Base application setup

Signed-off-by: Jan Tytgat <jan.tytgat@corelayer.eu>

pkg/application/application.go

@@ -0,0 +1,38 @@
+package application
+
+import (
+	"context"
+	"fmt"
+
+	"github.com/spf13/cobra"
+)
+
+type Application interface {
+	Start(ctx context.Context) error
+	Shutdown() error
+}
+
+func New(c Config) (Application, error) {
+	var cmd *cobra.Command
+	var err error
+	if cmd, err = c.getRootCommand(); err != nil {
+		return nil, err
+	}
+
+	return &application{
+		cmd: cmd,
+	}, nil
+}
+
+type application struct {
+	cmd *cobra.Command
+}
+
+func (a *application) Start(ctx context.Context) error {
+	return a.cmd.ExecuteContext(ctx)
+}
+
+func (a *application) Shutdown() error {
+	fmt.Println("Shutdown")
+	return nil
+}

pkg/application/application_test.go

@@ -0,0 +1 @@
+package application

pkg/application/commander.go

@@ -0,0 +1,28 @@
+package application
+
+import "github.com/spf13/cobra"
+
+type Commander interface {
+	Initialize(f func(c *cobra.Command)) *cobra.Command
+}
+
+type Command struct {
+	Command     *cobra.Command
+	SubCommands []Commander
+	Configure   func(c *cobra.Command)
+}
+
+func (c Command) Initialize(f func(c *cobra.Command)) *cobra.Command {
+	if f != nil {
+		f(c.Command)
+	}
+
+	if c.Configure != nil {
+		c.Configure(c.Command)
+	}
+
+	for _, sub := range c.SubCommands {
+		c.Command.AddCommand(sub.Initialize(f))
+	}
+	return c.Command
+}

pkg/application/config.go

@@ -0,0 +1,110 @@
+package application
+
+import (
+	"errors"
+	"fmt"
+	"os"
+	"time"
+
+	"github.com/spf13/cobra"
+
+	"git.flexabyte.io/flexabyte/go-kit/pkg/semver"
+)
+
+type Config struct {
+	Name                     string
+	Title                    string
+	Banner                   string
+	Version                  string
+	EnableGracefulShutdown   bool
+	OverrideRunE             func(cmd *cobra.Command, args []string) error
+	PersistentPreRunE        []func(cmd *cobra.Command, args []string) error // collection of PreRunE functions
+	PersistentPostRunE       []func(cmd *cobra.Command, args []string) error // collection of PostRunE functions
+	ShutdownSignals          []os.Signal
+	ShutdownTimeout          time.Duration
+	SubCommands              []Command
+	SubCommandInitializeFunc func(cmd *cobra.Command)
+	ValidArgs                []string
+}
+
+func (c Config) getRootCommand() (*cobra.Command, error) {
+	var err error
+	if err = c.Validate(); err != nil {
+		return nil, err
+	}
+
+	var long string
+	if c.Banner != "" {
+		long = c.Banner + "\n" + c.Title
+	} else {
+		long = c.Title
+	}
+
+	cmd := &cobra.Command{
+		Use:                c.Name,
+		Short:              c.Title,
+		Long:               long,
+		PersistentPreRunE:  persistentPreRunFuncE,
+		PersistentPostRunE: persistentPostRunFuncE,
+		RunE:               runFuncE,
+		SilenceErrors:      true,
+		SilenceUsage:       true,
+	}
+
+	if c.OverrideRunE != nil {
+		cmd.RunE = c.OverrideRunE
+	}
+
+	for _, subcommand := range c.SubCommands {
+		cmd.AddCommand(subcommand.Initialize(c.SubCommandInitializeFunc))
+	}
+
+	var v semver.Version
+	if v, err = c.ParseVersion(); err != nil {
+		return nil, err
+	}
+
+	configureVersionFlag(cmd, v)                          // Configure app for version information
+	configureOutputFlags(cmd)                             // Configure verbosity
+	configureLoggingFlags(cmd)                            // Configure logging
+	cmd.PersistentFlags().SetNormalizeFunc(normalizeFunc) // normalize persistent flags
+
+	return cmd, nil
+}
+
+func (c Config) ParseVersion() (semver.Version, error) {
+	return semver.Parse(c.Version)
+}
+
+func (c Config) RegisterCommand(cmd Commander, f func(*cobra.Command)) {
+	appCmd.AddCommand(cmd.Initialize(f))
+}
+
+func (c Config) RegisterCommands(cmds []Commander, f func(*cobra.Command)) {
+	for _, cmd := range cmds {
+		appCmd.AddCommand(cmd.Initialize(f))
+	}
+}
+
+func (c Config) RegisterPersistentPreRunE(f func(cmd *cobra.Command, args []string) error) {
+	persistentPreRunE = append(persistentPreRunE, f)
+}
+
+func (c Config) RegisterPersistentPostRunE(f func(cmd *cobra.Command, args []string) error) {
+	persistentPostRunE = append(persistentPostRunE, f)
+}
+
+func (c Config) Validate() error {
+	if c.Name == "" {
+		return errors.New("name is required")
+	}
+	if c.Title == "" {
+		return errors.New("title is required")
+	}
+
+	var err error
+	if _, err = semver.Parse(c.Version); err != nil {
+		return fmt.Errorf("invalid version: %s", c.Version)
+	}
+	return nil
+}

pkg/application/config_test.go

@@ -0,0 +1,22 @@
+package application
+
+import (
+	"testing"
+)
+
+func TestConfig_Validate(t *testing.T) {
+	tests := []struct {
+		name    string
+		config  Config
+		wantErr bool
+	}{
+		{},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			if err := tt.config.Validate(); (err != nil) != tt.wantErr {
+				t.Errorf("Validate() error = %v, wantErr %v", err, tt.wantErr)
+			}
+		})
+	}
+}

pkg/application/globals.go

@@ -0,0 +1,105 @@
+package application
+
+import (
+	"io"
+	"log/slog"
+	"os"
+	"reflect"
+	"runtime"
+
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+
+	"git.flexabyte.io/flexabyte/go-kit/pkg/slogd"
+	"git.flexabyte.io/flexabyte/go-kit/pkg/slogd_colored"
+)
+
+var (
+	appName            string
+	appCmd             *cobra.Command
+	persistentPreRunE  []func(cmd *cobra.Command, args []string) error // collection of PreRunE functions
+	persistentPostRunE []func(cmd *cobra.Command, args []string) error // collection of PostRunE functions
+	outWriter          io.Writer                                       = os.Stdout
+	// version            semver.Version
+)
+
+func helpFuncE(cmd *cobra.Command, args []string) error {
+	return cmd.Help()
+}
+
+func normalizeFunc(f *pflag.FlagSet, name string) pflag.NormalizedName {
+	// switch name {
+	// case "no-color":
+	// 	name = "log-type"
+	// 	break
+	// }
+	return pflag.NormalizedName(name)
+}
+
+func persistentPreRunFuncE(cmd *cobra.Command, args []string) error {
+	slogd.SetLevel(slogd.Level(logLevelFlag))
+	if slogd.ActiveHandler() == slogd_colored.HandlerColor && noColorFlag {
+		slogd.UseHandler(slogd.HandlerText)
+		cmd.SetContext(slogd.WithContext(cmd.Context()))
+	}
+
+	slogd.FromContext(cmd.Context()).Log(cmd.Context(), slogd.LevelTrace, "starting application", slog.String("command", cmd.CommandPath()))
+	slogd.FromContext(cmd.Context()).Log(cmd.Context(), slogd.LevelTrace, "executing PersistentPreRun")
+
+	// Make sure we can always get the version
+	if versionFlag || cmd.Use == versionName {
+		slogd.FromContext(cmd.Context()).LogAttrs(cmd.Context(), slogd.LevelTrace, "overriding command", slog.String("old_function", runtime.FuncForPC(reflect.ValueOf(cmd.RunE).Pointer()).Name()), slog.String("new_function", runtime.FuncForPC(reflect.ValueOf(versionRunFuncE).Pointer()).Name()))
+		cmd.RunE = versionRunFuncE
+		return nil
+	}
+
+	// Make sure that we show the app help if no commands or flags are passed
+	if cmd.CalledAs() == appName && runtime.FuncForPC(reflect.ValueOf(cmd.RunE).Pointer()).Name() == runtime.FuncForPC(reflect.ValueOf(runFuncE).Pointer()).Name() {
+		slogd.FromContext(cmd.Context()).LogAttrs(cmd.Context(), slogd.LevelTrace, "overriding command", slog.String("old_function", runtime.FuncForPC(reflect.ValueOf(cmd.RunE).Pointer()).Name()), slog.String("new_function", runtime.FuncForPC(reflect.ValueOf(helpFuncE).Pointer()).Name()))
+
+		cmd.RunE = helpFuncE
+		return nil
+	}
+
+	// TODO move to front??
+	if quietFlag {
+		slogd.FromContext(cmd.Context()).LogAttrs(cmd.Context(), slogd.LevelDebug, "activating quiet mode")
+		outWriter = io.Discard
+	}
+
+	if persistentPreRunE == nil {
+		return nil
+	}
+
+	var err error
+	for _, preRun := range persistentPreRunE {
+		slogd.FromContext(cmd.Context()).Log(cmd.Context(), slogd.LevelTrace, "executing PersistentPreRun function", slog.String("function", runtime.FuncForPC(reflect.ValueOf(preRun).Pointer()).Name()))
+		if err = preRun(cmd, args); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func persistentPostRunFuncE(cmd *cobra.Command, args []string) error {
+	defer slogd.FromContext(cmd.Context()).Log(cmd.Context(), slogd.LevelTrace, "stopping application", slog.String("command", cmd.CommandPath()))
+	slogd.FromContext(cmd.Context()).Log(cmd.Context(), slogd.LevelTrace, "executing PersistentPostRunE")
+
+	if persistentPostRunE == nil {
+		return nil
+	}
+
+	var err error
+	for _, postRun := range persistentPostRunE {
+		slogd.FromContext(cmd.Context()).Log(cmd.Context(), slogd.LevelTrace, "executing PersistentPostRun function", slog.String("function", runtime.FuncForPC(reflect.ValueOf(postRun).Pointer()).Name()))
+		if err = postRun(cmd, args); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+// appRunE is an empty catch function to allow overrides through persistentPreRunE
+func runFuncE(cmd *cobra.Command, args []string) error {
+	return nil
+}

pkg/application/logging.go

@@ -0,0 +1,35 @@
+package application
+
+import (
+	"github.com/spf13/cobra"
+)
+
+const (
+	LogOutputStdOut = "stdout"
+	LogOutputStdErr = "stderr"
+	LogOutputFile   = "file"
+)
+
+var logLevelFlag string
+var logOutputFlag string
+var logTypeFlag string
+
+func addLogLevelFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().StringVarP(&logLevelFlag, "log-level", "", "info", "Set log level (trace, debug, info, warn, error, fatal)")
+}
+
+func addLogOutputFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().StringVarP(&logOutputFlag, "log-outWriter", "", "stderr", "Set log outWriter (stdout, stderr, file)")
+}
+
+func addLogTypeFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().StringVarP(&logTypeFlag, "log-type", "", "text", "Set log type (text, json, color)")
+}
+
+func configureLoggingFlags(cmd *cobra.Command) {
+	addLogLevelFlag(cmd)
+	addLogOutputFlag(cmd)
+	addLogTypeFlag(cmd)
+
+	cmd.MarkFlagsMutuallyExclusive("no-color", "log-type")
+}

pkg/application/output.go

@@ -0,0 +1,36 @@
+package application
+
+import "github.com/spf13/cobra"
+
+var jsonOutputFlag bool
+var noColorFlag bool
+var quietFlag bool
+var verboseFlag bool
+
+func addJsonOutputFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().BoolVarP(&jsonOutputFlag, "json", "", false, "Enable JSON outWriter")
+}
+
+func addNoColorFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().BoolVarP(&noColorFlag, "no-color", "", false, "Disable color outWriter")
+}
+
+func addQuietFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().BoolVarP(&quietFlag, "quiet", "q", false, "Enable quiet mode")
+}
+
+func addVerboseFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().BoolVarP(&verboseFlag, "verbose", "v", false, "Enable verbose outWriter")
+}
+
+func configureOutputFlags(cmd *cobra.Command) {
+	addJsonOutputFlag(cmd)
+	addNoColorFlag(cmd)
+	addVerboseFlag(cmd)
+	addQuietFlag(cmd)
+
+	cmd.MarkFlagsMutuallyExclusive("verbose", "quiet", "json")
+	cmd.MarkFlagsMutuallyExclusive("json", "no-color")
+	cmd.MarkFlagsMutuallyExclusive("quiet", "no-color")
+
+}

pkg/application/version.go

@@ -0,0 +1,69 @@
+package application
+
+import (
+	"encoding/json"
+	"fmt"
+
+	"github.com/spf13/cobra"
+
+	"git.flexabyte.io/flexabyte/go-kit/pkg/semver"
+)
+
+const (
+	versionName      = "version"
+	versionShortHand = "V"
+	versionUsage     = "Show version information"
+)
+
+var (
+	version     semver.Version
+	versionFlag bool
+	versionCmd  = &cobra.Command{
+		Use:   versionName,
+		Short: versionUsage,
+		RunE:  versionRunFuncE,
+	}
+)
+
+func addVersionFlag(cmd *cobra.Command) {
+	cmd.PersistentFlags().BoolVarP(&versionFlag, versionName, versionShortHand, false, versionUsage)
+}
+
+func configureVersionFlag(cmd *cobra.Command, v semver.Version) {
+	version = v
+	cmd.AddCommand(versionCmd)
+	addVersionFlag(cmd)
+}
+
+func printVersion(v semver.Version) string {
+	var output string
+	if !verboseFlag {
+		output = v.String()
+	}
+
+	if jsonOutputFlag {
+		var b []byte
+		b, _ = json.Marshal(v)
+		output = string(b)
+	}
+
+	if output != "" {
+		return output
+	}
+
+	return fmt.Sprintf(
+		"Full: %s\nVersion: %s\nChannel: %s\nCommit: %s\nDate: %s",
+		v.String(),
+		v.Number(),
+		v.Release(),
+		v.Commit(),
+		v.Date(),
+	)
+}
+
+func versionRunFuncE(cmd *cobra.Command, args []string) error {
+	if _, err := fmt.Fprintln(outWriter, printVersion(version)); err != nil {
+		return err
+	}
+	return nil
+}