cmd/gomote: list swarming builders on create

If a create is issued without a gomote instance type, the gomote
client will query the gomote server for all available instance types.
This adds the ability to query for swarming builder types.

Updates golang/go#61773
For golang/go#61772

Change-Id: If8d9a2d6b0aa509aafd199ec140659cb7d664308
Reviewed-on: https://go-review.googlesource.com/c/build/+/518799
Reviewed-by: Dmitri Shuralyov <[email protected]>
TryBot-Result: Gopher Robot <[email protected]>
Reviewed-by: Dmitri Shuralyov <[email protected]>
Run-TryBot: Carlos Amedee <[email protected]>
LUCI-TryBot-Result: Go LUCI <[email protected]>

cmd/gomote/create.go

@@ -78,6 +78,16 @@ func builders() (bt []builderType) {
 	return
 }
 
+func swarmingBuilders() ([]string, error) {
+	ctx, _ := context.WithTimeout(context.Background(), 5*time.Second)
+	client := gomoteServerClient(ctx)
+	resp, err := client.ListSwarmingBuilders(ctx, &protos.ListSwarmingBuildersRequest{})
+	if err != nil {
+		return nil, fmt.Errorf("unable to retrieve swarming builders: %s", err)
+	}
+	return resp.Builders, nil
+}
+
 func create(args []string) error {
 	fs := flag.NewFlagSet("create", flag.ContinueOnError)
 
@@ -91,18 +101,30 @@ func create(args []string) error {
 		fmt.Fprintln(os.Stderr, "added to that group.")
 		fs.PrintDefaults()
 		fmt.Fprintln(os.Stderr, "\nValid types:")
-		for _, bt := range builders() {
-			var warn string
-			if bt.IsReverse {
-				if bt.ExpectNum > 0 {
-					warn = fmt.Sprintf("   [limited capacity: %d machines]", bt.ExpectNum)
-				} else {
-					warn = "   [limited capacity]"
+		if luciEnabled() {
+			swarmingBuilders, err := swarmingBuilders()
+			if err != nil {
+				fmt.Fprintf(os.Stderr, " %s\n", err)
+			} else {
+				for _, builder := range swarmingBuilders {
+					fmt.Fprintf(os.Stderr, "  * %s\n", builder)
+				}
+			}
+			os.Exit(1)
+		} else {
+			for _, bt := range builders() {
+				var warn string
+				if bt.IsReverse {
+					if bt.ExpectNum > 0 {
+						warn = fmt.Sprintf("   [limited capacity: %d machines]", bt.ExpectNum)
+					} else {
+						warn = "   [limited capacity]"
+					}
 				}
+				fmt.Fprintf(os.Stderr, "  * %s%s\n", bt.Name, warn)
 			}
-			fmt.Fprintf(os.Stderr, "  * %s%s\n", bt.Name, warn)
+			os.Exit(1)
 		}
-		os.Exit(1)
 	}
 	var status bool
 	fs.BoolVar(&status, "status", true, "print regular status updates while waiting")

cmd/gomote/gomote.go

@@ -148,6 +148,7 @@ import (
 	"fmt"
 	"os"
 	"sort"
+	"strconv"
 
 	"golang.org/x/build/buildenv"
 	"golang.org/x/build/buildlet"
@@ -296,3 +297,8 @@ func instanceDoesNotExist(err error) bool {
 	}
 	return false
 }
+
+func luciEnabled() bool {
+	on, _ := strconv.ParseBool(os.Getenv("GOMOTELUCI"))
+	return on
+}