cli: refactor to allow definition of subcommands next to their implementation

cli/cli.go

@@ -0,0 +1,105 @@
+package cli
+
+import (
+	"fmt"
+	"github.com/spf13/cobra"
+	"github.com/spf13/pflag"
+	"github.com/zrepl/zrepl/config"
+	"os"
+)
+
+var rootArgs struct {
+	configPath string
+}
+
+var rootCmd = &cobra.Command{
+	Use:   "zrepl",
+	Short: "One-stop ZFS replication solution",
+}
+
+var bashcompCmd = &cobra.Command{
+	Use:   "bashcomp path/to/out/file",
+	Short: "generate bash completions",
+	Run: func(cmd *cobra.Command, args []string) {
+		if len(args) != 1 {
+			fmt.Fprintf(os.Stderr, "specify exactly one positional agument\n")
+			cmd.Usage()
+			os.Exit(1)
+		}
+		if err := rootCmd.GenBashCompletionFile(args[0]); err != nil {
+			fmt.Fprintf(os.Stderr, "error generating bash completion: %s", err)
+			os.Exit(1)
+		}
+	},
+	Hidden: true,
+}
+
+func init() {
+	rootCmd.PersistentFlags().StringVar(&rootArgs.configPath, "config", "", "config file path")
+	rootCmd.AddCommand(bashcompCmd)
+}
+
+type Subcommand struct {
+	Use             string
+	Short           string
+	NoRequireConfig bool
+	Run             func(subcommand *Subcommand, args []string) error
+	SetupFlags      func(f *pflag.FlagSet)
+
+	config *config.Config
+	configErr error
+}
+
+func (s *Subcommand) ConfigParsingError() error {
+	return s.configErr
+}
+
+func (s *Subcommand) Config() *config.Config {
+	if !s.NoRequireConfig && s.config == nil {
+		panic("command that requires config is running and has no config set")
+	}
+	return s.config
+}
+
+func (s *Subcommand) run(cmd *cobra.Command, args []string) {
+	s.tryParseConfig()
+	err := s.Run(s, args)
+	if err != nil {
+		fmt.Fprintf(os.Stderr, "%s\n", err)
+		os.Exit(1)
+	}
+}
+
+func (s *Subcommand) tryParseConfig() {
+	config, err := config.ParseConfig(rootArgs.configPath)
+	s.configErr = err
+	if err != nil {
+		if s.NoRequireConfig {
+			// doesn't matter
+			return
+		} else {
+			fmt.Fprintf(os.Stderr, "could not parse config: %s\n", err)
+			os.Exit(1)
+		}
+	}
+	s.config = config
+}
+
+func AddSubcommand(s *Subcommand) {
+	cmd := cobra.Command{
+		Use: s.Use,
+		Short: s.Short,
+		Run: s.run,
+	}
+	if s.SetupFlags != nil {
+		s.SetupFlags(cmd.Flags())
+	}
+	rootCmd.AddCommand(&cmd)
+}
+
+
+func Run() {
+	if err := rootCmd.Execute(); err != nil {
+		os.Exit(1)
+	}
+}

client/configcheck.go

@@ -1,8 +1,36 @@
 package client
 
-import "github.com/zrepl/zrepl/config"
+import (
+	"encoding/json"
+	"github.com/kr/pretty"
+	"github.com/spf13/pflag"
+	"github.com/zrepl/yaml-config"
+	"github.com/zrepl/zrepl/cli"
+	"os"
+)
 
-func RunConfigcheck(conf *config.Config, args []string) error {
-	// TODO: do the 'build' steps, e.g. build the jobs and see if that fails
-	return nil
+var configcheckArgs struct {
+	format string
 }
+
+var ConfigcheckCmd = &cli.Subcommand{
+	Use: "configcheck",
+	Short: "check if config can be parsed without errors",
+	SetupFlags: func(f *pflag.FlagSet) {
+		f.StringVar(&configcheckArgs.format, "format", "", "dump parsed config object [pretty|yaml|json]")
+	},
+	Run: func(subcommand *cli.Subcommand, args []string) error {
+		switch configcheckArgs.format {
+		case "pretty":
+			_, err := pretty.Println(subcommand.Config())
+			return err
+		case "json":
+			return json.NewEncoder(os.Stdout).Encode(subcommand.Config())
+		case "yaml":
+			return yaml.NewEncoder(os.Stdout).Encode(subcommand.Config())
+		default: // no output
+		}
+		return nil
+	},
+}
+

client/pprof.go

@@ -1,17 +1,48 @@
 package client
 
 import (
+	"errors"
+	"github.com/zrepl/zrepl/cli"
 	"github.com/zrepl/zrepl/config"
 	"github.com/zrepl/zrepl/daemon"
 	"log"
 	"os"
 )
 
-type PProfArgs struct {
+var pprofArgs struct {
 	daemon.PprofServerControlMsg
 }
 
-func RunPProf(conf *config.Config, args PProfArgs) {
+var PprofCmd = &cli.Subcommand{
+	Use:   "pprof off | [on TCP_LISTEN_ADDRESS]",
+	Short: "start a http server exposing go-tool-compatible profiling endpoints at TCP_LISTEN_ADDRESS",
+	Run: func(subcommand *cli.Subcommand, args []string) error {
+		if len(args) < 1 {
+			goto enargs
+		}
+		switch args[0] {
+		case "on":
+			pprofArgs.Run = true
+			if len(args) != 2 {
+				return errors.New("must specify TCP_LISTEN_ADDRESS as second positional argument")
+			}
+			pprofArgs.HttpListenAddress = args[1]
+		case "off":
+			if len(args) != 1 {
+				goto enargs
+			}
+			pprofArgs.Run = false
+		}
+
+		RunPProf(subcommand.Config())
+		return nil
+	enargs:
+		return errors.New("invalid number of positional arguments")
+
+	},
+}
+
+func RunPProf(conf *config.Config) {
 	log := log.New(os.Stderr, "", 0)
 
 	die := func() {
@@ -26,7 +57,7 @@ func RunPProf(conf *config.Config, args PProfArgs) {
 		log.Printf("error creating http client: %s", err)
 		die()
 	}
-	err = jsonRequestResponse(httpc, daemon.ControlJobEndpointPProf, args.PprofServerControlMsg, struct{}{})
+	err = jsonRequestResponse(httpc, daemon.ControlJobEndpointPProf, pprofArgs.PprofServerControlMsg, struct{}{})
 	if err != nil {
 		log.Printf("error sending control message: %s", err)
 		die()

client/signal.go

@@ -2,11 +2,20 @@ package client
 
 import (
 	"github.com/pkg/errors"
+	"github.com/zrepl/zrepl/cli"
 	"github.com/zrepl/zrepl/config"
 	"github.com/zrepl/zrepl/daemon"
 )
 
-func RunSignal(config *config.Config, args []string) error {
+var SignalCmd = &cli.Subcommand{
+	Use:   "signal [wakeup|reset] JOB",
+	Short: "wake up a job from wait state or abort its current invocation",
+	Run: func(subcommand *cli.Subcommand, args []string) error {
+		return runSignalCmd(subcommand.Config(), args)
+	},
+}
+
+func runSignalCmd(config *config.Config, args []string) error {
 	if len(args) != 2 {
 		return errors.Errorf("Expected 2 arguments: [wakeup|reset] JOB")
 	}

client/status.go

@@ -4,21 +4,22 @@ import (
 	"fmt"
 	"github.com/nsf/termbox-go"
 	"github.com/pkg/errors"
+	"github.com/spf13/pflag"
 	"github.com/zrepl/yaml-config"
-	"github.com/zrepl/zrepl/config"
+	"github.com/zrepl/zrepl/cli"
 	"github.com/zrepl/zrepl/daemon"
 	"github.com/zrepl/zrepl/daemon/job"
 	"github.com/zrepl/zrepl/daemon/pruner"
 	"github.com/zrepl/zrepl/replication"
 	"github.com/zrepl/zrepl/replication/fsrep"
+	"io"
 	"math"
+	"net/http"
+	"os"
 	"sort"
 	"strings"
 	"sync"
 	"time"
-	"io"
-	"os"
-	"net/http"
 )
 
 type tui struct {
@@ -73,17 +74,26 @@ func (t *tui) addIndent(indent int) {
 	t.moveLine(0, 0)
 }
 
-type StatusFlags struct {
+var statusFlags struct {
 	Raw bool
 }
 
-func RunStatus(flags StatusFlags, config *config.Config, args []string) error {
-	httpc, err := controlHttpClient(config.Global.Control.SockPath)
+var StatusCmd = &cli.Subcommand{
+	Use:   "status",
+	Short: "show job activity or dump as JSON for monitoring",
+	SetupFlags: func(f *pflag.FlagSet) {
+		f.BoolVar(&statusFlags.Raw, "raw", false, "dump raw status description from zrepl daemon")
+	},
+	Run: runStatus,
+}
+
+func runStatus(s *cli.Subcommand, args []string) error {
+	httpc, err := controlHttpClient(s.Config().Global.Control.SockPath)
 	if err != nil {
 		return err
 	}
 
-	if flags.Raw {
+	if statusFlags.Raw {
 		resp, err := httpc.Get("http://unix"+daemon.ControlJobEndpointStatus)
 		if err != nil {
 			return err

client/stdinserver.go

@@ -1,18 +1,26 @@
 package client
 
 import (
+	"github.com/zrepl/zrepl/cli"
 	"os"
 
 	"context"
+	"errors"
 	"github.com/problame/go-netssh"
+	"github.com/zrepl/zrepl/config"
 	"log"
 	"path"
-	"github.com/zrepl/zrepl/config"
-	"errors"
 )
 
+var StdinserverCmd = &cli.Subcommand{
+	Use:   "stdinserver CLIENT_IDENTITY",
+	Short: "stdinserver transport mode (started from authorized_keys file as forced command)",
+	Run: func(subcommand *cli.Subcommand, args []string) error {
+		return runStdinserver(subcommand.Config(), args)
+	},
+}
 
-func RunStdinserver(config *config.Config, args []string) error {
+func runStdinserver(config *config.Config, args []string) error {
 
 	// NOTE: the netssh proxying protocol requires exiting with non-zero status if anything goes wrong
 	defer os.Exit(1)

client/version.go

@@ -2,27 +2,39 @@ package client
 
 import (
 	"fmt"
+	"github.com/spf13/pflag"
+	"github.com/zrepl/zrepl/cli"
 	"github.com/zrepl/zrepl/config"
 	"github.com/zrepl/zrepl/daemon"
 	"github.com/zrepl/zrepl/version"
 	"os"
 )
 
-type VersionArgs struct {
+var versionArgs struct {
 	Show   string
 	Config *config.Config
+	ConfigErr error
 }
 
-func RunVersion(args VersionArgs) {
+var VersionCmd = &cli.Subcommand{
+	Use:   "version",
+	Short: "print version of zrepl binary and running daemon",
+	NoRequireConfig: true,
+	SetupFlags: func(f *pflag.FlagSet) {
+		f.StringVar(&versionArgs.Show, "show", "", "version info to show (client|daemon)")
+	},
+	Run: func(subcommand *cli.Subcommand, args []string) error {
+		versionArgs.Config = subcommand.Config()
+		versionArgs.ConfigErr = subcommand.ConfigParsingError()
+		return runVersionCmd()
+	},
+}
 
-	die := func() {
-		fmt.Fprintf(os.Stderr, "exiting after error\n")
-		os.Exit(1)
-	}
+func runVersionCmd() error {
+	args := versionArgs
 
 	if args.Show != "daemon" && args.Show != "client" && args.Show != "" {
-		fmt.Fprintf(os.Stderr, "show flag must be 'client' or 'server' or be left empty")
-		die()
+		return fmt.Errorf("show flag must be 'client' or 'server' or be left empty")
 	}
 
 	var clientVersion, daemonVersion *version.ZreplVersionInformation
@@ -32,17 +44,19 @@ func RunVersion(args VersionArgs) {
 	}
 	if args.Show == "daemon" || args.Show == "" {
 
+		if args.ConfigErr != nil {
+			return fmt.Errorf("config parsing error: %s", args.ConfigErr)
+		}
+
 		httpc, err := controlHttpClient(args.Config.Global.Control.SockPath)
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "server: error: %s\n", err)
-			die()
+			return fmt.Errorf("server: error: %s\n", err)
 		}
 
 		var info version.ZreplVersionInformation
 		err = jsonRequestResponse(httpc, daemon.ControlJobEndpointVersion, "", &info)
 		if err != nil {
-			fmt.Fprintf(os.Stderr, "server: error: %s\n", err)
-			die()
+			return fmt.Errorf("server: error: %s\n", err)
 		}
 		daemonVersion = &info
 		fmt.Printf("server: %s\n", daemonVersion.String())
@@ -54,4 +68,5 @@ func RunVersion(args VersionArgs) {
 		}
 	}
 
+	return nil
 }

daemon/main.go

@@ -1,7 +1,16 @@
 package daemon
 
 import (
+	"github.com/zrepl/zrepl/cli"
 	"github.com/zrepl/zrepl/logger"
 )
 
 type Logger = logger.Logger
+
+var DaemonCmd = &cli.Subcommand {
+	Use:   "daemon",
+	Short: "run the zrepl daemon",
+	Run: func(subcommand *cli.Subcommand, args []string) error {
+		return Run(subcommand.Config())
+	},
+}

main.go

@@ -2,172 +2,21 @@
 package main
 
 import (
-	"errors"
-	"github.com/spf13/cobra"
+	"github.com/zrepl/zrepl/cli"
 	"github.com/zrepl/zrepl/client"
-	"github.com/zrepl/zrepl/config"
 	"github.com/zrepl/zrepl/daemon"
-	"log"
-	"os"
-	"fmt"
 )
 
-var rootCmd = &cobra.Command{
-	Use:   "zrepl",
-	Short: "One-stop ZFS replication solution",
-}
-
-var daemonCmd = &cobra.Command{
-	Use:   "daemon",
-	Short: "run the zrepl daemon",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err != nil {
-			return err
-		}
-		return daemon.Run(conf)
-	},
-}
-
-var signalCmd = &cobra.Command{
-	Use:   "signal [wakeup|reset] JOB",
-	Short: "wake up a job from wait state or abort its current invocation",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err != nil {
-			return err
-		}
-		return client.RunSignal(conf, args)
-	},
-}
-
-var statusCmdFlags client.StatusFlags
-
-var statusCmd = &cobra.Command{
-	Use:   "status",
-	Short: "show job activity or dump as JSON for monitoring",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err != nil {
-			return err
-		}
-		return client.RunStatus(statusCmdFlags, conf, args)
-	},
-}
-
-var stdinserverCmd = &cobra.Command{
-	Use:   "stdinserver CLIENT_IDENTITY",
-	Short: "stdinserver transport mode (started from authorized_keys file as forced command)",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err != nil {
-			return err
-		}
-		return client.RunStdinserver(conf, args)
-	},
-}
-
-
-var bashcompCmd = &cobra.Command{
-	Use:   "bashcomp path/to/out/file",
-	Short: "generate bash completions",
-	Run: func(cmd *cobra.Command, args []string) {
-		if len(args) != 1 {
-			fmt.Fprintf(os.Stderr, "specify exactly one positional agument\n")
-			cmd.Usage()
-			os.Exit(1)
-		}
-		if err := rootCmd.GenBashCompletionFile(args[0]); err != nil {
-			fmt.Fprintf(os.Stderr, "error generating bash completion: %s", err)
-			os.Exit(1)
-		}
-	},
-	Hidden: true,
-}
-
-var configcheckCmd = &cobra.Command{
-	Use: "configcheck",
-	Short: "check if config can be parsed without errors",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err != nil {
-			return err
-		}
-		return client.RunConfigcheck(conf, args)
-	},
-}
-
-var versionCmdArgs client.VersionArgs
-var versionCmd = &cobra.Command{
-	Use:   "version",
-	Short: "print version of zrepl binary and running daemon",
-	Run: func(cmd *cobra.Command, args []string) {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err == nil {
-			versionCmdArgs.Config = conf
-		}
-		client.RunVersion(versionCmdArgs)
-	},
-}
-
-var pprofCmd = &cobra.Command{
-	Use:   "pprof off | [on TCP_LISTEN_ADDRESS]",
-	Short: "start a http server exposing go-tool-compatible profiling endpoints at TCP_LISTEN_ADDRESS",
-	RunE: func(cmd *cobra.Command, args []string) error {
-		conf, err := config.ParseConfig(rootArgs.configFile)
-		if err != nil {
-			return err
-		}
-
-		var pprofCmdArgs client.PProfArgs
-		if cmd.Flags().NArg() < 1 {
-			goto enargs
-		}
-		switch cmd.Flags().Arg(0) {
-		case "on":
-			pprofCmdArgs.Run = true
-			if cmd.Flags().NArg() != 2 {
-				return errors.New("must specify TCP_LISTEN_ADDRESS as second positional argument")
-			}
-			pprofCmdArgs.HttpListenAddress = cmd.Flags().Arg(1)
-		case "off":
-			if cmd.Flags().NArg() != 1 {
-				goto enargs
-			}
-			pprofCmdArgs.Run = false
-		}
-
-		client.RunPProf(conf, pprofCmdArgs)
-		return nil
-	enargs:
-		return errors.New("invalid number of positional arguments")
-
-	},
-}
-
-var rootArgs struct {
-	configFile string
-}
-
 func init() {
-	//cobra.OnInitialize(initConfig)
-	rootCmd.PersistentFlags().StringVar(&rootArgs.configFile, "config", "", "config file path")
-	rootCmd.AddCommand(daemonCmd)
-	rootCmd.AddCommand(signalCmd)
-	statusCmd.Flags().BoolVar(&statusCmdFlags.Raw, "raw", false, "dump raw status description from zrepl daemon")
-	rootCmd.AddCommand(statusCmd)
-	rootCmd.AddCommand(stdinserverCmd)
-	rootCmd.AddCommand(bashcompCmd)
-	rootCmd.AddCommand(configcheckCmd)
-	versionCmd.Flags().StringVar(&versionCmdArgs.Show, "show", "", "version info to show (client|daemon)")
-	rootCmd.AddCommand(versionCmd)
-	rootCmd.AddCommand(pprofCmd)
+	cli.AddSubcommand(daemon.DaemonCmd)
+	cli.AddSubcommand(client.StatusCmd)
+	cli.AddSubcommand(client.SignalCmd)
+	cli.AddSubcommand(client.StdinserverCmd)
+	cli.AddSubcommand(client.ConfigcheckCmd)
+	cli.AddSubcommand(client.VersionCmd)
+	cli.AddSubcommand(client.PprofCmd)
 }
 
 func main() {
-
-	if err := rootCmd.Execute(); err != nil {
-		log.Printf("error executing root command: %s", err)
-		os.Exit(1)
-	}
+	cli.Run()
 }