of the index.ts file.

import { getInput } from '@actions/core';
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Update the workflow

Finally, we need to update the workflow to pass the input to the action.

- uses: ./
    name: 'Leonardo'
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By adding the with section, we're passing the name input to the action.

Run the hello action

We can now run the action again and see the input being passed to the action.

Input passed to the action

If it doesn't work (Error: Cannot find module '@actions/core') that's ok, we'll fix it in the next section when we inlude @vercel/ncc in the workflow.


And that was it for today! if you have any question or suggestion, feel free to add a comment :)

See you in the next chapter!

Thanks for reading this article, I hope you found it interesting!

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Top comments (1)

sidswirl profile image
Sid Probstein

Thanks for this!