rails.request.exceptions also reports intended exceptions

[OleMchls]

Hey there,

so we just found some strange exceptions in our graphs. After digging into it, I found that actually when Rails raise RecordNotFound, error it will also appear in our graphs as rails.request.exceptions which is somehow technically right.

As you can see here

librato-rails/lib/librato/rails/subscribers/controller.rb

Line 23 in 139423b

exception = event.payload[:exception]

exception is :exception=>["ActiveRecord::RecordNotFound", "Couldn't find Design with 'id'=276"]

But then Rails answers the HTTP request with a HTTP 404 which is again correct. But I do not have any other graph indicating exceptions. So what I miss is a way to graph all exceptions which actually cause our system to fail.

Any ideas? Thoughts?

[nextmat]

Hmm. Yes, this is a tricky issue because what we are reporting is the number of exceptions that are bubble out of a controller actions to the layer above. The global exception handlers for things like RecordNotFound are above the instrumented layer, so they appear in that count.

Did you write your own handler for the RecordNotFound exceptions or are you using the default Rails one?

[OleMchls]

We rely on the default Rails implementation. As a work around we're using rails.request.exceptions for now. But in general I'd like to have a metric for actual failures. Maybe something like bugsnack or new relic tracking. I guess they are just trapping a exit or a exception which causes the process to fail.

[nextmat]

Does rack.request.exceptions give you a more accurate number?

[OleMchls]

More accurate? - maybe.
Correct? - I don't know.

But! The RecordNotFound exceptions are not included, that is what I know
for sure :D But it feels more like a workaround, but at least fixes my
problem for now.

On Thu, Jul 31, 2014 at 12:16 AM, Matt Sanders [email protected]
wrote:

Does rack.request.exceptions give you a more accurate number?

—
Reply to this email directly or view it on GitHub
#87 (comment)
.

[OleMchls]

What do you mean with accurate? It's more like what I would expect. Even if
I still don't know what it tracks exactly. But I've checked and at least
the RecordNotFound errors are not tracked by that :)

On Thursday, July 31, 2014, Matt Sanders [email protected] wrote:

Does rack.request.exceptions give you a more accurate number?

—
Reply to this email directly or view it on GitHub
#87 (comment)
.

[nextmat]

Right, so rack.request.exceptions gives you the number of exceptions that reach the middleware stack (and aren't caught in it), so it should include exceptions that aren't being handled by rails. Sounded like that might be more what you wanted.

[OleMchls]

True, but then I'd propose for this gem to get rid of rails.request.exceptions because it submits falsy values, and as of rack.request.exceptions is anyway part of this gem it won't confuse future users 😉

[nextmat]

@jderrett @kellym any thoughts on this?

[nextmat]

Just following up on this after lots of thought. I'd like to drop reporting this entirely in our next major ver as I think it does more harm than good. /cc @chancefeick @bdehamer