Skip to content

gh-actions-parse-json.md

Latest commit

 

History

History
131 lines (96 loc) · 3.99 KB

gh-actions-parse-json.md

File metadata and controls

131 lines (96 loc) · 3.99 KB

Parsing JSON output from a GitHub Issue template in a GitHub Action

Steps:

  • Set up an issue template
  • Set up an action to look at new issues that get created for that template (I do this by looking for a specific label)
  • Parse the issue body into JSON
  • Use the built-in fromJSON method to get specific fields from the JSON

Set up an issue template

This method uses peter-murray/issue-forms-body-parser@v2.0.0, which requires thetemplate for the issue to be set up in a specific way.

The action supports more complex key/value pairs than just {"key": "val"} (like lists, etc) but I have only tried it with URLs.

This is the issue template I use:

# .github/ISSUE_TEMPLATE/new-issue.md
---
name: Add to TBR
about: 'Add a new link to TBR '
title: 'Add [TITLE] to TBR '
labels: tbr
assignees: ''

---

### >>link<<

[LINK]

When someone creates an issue with this template, the issue will:

  • auto-fill the title as Add [TITLE] to TBR
  • auto-fill the body with a header ### >>link<< and a body [LINK].

The user replaces [LINK] with a URL, and [TITLE] in the title of the issue with whatever they want. The user should not change the heading. The >>link<< part is important -- that's how the action we're using will know how to parse the issue into JSON.

Set up an action to look at new issues that get created for that template

This action looks for issues that have been newly opened, or have been newly-labeled.

# .github/workflows/new_issue.yml
name: Process issues

on:
  issues:
    types: [labeled, opened]

jobs:
  create-issue-comment:
    runs-on: ubuntu-latest
    outputs:
      issue_json: ${{ steps.set-json.outputs.issue_json }}

Parse the issue body into JSON

Create a step called parse to parse the issue body using peter-murray/issue-forms-body-parser@v2.0.0.

This example shows why the formatting of the issue template was so important. label_marker_start contains the characters that mark out a new value, and label_marker_end marks the end of that key. Whatever comes after that is the value.

So this issue template:

## >>link<<
https://example.com

Will create this JSON:

{
  "link": "https://example.com"
}

And this yaml add the parse step, then echo the result to the console when the action runs.

jobs:
  create-issue-comment:
    ... 
    steps:
      # Parse the JSON from the issue body
      - name: Parse issue
        id: parse
        uses: peter-murray/issue-forms-body-parser@v2.0.0
        with:
          issue_id: ${{ github.event.issue.number }}
          # These arguments correspond to the formatting in the issue template
          separator: '###'
          label_marker_start: '>>'
          label_marker_end: '<<'

      # Show the parsed JSON
      - name: Show parsed data JSON
        run: |
          echo "${{ steps.parse.outputs.payload }}"

Use the built-in fromJSON method to get specific fields from the JSON

You can introspect the JSON output and access specific fields using the built-in fromJSON method.

The set-json step sets the JSON payload from the parse step as an output using $GITHUB_OUTPUT.

Then the see-link step uses env to run fromJSON on the JSON output from the issue, then runs echo "${link}" to print the link to the console.

I'm going to be totally honest that I don't 100% understand how this works but I know that it does.

jobs:
  create-issue-comment:
    ... 
    steps:
      ... 
      # Save the parsed JSON as output
      - name: Set JSON output 
        id: set-json
        run: echo "issue_json=${{ steps.parse.outputs.payload }}" >> $GITHUB_OUTPUT

      # See the link
      - name: From JSON
        id: see-link
        env: ${{ fromJSON(steps.parse.outputs.payload) }}
        run: echo "${link}"