Uncaught promise

Describe the bug

Uncaught promise!

There is a rule in Node.JS that you must surround all new Promises with a catch. This is typically done using try ... catch inbetween async await syntax, or using the chainable Promise .catch() interface.

The fact that a promise was created without this structure indicates that the apm node programmer may not have understood a fundamental concept, and therefore you might also want to review all other Promise structures throughout the code, to be thorough about how these are handled.

The side-effect is that while APM is loaded, some redis errors are not catchable, therefore the application cannot recover from failure.

A secondary future effect is that the process may be forced to exit.

{
	"ts": "2019-11-13T21:46:58.039Z",
	"src": "internal/process/warning.js:27:3",
	"error": "(node:19157) UnhandledPromiseRejectionWarning: ReplyError: WRONGTYPE Operation against a key holding the wrong kind of value\n    at parseError (/workspace/projectX/node_modules/redis-parser/lib/parser.js:179:12)\n    at parseType (/workspace/projectX/node_modules/redis-parser/lib/parser.js:302:14)",
	"data": {}
}
{
	"ts": "2019-11-13T21:46:58.040Z",
	"src": "internal/process/warning.js:27:3",
	"error": "(node:19157) UnhandledPromiseRejectionWarning: Unhandled promise rejection. This error originated either by throwing inside of an async function without a catch block, or by rejecting a promise which was not handled with .catch(). (rejection id: 2)",
	"data": {}
}
{
	"ts": "2019-11-13T21:46:58.040Z",
	"src": "internal/process/warning.js:27:3",
	"error": "(node:19157) [DEP0018] DeprecationWarning: Unhandled promise rejections are deprecated. In the future, promise rejections that are not handled will terminate the Node.js process with a non-zero exit code.",
	"data": {}
}

To Reproduce

Steps to reproduce the behavior:

1. Create a Hash by means necessary. HSET a b c
2. Then try to read it with the wrong command, using ioredis library with elastic-apm-node module loaded. GET a
3. Observe error thrown. While it is correct that Redis error should be thrown here, it is INCORRECT that it should be made UNCATCHABLE due to interference by the APM library, resulting in process exit.

Expected behavior

I expect when such an error is thrown, that I can catch and handle it. Like so:

(async () => {
try {
  await redis.hget('a');
}
catch(e) {
  debugger; // should break here, but doesn't (only while APM is loaded)
}
})();

Environment (please complete the following information)

• OS: Linux
• Node.js version: v12.12.0
• APM Server version: N/A
• Agent version: 3.1.0

How are you starting the agent? (please tick one of the boxes)

• Calling agent.start() directly (e.g. require('elastic-apm-node').start(...))
• Requiring elastic-apm-node/start from within the source code
• Starting node with -r elastic-apm-node/start

Additional context

APM is nice. Plz fix. Also we’re a paying elastic enterprise customer (Ancestry)

package.json

    "elastic-apm-node": "^3.1.0",
    "ioredis": "^4.11.2",

[axw]

The fix has been released in v3.2.0.

[ancms2600]

Thank you! ❤️