cmd/gomoteserver: create gomote server

This change copies the gomote server functionality from the coordinator
into a new server. This will require refactoring after this initial CL.

Updates golang/go#61912
For golang/go#61772

Change-Id: I25ef657f4512d034bdc3e98bf2718e5e768be1c4
Reviewed-on: https://go-review.googlesource.com/c/build/+/519475
Run-TryBot: Carlos Amedee <[email protected]>
Auto-Submit: Carlos Amedee <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>

cmd/gomoteserver/gomoteserver.go

@@ -0,0 +1,164 @@
+// Copyright 2023 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.
+
+//go:build go1.20 && (linux || darwin)
+
+package main
+
+import (
+	"context"
+	"errors"
+	"flag"
+	"fmt"
+	"log"
+	"net/http"
+	"strings"
+	"time"
+
+	"cloud.google.com/go/compute/metadata"
+	"cloud.google.com/go/storage"
+	"golang.org/x/build/buildenv"
+	"golang.org/x/build/internal/access"
+	"golang.org/x/build/internal/coordinator/pool"
+	"golang.org/x/build/internal/coordinator/remote"
+	"golang.org/x/build/internal/coordinator/schedule"
+	"golang.org/x/build/internal/gomote"
+	gomotepb "golang.org/x/build/internal/gomote/protos"
+	"golang.org/x/build/internal/https"
+	"golang.org/x/build/internal/secret"
+	"golang.org/x/build/internal/swarmclient"
+	"google.golang.org/api/option"
+	"google.golang.org/grpc"
+)
+
+var (
+	sshAddr      = flag.String("ssh_addr", ":2222", "Address the gomote SSH server should listen on")
+	buildEnvName = flag.String("env", "", "The build environment configuration to use. Not required if running in dev mode locally or prod mode on GCE.")
+	mode         = flag.String("mode", "", "Valid modes are 'dev', 'prod', or '' for auto-detect. dev means localhost development, not be confused with staging on go-dashboard-dev, which is still the 'prod' mode.")
+)
+
+func main() {
+	log.Println("starting gomote server")
+	flag.Parse()
+	if err := secret.InitFlagSupport(context.Background()); err != nil {
+		log.Fatalln(err)
+	}
+	privateKey := secret.Flag(secret.NameGomoteSSHPrivateKey, "SendGrid API key for workflows involving sending email.")
+	publicKey := secret.Flag(secret.NameGomoteSSHPublicKey, "SendGrid API key for workflows involving sending email.")
+
+	sp := remote.NewSessionPool(context.Background())
+	sshCA := mustRetrieveSSHCertificateAuthority()
+	var sched = schedule.NewScheduler()
+
+	var gomoteBucket string
+	var opts []grpc.ServerOption
+	if *buildEnvName == "" && *mode != "dev" && metadata.OnGCE() {
+		projectID, err := metadata.ProjectID()
+		if err != nil {
+			log.Fatalf("metadata.ProjectID() = %v", err)
+		}
+		env := buildenv.ByProjectID(projectID)
+		gomoteBucket = env.GomoteTransferBucket
+		var coordinatorBackend, serviceID = "coordinator-internal-iap", ""
+		if serviceID = env.IAPServiceID(coordinatorBackend); serviceID == "" {
+			log.Fatalf("unable to retrieve Service ID for backend service=%q", coordinatorBackend)
+		}
+		opts = append(opts, grpc.UnaryInterceptor(access.RequireIAPAuthUnaryInterceptor(access.IAPSkipAudienceValidation)))
+		opts = append(opts, grpc.StreamInterceptor(access.RequireIAPAuthStreamInterceptor(access.IAPSkipAudienceValidation)))
+	}
+	grpcServer := grpc.NewServer(opts...)
+	gomoteServer := gomote.New(sp, sched, sshCA, gomoteBucket, mustStorageClient(), mustLUCIConfigClient())
+	gomotepb.RegisterGomoteServiceServer(grpcServer, gomoteServer)
+
+	mux := http.NewServeMux()
+	mux.HandleFunc("/reverse", pool.HandleReverse)
+	mux.HandleFunc("/", grpcHandlerFunc(grpcServer, handleStatus)) // Serve a status page.
+
+	configureSSHServer := func() (*remote.SSHServer, error) {
+		if *privateKey != "" && *publicKey != "" {
+			return remote.NewSSHServer(*sshAddr, []byte(*privateKey), []byte(*publicKey), sshCA, sp)
+		}
+		if *mode != "dev" {
+			return nil, errors.New("SSH key pair is not configured")
+		}
+		priKey, pubKey, err := remote.SSHKeyPair()
+		if err != nil {
+			return nil, fmt.Errorf("unable to generate development SSH key pair: %s", err)
+		}
+		return remote.NewSSHServer(*sshAddr, priKey, pubKey, sshCA, sp)
+	}
+	sshServ, err := configureSSHServer()
+	if err != nil {
+		log.Printf("unable to configure SSH server: %s", err)
+	} else {
+		go func() {
+			log.Printf("running SSH server on %s", *sshAddr)
+			err := sshServ.ListenAndServe()
+			log.Printf("SSH server ended with error: %v", err)
+		}()
+		defer func() {
+			err := sshServ.Close()
+			if err != nil {
+				log.Printf("unable to close SSH server: %s", err)
+			}
+		}()
+	}
+	log.Fatalln(https.ListenAndServe(context.Background(), mux))
+}
+
+func mustLUCIConfigClient() *swarmclient.ConfigClient {
+	ctx, cancel := context.WithTimeout(context.Background(), 10*time.Second)
+	defer cancel()
+	c, err := swarmclient.NewConfigClient(ctx)
+	if err != nil {
+		log.Fatalf("unable to create LUCI config client: %s", err)
+	}
+	return c
+}
+
+func mustRetrieveSSHCertificateAuthority() (privateKey []byte) {
+	privateKey, _, err := remote.SSHKeyPair()
+	if err != nil {
+		log.Fatalf("unable to create SSH CA cert: %s", err)
+	}
+	return privateKey
+}
+
+func mustStorageClient() *storage.Client {
+	if metadata.OnGCE() {
+		return pool.NewGCEConfiguration().StorageClient()
+	}
+	storageClient, err := storage.NewClient(context.Background(), option.WithoutAuthentication())
+	if err != nil {
+		log.Fatalf("unable to create storage client: %s", err)
+	}
+	return storageClient
+}
+
+func fromSecret(ctx context.Context, sc *secret.Client, secretName string) (string, error) {
+	ctx, cancel := context.WithTimeout(context.Background(), 5*time.Second)
+	defer cancel()
+	return sc.Retrieve(ctx, secretName)
+}
+
+// grpcHandlerFunc creates handler which intercepts requests intended for a GRPC server and directs the calls to the server.
+// All other requests are directed toward the passed in handler.
+func grpcHandlerFunc(gs *grpc.Server, h http.HandlerFunc) http.HandlerFunc {
+	return func(w http.ResponseWriter, r *http.Request) {
+		if r.ProtoMajor == 2 && strings.HasPrefix(r.Header.Get("Content-Type"), "application/grpc") {
+			gs.ServeHTTP(w, r)
+			return
+		}
+		h(w, r)
+	}
+}
+
+func handleStatus(w http.ResponseWriter, r *http.Request) {
+	if r.URL.Path != "/" {
+		http.NotFound(w, r)
+		return
+	}
+	w.Header().Set("Content-Type", "text/plain")
+	fmt.Fprintf(w, "gomote status page placeholder")
+}