TypeError: Cannot read property 'message' of undefined

[skeetmtp]

Hello,

Got this Unhandled Rejection:

TypeError: Cannot read property 'message' of undefined
at TracerStore._handleErrors (packages/montiapm:agent/lib/tracer/tracer_store.js:64:51)
at TracerStore.addTrace (packages/montiapm:agent/lib/tracer/tracer_store.js:32:10)
at MethodsModel.processMethod (packages/montiapm:agent/lib/models/methods.js:83:20)
at Session.sessionProto.send (packages/montiapm:agent/lib/hijack/wrap_session.js:158:31)
at Session.kadira_Session_send [as send] (packages/montiapm:agent/lib/hijack/set_labels.js:9:25)
at packages/ddp-server/livedata_server.js:940:16

with
monti-apm-agent v2.49.3
cult-of-coders/redis-oplog latest

Error not occurred often, but make us a bit uncomfortable enabling monti apm by default

[zodern]

Thanks for reporting this @skeetmtp. I'm not finding a way that the agent could store an undefined error in the trace. Do you use any trace filters (Kadira.tracer.addFilter/Monti.tracer.addFilter), or manually add events to the trace (Kadira.tracer.event/Monti.tracer.event)?

[skeetmtp]

Hello,

Nop, I cannot find any occurence of "tracer.addFilter" or "tracer.event" in our codebase

[zodern]

I released version 2.49.4 to handle invalid errors in traces, though I'm still not sure why it is happening.

If you set the env var DEBUG to kadira:ts, it will log a message when this happens: trace does not have valid error along with the full trace.

[brianlukoff]

We just saw the same thing (also using redis-oplog, but the Meteor 3 branch), using the 3.0.0-beta.4 version of montiapm:agent. Unfortunately it has only happened once and only in production so we haven't been able to catch it with debug logging.

We do use addFilter but only to redact sensitive parameters:

  Monti.tracer.addFilter((eventType, data, { type: traceType, name: traceName }) => {
    delete data.params;
    return data;
  });
  
  Monti.tracer.addFilter((eventType, data) => {
    delete data.selector;
    return data;
  });