This PR removes the xds_client implementation from eds balancer, and replaces it with a xds_client wrapper. (The xds_client wrapper has very similar API as the old xds_client implementation, so the change in the eds balancer is minimal).
The eds balancer currently doesn't look for xds_client from attributes, and always creates a new xds_client. The attributes change will be done in a following up change.
* 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
The xds client will parse the EDS response, and give the parse result to eds balancer, so the balancer doesn't need to deal with proto directly.
Also moved `ClusterLoadAssignmentBuilder` to another pacakge to be shared by tests in different packages.
Generated protobuf messages contain internal data structures
that general purpose comparison functions (e.g., reflect.DeepEqual,
pretty.Compare, etc) do not properly compare. It is already the case
today that these functions may report a difference when two messages
are actually semantically equivalent.
Fix all usages by either calling proto.Equal directly if
the top-level types are themselves proto.Message, or by calling
cmp.Equal with the cmp.Comparer(proto.Equal) option specified.
This option teaches cmp to use proto.Equal anytime it encounters
proto.Message types.
Each priority maps to a balancer group.
When a priority is in use, its balancer group is started, and it will close the balancer groups with lower priorities. When a priority is down (no connection ready), it will start the next priority balancer group.
Fields are added in: https://github.com/grpc/grpc-proto/pull/64
Other changes:
- Move XDSConfig from internal to balancer
- Later we will add a separate config for CDS balancer
- generate service_config.pb.go and test with json generated from proto message
This PR moves the unbounded buffer implementation found in
`scStateUpdateBuffer` to the internal package. It also makes the buffer
work with `interface{}` type.
This addresses a TODO in the existing code. This will also help with the
eventual `BalancerManager` implementation which will supersede the
`ccBalancerWrapper` implementation found in balancer_conn_wrappers.go.
This is necessary because there's another way to select grpclb (by specifying grpclb in service config's balancing policy field). So it's possible that grpclb is picked, but resolver doesn't have any balancer addresses.
When an update without balancer address is received, grpclb closes the underlying ClientConn to remote balancer, and enters fallback mode.
Note that grpclb waits until the ClientConn and the RPC goroutines are actually closed to do the fallback work. This can avoid race caused by async close.
