This PR refactors xds_client to support multiples watches. Those watches can be for the same type and same resource_name.
There's upper level `Client` and lower level `v2client`. Before this change, all logic was in `v2client`, and `Client` was a thin wrapper.
This PR moves some of the functionality from `v2client` to `Client`. New layers:
- Upper level `Client`
- keeps a list of watchers
- provides method `func WatchXXX() (cancel func())`
- has `WatchService()` which involves `LDS` and `RDS`
- handles resources from the xDS responses and dispatch to the watchers
- including multiple watchers for the same resource_name
- keeps cache
- and checks cache for new watches
- Lower level `v2client`
- is a dumb client that
- manages ADS stream
- sends a new xDS request when add/remove watch
- parses xDS responses
- It doesn't call watchers, but forwards all parsed results to upper Client
- handles ACK/NACK
- supports `addWatch(type, name)` and `removeWatch(type, name)`
- instead of `func watchCDS() func()`, which is now moved up to upper `Client`
Also includes other changes:
- Corresponding test changes (some tests for `v2client` were moved to `Client`)
- Method and type renaming
- CDS/EDS -> Cluster/Endpoints
- callback functions all accept updates as non-pointers
- More logs in xds bootstrap/resolver/cds/eds
- Bootstrap file content/error
- Request/response on ADS stream
- Actions by client/resolver/balancer
- Content of updates
- Logs prefixed with component name and id
- `[xds-bootstrap]`
- `[xds-client <address>]`
- `[cds-lb <address>]`
- `[eds-lb <address>]`
* Modified tests to use tlogger.
* Fail on errors, with error expectations.
* Added expects and MixedCapsed grpclb_config tests
* Moved tlogger to grpctest, moved leakcheck tester to grpctest.go
* Added ExpectErrorN()
* Removed redundant leak checks
* Fixed new test
* Made tlogger globals into tlogger methods
* ErrorsLeft -> EndTest
* Removed some redundant lines
* Fixed error in test and empty map in EndTest
* Add a helper to the fakexds package to return a ClientConn talking to
the fake server.
* Tests will make use of this ClientConn wherever required, or they will
directly pass the fake server's address as the balancerName to the
xdsclient.New() function, thus exercising that code path as well.
* Add grpc.WithTimeout to list in vet.sh
Doug Fawley