K8s: Use grafana executable for standalone api service (#77904)

Co-authored-by: Dan Cech <dcech@grafana.com>

.github/CODEOWNERS

@@ -69,7 +69,7 @@
 /pkg/apis/ @grafana/grafana-app-platform-squad
 /pkg/bus/ @grafana/backend-platform
 /pkg/cmd/ @grafana/backend-platform
-/pkg/cmd/grafana-example-apiserver @grafana/grafana-app-platform-squad
+/pkg/cmd/grafana/apiserver @grafana/grafana-app-platform-squad
 /pkg/components/apikeygen/ @grafana/identity-access-team
 /pkg/components/satokengen/ @grafana/identity-access-team
 /pkg/components/dashdiffs/ @grafana/backend-platform

.gitignore

@@ -78,7 +78,7 @@ public/css/*.min.css
 /data/*
 /bin/*
 
-# any certificates generated by grafana-example-apiserver
+# any certificates generated by grafana apiserver
 apiserver.local.config/
 
 # devenv

Makefile

@@ -7,7 +7,7 @@ WIRE_TAGS = "oss"
 -include local/Makefile
 include .bingo/Variables.mk
 
-.PHONY: all deps-go deps-js deps build-go build-backend build-example-apiserver build-server build-cli build-js build build-docker-full build-docker-full-ubuntu lint-go golangci-lint test-go test-js gen-ts test run run-frontend clean devenv devenv-down protobuf drone help gen-go gen-cue fix-cue
+.PHONY: all deps-go deps-js deps build-go build-backend build-server build-cli build-js build build-docker-full build-docker-full-ubuntu lint-go golangci-lint test-go test-js gen-ts test run run-frontend clean devenv devenv-down protobuf drone help gen-go gen-cue fix-cue
 
 GO = go
 GO_FILES ?= ./pkg/...
@@ -132,10 +132,6 @@ build-server: ## Build Grafana server.
 	@echo "build server"
 	$(GO) run build.go $(GO_BUILD_FLAGS) build-server
 
-build-example-apiserver: ## Build Grafana example-apiserver application.
-	@echo "build grafana-cli"
-	$(GO) run build.go $(GO_BUILD_FLAGS) build-example-apiserver
-
 build-cli: ## Build Grafana CLI application.
 	@echo "build grafana-cli"
 	$(GO) run build.go $(GO_BUILD_FLAGS) build-cli

pkg/build/cmd.go

@@ -17,13 +17,12 @@ const (
 	GoOSWindows = "windows"
 	GoOSLinux   = "linux"
 
-	BackendBinary          = "grafana"
-	ExampleAPIServerBinary = "grafana-example-apiserver"
-	ServerBinary           = "grafana-server"
-	CLIBinary              = "grafana-cli"
+	BackendBinary = "grafana"
+	ServerBinary  = "grafana-server"
+	CLIBinary     = "grafana-cli"
 )
 
-var binaries = []string{BackendBinary, ExampleAPIServerBinary, ServerBinary, CLIBinary}
+var binaries = []string{BackendBinary, ServerBinary, CLIBinary}
 
 func logError(message string, err error) int {
 	log.Println(message, err)
@@ -86,13 +85,6 @@ func RunCmd() int {
 				return 1
 			}
 
-		case "build-example-apiserver":
-			clean(opts)
-			if err := doBuild("grafana-example-apiserver", "./pkg/cmd/grafana-example-apiserver", opts); err != nil {
-				log.Println(err)
-				return 1
-			}
-
 		case "build-cli":
 			clean(opts)
 			if err := doBuild("grafana-cli", "./pkg/cmd/grafana-cli", opts); err != nil {

pkg/build/grafana/build.go

@@ -12,7 +12,7 @@ import (
 	"github.com/grafana/grafana/pkg/build/golangutils"
 )
 
-var binaries = []string{"grafana", "grafana-example-apiserver", "grafana-server", "grafana-cli"}
+var binaries = []string{"grafana", "grafana-server", "grafana-cli"}
 
 const (
 	SuffixEnterprise2 = "-enterprise2"

pkg/cmd/grafana-example-apiserver/main.go

@@ -1,50 +0,0 @@
-package main
-
-import (
-	"os"
-
-	"github.com/spf13/cobra"
-	genericapiserver "k8s.io/apiserver/pkg/server"
-	"k8s.io/component-base/cli"
-)
-
-func NewCommandStartExampleAPIServer(defaults *ExampleServerOptions, stopCh <-chan struct{}) *cobra.Command {
-	o := *defaults
-	cmd := &cobra.Command{
-		Short: "Launch the example API server",
-		Long:  "Launch the example API server",
-		RunE: func(c *cobra.Command, args []string) error {
-			if err := o.Complete(); err != nil {
-				return err
-			}
-
-			config, err := o.Config()
-			if err != nil {
-				return err
-			}
-
-			if err := o.RunExampleServer(config, stopCh); err != nil {
-				return err
-			}
-			return nil
-		},
-	}
-
-	flags := cmd.Flags()
-	o.RecommendedOptions.AddFlags(flags)
-
-	return cmd
-}
-
-func main() {
-	stopCh := genericapiserver.SetupSignalHandler()
-	options, err := NewExampleServerOptions(os.Stdout, os.Stderr)
-	if err != nil {
-		panic(err)
-	}
-
-	cmd := NewCommandStartExampleAPIServer(options, stopCh)
-
-	code := cli.Run(cmd)
-	os.Exit(code)
-}

pkg/cmd/grafana/apiserver/README.md

@@ -1,4 +1,4 @@
-# grafana-example-apiserver
+# grafana apiserver (standalone)
 
 The example-apiserver closely resembles the 
 [sample-apiserver](https://github.com/kubernetes/sample-apiserver/tree/master) project in code and thus
@@ -19,7 +19,7 @@ can be used as a root server for this example-apiserver (in aggregated mode). He
 kind cluster and that you can provide its kubeconfig in the parameters to the example-apiserver.
 
 ```shell
-go run ./pkg/cmd/grafana-example-apiserver \
+go run ./pkg/cmd/grafana apiserver example.grafana.app\
   --authentication-kubeconfig ~/.kube/config \
   --authorization-kubeconfig ~/.kube/config \
   --kubeconfig ~/.kube/config \

pkg/cmd/grafana/apiserver/cmd.go

@@ -0,0 +1,75 @@
+package apiserver
+
+import (
+	"fmt"
+	"os"
+
+	"github.com/spf13/cobra"
+	genericapiserver "k8s.io/apiserver/pkg/server"
+	"k8s.io/apiserver/pkg/server/options"
+	"k8s.io/component-base/cli"
+)
+
+func newCommandStartExampleAPIServer(o *ExampleServerOptions, stopCh <-chan struct{}) *cobra.Command {
+	// While this exists as an experimental feature, we require adding the scarry looking command line
+	devAcknowledgementFlag := "grafana-enable-experimental-apiserver"
+	devAcknowledgementNotice := "The apiserver command is in heavy development.  The entire setup is subject to change without notice"
+
+	cmd := &cobra.Command{
+		Use:   "apiserver [api group(s)]",
+		Short: "Run the grafana apiserver",
+		Long: "Run a standalone kubernetes based apiserver that can be aggregated by a root apiserver. " +
+			devAcknowledgementNotice,
+		Example: fmt.Sprintf("grafana apiserver example.grafana.app --%s", devAcknowledgementFlag),
+		PersistentPreRun: func(cmd *cobra.Command, args []string) {
+			ok, err := cmd.Flags().GetBool(devAcknowledgementFlag)
+			if !ok || err != nil {
+				fmt.Printf("requires running with the flag: --%s\n\n%s\n\n",
+					devAcknowledgementFlag, devAcknowledgementNotice)
+				os.Exit(1)
+			}
+		},
+		RunE: func(c *cobra.Command, args []string) error {
+			// Load each group from the args
+			if err := o.LoadAPIGroupBuilders(args[1:]); err != nil {
+				return err
+			}
+
+			// Finish the config (applies all defaults)
+			if err := o.Complete(); err != nil {
+				return err
+			}
+
+			config, err := o.Config()
+			if err != nil {
+				return err
+			}
+
+			if err := o.RunExampleServer(config, stopCh); err != nil {
+				return err
+			}
+			return nil
+		},
+	}
+
+	// Register grafana flags
+	cmd.PersistentFlags().Bool(devAcknowledgementFlag, false, devAcknowledgementNotice)
+
+	// Register standard k8s flags with the command line
+	o.RecommendedOptions = options.NewRecommendedOptions(
+		defaultEtcdPathPrefix,
+		Codecs.LegacyCodec(), // the codec is passed to etcd and not used
+	)
+	o.RecommendedOptions.AddFlags(cmd.Flags())
+
+	return cmd
+}
+
+func RunCLI() int {
+	stopCh := genericapiserver.SetupSignalHandler()
+
+	options := newExampleServerOptions(os.Stdout, os.Stderr)
+	cmd := newCommandStartExampleAPIServer(options, stopCh)
+
+	return cli.Run(cmd)
+}

pkg/cmd/grafana/apiserver/server.go

@@ -1,11 +1,11 @@
-package main
+package apiserver
 
 import (
 	"fmt"
 	"io"
 	"net"
 
-	exampleAPI "github.com/grafana/grafana/pkg/registry/apis/example"
+	"github.com/grafana/grafana/pkg/registry/apis/example"
 	grafanaAPIServer "github.com/grafana/grafana/pkg/services/grafana-apiserver"
 
 	metav1 "k8s.io/apimachinery/pkg/apis/meta/v1"
@@ -43,34 +43,47 @@ func init() {
 
 // ExampleServerOptions contains the state for the apiserver
 type ExampleServerOptions struct {
+	builders           []grafanaAPIServer.APIGroupBuilder
 	RecommendedOptions *options.RecommendedOptions
-	Builders           []grafanaAPIServer.APIGroupBuilder
 	AlternateDNS       []string
 
 	StdOut io.Writer
 	StdErr io.Writer
 }
 
-func NewExampleServerOptions(out, errOut io.Writer) (*ExampleServerOptions, error) {
-	builder := &exampleAPI.TestingAPIBuilder{}
-
-	// Install schema
-	if err := builder.InstallSchema(Scheme); err != nil {
-		return nil, err
-	}
-
+func newExampleServerOptions(out, errOut io.Writer) *ExampleServerOptions {
 	return &ExampleServerOptions{
-		Builders: []grafanaAPIServer.APIGroupBuilder{builder},
-		RecommendedOptions: options.NewRecommendedOptions(
-			defaultEtcdPathPrefix,
-			Codecs.LegacyCodec(builder.GetGroupVersion()),
-		),
 		StdOut: out,
 		StdErr: errOut,
-	}, nil
+	}
 }
 
-func (o ExampleServerOptions) Config() (*genericapiserver.RecommendedConfig, error) {
+func (o *ExampleServerOptions) LoadAPIGroupBuilders(args []string) error {
+	o.builders = []grafanaAPIServer.APIGroupBuilder{}
+	for _, g := range args {
+		switch g {
+		// No dependencies for testing
+		case "example.grafana.app":
+			o.builders = append(o.builders, &example.TestingAPIBuilder{})
+		default:
+			return fmt.Errorf("unknown group: %s", g)
+		}
+	}
+
+	if len(o.builders) < 1 {
+		return fmt.Errorf("expected group name(s) in the command line arguments")
+	}
+
+	// Install schemas
+	for _, b := range o.builders {
+		if err := b.InstallSchema(Scheme); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func (o *ExampleServerOptions) Config() (*genericapiserver.RecommendedConfig, error) {
 	if err := o.RecommendedOptions.SecureServing.MaybeDefaultWithSelfSignedCerts("localhost", o.AlternateDNS, []net.IP{netutils.ParseIPSloppy("127.0.0.1")}); err != nil {
 		return nil, fmt.Errorf("error creating self-signed certificates: %v", err)
 	}
@@ -94,18 +107,18 @@ func (o ExampleServerOptions) Config() (*genericapiserver.RecommendedConfig, err
 // Validate validates ExampleServerOptions
 // NOTE: we don't call validate on the top level recommended options as it doesn't like skipping etcd-servers
 // the function is left here for troubleshooting any other config issues
-func (o ExampleServerOptions) Validate(args []string) error {
+func (o *ExampleServerOptions) Validate(args []string) error {
 	errors := []error{}
 	errors = append(errors, o.RecommendedOptions.Validate()...)
 	return utilerrors.NewAggregate(errors)
 }
 
 // Complete fills in fields required to have valid data
-func (o ExampleServerOptions) Complete() error {
+func (o *ExampleServerOptions) Complete() error {
 	return nil
 }
 
-func (o ExampleServerOptions) RunExampleServer(config *genericapiserver.RecommendedConfig, stopCh <-chan struct{}) error {
+func (o *ExampleServerOptions) RunExampleServer(config *genericapiserver.RecommendedConfig, stopCh <-chan struct{}) error {
 	delegationTarget := genericapiserver.NewEmptyDelegate()
 	completedConfig := config.Complete()
 	server, err := completedConfig.New("example-apiserver", delegationTarget)
@@ -114,7 +127,7 @@ func (o ExampleServerOptions) RunExampleServer(config *genericapiserver.Recommen
 	}
 
 	// Install the API Group+version
-	for _, b := range o.Builders {
+	for _, b := range o.builders {
 		g, err := b.GetAPIGroupInfo(Scheme, Codecs, completedConfig.RESTOptionsGetter)
 		if err != nil {
 			return err

pkg/cmd/grafana/main.go

@@ -9,6 +9,7 @@ import (
 
 	gcli "github.com/grafana/grafana/pkg/cmd/grafana-cli/commands"
 	gsrv "github.com/grafana/grafana/pkg/cmd/grafana-server/commands"
+	"github.com/grafana/grafana/pkg/cmd/grafana/apiserver"
 )
 
 // The following variables cannot be constants, since they can be overridden through the -X link flag
@@ -32,6 +33,18 @@ func main() {
 		Commands: []*cli.Command{
 			gcli.CLICommand(version),
 			gsrv.ServerCommand(version, commit, enterpriseCommit, buildBranch, buildstamp),
+			{
+				// The kubernetes standalone apiserver service runner
+				Name:  "apiserver",
+				Usage: "run a standalone api service (experimental)",
+				// Skip parsing flags because the command line is actually managed by cobra
+				SkipFlagParsing: true,
+				Action: func(context *cli.Context) error {
+					// exit here because apiserver handles its own error output
+					os.Exit(apiserver.RunCLI())
+					return nil
+				},
+			},
 		},
 		CommandNotFound:      cmdNotFound,
 		EnableBashCompletion: true,