puller.js

global.XMLHttpRequest = require("xmlhttprequest").XMLHttpRequest;

const Octokit = require('@octokit/rest');

exports.openMergeRequest = () => {
    const octokit = new Octokit({
        auth: `token ${process.env.GITHUB_TOKEN}`
    });
    return octokit.pulls.create({
        owner: process.env.baseRepoOwner,
        repo: process.env.repoName,
        head: `${process.env.headRepoOwner}:${process.env.headRepoBranch}`,
        base: process.env.baseRepoBranch,
        title: 'Automatic syncing pull request',
        body: `Automatic syncing pull request for ${new Date()}`,
        maintainer_can_modify: false
    });
};

exports.handleError = error => {
    if (error.name === "HttpError" &&
        error.status === 422 &&
        error.errors) {
        let message = error.errors[0].message;
        if (message.includes('No commits between'))
            return {
                status: 'Success',
                message: 'No new commits found'
            };
        else if (message.includes('A pull request already exists'))
            return {
                status: 'Success',
                message: 'A pull request already exists'
            };
        else
            return error;
    } else
        return error;
};

exports.puller = async () => {
    const openMergeRequest = exports.openMergeRequest;
    const handleError = exports.handleError;

    console.log(`Trying to open a pull request on repository ${process.env.repoName} from ${process.env.headRepoOwner}:${process.env.headRepoBranch} to ${process.env.baseRepoOwner}:${process.env.baseRepoBranch}`);

    return openMergeRequest()
        .then(() => {
            const message = {
                status: 'Success',
                message: 'Pull request created'
            };
            console.log(message);
            return message;
        })
        .catch(error => {
            const message = handleError(error);
            console.log(message);
            return message;
        });
};