errors: rewrite errors to follow go best practices

Errors should not start capitalised and they should not contain the word error
or state that they "failed" as we already know it is an error

Signed-off-by: Kristoffer Dalby <kristoffer@dalby.cc>

hscontrol/app.go

@@ -121,7 +121,7 @@ func NewHeadscale(cfg *types.Config) (*Headscale, error) {
 
 	noisePrivateKey, err := readOrCreatePrivateKey(cfg.NoisePrivateKeyPath)
 	if err != nil {
-		return nil, fmt.Errorf("failed to read or create Noise protocol private key: %w", err)
+		return nil, fmt.Errorf("reading or creating Noise protocol private key: %w", err)
 	}
 
 	s, err := state.NewState(cfg)
@@ -206,7 +206,7 @@ func NewHeadscale(cfg *types.Config) (*Headscale, error) {
 	if cfg.DERP.ServerEnabled {
 		derpServerKey, err := readOrCreatePrivateKey(cfg.DERP.ServerPrivateKeyPath)
 		if err != nil {
-			return nil, fmt.Errorf("failed to read or create DERP server private key: %w", err)
+			return nil, fmt.Errorf("reading or creating DERP server private key: %w", err)
 		}
 
 		if derpServerKey.Equal(*noisePrivateKey) {
@@ -339,7 +339,7 @@ func (h *Headscale) grpcAuthenticationInterceptor(ctx context.Context,
 	if !ok {
 		return ctx, status.Errorf(
 			codes.InvalidArgument,
-			"Retrieving metadata is failed",
+			"retrieving metadata",
 		)
 	}
 
@@ -347,7 +347,7 @@ func (h *Headscale) grpcAuthenticationInterceptor(ctx context.Context,
 	if !ok {
 		return ctx, status.Errorf(
 			codes.Unauthenticated,
-			"Authorization token is not supplied",
+			"authorization token not supplied",
 		)
 	}
 
@@ -362,7 +362,7 @@ func (h *Headscale) grpcAuthenticationInterceptor(ctx context.Context,
 
 	valid, err := h.state.ValidateAPIKey(strings.TrimPrefix(token, AuthPrefix))
 	if err != nil {
-		return ctx, status.Error(codes.Internal, "failed to validate token")
+		return ctx, status.Error(codes.Internal, "validating token")
 	}
 
 	if !valid {
@@ -526,7 +526,7 @@ func (h *Headscale) Serve() error {
 
 	derpMap, err := derp.GetDERPMap(h.cfg.DERP)
 	if err != nil {
-		return fmt.Errorf("failed to get DERPMap: %w", err)
+		return fmt.Errorf("getting DERPMap: %w", err)
 	}
 
 	if h.cfg.DERP.ServerEnabled && h.cfg.DERP.AutomaticallyAddEmbeddedDerpRegion {
@@ -586,7 +586,7 @@ func (h *Headscale) Serve() error {
 
 	err = h.ensureUnixSocketIsAbsent()
 	if err != nil {
-		return fmt.Errorf("unable to remove old socket file: %w", err)
+		return fmt.Errorf("removing old socket file: %w", err)
 	}
 
 	socketDir := filepath.Dir(h.cfg.UnixSocket)
@@ -597,12 +597,12 @@ func (h *Headscale) Serve() error {
 
 	socketListener, err := net.Listen("unix", h.cfg.UnixSocket)
 	if err != nil {
-		return fmt.Errorf("failed to set up gRPC socket: %w", err)
+		return fmt.Errorf("setting up gRPC socket: %w", err)
 	}
 
 	// Change socket permissions
 	if err := os.Chmod(h.cfg.UnixSocket, h.cfg.UnixSocketPermission); err != nil {
-		return fmt.Errorf("failed change permission of gRPC socket: %w", err)
+		return fmt.Errorf("changing gRPC socket permission: %w", err)
 	}
 
 	grpcGatewayMux := grpcRuntime.NewServeMux()
@@ -687,7 +687,7 @@ func (h *Headscale) Serve() error {
 
 		grpcListener, err = net.Listen("tcp", h.cfg.GRPCAddr)
 		if err != nil {
-			return fmt.Errorf("failed to bind to TCP address: %w", err)
+			return fmt.Errorf("binding to TCP address: %w", err)
 		}
 
 		errorGroup.Go(func() error { return grpcServer.Serve(grpcListener) })
@@ -722,7 +722,7 @@ func (h *Headscale) Serve() error {
 		httpListener, err = net.Listen("tcp", h.cfg.Addr)
 	}
 	if err != nil {
-		return fmt.Errorf("failed to bind to TCP address: %w", err)
+		return fmt.Errorf("binding to TCP address: %w", err)
 	}
 
 	errorGroup.Go(func() error { return httpServer.Serve(httpListener) })
@@ -738,7 +738,7 @@ func (h *Headscale) Serve() error {
 	if h.cfg.MetricsAddr != "" {
 		debugHTTPListener, err = (&net.ListenConfig{}).Listen(ctx, "tcp", h.cfg.MetricsAddr)
 		if err != nil {
-			return fmt.Errorf("failed to bind to TCP address: %w", err)
+			return fmt.Errorf("binding to TCP address: %w", err)
 		}
 
 		debugHTTPServer = h.debugHTTPServer()
@@ -977,14 +977,14 @@ func readOrCreatePrivateKey(path string) (*key.MachinePrivate, error) {
 		machineKeyStr, err := machineKey.MarshalText()
 		if err != nil {
 			return nil, fmt.Errorf(
-				"failed to convert private key to string for saving: %w",
+				"converting private key to string for saving: %w",
 				err,
 			)
 		}
 		err = os.WriteFile(path, machineKeyStr, privateKeyFileMode)
 		if err != nil {
 			return nil, fmt.Errorf(
-				"failed to save private key to disk at path %q: %w",
+				"saving private key to disk at path %q: %w",
 				path,
 				err,
 			)
@@ -992,14 +992,14 @@ func readOrCreatePrivateKey(path string) (*key.MachinePrivate, error) {
 
 		return &machineKey, nil
 	} else if err != nil {
-		return nil, fmt.Errorf("failed to read private key file: %w", err)
+		return nil, fmt.Errorf("reading private key file: %w", err)
 	}
 
 	trimmedPrivateKey := strings.TrimSpace(string(privateKey))
 
 	var machineKey key.MachinePrivate
 	if err = machineKey.UnmarshalText([]byte(trimmedPrivateKey)); err != nil {
-		return nil, fmt.Errorf("failed to parse private key: %w", err)
+		return nil, fmt.Errorf("parsing private key: %w", err)
 	}
 
 	return &machineKey, nil