async-flush.js

const Sentry = require("@sentry/node");

const DELIVERY_TIME = process.argv[2];
const TIMEOUT = process.argv[3];

console.log(`\nDelivery time: ${DELIVERY_TIME / 1000}s`);
console.log(`Timeout: ${TIMEOUT / 1000}s`);

// @ignore-start Helper function
async function sleep() {
  let i = 1;
  const log = setInterval(
    () => (console.log(`Delivery takes ${i}s...`), i++),
    1000
  );

  return new Promise(resolve =>
    setTimeout(() => {
      clearInterval(log);
      resolve();
    }, DELIVERY_TIME)
  );
}

class SlowNetwork extends Sentry.Transports.BaseTransport {
  async captureEvent(event) {
    // Simulating a long delivery time
    await sleep();
    console.log("\n", event);
    return {
      status: "success"
    };
  }
}
// @ignore-end

Sentry.init({
  dsn: "https://example@sentry.io/1337",
  transport: SlowNetwork,
  async beforeSend(event) {
    console.log("\nCaught an exception!");
    return event;
  }
});

async function handler() {
  try {
    // Some user-land code
    Sentry.configureScope(scope => scope.setExtra("answer", "42"));
    throw new Error("omg it broke");
  } catch (e) {
    Sentry.captureException(e);

    if (await Sentry.flush(TIMEOUT)) {
      console.log("\nException delivered.\n");
    } else {
      console.log("\nTimeout reached, terminate the process.\n");
      process.exit(1);
    }
  }
}

handler();