runsc metric-server: Move metric server to its own binary.

This creates a separate `go_binary` target for the metric server, and changes
the `runsc metric-server` subcommand to call it instead of directly executing
metric server code. This helps avoid Go library dependencies used only by the
metric server into the `runsc` binary.

PiperOrigin-RevId: 559221695

runsc/cmd/BUILD

@@ -70,6 +70,7 @@ go_library(
         "//pkg/unet",
         "//pkg/urpc",
         "//runsc/boot",
+        "//runsc/cmd/metricserver",
         "//runsc/cmd/util",
         "//runsc/config",
         "//runsc/console",
@@ -77,7 +78,6 @@ go_library(
         "//runsc/flag",
         "//runsc/fsgofer",
         "//runsc/fsgofer/filter",
-        "//runsc/metricserver",
         "//runsc/metricserver/containermetrics",
         "//runsc/mitigate",
         "//runsc/profile",

runsc/cmd/metric_server.go

@@ -16,17 +16,22 @@ package cmd
 
 import (
 	"context"
+	"fmt"
+	"os"
 
 	"github.com/google/subcommands"
+	"gvisor.dev/gvisor/runsc/cmd/metricserver"
 	"gvisor.dev/gvisor/runsc/cmd/util"
 	"gvisor.dev/gvisor/runsc/config"
 	"gvisor.dev/gvisor/runsc/flag"
-	"gvisor.dev/gvisor/runsc/metricserver"
 )
 
 // MetricServer implements subcommands.Command for the "metric-server" command.
 type MetricServer struct {
-	Server metricserver.Server
+	ExporterPrefix         string
+	PIDFile                string
+	ExposeProfileEndpoints bool
+	AllowUnknownRoot       bool
 }
 
 // Name implements subcommands.Command.Name.
@@ -47,10 +52,10 @@ func (*MetricServer) Usage() string {
 
 // SetFlags implements subcommands.Command.SetFlags.
 func (m *MetricServer) SetFlags(f *flag.FlagSet) {
-	f.StringVar(&m.Server.ExporterPrefix, "exporter-prefix", "runsc_", "Prefix for all metric names, following Prometheus exporter convention")
-	f.StringVar(&m.Server.PIDFile, "pid-file", "", "If set, write the metric server's own PID to this file after binding to the --metric-server address. The parent directory of this file must already exist.")
-	f.BoolVar(&m.Server.ExposeProfileEndpoints, "allow-profiling", false, "If true, expose /runsc-metrics/profile-cpu and /runsc-metrics/profile-heap to get profiling data about the metric server")
-	f.BoolVar(&m.Server.AllowUnknownRoot, "allow-unknown-root", false, "if set, the metric server will keep running regardless of the existence of --root or the metric server's ability to access it.")
+	f.StringVar(&m.ExporterPrefix, "exporter-prefix", "runsc_", "Prefix for all metric names, following Prometheus exporter convention")
+	f.StringVar(&m.PIDFile, "pid-file", "", "If set, write the metric server's own PID to this file after binding to the --metric-server address. The parent directory of this file must already exist.")
+	f.BoolVar(&m.ExposeProfileEndpoints, "allow-profiling", false, "If true, expose /runsc-metrics/profile-cpu and /runsc-metrics/profile-heap to get profiling data about the metric server")
+	f.BoolVar(&m.AllowUnknownRoot, "allow-unknown-root", false, "if set, the metric server will keep running regardless of the existence of --root or the metric server's ability to access it.")
 }
 
 // Execute implements subcommands.Command.Execute.
@@ -59,13 +64,22 @@ func (m *MetricServer) Execute(ctx context.Context, f *flag.FlagSet, args ...any
 		f.Usage()
 		return subcommands.ExitUsageError
 	}
-	m.Server.Config = args[0].(*config.Config)
-	if m.Server.Config.MetricServer == "" || m.Server.Config.RootDir == "" {
-		f.Usage()
-		return subcommands.ExitUsageError
+	var newArgs []string
+	newArgs = append(newArgs, metricserver.BinaryName)
+	newArgs = append(newArgs, args[0].(*config.Config).ToFlags()...)
+	newArgs = append(newArgs,
+		fmt.Sprintf("--metricserver-exporter-prefix=%s", m.ExporterPrefix),
+		fmt.Sprintf("--metricserver-pid-file=%s", m.PIDFile),
+		fmt.Sprintf("--metricserver-allow-profiling=%t", m.ExposeProfileEndpoints),
+		fmt.Sprintf("--metricserver-allow-unknown-root=%t", m.AllowUnknownRoot),
+	)
+	err := metricserver.Exec(metricserver.Options{
+		Argv: newArgs,
+		Envv: os.Environ(),
+	})
+	if err != nil {
+		util.Fatalf("metric server: %v", err)
 	}
-	if err := m.Server.Run(ctx); err != nil {
-		return util.Errorf("%v", err)
-	}
-	return subcommands.ExitSuccess
+	util.Fatalf("unreachable")
+	return subcommands.ExitFailure
 }

runsc/cmd/metricserver/BUILD

@@ -0,0 +1,29 @@
+load("//tools:defs.bzl", "go_binary")
+load("//tools/embeddedbinary:defs.bzl", "embedded_binary_go_library")
+
+package(
+    default_applicable_licenses = ["//:license"],
+    licenses = ["notice"],
+)
+
+go_binary(
+    name = "metricserver_bin",
+    srcs = [
+        "metricserver_main.go",
+    ],
+    deps = [
+        "//runsc/cmd/util",
+        "//runsc/config",
+        "//runsc/flag",
+        "//runsc/metricserver",
+        "@com_github_google_subcommands//:go_default_library",
+    ],
+)
+
+embedded_binary_go_library(
+    name = "metricserver",
+    binary = ":metricserver_bin",
+    visibility = [
+        "//runsc:__subpackages__",
+    ],
+)

runsc/cmd/metricserver/metricserver_main.go

@@ -0,0 +1,61 @@
+// Copyright 2023 The gVisor 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.
+
+// The metricserver binary is a separate binary that implements the
+// 'runsc metric-server' subcommand.
+package main
+
+import (
+	"context"
+	"os"
+
+	"github.com/google/subcommands"
+	"gvisor.dev/gvisor/runsc/cmd/util"
+	"gvisor.dev/gvisor/runsc/config"
+	"gvisor.dev/gvisor/runsc/flag"
+	"gvisor.dev/gvisor/runsc/metricserver"
+)
+
+// Main returns the status code of the metric server.
+func Main() subcommands.ExitStatus {
+	ctx := context.Background()
+	config.RegisterFlags(flag.CommandLine)
+	server := metricserver.Server{}
+	flag.CommandLine.StringVar(&server.ExporterPrefix, "metricserver-exporter-prefix", "runsc_", "Prefix for all metric names, following Prometheus exporter convention")
+	flag.CommandLine.StringVar(&server.PIDFile, "metricserver-pid-file", "", "If set, write the metric server's own PID to this file after binding to the --metric-server address. The parent directory of this file must already exist.")
+	flag.CommandLine.BoolVar(&server.ExposeProfileEndpoints, "metricserver-allow-profiling", false, "If true, expose /runsc-metrics/profile-cpu and /runsc-metrics/profile-heap to get profiling data about the metric server")
+	flag.CommandLine.BoolVar(&server.AllowUnknownRoot, "metricserver-allow-unknown-root", false, "if set, the metric server will keep running regardless of the existence of --root or the metric server's ability to access it.")
+	flag.Parse()
+	if flag.CommandLine.NArg() != 0 {
+		flag.CommandLine.Usage()
+		return subcommands.ExitUsageError
+	}
+	conf, err := config.NewFromFlags(flag.CommandLine)
+	if err != nil {
+		util.Fatalf(err.Error())
+	}
+	if conf.MetricServer == "" || conf.RootDir == "" {
+		flag.CommandLine.Usage()
+		return subcommands.ExitUsageError
+	}
+	server.Config = conf
+	if err := server.Run(ctx); err != nil {
+		return util.Errorf("%v", err)
+	}
+	return subcommands.ExitSuccess
+}
+
+func main() {
+	os.Exit(int(Main()))
+}

test/metricclient/metricclient.go

@@ -184,7 +184,7 @@ func (c *MetricClient) SpawnServer(ctx context.Context, baseConf *config.Config,
 	if c.server != nil {
 		return errors.New("this metric client already has a server associated with it")
 	}
-	bindCtx, bindCancel := context.WithTimeout(ctx, 5*time.Second)
+	bindCtx, bindCancel := context.WithTimeout(ctx, 20*time.Second)
 	defer bindCancel()
 	launchBackoff := backoff.WithContext(&backoff.ExponentialBackOff{
 		InitialInterval:     time.Millisecond,