cmd/coordinator,cmd/retrybuilds: add wipe API to coordinator

As part of our migration to combine codebases of the Build Dashboard and
the Coordinator, the first step is to start calling a Coordinator API
for wiping release status of failed builds. This adds a gRPC API to the
coordinator, listening on the same port as the HTTPS listeners.

The Coordinator API in this implementation simply validates and forwards
a request to the dashboard API.

This change also updates cmd/retrybuilds to optionally use the
Coordinator gRPC API for wiping.

Tested locally using the live Dashboard API.

Updates golang/go#34744

Change-Id: I4b34b064625193eb11a280565d701605064a8443
Reviewed-on: https://go-review.googlesource.com/c/build/+/219120
Run-TryBot: Alexander Rakoczy <alex@golang.org>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Carlos Amedee <carlos@golang.org>

cmd/coordinator/coordinator.go

@@ -45,7 +45,9 @@ import (
 	"unicode"
 
 	"go4.org/syncutil"
-	grpc "grpc.go4.org"
+	"golang.org/x/build/cmd/coordinator/protos"
+	"google.golang.org/grpc"
+	grpc4 "grpc.go4.org"
 
 	"cloud.google.com/go/errorreporting"
 	"cloud.google.com/go/storage"
@@ -162,8 +164,9 @@ func listenAndServeTLS() {
 }
 
 func serveTLS(ln net.Listener) {
+	// Support HTTP/2 for gRPC handlers.
 	config := &tls.Config{
-		NextProtos: []string{"http/1.1"},
+		NextProtos: []string{"http/1.1", "h2"},
 	}
 
 	if autocertManager != nil {
@@ -240,6 +243,9 @@ func (fn loggerFunc) CreateSpan(event string, optText ...string) spanlog.Span {
 // autocertManager is non-nil if LetsEncrypt is in use.
 var autocertManager *autocert.Manager
 
+// grpcServer is a shared gRPC server. It is global, as it needs to be used in places that aren't factored otherwise.
+var grpcServer = grpc.NewServer()
+
 func main() {
 	flag.Parse()
 
@@ -293,12 +299,14 @@ func main() {
 
 	addHealthCheckers(context.Background())
 
-	cc, err := grpc.NewClient(http.DefaultClient, "https://maintner.golang.org")
+	cc, err := grpc4.NewClient(http.DefaultClient, "https://maintner.golang.org")
 	if err != nil {
 		log.Fatal(err)
 	}
 	maintnerClient = apipb.NewMaintnerServiceClient(cc)
 
+	gs := &gRPCServer{dashboardURL: "https://build.golang.org"}
+	protos.RegisterCoordinatorServer(grpcServer, gs)
 	http.HandleFunc("/", handleStatus)
 	http.HandleFunc("/debug/goroutines", handleDebugGoroutines)
 	http.HandleFunc("/debug/watcher/", handleDebugWatcher)

cmd/coordinator/protos/coordinator.proto

@@ -0,0 +1,22 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+
+syntax = "proto3";
+
+package protos;
+
+service Coordinator {
+  // ClearResults clears build failures from the coordinator to force them to rebuild.
+  rpc ClearResults(ClearResultsRequest) returns (ClearResultsResponse) {}
+}
+
+// ClearResultsRequest specifies the data needed to clear a result.
+message ClearResultsRequest {
+  // builder is the builder to clear results.
+  string builder = 1;
+  // hash is the commit hash to clear results.
+  string hash = 2;
+}
+
+message ClearResultsResponse {}

cmd/coordinator/protos/protos.go

@@ -0,0 +1,11 @@
+// Copyright 2020 The Go Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style
+// license that can be found in the LICENSE file.
+package protos
+
+// Run "go generate" in this directory to update. You need to have:
+//
+// - a protoc binary (see https://github.com/golang/protobuf#installation)
+// - go get -u github.com/golang/protobuf/protoc-gen-go
+
+//go:generate protoc --proto_path=$GOPATH/src:. --go_out=plugins=grpc:. coordinator.proto