Sends Slack Message by receiving a cloudwatch log identified by a tag

send_slack_message_from_cloudwatch_logs.js

/**
* EXAMPLE: [ONBOARDING]Someone has just signed up!
**/

const https = require('https');
const zlib = require('zlib');

exports.handler = (event, context, callback) => {
  const options = {
    hostname: "hooks.slack.com",
    method: "POST",
    path: "/services/webhook_hash/hash",
  };
  
  let message = "";
  
  if (event.awslogs && event.awslogs.data) {
    const payload = Buffer.from(event.awslogs.data, 'base64');

    const logevents = JSON.parse(zlib.unzipSync(payload).toString()).logEvents;

    for (const logevent of logevents) {
      message += logevent.message; 
    }
  }
  
  if (message === "") {
    return;
  }
  
  const bracketPosition = message.indexOf("]");
  const newMessage = message.substr(bracketPosition + 1);
  const text = newMessage.length < 5 ? message : newMessage;
  
  const payload = JSON.stringify({
    'channel': '#slack-channel',
    'username': 'Platform Bot',
    'text': `*${text}* :partying_face:`,
    'icon_emoji': ':aws:',
    'attachments': []
  });
  
  const req = https.request(options,
      (res) => res.on("data", () => callback(null, "OK")))
  req.on("error", (error) => callback(JSON.stringify(error)));
  req.write(payload);
  req.end();
}