GitHub Actions: How to pass toJSON() result to shell commands

Question

So, I'm working with Github Actions on end-to-end testing. The setup I'm looking at is having one job retrieve a list of urls to be tested, and my second job creates a matrix with that list and tests them all. My problem here is that when I actually run my testing script, it has to be done from the command line, because I'm using Playwright. Therefore I can't use my matrix object directly; I have to output it to a JSON file. The problem is that toJSON creates invalid pretty-printed JSON when I output it to my file, which breaks my script. Here's my code:

name: <name>

on:
    push:
    workflow_dispatch:

jobs:
    fetch_strategic_urls:
        runs-on: ubuntu-latest
        outputs:
            urls: ${{ steps.req-urls.outputs.urls }}
        steps:
            - name: Request Urls
              id: req-urls
              run: |
                  export RESPONSE=$(
                    curl -X GET -H "Accept: application/json" <api-endpoint>)
                  echo "::set-output name=urls::$RESPONSE"
    run_tests:
        runs-on: ubuntu-latest
        strategy:
            matrix:
                url: ${{needs.fetch_strategic_urls.outputs.urls}}
        needs: fetch_strategic_urls
        steps:
            - ...
            - ...
            - run: |
                  ls
                  echo '${{ toJSON(matrix.url) }}' >> props.json
                  cat props.json
                  npm test
              working-directory: E2E.Tests

No matter which configuration of echo ${{matrix.url}} >> props.json I've tried (cat <<'EOF' > props.json ${{matrix.url}}, adding and removing quotes), it always produced JSON files that have no quotes, i.e.: { url: string } instead of {"url": "string"}, which is invalid. This is obviously pretty breaking behavior. I've seen a lot of people online recommending jq, but I don't see how I would use it in this case, since I doubt jq can parse a GitHub-type JSON object, which is necessary for me to use when sharding my jobs. Any help is greatly appreciated!

Please don't just paste your entire YAML, but create a [minimal reproducer](https://stackoverflow.com/help/minimal-reproducible-example) — rethab, Jul 12 '22 at 14:44

pynexj · Accepted Answer · 2022-07-13T04:02:47.580

6

It's not easy to put a JSON doc directly in the command line. You can use env vars.

- shell: bash
  env:
    JSON_DOC: ${{ toJSON(some.var) }}
  run: |
    printf '%s\n' "$JSON_DOC" > foo.json
    cat foo.json
    ...

edited Jul 13 '22 at 04:02

answered Jul 12 '22 at 16:53

pynexj

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This actually worked fantastically, after I spent so long on different solutions. Thank you! – WubbaLubbaDubbDubb Jul 13 '22 at 14:13

score 2 · Answer 2 · answered Oct 28 '22 at 10:13

2

Github actions documenation has a solution here:

name: Context testing
on: push

jobs:
  dump_contexts_to_log:
    runs-on: ubuntu-latest
    steps:
      - name: Dump GitHub context
        id: github_context_step
        run: echo '${{ toJSON(github) }}'

From https://docs.github.com/en/actions/learn-github-actions/contexts#example-printing-context-information-to-the-log

answered Oct 28 '22 at 10:13

alliannas

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this does not work if toJSON() result includes `'` chars. – sexpect - Expect for Shells Apr 16 '23 at 15:36

GitHub Actions: How to pass toJSON() result to shell commands

2 Answers2

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