Report unhandledRejections and uncaughtExceptions to Sentry (#17014)

* Report to Sentry in error handlers

* Support optional metadata

lib/failbot.js

@@ -76,7 +76,7 @@ module.exports = class FailBot {
    * @param {Error} error
    * @param {any} metadata
    */
-  async sendException (error, metadata) {
+  async sendException (error, metadata = {}) {
     const data = Object.assign({ app: this.app }, this.getFailbotContext(), metadata)
     const body = this.formatJSON(error, Object.assign({ app: this.app }, data))
 

lib/handle-exceptions.js

@@ -1,8 +1,16 @@
-process.on('uncaughtException', err => {
+const FailBot = require('./failbot')
+
+process.on('uncaughtException', async err => {
   if (err.code === 'MODULE_NOT_FOUND') {
     console.error('\n\n🔥 Uh oh! It looks you are missing a required npm module.')
     console.error('Please run `npm install` to make sure you have all the required dependencies.\n\n')
   }
 
   console.error(err)
+  await FailBot.report(err)
+})
+
+process.on('unhandledRejection', async err => {
+  console.error(err)
+  await FailBot.report(err)
 })