Get rid of dynamic errors

.golangci.yaml

@@ -30,7 +30,6 @@ linters:
 
     # We should strive to enable these:
     - wrapcheck
-    - goerr113
     - dupl
     - makezero
 

app.go

@@ -52,6 +52,11 @@ const (
 	Sqlite          = "sqlite3"
 	updateInterval  = 5000
 	HTTPReadTimeout = 30 * time.Second
+
+	errUnsupportedDatabase                 = Error("unsupported DB")
+	errUnsupportedLetsEncryptChallengeType = Error(
+		"unknown value for Lets Encrypt challenge type",
+	)
 )
 
 // Config contains the initial Headscale configuration.
@@ -166,7 +171,7 @@ func NewHeadscale(cfg Config) (*Headscale, error) {
 	case Sqlite:
 		dbString = cfg.DBpath
 	default:
-		return nil, errors.New("unsupported DB")
+		return nil, errUnsupportedDatabase
 	}
 
 	app := Headscale{
@@ -626,7 +631,7 @@ func (h *Headscale) getTLSSettings() (*tls.Config, error) {
 			return certManager.TLSConfig(), nil
 
 		default:
-			return nil, errors.New("unknown value for TLSLetsEncryptChallengeType")
+			return nil, errUnsupportedLetsEncryptChallengeType
 		}
 	} else if h.cfg.TLSCertPath == "" {
 		if !strings.HasPrefix(h.cfg.ServerURL, "http://") {

cmd/headscale/cli/namespaces.go

@@ -4,6 +4,7 @@ import (
 	"fmt"
 
 	survey "github.com/AlecAivazis/survey/v2"
+	"github.com/juanfont/headscale"
 	v1 "github.com/juanfont/headscale/gen/go/headscale/v1"
 	"github.com/pterm/pterm"
 	"github.com/rs/zerolog/log"
@@ -19,6 +20,10 @@ func init() {
 	namespaceCmd.AddCommand(renameNamespaceCmd)
 }
 
+const (
+	errMissingParameter = headscale.Error("missing parameters")
+)
+
 var namespaceCmd = &cobra.Command{
 	Use:   "namespaces",
 	Short: "Manage the namespaces of Headscale",
@@ -29,7 +34,7 @@ var createNamespaceCmd = &cobra.Command{
 	Short: "Creates a new namespace",
 	Args: func(cmd *cobra.Command, args []string) error {
 		if len(args) < 1 {
-			return fmt.Errorf("missing parameters")
+			return errMissingParameter
 		}
 
 		return nil
@@ -71,7 +76,7 @@ var destroyNamespaceCmd = &cobra.Command{
 	Short: "Destroys a namespace",
 	Args: func(cmd *cobra.Command, args []string) error {
 		if len(args) < 1 {
-			return fmt.Errorf("missing parameters")
+			return errMissingParameter
 		}
 
 		return nil
@@ -197,7 +202,7 @@ var renameNamespaceCmd = &cobra.Command{
 	Args: func(cmd *cobra.Command, args []string) error {
 		expectedArguments := 2
 		if len(args) < expectedArguments {
-			return fmt.Errorf("missing parameters")
+			return errMissingParameter
 		}
 
 		return nil

cmd/headscale/cli/preauthkeys.go

@@ -178,7 +178,7 @@ var expirePreAuthKeyCmd = &cobra.Command{
 	Short: "Expire a preauthkey",
 	Args: func(cmd *cobra.Command, args []string) error {
 		if len(args) < 1 {
-			return fmt.Errorf("missing parameters")
+			return errMissingParameter
 		}
 
 		return nil

cmd/headscale/cli/utils.go

@@ -81,6 +81,7 @@ func LoadConfig(path string) error {
 		errorText += "Fatal config error: server_url must start with https:// or http://\n"
 	}
 	if errorText != "" {
+		//nolint
 		return errors.New(strings.TrimSuffix(errorText, "\n"))
 	} else {
 		return nil
@@ -305,6 +306,8 @@ func getHeadscaleApp() (*headscale.Headscale, error) {
 	// to avoid races
 	minInactivityTimeout, _ := time.ParseDuration("65s")
 	if viper.GetDuration("ephemeral_node_inactivity_timeout") <= minInactivityTimeout {
+		// TODO: Find a better way to return this text
+		//nolint
 		err := fmt.Errorf(
 			"ephemeral_node_inactivity_timeout (%s) is set too low, must be more than %s",
 			viper.GetString("ephemeral_node_inactivity_timeout"),

db.go

@@ -9,7 +9,10 @@ import (
 	"gorm.io/gorm/logger"
 )
 
-const dbVersion = "1"
+const (
+	dbVersion        = "1"
+	errValueNotFound = Error("not found")
+)
 
 // KV is a key-value store in a psql table. For future use...
 type KV struct {
@@ -92,7 +95,7 @@ func (h *Headscale) getValue(key string) (string, error) {
 		result.Error,
 		gorm.ErrRecordNotFound,
 	) {
-		return "", errors.New("not found")
+		return "", errValueNotFound
 	}
 
 	return row.Value, nil

machine.go

@@ -20,6 +20,12 @@ import (
 	"tailscale.com/types/wgkey"
 )
 
+const (
+	errMachineNotFound            = Error("machine not found")
+	errMachineAlreadyRegistered   = Error("machine already registered")
+	errMachineRouteIsNotAvailable = Error("route is not available on machine")
+)
+
 // Machine is a Headscale client.
 type Machine struct {
 	ID          uint64 `gorm:"primary_key"`
@@ -248,7 +254,7 @@ func (h *Headscale) GetMachine(namespace string, name string) (*Machine, error)
 		}
 	}
 
-	return nil, fmt.Errorf("machine not found")
+	return nil, errMachineNotFound
 }
 
 // GetMachineByID finds a Machine by ID and returns the Machine struct.
@@ -615,7 +621,7 @@ func (h *Headscale) RegisterMachine(
 		result.Error,
 		gorm.ErrRecordNotFound,
 	) {
-		return nil, errors.New("Machine not found")
+		return nil, errMachineNotFound
 	}
 
 	log.Trace().
@@ -624,7 +630,7 @@ func (h *Headscale) RegisterMachine(
 		Msg("Attempting to register machine")
 
 	if machine.isAlreadyRegistered() {
-		err := errors.New("Machine already registered")
+		err := errMachineAlreadyRegistered
 		log.Error().
 			Caller().
 			Err(err).
@@ -740,9 +746,9 @@ func (h *Headscale) EnableRoutes(machine *Machine, routeStrs ...string) error {
 	for _, newRoute := range newRoutes {
 		if !containsIPPrefix(availableRoutes, newRoute) {
 			return fmt.Errorf(
-				"route (%s) is not available on node %s",
+				"route (%s) is not available on node %s: %w",
 				machine.Name,
-				newRoute,
+				newRoute, errMachineRouteIsNotAvailable,
 			)
 		}
 	}

preauth_keys.go

@@ -16,6 +16,7 @@ const (
 	errPreAuthKeyNotFound          = Error("AuthKey not found")
 	errPreAuthKeyExpired           = Error("AuthKey expired")
 	errSingleUseAuthKeyHasBeenUsed = Error("AuthKey has already been used")
+	errNamespaceMismatch           = Error("namespace mismatch")
 )
 
 // PreAuthKey describes a pre-authorization key usable in a particular namespace.
@@ -87,7 +88,7 @@ func (h *Headscale) GetPreAuthKey(namespace string, key string) (*PreAuthKey, er
 	}
 
 	if pak.Namespace.Name != namespace {
-		return nil, errors.New("Namespace mismatch")
+		return nil, errNamespaceMismatch
 	}
 
 	return pak, nil

routes.go

@@ -2,12 +2,15 @@ package headscale
 
 import (
 	"encoding/json"
-	"fmt"
 
 	"gorm.io/datatypes"
 	"inet.af/netaddr"
 )
 
+const (
+	errRouteIsNotAvailable = Error("route is not available")
+)
+
 // Deprecated: use machine function instead
 // GetAdvertisedNodeRoutes returns the subnet routes advertised by a node (identified by
 // namespace and node name).
@@ -129,7 +132,7 @@ func (h *Headscale) EnableNodeRoute(
 	}
 
 	if !available {
-		return fmt.Errorf("route (%s) is not available on node %s", nodeName, routeStr)
+		return errRouteIsNotAvailable
 	}
 
 	routes, err := json.Marshal(enabledRoutes)

utils.go

@@ -20,6 +20,12 @@ import (
 	"tailscale.com/types/wgkey"
 )
 
+const (
+	errCannotDecryptReponse = Error("cannot decrypt response")
+	errResponseMissingNonce = Error("response missing nonce")
+	errCouldNotAllocateIP   = Error("could not find any suitable IP")
+)
+
 // Error is used to compare errors as per https://dave.cheney.net/2016/04/07/constant-errors
 type Error string
 
@@ -46,7 +52,7 @@ func decodeMsg(
 	}
 	// fmt.Println(string(decrypted))
 	if err := json.Unmarshal(decrypted, output); err != nil {
-		return fmt.Errorf("response: %w", err)
+		return err
 	}
 
 	return nil
@@ -55,7 +61,7 @@ func decodeMsg(
 func decryptMsg(msg []byte, pubKey *wgkey.Key, privKey *wgkey.Private) ([]byte, error) {
 	var nonce [24]byte
 	if len(msg) < len(nonce)+1 {
-		return nil, fmt.Errorf("response missing nonce, len=%d", len(msg))
+		return nil, errResponseMissingNonce
 	}
 	copy(nonce[:], msg)
 	msg = msg[len(nonce):]
@@ -63,7 +69,7 @@ func decryptMsg(msg []byte, pubKey *wgkey.Key, privKey *wgkey.Private) ([]byte,
 	pub, pri := (*[32]byte)(pubKey), (*[32]byte)(privKey)
 	decrypted, ok := box.Open(nil, msg, &nonce, pub, pri)
 	if !ok {
-		return nil, fmt.Errorf("cannot decrypt response")
+		return nil, errCannotDecryptReponse
 	}
 
 	return decrypted, nil
@@ -106,7 +112,7 @@ func (h *Headscale) getAvailableIP() (*netaddr.IP, error) {
 
 	for {
 		if !ipPrefix.Contains(ip) {
-			return nil, fmt.Errorf("could not find any suitable IP in %s", ipPrefix)
+			return nil, errCouldNotAllocateIP
 		}
 
 		// Some OS (including Linux) does not like when IPs ends with 0 or 255, which
@@ -143,7 +149,7 @@ func (h *Headscale) getUsedIPs() ([]netaddr.IP, error) {
 		if addr != "" {
 			ip, err := netaddr.ParseIP(addr)
 			if err != nil {
-				return nil, fmt.Errorf("failed to parse ip from database, %w", err)
+				return nil, fmt.Errorf("failed to parse ip from database: %w", err)
 			}
 
 			ips[index] = ip