cmd/headscale/cli: convert remaining commands to RunE

Convert the 10 commands that were still using Run with
ErrorOutput/SuccessOutput or log.Fatal/os.Exit:

- backfillNodeIPsCmd: use grpcRunE-style manual connection with
  error returns; simplify the confirm/force logic
- getPolicy, setPolicy, checkPolicy: replace ErrorOutput with
  fmt.Errorf returns in both the bypass-gRPC and gRPC paths
- serveCmd, configTestCmd: replace log.Fatal with error returns
- mockOidcCmd: replace log.Error+os.Exit with error return
- versionCmd, generatePrivateKeyCmd: replace SuccessOutput with
  printOutput
- dumpConfigCmd: return the error instead of swallowing it

cmd/headscale/cli/configtest.go

@@ -1,7 +1,8 @@
 package cli
 
 import (
-	"github.com/rs/zerolog/log"
+	"fmt"
+
 	"github.com/spf13/cobra"
 )
 
@@ -13,10 +14,12 @@ var configTestCmd = &cobra.Command{
 	Use:   "configtest",
 	Short: "Test the configuration.",
 	Long:  "Run a test of the configuration and exit.",
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		_, err := newHeadscaleServerWithConfig()
 		if err != nil {
-			log.Fatal().Caller().Err(err).Msg("error initializing")
+			return fmt.Errorf("configuration error: %w", err)
 		}
+
+		return nil
 	},
 }

cmd/headscale/cli/dump_config.go

@@ -18,11 +18,12 @@ var dumpConfigCmd = &cobra.Command{
 	Args: func(cmd *cobra.Command, args []string) error {
 		return nil
 	},
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		err := viper.WriteConfigAs("/etc/headscale/config.dump.yaml")
 		if err != nil {
-			//nolint
-			fmt.Println("Failed to dump config")
+			return fmt.Errorf("dumping config: %w", err)
 		}
+
+		return nil
 	},
 }

cmd/headscale/cli/generate.go

@@ -21,22 +21,17 @@ var generateCmd = &cobra.Command{
 var generatePrivateKeyCmd = &cobra.Command{
 	Use:   "private-key",
 	Short: "Generate a private key for the headscale server",
-	Run: func(cmd *cobra.Command, args []string) {
-		output, _ := cmd.Flags().GetString("output")
+	RunE: func(cmd *cobra.Command, args []string) error {
 		machineKey := key.NewMachine()
 
 		machineKeyStr, err := machineKey.MarshalText()
 		if err != nil {
-			ErrorOutput(
-				err,
-				fmt.Sprintf("Error getting machine key from flag: %s", err),
-				output,
-			)
+			return fmt.Errorf("marshalling machine key: %w", err)
 		}
 
-		SuccessOutput(map[string]string{
+		return printOutput(cmd, map[string]string{
 			"private_key": string(machineKeyStr),
 		},
-			string(machineKeyStr), output)
+			string(machineKeyStr))
 	},
 }

cmd/headscale/cli/mockoidc.go

@@ -34,12 +34,13 @@ var mockOidcCmd = &cobra.Command{
 	Use:   "mockoidc",
 	Short: "Runs a mock OIDC server for testing",
 	Long:  "This internal command runs a OpenID Connect for testing purposes",
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		err := mockOIDC()
 		if err != nil {
-			log.Error().Err(err).Msgf("error running mock OIDC server")
-			os.Exit(1)
+			return fmt.Errorf("running mock OIDC server: %w", err)
 		}
+
+		return nil
 	},
 }
 

cmd/headscale/cli/nodes.go

@@ -14,7 +14,6 @@ import (
 	"github.com/pterm/pterm"
 	"github.com/samber/lo"
 	"github.com/spf13/cobra"
-	"google.golang.org/grpc/status"
 	"google.golang.org/protobuf/types/known/timestamppb"
 	"tailscale.com/types/key"
 )
@@ -357,9 +356,7 @@ all nodes that are missing.
 If you remove IPv4 or IPv6 prefixes from the config,
 it can be run to remove the IPs that should no longer
 be assigned to nodes.`,
-	Run: func(cmd *cobra.Command, args []string) {
-		output, _ := cmd.Flags().GetString("output")
-
+	RunE: func(cmd *cobra.Command, args []string) error {
 		confirm := false
 
 		force, _ := cmd.Flags().GetBool("force")
@@ -367,25 +364,23 @@ be assigned to nodes.`,
 			confirm = util.YesNo("Are you sure that you want to assign/remove IPs to/from nodes?")
 		}
 
-		if confirm || force {
-			ctx, client, conn, cancel, err := newHeadscaleCLIWithConfig()
-			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Error connecting: %s", err), output)
-			}
-			defer cancel()
-			defer conn.Close()
-
-			changes, err := client.BackfillNodeIPs(ctx, &v1.BackfillNodeIPsRequest{Confirmed: confirm || force})
-			if err != nil {
-				ErrorOutput(
-					err,
-					"Error backfilling IPs: "+status.Convert(err).Message(),
-					output,
-				)
-			}
-
-			SuccessOutput(changes, "Node IPs backfilled successfully", output)
+		if !confirm && !force {
+			return nil
 		}
+
+		ctx, client, conn, cancel, err := newHeadscaleCLIWithConfig()
+		if err != nil {
+			return fmt.Errorf("connecting to headscale: %w", err)
+		}
+		defer cancel()
+		defer conn.Close()
+
+		changes, err := client.BackfillNodeIPs(ctx, &v1.BackfillNodeIPsRequest{Confirmed: true})
+		if err != nil {
+			return fmt.Errorf("backfilling IPs: %w", err)
+		}
+
+		return printOutput(cmd, changes, "Node IPs backfilled successfully")
 	},
 }
 

cmd/headscale/cli/policy.go

@@ -1,6 +1,7 @@
 package cli
 
 import (
+	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -19,6 +20,8 @@ const (
 	bypassFlag = "bypass-grpc-and-access-database-directly" //nolint:gosec // not a credential
 )
 
+var errAborted = errors.New("command aborted by user")
+
 func init() {
 	rootCmd.AddCommand(policyCmd)
 
@@ -54,11 +57,8 @@ var getPolicy = &cobra.Command{
 	Use:     "get",
 	Short:   "Print the current ACL Policy",
 	Aliases: []string{"show", "view", "fetch"},
-	Run: func(cmd *cobra.Command, args []string) {
-		output, _ := cmd.Flags().GetString("output")
-
-		var policy string
-
+	RunE: func(cmd *cobra.Command, args []string) error {
+		var policyData string
 		if bypass, _ := cmd.Flags().GetBool(bypassFlag); bypass {
 			confirm := false
 
@@ -68,51 +68,46 @@ var getPolicy = &cobra.Command{
 			}
 
 			if !confirm && !force {
-				ErrorOutput(nil, "Aborting command", output)
-				return
+				return errAborted
 			}
 
 			cfg, err := types.LoadServerConfig()
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed loading config: %s", err), output)
+				return fmt.Errorf("loading config: %w", err)
 			}
 
-			d, err := db.NewHeadscaleDatabase(
-				cfg,
-				nil,
-			)
+			d, err := db.NewHeadscaleDatabase(cfg, nil)
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed to open database: %s", err), output)
+				return fmt.Errorf("opening database: %w", err)
 			}
 
 			pol, err := d.GetPolicy()
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed loading Policy from database: %s", err), output)
+				return fmt.Errorf("loading policy from database: %w", err)
 			}
 
-			policy = pol.Data
+			policyData = pol.Data
 		} else {
 			ctx, client, conn, cancel, err := newHeadscaleCLIWithConfig()
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Error connecting: %s", err), output)
+				return fmt.Errorf("connecting to headscale: %w", err)
 			}
 			defer cancel()
 			defer conn.Close()
 
-			request := &v1.GetPolicyRequest{}
-
-			response, err := client.GetPolicy(ctx, request)
+			response, err := client.GetPolicy(ctx, &v1.GetPolicyRequest{})
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed loading ACL Policy: %s", err), output)
+				return fmt.Errorf("loading ACL policy: %w", err)
 			}
 
-			policy = response.GetPolicy()
+			policyData = response.GetPolicy()
 		}
 
-		// TODO(pallabpain): Maybe print this better?
-		// This does not pass output as we dont support yaml, json or json-line
-		// output for this command. It is HuJSON already.
-		SuccessOutput("", policy, "")
+		// This does not pass output format as we don't support yaml, json or
+		// json-line output for this command. It is HuJSON already.
+		fmt.Println(policyData)
+
+		return nil
 	},
 }
 
@@ -123,19 +118,18 @@ var setPolicy = &cobra.Command{
 	Updates the existing ACL Policy with the provided policy. The policy must be a valid HuJSON object.
 	This command only works when the acl.policy_mode is set to "db", and the policy will be stored in the database.`,
 	Aliases: []string{"put", "update"},
-	Run: func(cmd *cobra.Command, args []string) {
-		output, _ := cmd.Flags().GetString("output")
+	RunE: func(cmd *cobra.Command, args []string) error {
 		policyPath, _ := cmd.Flags().GetString("file")
 
 		f, err := os.Open(policyPath)
 		if err != nil {
-			ErrorOutput(err, fmt.Sprintf("Error opening the policy file: %s", err), output)
+			return fmt.Errorf("opening policy file: %w", err)
 		}
 		defer f.Close()
 
 		policyBytes, err := io.ReadAll(f)
 		if err != nil {
-			ErrorOutput(err, fmt.Sprintf("Error reading the policy file: %s", err), output)
+			return fmt.Errorf("reading policy file: %w", err)
 		}
 
 		if bypass, _ := cmd.Flags().GetBool(bypassFlag); bypass {
@@ -147,80 +141,79 @@ var setPolicy = &cobra.Command{
 			}
 
 			if !confirm && !force {
-				ErrorOutput(nil, "Aborting command", output)
-				return
+				return errAborted
 			}
 
 			cfg, err := types.LoadServerConfig()
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed loading config: %s", err), output)
+				return fmt.Errorf("loading config: %w", err)
 			}
 
-			d, err := db.NewHeadscaleDatabase(
-				cfg,
-				nil,
-			)
+			d, err := db.NewHeadscaleDatabase(cfg, nil)
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed to open database: %s", err), output)
+				return fmt.Errorf("opening database: %w", err)
 			}
 
 			users, err := d.ListUsers()
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed to load users for policy validation: %s", err), output)
+				return fmt.Errorf("loading users for policy validation: %w", err)
 			}
 
 			_, err = policy.NewPolicyManager(policyBytes, users, views.Slice[types.NodeView]{})
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Error parsing the policy file: %s", err), output)
-				return
+				return fmt.Errorf("parsing policy file: %w", err)
 			}
 
 			_, err = d.SetPolicy(string(policyBytes))
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Failed to set ACL Policy: %s", err), output)
+				return fmt.Errorf("setting ACL policy: %w", err)
 			}
 		} else {
 			request := &v1.SetPolicyRequest{Policy: string(policyBytes)}
 
 			ctx, client, conn, cancel, err := newHeadscaleCLIWithConfig()
 			if err != nil {
-				ErrorOutput(err, fmt.Sprintf("Error connecting: %s", err), output)
+				return fmt.Errorf("connecting to headscale: %w", err)
 			}
 			defer cancel()
 			defer conn.Close()
 
-			if _, err := client.SetPolicy(ctx, request); err != nil { //nolint:noinlineerr
-				ErrorOutput(err, fmt.Sprintf("Failed to set ACL Policy: %s", err), output)
+			_, err = client.SetPolicy(ctx, request)
+			if err != nil {
+				return fmt.Errorf("setting ACL policy: %w", err)
 			}
 		}
 
-		SuccessOutput(nil, "Policy updated.", "")
+		fmt.Println("Policy updated.")
+
+		return nil
 	},
 }
 
 var checkPolicy = &cobra.Command{
 	Use:   "check",
 	Short: "Check the Policy file for errors",
-	Run: func(cmd *cobra.Command, args []string) {
-		output, _ := cmd.Flags().GetString("output")
+	RunE: func(cmd *cobra.Command, args []string) error {
 		policyPath, _ := cmd.Flags().GetString("file")
 
 		f, err := os.Open(policyPath)
 		if err != nil {
-			ErrorOutput(err, fmt.Sprintf("Error opening the policy file: %s", err), output)
+			return fmt.Errorf("opening policy file: %w", err)
 		}
 		defer f.Close()
 
 		policyBytes, err := io.ReadAll(f)
 		if err != nil {
-			ErrorOutput(err, fmt.Sprintf("Error reading the policy file: %s", err), output)
+			return fmt.Errorf("reading policy file: %w", err)
 		}
 
 		_, err = policy.NewPolicyManager(policyBytes, nil, views.Slice[types.NodeView]{})
 		if err != nil {
-			ErrorOutput(err, fmt.Sprintf("Error parsing the policy file: %s", err), output)
+			return fmt.Errorf("parsing policy file: %w", err)
 		}
 
-		SuccessOutput(nil, "Policy is valid", "")
+		fmt.Println("Policy is valid")
+
+		return nil
 	},
 }

cmd/headscale/cli/serve.go

@@ -5,7 +5,6 @@ import (
 	"fmt"
 	"net/http"
 
-	"github.com/rs/zerolog/log"
 	"github.com/spf13/cobra"
 	"github.com/tailscale/squibble"
 )
@@ -20,7 +19,7 @@ var serveCmd = &cobra.Command{
 	Args: func(cmd *cobra.Command, args []string) error {
 		return nil
 	},
-	Run: func(cmd *cobra.Command, args []string) {
+	RunE: func(cmd *cobra.Command, args []string) error {
 		app, err := newHeadscaleServerWithConfig()
 		if err != nil {
 			if squibbleErr, ok := errors.AsType[squibble.ValidationError](err); ok {
@@ -28,12 +27,14 @@ var serveCmd = &cobra.Command{
 				fmt.Println(squibbleErr.Diff)
 			}
 
-			log.Fatal().Caller().Err(err).Msg("error initializing")
+			return fmt.Errorf("initializing: %w", err)
 		}
 
 		err = app.Serve()
 		if err != nil && !errors.Is(err, http.ErrServerClosed) {
-			log.Fatal().Caller().Err(err).Msg("headscale ran into an error and had to shut down")
+			return fmt.Errorf("headscale ran into an error and had to shut down: %w", err)
 		}
+
+		return nil
 	},
 }

cmd/headscale/cli/version.go

@@ -14,11 +14,9 @@ var versionCmd = &cobra.Command{
 	Use:   "version",
 	Short: "Print the version.",
 	Long:  "The version of headscale.",
-	Run: func(cmd *cobra.Command, args []string) {
-		output, _ := cmd.Flags().GetString("output")
-
+	RunE: func(cmd *cobra.Command, args []string) error {
 		info := types.GetVersionInfo()
 
-		SuccessOutput(info, info.String(), output)
+		return printOutput(cmd, info, info.String())
 	},
 }