server target command (#74408)

feat: add grafana server target command

pkg/cmd/grafana-server/commands/cli.go

@@ -44,6 +44,7 @@ func ServerCommand(version, commit, buildBranch, buildstamp string) *cli.Command
 				Context:     context,
 			})
 		},
+		Subcommands: []*cli.Command{TargetCommand(version, commit, buildBranch, buildstamp)},
 	}
 }
 
@@ -132,7 +133,12 @@ func validPackaging(packaging string) string {
 	return "unknown"
 }
 
-func listenToSystemSignals(ctx context.Context, s *server.Server) {
+// a small interface satisfied by the server and moduleserver
+type gserver interface {
+	Shutdown(context.Context, string) error
+}
+
+func listenToSystemSignals(ctx context.Context, s gserver) {
 	signalChan := make(chan os.Signal, 1)
 	sighupChan := make(chan os.Signal, 1)
 

pkg/cmd/grafana-server/commands/target.go

@@ -0,0 +1,108 @@
+package commands
+
+import (
+	"context"
+	"fmt"
+	"os"
+	"runtime/debug"
+	"strings"
+
+	"github.com/urfave/cli/v2"
+
+	"github.com/grafana/grafana/pkg/api"
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/server"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+func TargetCommand(version, commit, buildBranch, buildstamp string) *cli.Command {
+	return &cli.Command{
+		Name:  "target",
+		Usage: "target specific grafana dskit services",
+		Flags: commonFlags,
+		Action: func(context *cli.Context) error {
+			return RunTargetServer(ServerOptions{
+				Version:     version,
+				Commit:      commit,
+				BuildBranch: buildBranch,
+				BuildStamp:  buildstamp,
+				Context:     context,
+			})
+		},
+	}
+}
+
+func RunTargetServer(opts ServerOptions) error {
+	if Version || VerboseVersion {
+		fmt.Printf("Version %s (commit: %s, branch: %s)\n", opts.Version, opts.Commit, opts.BuildBranch)
+		if VerboseVersion {
+			fmt.Println("Dependencies:")
+			if info, ok := debug.ReadBuildInfo(); ok {
+				for _, dep := range info.Deps {
+					fmt.Println(dep.Path, dep.Version)
+				}
+			}
+		}
+		return nil
+	}
+
+	logger := log.New("cli")
+	defer func() {
+		if err := log.Close(); err != nil {
+			fmt.Fprintf(os.Stderr, "Failed to close log: %s\n", err)
+		}
+	}()
+
+	if err := setupProfiling(Profile, ProfileAddr, ProfilePort); err != nil {
+		return err
+	}
+	if err := setupTracing(Tracing, TracingFile, logger); err != nil {
+		return err
+	}
+
+	defer func() {
+		// If we've managed to initialize them, this is the last place
+		// where we're able to log anything that'll end up in Grafana's
+		// log files.
+		// Since operators are not always looking at stderr, we'll try
+		// to log any and all panics that are about to crash Grafana to
+		// our regular log locations before exiting.
+		if r := recover(); r != nil {
+			reason := fmt.Sprintf("%v", r)
+			logger.Error("Critical error", "reason", reason, "stackTrace", string(debug.Stack()))
+			panic(r)
+		}
+	}()
+
+	setBuildInfo(opts)
+	checkPrivileges()
+
+	configOptions := strings.Split(ConfigOverrides, " ")
+	cfg, err := setting.NewCfgFromArgs(setting.CommandLineArgs{
+		Config:   ConfigFile,
+		HomePath: HomePath,
+		// tailing arguments have precedence over the options string
+		Args: append(configOptions, opts.Context.Args().Slice()...),
+	})
+	if err != nil {
+		return err
+	}
+
+	s, err := server.InitializeModuleServer(
+		cfg,
+		server.Options{
+			PidFile:     PidFile,
+			Version:     opts.Version,
+			Commit:      opts.Commit,
+			BuildBranch: opts.BuildBranch,
+		},
+		api.ServerOptions{},
+	)
+	if err != nil {
+		return err
+	}
+
+	ctx := context.Background()
+	go listenToSystemSignals(ctx, s)
+	return s.Run()
+}