Small refactor of tests:
- Add a channel to remoteBalancer on which to send received stats messages
- Change runAndGetStats to runAndCheckStats to allow for faster successful test
runs (no longer need to sleep for one whole second per test).
- Remove redundant leak check from runAndCheckStats, otherwise excess load
report messages not read from the channel will result in an infinite loop.
- Add String method to rpcStats to avoid data race between merging and printing.
Keep the drop index from the previous picker when regenerating picker due to
subchannel state change. Only reset the drop index when picker is regenerated
because of a serverlist update.
fixes#2623
This PR splits out grpclb from grpc. I have made the PR in several commits so you can see more clearly the steps that happened.
There are a few possibly contentious points that I would like to make clear up front:
* grpclb will no longer autoload as a load balancer. I think this is okay, as service config is not widely (at all?) used, and I believe this is the only way to access it.
* `internal` is used more, as a way of having code shared between packages without exposing types
* ConnectivityStateEvaluator, as used by grpclb, is no longer thread safe. I believe there is an outer mutex that guards access, but I want to point out this subtle change up here.
All but one tests pass with this, due to another cyclic dependency. I can fix this, but it is a little more widely scoped (such as exposing grpc.server and grpc.errorDesc in the internal package). This PR is a nearly-passing sample of that last step to get this working.
PTAL @menghanl @dfawley
Doug Fawley
Ning Xie
Menghan Li
Carl Mastrangelo