TSCacheUrlSet callable only once

[traeak]

When chaining plugins together only the first TSCacheUrlSet wins. For cache_range_requests this failure is only printed as a debug.

For cachekey followed by cache_range_requests the result is that only the very first cached range ends up being served for every single subequent range request.

For cache_range_requests followed by cachekey the results could be catastrophic.

As a workaround for this case the cachekey plugin can be used to add the range header to the cache key.

There is an existing api around TSCacheKey which could possibly be extended to accommodate plugins progressively manipulating the cache key.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. Marking it stale to flag it for further consideration by the community.

[bryancall]

The API checks to see if the cache key has already been set (@SolidWallOfCode found this):
https://github.com/apache/trafficserver/blob/master/src/traffic_server/InkAPI.cc#L8096

Please send an email to the mailing list to get approval on changing the API so it can be reset.

When discussing we on the PR/issue scrub we talked about having set/get API and possibly not having the URL be required and just use a string.

[github-actions]

This issue has been automatically marked as stale because it has not had recent activity. Marking it stale to flag it for further consideration by the community.

[traeak]

Changing from url to string would likely be a good idea.