Best way to identify an http transaction error about go-agent

[willnewrelic]

Hi Dan

I presume you are using WrapHandle and/or WrapHandleFunc and would like to notice an error in one of your handlers? Use type assertion on the http.ResponseWriter:

func noticeError(w http.ResponseWriter, r *http.Request) {
    if txn, ok := w.(newrelic.Transaction); ok {
        txn.NoticeError(errors.New("my error message"))
    }
}

[danbrakeley]

So when I do that, I end up with 2 errors in new relic, not 1.

[willnewrelic]

Disabling the normal http response code error instrumentation (and using NoticeError) will be easier than modifying the agent. I recommend adding the following configuration:

cfg.ErrorCollector.IgnoreStatusCodes = []int{500, 501} // and any other codes

I understand the friction here: It would be nice to easily add some "why" context to the automatically captured response code errors. We will contemplate this.

[danbrakeley]

Excellent, that was what I was trying to get at. I was about to ask if there was a way to disable the default status code error. Thanks, I'll try that now!

[danbrakeley]

@willnewrelic Hmm, on second thought, this sucks. If I want to never have those errors fire, I need to list all 400 and 500 status codes?

Alternatively, I can add my error to the current transaction via AddAttribute, and in the new Error Analytics view, I can click on that custom attribute to get a listing by count of each error string. That seems like the best solution so far.

[willnewrelic]

Understood. A setting to disable status code errors entirely would be great here. We will discuss this.

Happy to hear the attribute/error-analytics approach is working!

[lpetre]

Are you suggesting a way to disable the status code errors per-transaction or globally?

[willnewrelic]

@lpetre Considering anything and everything! A transaction method for per-transaction disabling would be more powerful, but a global config setting in the Config would be simpler for customers that want to always have it disabled.