Re: [opensource-dev] HTTP asset fetching will soon be mandatory

[Henri Beauchamp]

On Mon, 29 Oct 2018 17:59:13 -0400, Oz Linden (Scott Lawrence) wrote:

> On 2018-10-19 09:52 , Henri Beauchamp wrote:
>
> > My viewer has long been updated to make use of the newest HTTP fetching
> > capabilities, but it also implements an automatic fallback to UDP fetches
> > when HTTP ones fail (i.e. a texture failing to be served via HTTP is
> > automatically re-requested using UDP).
>
> Better to requeue the request to HTTP after a suitable backoff (unless 
> of course you get a error that indicates that a retry would not work).

The fallback happens only for unrecoverable errors, of course (for other
errors the HTTP retry policy is used)...

> > Also, will AIS be made mandatory or will the non-AIS HTTP inventory
> > operations still be available ?  The reason for this question is that
> > AIS is still suffering failures from time to time, and the only solution
> > in that case is to disable it (or restart the sim)...
>
> The effort to disable the UDP inventory operations is separate;

Well, the effort should concentrate on making AIS3 operations reliable,
because so far, they never have been. I'm still getting 400 errors from
time to time, causing failures to update the inventory when they happen
(which in turn may cause rezzing failures, when it affects the COF).

As long as AIS3 is not 100% reliable, I would strongly advise *NOT* to
disable UDP inventory operations...

> but if there are UDP inventory operations you're using now that can be
> done through AIS, then you should be making those changes.

This has been implemented years ago in my viewer, so I'm not worried
about the code changes (already done) but only about the reliability
of inventory ops for the end user...

Henri.
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Re: [opensource-dev] HTTP asset fetching will soon be mandatory

[John Nagle]

On 10/30/2018 02:42 AM, Henri Beauchamp wrote:
> On Mon, 29 Oct 2018 17:59:13 -0400, Oz Linden (Scott Lawrence) wrote:
> 
>> On 2018-10-19 09:52 , Henri Beauchamp wrote:
>>
>>> My viewer has long been updated to make use of the newest HTTP fetching
>>> capabilities, but it also implements an automatic fallback to UDP fetches
>>> when HTTP ones fail (i.e. a texture failing to be served via HTTP is
>>> automatically re-requested using UDP).
>>
>> Better to requeue the request to HTTP after a suitable backoff (unless
>> of course you get a error that indicates that a retry would not work).
> 
> The fallback happens only for unrecoverable errors, of course (for other
> errors the HTTP retry policy is used)...

 I see 404 errors for capabilities frequently in Firestorm logs.
This shows up at region crossings as the viewer is fetching info
from the sim being entered. This may be a race condition, and
retrying may help.  Dropping to UDP probably isn't helpful.

 Asset fetches sometimes fail with 5xx errors indicating
problems with the CDN system caches.  When you ask the CDN
for an asset, you're really talking to (I think) a Nginx cache
server, which requests the asset from AWS. If the cache to AWS
request isn't filled quickly, you get a bogus error from the
cache system.  I've seen this occasionally.

 So I'd suggest retrying a few more times, at maybe 1 second,
on what look like hard errors on any URL that the sim gives you.
They're supposed to be valid URLs, after all.

John Nagle
Animats resident


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