Execute comment from issues and pull requests

Say “hello, world”

You can make GitHub Actions Bot to say “hello, world”.

Post comment below on your issue or pull request.

For shorter, you can use as follows.

@github-actions run

(async () => {
  await postComment("hello, world`");

Introduce this action

Put .github/workflows/comment-run.yml to introduce comment-run.

# .github/workflows/comment-run.yml
name: "Comment run"
    types: [created, edited]

    runs-on: ubuntu-18.04
    - uses: actions/[email protected]
        # 0 indicates all history
        fetch-depth: 0
    - uses: nwtgck/[email protected]
        github-token: ${{ secrets.GITHUB_TOKEN }}
        allowed-associations: '["OWNER"]'

You can introduce comment-run with the following command.

mkdir -p .github/workflows/ && cd .github/workflows/ && wget https://gist.githubusercontent.com/nwtgck/a9b291f6869db42ecc3d9e30d0a0494c/raw/comment-run.yml

After introducing this, create new issue or pull request and post @github-actions run comment.

Comment author who can run scripts

By default, only owner can execute the scripts. You can change allowed-associations: '["OWNER"]' in the yaml above.

Here are examples.

  • allowed-associations: '["OWNER"]'
  • allowed-associations: '["OWNER", "MEMBER"]'
  • allowed-associations: '["OWNER", "COLLABORATOR"]'

Learn more: CommentAuthorAssociation | GitHub Developer Guide

Useful examples

LGTM Image

Post random LGTM image with LGTM.in/g.


@github-actions run

LGTM 👍 ```js (async () => { const res = await fetch("https://lgtm.in/g", { redirect: 'manual' }); const webSiteUrl = res.headers.get('location'); const picUrl = new URL(webSiteUrl); picUrl.pathname = picUrl.pathname.replace("/i/", "/p/"); postComment(`![LGTM](${picUrl.href})`); })(); ```

Update all npm packages

Although Dependabot is useful, sometimes you might think bump all packages up. This comment allows you to do this.

@github-actions run

function exec(cmd) {

// Config
const gitUserEmail = "github-actions[bot]@users.noreply.github.com";
const gitUserName = "github-actions[bot]";
const prBranchName = "comment-run/npm-update";

const baseBranchName = context.payload.repository.default_branch";
exec(`git config --global user.email "${gitUserEmail}"`);
exec(`git config --global user.name "${gitUserName}"`);
exec(`git fetch --all`);
exec(`git checkout ${baseBranchName}`);
exec(`git checkout -b ${prBranchName}`);

const packageJson = JSON.parse(require('fs').readFileSync('package.json'));
const depStr = Object.keys(packageJson.dependencies || {}).join(' ');
const devDepStr = Object.keys(packageJson.devDependencies || {}).join(' ');
exec(`npm i ${depStr} ${devDepStr}`);

exec("git status");
exec("git add package*json");
exec(`git commit -m 'chore(deps): update npm dependencies'`);
exec(`git push -fu origin ${prBranchName}`);

(async () => {
  await githubClient.pulls.create({
    base: baseBranchName,
    head: prBranchName,
    owner: context.repo.owner,
    repo: context.repo.repo,
    title: "chore(deps): update npm dependencies",
    body: "update npm dependencies",

PR merge preview

GitHub Actions do not pass secrets to pull request from forked repositories. This security feature may restricts GitHub Actions usages. This comment is created to resolve the problem

@github-actions run

🚀 Merge preview ```js (async () => { // Get pull-req URL like "https://api.github.com/repos/nwtgck/actions-merge-preview/pulls/4" const pullReqUrl = context.payload.issue.pull_request.url; const githubUser = context.payload.repository.owner.login; const res = await fetch(pullReqUrl, { headers: [ ['Authorization', `Basic ${Buffer.from(`${githubUser}:${githubToken}`).toString('base64')}`] ] }); const resJson = await res.json(); const prUserName = resJson.head.user.login; const baseBranchName = resJson.base.ref; const branchName = resJson.head.ref; const fullRepoName = resJson.head.repo.full_name; const previewBranchName = `actions-merge-preview/${prUserName}-${branchName}`; execSync(`git config --global user.email "github-actions[bot]@users.noreply.github.com"`); execSync(`git config --global user.name "github-actions[bot]"`); // (from: https://stackoverflow.com/a/23987039/2885946) execSync(`git fetch --all`); console.log(execSync(`git checkout ${baseBranchName}`).toString()); console.log(execSync(`git checkout -b ${previewBranchName} ${baseBranchName}`).toString()); console.log(execSync(`git pull https://github.com/${fullRepoName}.git ${branchName}`).toString()); // Push preview branch // NOTE: Force push (should be safe because preview branch always start with "actions-merge-preview/") execSync(`git push -fu origin ${previewBranchName}`); const baseRepoFullName = context.payload.repository.full_name; // Create GitHub client const githubClient = new GitHub(githubToken); // Comment body const commentBody = `🚀 Preview branch: n`; // Comment the deploy URL await postComment(commentBody); })(); ```

SSH in GitHub Actions over Piping Server

This comment allows you to go inside of GitHub Actions environment.

SSH over Piping Server

SSH over Piping Server terminal

@github-actions run

🌐 SSH debug over Piping Server ```js (async () => { const pathLen = 64; const aPath = randomString(pathLen); const bPath = randomString(pathLen); console.log(execSync(` chmod 755 "$HOME" ls -lA /home authorized_keys_file="$(sshd -T 2>/dev/null | grep -E '^authorizedkeysfile ' | cut -d ' ' -f 2)" authorized_keys_file="$(cd && realpath -m "$authorized_keys_file")" sshd_config_dir="$(dirname "$authorized_keys_file")" (umask 0077 && mkdir "$sshd_config_dir") echo $authorized_keys_file; # (from: https://qiita.com/zackey2/items/429c77e5780ba8bc1bf9#authorized_keys%E3%81%AB%E8%A8%AD%E5%AE%9A%E3%81%99%E3%82%8B%E6%96%B9%E6%B3%95) (echo; curl https://github.com/nwtgck.keys; echo) >> ~/.ssh/authorized_keys sudo apt install -y socat; `).toString()); // Comment new session const commentBody = ` ## 🌐 New SSH session Run the commands below in different terminals. ```bash socat TCP-LISTEN:31376 'EXEC:curl -NsS https\://ppng.io/${bPath}!!EXEC:curl -NsST - https\://ppng.io/${aPath}' ``` ```bash ssh-keygen -R '[localhost]:31376' ssh -p 31376 [email protected] ``` `; await githubClient.issues.createComment({ issue_number: context.issue.number, owner: context.repo.owner, repo: context.repo.repo, body: commentBody }); execSync(`socat 'EXEC:curl -NsS https\://ppng.io/${aPath}!!EXEC:curl -NsST - https\://ppng.io/${bPath}' TCP:`); })(); // (from: https://stackoverflow.com/a/1349426/2885946) function randomString(length) { let result = ''; const characters = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789'; const charactersLength = characters.length; for ( var i = 0; i < length; i++ ) { result += characters.charAt(Math.floor(Math.random() * charactersLength)); } return result; } ``` ## References * ) * Thanks Cryolite!

TIPS: Saved replies

“Saved replies” fits this action very much.

Saved replies

You can save “Saved replies” as follows.

Avatar icon > Settings > Saved replies

TIPS: Run other languages

This action supports shebang (#!), so you can run shell and Python as follows.

@github-actions run

#! /bin/sh
pip install numpy

#! /usr/bin/python
import numpy as np

print(np.array([1, 2, 3]))

Here are examples.

TIPS: Use existing package, TypeScript and manage on GitHub

When your comment-run scripts are matured, you might want to use TypeScript for maintainability.
The following repository uses existing npm packages and TypeScript.


Built bundle .js files are hosted on GitHub Pages. So, your comment will be as follows.

@github-actions run

(async () => {
  const url = "https://nwtgck.github.io/comment-run-scripts/hello-world-comment.js";
  const js = await (await fetch(url)).text();

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