Relands #34785, which was reverted in #34818.
The first commit is the revert. The second commit removes the gtest
dependency from the xds_server library, which should address the
testonly problem internally.
This should address one of the failures we're seeing in #34224.
The test failure is caused by the changes in timing triggering a race
condition. In the code at head, we delay sending out the subscription
for the first CDS watch until we've already seen the other two CDS
watches, because the previous send_message op has not yet completed, and
by the time it does, we've seen all 3 watches, so we can send a
subscription for all 3 at the same time. With the WorkSerializer change,
the send_message op is complete by the time we see the first CDS watch,
so we subscribe to only that resource, and then later add the other two.
The result is that we'll NACK twice with two different messages, the
first one including only the error about the first resource, and the
second one including all three.
I suspect this same race condition would have been triggered eventually
by the EventEngine migration anyway; the current test basically depends
on the single-thread timing of the iomgr approach. So I'm addressing it
by replacing the e2e test with a unit test that covers the same cases
without the timing issue.
This bug occurred when the same xDS server was configured twice in the
same bootstrap config, once in an authority and again as the top-level
server. In that case, we were incorrectly failing to de-dup them and
were creating a separate channel for the LRS stream than the one that
already existed for the ADS stream. We fix this by canonicalizing the
server keys the same way in both cases.
As a separate follow-up item, I will work on trying to find a better way
to key these maps that does not suffer from this kind of fragility.
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* Fix XdsClient for multiple watchers on the same resource
* xds_end2end_test: Don't use XdsCredentials for XdsRbacNackTests
* Use separate response states for EDS and RDS resources
* Reviewer comments
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* Remove blank link
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Eugene Ostroukhov