GitHub Action using ImageMagick: Create a PNG and commit it to the repo

[KasparJohannesSchneider]

I asked this question earlier today on Stack Overflow, however, I think it fits better here…

Background
I’m maintaining a forked repository that contains a LaTeX project. The README.md contains a .png preview of the .pdf, compiled from the example .tex file included in the repo. I often forget to update the .png version using the following ImageMagick command:

    magick convert -density 1200 -background white -alpha off Twenty-Seconds-Icons_cv.pdf -quality 90 Twenty-Seconds-Icons_cv.png

Thus I would like to automate this process using GitHub Actions.

Workflow
I think the main.yml file should look something like this, however, I don’t fully understand what I am doing.

name: PDF to PNG
on:
  push:
    branches:
      - kaspar
  pull_request:
    branches:
      - kaspar
jobs:

build:

runs-on: ubuntu-latest

steps:

- name: Install ImageMagick

run: sudo apt install imagemagick # Seems to work and already be included with ubuntu-latest...

- name: Convert PDF to PNG

run: # How?

- name: Commit the updated PNG

run: # How?

Output:

Run sudo apt install imagemagick
  sudo apt install imagemagick
  shell: /usr/bin/bash -e {0}
WARNING: apt does not have a stable CLI interface. Use with caution in scripts.
Reading package lists...

Building dependency tree...

Reading state information...

imagemagick is already the newest version (8:6.9.10.23+dfsg-2.1ubuntu11.2).

0 upgraded, 0 newly installed, 0 to remove and 0 not upgraded.

Questions
It seems like this should be a pretty basic task, therefore, I would prefer to do everything from the main.yml file without creating a separate repository for this action, if possible.

1. It seems like I can just run bash shell commands with run: ; is this true?
2. How/where can I access the .pdf file in the repo from inside the GitHub Actions Ubuntu machine?
3. Where should I save the .png file, is there a ~ directory?
4. How can I commit the .png file generated by ImageMagick to the repo?
5. Would git commit <file> -m "updated png version of the CV" work?

[KasparJohannesSchneider]

It seems like I figured out the/a solution myself.
I would be very thankful for feedback (code review) since my experience with GitHub Actions is very limited…

name: PDF to PNG
on:
  push:
    branches:
      - kaspar
  pull_request:
    branches:
      - kaspar
jobs:

build:

runs-on: ubuntu-latest

steps:

- uses: actions/checkout@v2

- name: Install ghostscript

run: sudo apt install ghostscript

- name: Change ImageMagick security policy

run: |

DQT='"'

SRC="rights=${DQT}none${DQT} pattern=${DQT}PDF${DQT}"

RPL="rights=${DQT}read|write${DQT} pattern=${DQT}PDF${DQT}"

sudo sed -i "s/$SRC/$RPL/" /etc/ImageMagick-6/policy.xml

- name: Convert PDF to PNG

run: convert -density 900 -background white -alpha off Twenty-Seconds-Icons_cv.pdf -quality 90 Twenty-Seconds-Icons_cv.png

- name: Commit PNG

id: commit

run: |

git config --local user.email "action[bot]@github.com"

git config --local user.name "github-actions[bot]"

git add Twenty-Seconds-Icons_cv.png

if [-z "$(git status --porcelain)"]; then

echo "::set-output name=push::false"

else

git commit -m "[bot] updated Twenty-Seconds-Icons_cv.png"

echo "::set-output name=push::true"

fi

shell: bash

- name: Push Commit

if: steps.commit.outputs.push == 'true'

uses: ad-m/github-push-action@master

with:

github_token: ${{ secrets.SECRET_TOKEN }}

What I was doing wrong:

• I did not checkout the repository
• ghostscript was missing 👻
• The security policy for ImageMagic needs to be edited for it to process PDFs 😠
• On Ubuntu the ImageMagick command doesn’t work for 1200 dpi (900 is ok in my case), on Windows, this works just fine 🤷‍♂️t2:
• I found out how to commit and push

[junguler]

i was going insane trying to figure out how to use imagemagick in github actions, literally hours wasted and 100 of failed commits/runs in private repos, this really helped me so thank you