Use span's recordException to record Errors

[MichaelDoyle]

This follows the recommendations of Open Telemetry and will solve two outstanding issues for us.

1. Currently stacktraces are not appearing in Cloud Trace.
2. We need a nice normalized message and stacktrace for the dev ui.

Genkit Trace Store (AFTER)

"status": {
  "code": 2,
  "message": "Error: Got an error!"
 },
"timeEvents": {
  "timeEvent": [
    {
      "time": 1714531849038.1628,
      "annotation": {
        "attributes": {
          "exception.type": "Error",
          "exception.message": "Got an error!",
          "exception.stacktrace": "Error: Got an error!\n    at /Users/michaeldoyle/repos/src/genkit/js/samples/dev-ui-gallery/lib/main/flows.js:148:23\n    at Context.<anonymous> (/Users/michaeldoyle/repos/src/genkit/js/flow/lib/context.js:71:27)\n    at Generator.next (<anonymous>)\n    at /Users/michaeldoyle/repos/src/genkit/js/flow/lib/context.js:36:61\n    at new Promise (<anonymous>)\n    at __async (/Users/michaeldoyle/repos/src/genkit/js/flow/lib/context.js:20:10)\n    at Context.memoize (/Users/michaeldoyle/repos/src/genkit/js/flow/lib/context.js:67:12)\n    at Context.<anonymous> (/Users/michaeldoyle/repos/src/genkit/js/flow/lib/context.js:105:58)\n    at Generator.next (<anonymous>)\n    at /Users/michaeldoyle/repos/src/genkit/js/flow/lib/context.js:36:61"
        },
        "description": "exception"
      }
    }
  ]
}

Cloud Trace (BEFORE)

Caught Errors

Uncaught Errors

Cloud Trace (AFTER)

Caught Errors

Uncaught Errors

[pavelgj]

Oh, I just noticed the screenshots... this allows errors to be rendered nicely in Cloud Tracing?

[MichaelDoyle]

Oh, I just noticed the screenshots... this allows errors to be rendered nicely in Cloud Tracing?

It does. 😄 I talked to Kman yesterday about recording exceptions and apparently this was the expected behavior, but maybe got lost in the shuffle somewhere. I am going to run this by him just to make sure it matches his expectations.

One thing I am not 💯 on is that telemetry also has a concept of recording exceptions (via logging); not sure if there is any interplay between that and the trace data.