brigade.js

const { events, Job } = require("brigadier");

// The push event only contains the new commits being pushed. Instead we are
// looking at the pull_request changes, which might be overkill, but provides
// the ability to query all the commits on the PR.
events.on("pull_request", async function(e, project) {

    // The payload is a string we need to parse into JSON to access
    const ghData = JSON.parse(e.payload);

    // Notify GH that 
    var ghn = new Notification("dco-labeler", e, project);
    ghn.text = "Checking for DCO";
    await ghn.run();

    // Get the commits to iterate over
    var cj = new Job(`github-pr-commits`, "mattfarina/github-pr-commits:0.1.0");
    cj.env = {
        GITHUB_REPO: project.repo.name,
        GITHUB_TOKEN: project.secrets.ghToken,
        GITHUB_PR_NUMBER: ghData.number.toString(),
    }
    res = await cj.run();
    var tempJson = JSON.stringify(res.toString());
    tempJson = tempJson.replace(/\\n/g, "\\n")
                .replace(/\\'/g, "\\'")
                .replace(/\\"/g, '\\"')
                .replace(/\\&/g, "\\&")
                .replace(/\\r/g, "\\r")
                .replace(/\\t/g, "\\t")
                .replace(/\\b/g, "\\b")
                .replace(/\\f/g, "\\f");
    const commits = JSON.parse(tempJson);
    const re = /^Signed-off-by: (.*) <(.*)>$/im

    var count = 0, missed = 0;

    for (const {commit, parents} of commits) {
        // Skipping old commits that might be merged in but are not part of this PR.
        const isMerge = parents && parents.length > 1;
        if (isMerge) {
          continue;
        }
      
        var signedOff = re.exec(commit.message);

        if (signedOff === null){
            missed++;
        }
        count++
    }

    // A notification that some were missed
    if (missed > 0) {
        // This is paired with org wide probot DCO checking that will list
        // the commits missing a DCO signoff. We are interested in the label and
        // if this bot is seeing an issue for debugging.
        ghn.text = missed + " out of " + count + " commits are missing signoff";
        ghn.state = "failure";

        // Remove the label if already present
        var j = new Job(`github-label-remover`, "mattfarina/github-label-remover:0.1.1");
        j.env = {
            GITHUB_REPO: project.repo.name,
            GITHUB_ISSUE_LABEL: "Contribution%20Allowed",
            GITHUB_TOKEN: project.secrets.ghToken,
            GITHUB_ISSUE_NUMBER: ghData.number.toString(),
        }
        j.run();
    } else {
        ghn.text = "All commits have signoff";
        ghn.state = "success";

        // Add the label so the bot knows it can merge
        var j = new Job(`github-label-adder`, "mattfarina/github-label-adder:0.1.0");
        j.env = {
            GITHUB_REPO: project.repo.name,
            GITHUB_ISSUE_LABEL: "Contribution Allowed",
            GITHUB_TOKEN: project.secrets.ghToken,
            GITHUB_ISSUE_NUMBER: ghData.number.toString(),
        }
        j.run();
    }
    ghn.run();
})

class Notification {
    constructor(name, e, p) {
        this.proj = p;
        this.e = e;
        this.payload = e.payload;
        this.text = "";

        this.context = name;

        // count allows us to send the notification multiple times, with a distinct pod name
        // each time.
        this.count = 0;

        // One of: "success", "failure", "neutral", "cancelled", or "timed_out".
        this.state = "pending";
    }

    // Send a new notification, and return a Promise<result>.
    run() {
        this.count++
        var j = new Job(`${ this.context }-${ this.count }`, "technosophos/github-notify:1.0.0");
        j.env = {
            GH_REPO: this.proj.repo.name,
            GH_STATE: this.state,
            GH_TOKEN: this.proj.secrets.ghToken,
            GH_COMMIT: this.e.revision.commit,
            GH_DESCRIPTION: this.text,
            GH_CONTEXT: this.context,
        }
        return j.run();
    }
}