| /* |
| * |
| * Copyright 2022 gRPC authors. |
| * |
| * Licensed under the Apache License, Version 2.0 (the "License"); |
| * you may not use this file except in compliance with the License. |
| * You may obtain a copy of the License at |
| * |
| * http://www.apache.org/licenses/LICENSE-2.0 |
| * |
| * Unless required by applicable law or agreed to in writing, software |
| * distributed under the License is distributed on an "AS IS" BASIS, |
| * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| * See the License for the specific language governing permissions and |
| * limitations under the License. |
| * |
| */ |
| |
| // Package pickfirst contains helper functions to check for pickfirst load |
| // balancing of RPCs in tests. |
| package pickfirst |
| |
| import ( |
| "context" |
| "fmt" |
| "time" |
| |
| "google.golang.org/grpc" |
| "google.golang.org/grpc/peer" |
| "google.golang.org/grpc/resolver" |
| |
| testgrpc "google.golang.org/grpc/test/grpc_testing" |
| testpb "google.golang.org/grpc/test/grpc_testing" |
| ) |
| |
| // CheckRPCsToBackend makes a bunch of RPCs on the given ClientConn and verifies |
| // if the RPCs are routed to a peer matching wantAddr. |
| // |
| // Returns a non-nil error if context deadline expires before all RPCs begin to |
| // be routed to the peer matching wantAddr, or if the backend returns RPC errors. |
| func CheckRPCsToBackend(ctx context.Context, cc *grpc.ClientConn, wantAddr resolver.Address) error { |
| client := testgrpc.NewTestServiceClient(cc) |
| peer := &peer.Peer{} |
| // Make sure that 20 RPCs in a row reach the expected backend. Some |
| // tests switch from round_robin back to pick_first and call this |
| // function. None of our tests spin up more than 10 backends. So, |
| // waiting for 20 RPCs to reach a single backend would a decent |
| // indicator of having switched to pick_first. |
| count := 0 |
| for { |
| time.Sleep(time.Millisecond) |
| if ctx.Err() != nil { |
| return fmt.Errorf("timeout waiting for RPC to be routed to %s", wantAddr.Addr) |
| } |
| if _, err := client.EmptyCall(ctx, &testpb.Empty{}, grpc.Peer(peer)); err != nil { |
| // Some tests remove backends and check if pick_first is happening across |
| // the remaining backends. In such cases, RPCs can initially fail on the |
| // connection using the removed backend. Just keep retrying and eventually |
| // the connection using the removed backend will shutdown and will be |
| // removed. |
| continue |
| } |
| if peer.Addr.String() != wantAddr.Addr { |
| count = 0 |
| continue |
| } |
| count++ |
| if count > 20 { |
| break |
| } |
| } |
| // Make sure subsequent RPCs are all routed to the same backend. |
| for i := 0; i < 10; i++ { |
| if _, err := client.EmptyCall(ctx, &testpb.Empty{}, grpc.Peer(peer)); err != nil { |
| return fmt.Errorf("EmptyCall() = %v, want <nil>", err) |
| } |
| if gotAddr := peer.Addr.String(); gotAddr != wantAddr.Addr { |
| return fmt.Errorf("rpc sent to peer %q, want peer %q", gotAddr, wantAddr) |
| } |
| } |
| return nil |
| } |