Re: drop "Resource Error Logging" in favor of failed fetches in Resource Timing?

One potential reason to go with the REL approach is that there is always
the possibility that the resource containing the actual logging code is the
one that failed to load (ie, a failure in your CDN that served javascript).

In addition, I think you want more data than simply timing data -- for
example, if the failure happened in the SSL connection establishment it
could be useful if REL could tell you if it was because of an invalid cert,
if the connection timed out, etc.



On Fri, Oct 17, 2014 at 12:06 AM, Ilya Grigorik <igrigorik@google.com>
wrote:

> Navigation Error Logging [1] captures error data for document navigations
> + provides out-of-band reporting functionality when the page load fails.
> Resource Error Logging [2] provides error data for subresource fetches:
> same ResourceErrorLogging entry, but no automated reporting, just the JS
> API (you can report yourself).
>
> During yesterday's conference call Arvind raised the option of dropping
> Resource Error Logging spec in favor of simply exposing failed fetches as
> part of Resource Timing: you can setup an onload/onerror callback to detect
> failed subresource fetches, and RT would give you enough timing data to
> detect where the fetch has failed.
>
> 1) The RT route is more involved for the developer, as it requires setting
> up callbacks, etc.
> 2) RT route can't distinguish "abandoned" case - e.g. image is loading but
> user hits stop. That's a very different error from a fetch failing midway
> due to other connection errors.
> 3) RT route is much simpler from spec surface perspective...
>
> At the moment my personal preference would be to keep Resource Error
> Logging: simpler and more intuitive for the developer; I think (2) is a
> strong enough reason on its own. That said, curious what others think?
>
> ig
>
> [1]
> http://w3c.github.io/web-performance/specs/NavigationErrorLogging/Overview.html
> [2]
> http://w3c.github.io/web-performance/specs/ResourceErrorLogging/Overview.html
>
>
>
>