feat(log): add basic support for logging output

commands/commands.go

@@ -1,9 +1,69 @@
 package commands
 
-import "github.com/spf13/cobra"
+import (
+	"io"
+	"os"
+
+	"github.com/rs/zerolog"
+	"github.com/rs/zerolog/log"
+	"github.com/spf13/cobra"
+)
 
 type runEFunc func(cmd *cobra.Command, _ []string) error
 
+func WithPrettyLogging(
+	f func(cmd *cobra.Command, args []string) error,
+) func(cmd *cobra.Command, args []string) error {
+	return func(cmd *cobra.Command, args []string) error {
+		err := SetupZerolog(cmd)
+		if err != nil {
+			return err
+		}
+
+		return f(cmd, args)
+	}
+}
+
+func SetupZerolog(cmd *cobra.Command) error {
+	var levelStr string
+	if v := os.Getenv("EVM_DEBUG"); v != "" {
+		levelStr = "debug"
+	} else if v := os.Getenv("EVM_LOG_LEVEL"); v != "" {
+		levelStr = v
+	}
+
+	var out io.Writer = os.Stderr
+
+	if cmd != nil {
+		out = cmd.OutOrStderr()
+		fl := cmd.Flag("log-level")
+		if fl != nil && (fl.Changed || levelStr == "") {
+			levelStr = fl.Value.String()
+		}
+	}
+
+	if levelStr == "" {
+		levelStr = "info"
+	}
+
+	level, err := zerolog.ParseLevel(levelStr)
+	if err != nil {
+		return err
+	}
+
+	zerolog.SetGlobalLevel(level)
+	zerolog.TimeFieldFormat = ""
+
+	output := zerolog.ConsoleWriter{Out: out}
+	output.FormatTimestamp = func(i interface{}) string {
+		return ""
+	}
+
+	log.Logger = zerolog.New(output).With().Timestamp().Logger()
+
+	return nil
+}
+
 type validArgsFunc func(
 	cmd *cobra.Command,
 	args []string,

commands/config.go

@@ -11,7 +11,7 @@ func NewConfig(mgr *manager.Manager) (*cobra.Command, error) {
 		Short:     "Show evm environment/setup details",
 		Aliases:   []string{"env", "info"},
 		ValidArgs: []string{},
-		RunE:      configRunE(mgr),
+		RunE:      WithPrettyLogging(configRunE(mgr)),
 	}
 
 	cmd.Flags().StringP("format", "f", "", "output format (yaml or json)")

commands/evm.go

@@ -11,6 +11,11 @@ func NewEvm(mgr *manager.Manager) (*cobra.Command, error) {
 		Short: "A simple and opinionated Emacs Version Manager and build tool",
 	}
 
+	cmd.PersistentFlags().StringP(
+		"log-level", "l", "info",
+		"one of: trace, debug, info, warn, error, fatal, panic",
+	)
+
 	configCmd, err := NewConfig(mgr)
 	if err != nil {
 		return nil, err

commands/exec.go

@@ -22,7 +22,7 @@ func NewExec(mgr *manager.Manager) (*cobra.Command, error) {
 		DisableFlagsInUseLine: true,
 		Hidden:                true,
 		ValidArgsFunction:     execValidArgs(mgr),
-		RunE:                  execRunE(mgr),
+		RunE:                  WithPrettyLogging(execRunE(mgr)),
 	}
 
 	return cmd, nil

commands/list.go

@@ -15,7 +15,7 @@ func NewList(mgr *manager.Manager) (*cobra.Command, error) {
 		Aliases:           []string{"ls", "versions"},
 		Args:              cobra.ExactArgs(0),
 		ValidArgsFunction: noValidArgs,
-		RunE:              listRunE(mgr),
+		RunE:              WithPrettyLogging(listRunE(mgr)),
 	}
 
 	cmd.Flags().StringP("format", "f", "", "output format (yaml or json)")

commands/rehash.go

@@ -13,7 +13,7 @@ func NewRehash(mgr *manager.Manager) (*cobra.Command, error) {
 		Short:             "Update shims for all or specific versions",
 		Aliases:           []string{"reshim"},
 		ValidArgsFunction: rehashValidArgs(mgr),
-		RunE:              rehashRunE(mgr),
+		RunE:              WithPrettyLogging(rehashRunE(mgr)),
 	}
 
 	return cmd, nil

commands/use.go

@@ -14,7 +14,7 @@ func NewUse(mgr *manager.Manager) (*cobra.Command, error) {
 		Aliases:           []string{"activate", "switch"},
 		Args:              cobra.ExactArgs(1),
 		ValidArgsFunction: useValidArgs(mgr),
-		RunE:              useRunE(mgr),
+		RunE:              WithPrettyLogging(useRunE(mgr)),
 	}
 
 	return cmd, nil