test-node-top-level-failure-handles

[colinwilliams91]

Describe the Problem

In production, the app should have a few different avenues to gracefully fail (log, resume/restart)
top-level path: src\index.ts

Describe the Proposed Solution

In the "references" section there are 3 different process.on event listeners/handlers. Consider them from top to bottom ordered like this: 1, 2, 3

1. uncaughtExceptionMonitor

• create custom monitor class here that will handle application recover or restart from unhandled critical failure...

2. unhandledRejection

• implement application logging (just the invocations if Monitor class is robust enough), throwing an error, or other logic

3. uncaughtException

• test where fs.writeSync is outputting to, set up debugger/developer log directory...

References

/////////////////////////////////////////////////////////
///// #region top-level node critical-failure catch /////
process.on('uncaughtExceptionMonitor', (err, origin) => {
  console.error(`Critical failure, propagated to top-level from ${origin}, error: `, err);
  /* TODO: create custom monitor class here that will handle application recover or restart from unhandled critical failure... */
});

process.on('unhandledRejection', (reason, promise) => {
  console.log('Unhandled Rejection at:', promise, 'reason:', reason);
  /* TODO: application logging, throwing an error, or other logic here (bubbled up unhandled promises) */
});

process.on('uncaughtException', (err, origin) => {
  console.error("Critical Error -- app is about to explode... \n performing synchronous cleanup.. \n writing crash state to log file..");
  fs.writeSync(
    process.stderr.fd,
    `Caught exception: ${err}\n` +
    `Exception origin: ${origin}\n`,
  );
  console.error("goodbye.");
});
/////////////////////////////////////////////////////////
// #endregion ///////////////////////////////////////////