use cobra to support subcommands and add controller subcommand

Signed-off-by: Ryotaro Banno <[email protected]>

Dockerfile

@@ -10,7 +10,8 @@ COPY go.sum go.sum
 RUN go mod download
 
 # Copy the go source
-COPY cmd/main.go cmd/main.go
+COPY main.go main.go
+COPY cmd/ cmd/
 COPY api/ api/
 COPY internal/controller/ internal/controller/
 
@@ -20,7 +21,7 @@ COPY internal/controller/ internal/controller/
 # the docker BUILDPLATFORM arg will be linux/arm64 when for Apple x86 it will be linux/amd64. Therefore,
 # by leaving it empty we can ensure that the container and binary shipped on it will have the same platform.
 # TODO: RUN CGO_ENABLED=0 go build -a -o manager cmd/main.go
-RUN CGO_ENABLED=0 go build -o manager cmd/main.go
+RUN CGO_ENABLED=0 go build -o manager main.go
 
 FROM quay.io/cybozu/ceph:18.2.1.1
 WORKDIR /

Makefile

@@ -85,11 +85,11 @@ lint-fix: golangci-lint ## Run golangci-lint linter and perform fixes
 
 .PHONY: build
 build: manifests generate fmt vet ## Build manager binary.
-	go build -o bin/manager cmd/main.go
+	go build -o bin/manager main.go
 
 .PHONY: run
 run: manifests generate fmt vet ## Run a controller from your host.
-	go run ./cmd/main.go
+	go run main.go
 
 # If you wish to build the manager image targeting other platforms you can use the --platform flag.
 # (i.e. docker build --platform linux/arm64). However, you must enable docker buildKit for it.

charts/mantle/templates/deployment.yaml

@@ -58,6 +58,7 @@ spec:
           command:
             - /manager
           args:
+            - controller
             - --leader-elect
           env:
             - name: POD_NAMESPACE

cmd/main.go → cmd/controller/main.go

@@ -1,4 +1,4 @@
-package main
+package controller
 
 import (
 	"errors"
@@ -9,6 +9,7 @@ import (
 	// to ensure that exec-entrypoint and run can make use of them.
 	_ "k8s.io/client-go/plugin/pkg/client/auth"
 
+	"github.com/spf13/cobra"
 	"k8s.io/apimachinery/pkg/runtime"
 	utilruntime "k8s.io/apimachinery/pkg/util/runtime"
 	clientgoscheme "k8s.io/client-go/kubernetes/scheme"
@@ -22,34 +23,44 @@ import (
 	//+kubebuilder:scaffold:imports
 )
 
+var ControllerCmd = &cobra.Command{
+	Use: "controller",
+	RunE: func(cmd *cobra.Command, args []string) error {
+		return subMain()
+	},
+}
+
 var (
+	metricsAddr          string
+	enableLeaderElection bool
+	probeAddr            string
+	zapOpts              zap.Options
+
 	scheme   = runtime.NewScheme()
 	setupLog = ctrl.Log.WithName("setup")
 )
 
 func init() {
+	flags := ControllerCmd.Flags()
+	flags.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
+	flags.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
+	flags.BoolVar(&enableLeaderElection, "leader-elect", false,
+		"Enable leader election for controller manager. "+
+			"Enabling this will ensure there is only one active controller manager.")
+
+	goflags := flag.NewFlagSet("goflags", flag.ExitOnError)
+	zapOpts.Development = true
+	zapOpts.BindFlags(goflags)
+	flags.AddGoFlagSet(goflags)
+
 	utilruntime.Must(clientgoscheme.AddToScheme(scheme))
 
 	utilruntime.Must(mantlev1.AddToScheme(scheme))
 	//+kubebuilder:scaffold:scheme
 }
 
-func main() {
-	var metricsAddr string
-	var enableLeaderElection bool
-	var probeAddr string
-	flag.StringVar(&metricsAddr, "metrics-bind-address", ":8080", "The address the metric endpoint binds to.")
-	flag.StringVar(&probeAddr, "health-probe-bind-address", ":8081", "The address the probe endpoint binds to.")
-	flag.BoolVar(&enableLeaderElection, "leader-elect", false,
-		"Enable leader election for controller manager. "+
-			"Enabling this will ensure there is only one active controller manager.")
-	opts := zap.Options{
-		Development: true,
-	}
-	opts.BindFlags(flag.CommandLine)
-	flag.Parse()
-
-	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&opts)))
+func subMain() error {
+	ctrl.SetLogger(zap.New(zap.UseFlagOptions(&zapOpts)))
 
 	mgr, err := ctrl.NewManager(ctrl.GetConfigOrDie(), ctrl.Options{
 		Scheme:                 scheme,
@@ -71,13 +82,13 @@ func main() {
 	})
 	if err != nil {
 		setupLog.Error(err, "unable to start manager")
-		os.Exit(1)
+		return err
 	}
 
 	managedCephClusterID := os.Getenv("POD_NAMESPACE")
 	if managedCephClusterID == "" {
 		setupLog.Error(errors.New("POD_NAMESPACE is empty"), "POD_NAMESPACE is empty")
-		os.Exit(1)
+		return err
 	}
 
 	reconciler := controller.NewMantleBackupReconciler(
@@ -88,22 +99,24 @@ func main() {
 
 	if err = reconciler.SetupWithManager(mgr); err != nil {
 		setupLog.Error(err, "unable to create controller", "controller", "MantleBackup")
-		os.Exit(1)
+		return err
 	}
 	//+kubebuilder:scaffold:builder
 
 	if err := mgr.AddHealthzCheck("healthz", healthz.Ping); err != nil {
 		setupLog.Error(err, "unable to set up health check")
-		os.Exit(1)
+		return err
 	}
 	if err := mgr.AddReadyzCheck("readyz", healthz.Ping); err != nil {
 		setupLog.Error(err, "unable to set up ready check")
-		os.Exit(1)
+		return err
 	}
 
 	setupLog.Info("starting manager")
 	if err := mgr.Start(ctrl.SetupSignalHandler()); err != nil {
 		setupLog.Error(err, "problem running manager")
-		os.Exit(1)
+		return err
 	}
+
+	return nil
 }

cmd/root.go

@@ -0,0 +1,23 @@
+package cmd
+
+import (
+	"os"
+
+	"github.com/cybozu-go/mantle/cmd/controller"
+	"github.com/spf13/cobra"
+)
+
+var rootCmd = &cobra.Command{
+	Use: "mantle",
+}
+
+func init() {
+	rootCmd.AddCommand(controller.ControllerCmd)
+}
+
+func Execute() {
+	err := rootCmd.Execute()
+	if err != nil {
+		os.Exit(1)
+	}
+}

go.mod

@@ -5,7 +5,7 @@ go 1.21
 require (
 	github.com/onsi/ginkgo/v2 v2.11.0
 	github.com/onsi/gomega v1.27.10
-	gopkg.in/yaml.v2 v2.4.0
+	github.com/spf13/cobra v1.7.0
 	k8s.io/api v0.28.3
 	k8s.io/apimachinery v0.28.3
 	k8s.io/client-go v0.28.3
@@ -35,6 +35,7 @@ require (
 	github.com/google/pprof v0.0.0-20210720184732-4bb14d4b1be1 // indirect
 	github.com/google/uuid v1.3.0 // indirect
 	github.com/imdario/mergo v0.3.6 // indirect
+	github.com/inconshreveable/mousetrap v1.1.0 // indirect
 	github.com/josharian/intern v1.0.0 // indirect
 	github.com/json-iterator/go v1.1.12 // indirect
 	github.com/mailru/easyjson v0.7.7 // indirect
@@ -63,6 +64,7 @@ require (
 	google.golang.org/appengine v1.6.7 // indirect
 	google.golang.org/protobuf v1.30.0 // indirect
 	gopkg.in/inf.v0 v0.9.1 // indirect
+	gopkg.in/yaml.v2 v2.4.0 // indirect
 	gopkg.in/yaml.v3 v3.0.1 // indirect
 	k8s.io/apiextensions-apiserver v0.28.3 // indirect
 	k8s.io/component-base v0.28.3 // indirect

go.sum

@@ -8,6 +8,7 @@ github.com/cespare/xxhash/v2 v2.2.0/go.mod h1:VGX0DQ3Q6kWi7AoAeZDth3/j3BFtOZR5XL
 github.com/chzyer/logex v1.1.10/go.mod h1:+Ywpsq7O8HXn0nuIou7OrIPyXbp3wmkHB+jjWRnGsAI=
 github.com/chzyer/readline v0.0.0-20180603132655-2972be24d48e/go.mod h1:nSuG5e5PlCu98SY8svDHJxuZscDgtXS6KTTbou5AhLI=
 github.com/chzyer/test v0.0.0-20180213035817-a1ea475d72b1/go.mod h1:Q3SI9o4m/ZMnBNeIyt5eFwwo7qiLfzFZmjNmxjkiQlU=
+github.com/cpuguy83/go-md2man/v2 v2.0.2/go.mod h1:tgQtvFlXSQOSOSIRvRPT7W67SCa46tRHOmNcaadrF8o=
 github.com/creack/pty v1.1.9/go.mod h1:oKZEueFk5CKHvIhNR5MUki03XCEU+Q6VDXinZuGJ33E=
 github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
@@ -57,6 +58,8 @@ github.com/google/uuid v1.3.0/go.mod h1:TIyPZe4MgqvfeYDBFedMoGGpEw/LqOeaOT+nhxU+
 github.com/ianlancetaylor/demangle v0.0.0-20200824232613-28f6c0f3b639/go.mod h1:aSSvb/t6k1mPoxDqO4vJh6VOCGPwU4O0C2/Eqndh1Sc=
 github.com/imdario/mergo v0.3.6 h1:xTNEAn+kxVO7dTZGu0CegyqKZmoWFI0rF8UxjlB2d28=
 github.com/imdario/mergo v0.3.6/go.mod h1:2EnlNZ0deacrJVfApfmtdGgDfMuh/nq6Ok1EcJh5FfA=
+github.com/inconshreveable/mousetrap v1.1.0 h1:wN+x4NVGpMsO7ErUn/mUI3vEoE6Jt13X2s0bqwp9tc8=
+github.com/inconshreveable/mousetrap v1.1.0/go.mod h1:vpF70FUmC8bwa3OWnCshd2FqLfsEA9PFc4w1p2J65bw=
 github.com/jessevdk/go-flags v1.4.0/go.mod h1:4FA24M0QyGHXBuZZK/XkWh8h0e1EYbRYJSGM75WSRxI=
 github.com/josharian/intern v1.0.0 h1:vlS4z54oSdjm0bgjRigI+G1HpF+tI+9rE5LLzOg8HmY=
 github.com/josharian/intern v1.0.0/go.mod h1:5DoeVV0s6jJacbCEi61lwdGj/aVlrQvzHFFd8Hwg//Y=
@@ -102,6 +105,9 @@ github.com/prometheus/procfs v0.10.1 h1:kYK1Va/YMlutzCGazswoHKo//tZVlFpKYh+Pymzi
 github.com/prometheus/procfs v0.10.1/go.mod h1:nwNm2aOCAYw8uTR/9bWRREkZFxAUcWzPHWJq+XBB/FM=
 github.com/rogpeppe/go-internal v1.10.0 h1:TMyTOH3F/DB16zRVcYyreMH6GnZZrwQVAoYjRBZyWFQ=
 github.com/rogpeppe/go-internal v1.10.0/go.mod h1:UQnix2H7Ngw/k4C5ijL5+65zddjncjaFoBhdsK/akog=
+github.com/russross/blackfriday/v2 v2.1.0/go.mod h1:+Rmxgy9KzJVeS9/2gXHxylqXiyQDYRxCVz55jmeOWTM=
+github.com/spf13/cobra v1.7.0 h1:hyqWnYt1ZQShIddO5kBpj3vu05/++x6tJ6dg8EC572I=
+github.com/spf13/cobra v1.7.0/go.mod h1:uLxZILRyS/50WlhOIKD7W6V5bgeIt+4sICxh6uRMrb0=
 github.com/spf13/pflag v1.0.5 h1:iy+VFUOCP1a+8yFto/drg2CJ5u0yRoB7fZw3DKv/JXA=
 github.com/spf13/pflag v1.0.5/go.mod h1:McXfInJRrz4CZXVZOBLb0bTZqETkiAhM9Iw0y3An2Bg=
 github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME=

main.go

@@ -0,0 +1,7 @@
+package main
+
+import "github.com/cybozu-go/mantle/cmd"
+
+func main() {
+	cmd.Execute()
+}