SNS to Slack via Lambda

slack-sns.js

const https = require("https");
const util = require("util");

const SLACK_WEBHOOK_PATH = process.env.SLACK_WEBHOOK_PATH;
const SLACK_CHANNEL = process.env.SLACK_CHANNEL;
const SLACK_USERNAME = process.env.SLACK_USERNAME || "aws";
const SLACK_EMOJI = process.env.SLACK_EMOJI || ":aws:";

function noop (ret) {
    if (ret) {
        return ret;
    }
}

function notifySlack (payload) {
  var options = {
      method: "POST",
      hostname: "hooks.slack.com",
      port: 443,
      path: SLACK_WEBHOOK_PATH
  };

  var req = https.request(options, function (res) {
    res.setEncoding("utf8");
    res.on("data", noop);
  });

  req.on("error", function (e) {
    console.log("[ERROR] Problem with request: " + e.message);
  });

  req.write(util.format("%j", payload));
  req.end(function () {
    console.log("Done.");
  });
}

exports.handler = function (event, context, callback) {
  (event.Records || []).forEach(function (rec) {
    if (rec.Sns) {
      notifySlack({
          "channel": SLACK_CHANNEL,
          "username": SLACK_USERNAME,
          "text": "*" + rec.Sns.Subject + "* - " + rec.Sns.Message,
          "icon_emoji": SLACK_EMOJI,
          "mrkdwn": true
      });
    }
  });
};