add metrics, tracing, validation interceptors, add options: WithInterceptors, With{Client,Server}Interceptors

interceptors/validation/interceptors.go

@@ -0,0 +1 @@
+package validation

interceptors/validation/validation.go

@@ -0,0 +1,161 @@
+package validation
+
+import (
+	"context"
+
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc"
+	"google.golang.org/protobuf/proto"
+
+	"go.linka.cloud/grpc/errors"
+	"go.linka.cloud/grpc/interceptors"
+)
+
+// The validate interface starting with protoc-gen-validate v0.6.0.
+// See https://github.com/envoyproxy/protoc-gen-validate/pull/455.
+type validator interface {
+	Validate(all bool) error
+}
+
+// The validate interface prior to protoc-gen-validate v0.6.0.
+type validatorLegacy interface {
+	Validate() error
+}
+
+type validatorMultiError interface {
+	AllErrors() []error
+}
+
+type validatorError interface {
+	Field() string
+	Reason() string
+	Key() bool
+	Cause() error
+	ErrorName() string
+}
+
+func validatorErrorToGrpc(e validatorError) *errdetails.BadRequest_FieldViolation {
+	return &errdetails.BadRequest_FieldViolation{
+		Field:       e.Field(),
+		Description: e.Reason(),
+	}
+}
+
+func errToStatus(err error) error {
+	switch v := err.(type) {
+	case validatorError:
+		return errors.InvalidArgumentD(err, validatorErrorToGrpc(v))
+	case validatorMultiError:
+		var details []proto.Message
+		for _, v := range v.AllErrors() {
+			if d, ok := v.(validatorError); ok {
+				details = append(details, validatorErrorToGrpc(d))
+			}
+		}
+		return errors.InvalidArgumentd(err, details...)
+	default:
+		return errors.InvalidArgument(err)
+	}
+}
+
+func (i interceptor) validate(req interface{}) error {
+	switch v := req.(type) {
+	case validatorLegacy:
+		if err := v.Validate(); err != nil {
+			return errToStatus(err)
+		}
+	case validator:
+		if err := v.Validate(i.all); err != nil {
+			return errToStatus(err)
+		}
+	}
+	return nil
+}
+
+type interceptor struct {
+	all bool
+}
+
+func NewInterceptors(validateAll bool) interceptors.Interceptors {
+	return &interceptor{all: validateAll}
+}
+
+// UnaryServerInterceptor returns a new unary server interceptor that validates incoming messages.
+//
+// Invalid messages will be rejected with `InvalidArgument` before reaching any userspace handlers.
+func (i interceptor) UnaryServerInterceptor() grpc.UnaryServerInterceptor {
+	return func(ctx context.Context, req interface{}, info *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
+		if err := i.validate(req); err != nil {
+			return nil, err
+		}
+		return handler(ctx, req)
+	}
+}
+
+// UnaryClientInterceptor returns a new unary client interceptor that validates outgoing messages.
+//
+// Invalid messages will be rejected with `InvalidArgument` before sending the request to server.
+func (i interceptor) UnaryClientInterceptor() grpc.UnaryClientInterceptor {
+	return func(ctx context.Context, method string, req, reply interface{}, cc *grpc.ClientConn, invoker grpc.UnaryInvoker, opts ...grpc.CallOption) error {
+		if err := i.validate(req); err != nil {
+			return err
+		}
+		return invoker(ctx, method, req, reply, cc, opts...)
+	}
+}
+
+// StreamServerInterceptor returns a new streaming server interceptor that validates incoming messages.
+//
+// The stage at which invalid messages will be rejected with `InvalidArgument` varies based on the
+// type of the RPC. For `ServerStream` (1:m) requests, it will happen before reaching any userspace
+// handlers. For `ClientStream` (n:1) or `BidiStream` (n:m) RPCs, the messages will be rejected on
+// calls to `stream.Recv()`.
+func (i interceptor) StreamServerInterceptor() grpc.StreamServerInterceptor {
+	return func(srv interface{}, stream grpc.ServerStream, info *grpc.StreamServerInfo, handler grpc.StreamHandler) error {
+		wrapper := &recvWrapper{ServerStream: stream, i: i}
+		return handler(srv, wrapper)
+	}
+}
+
+func (i interceptor) StreamClientInterceptor() grpc.StreamClientInterceptor {
+	return func(ctx context.Context, desc *grpc.StreamDesc, cc *grpc.ClientConn, method string, streamer grpc.Streamer, opts ...grpc.CallOption) (grpc.ClientStream, error) {
+		desc.Handler = (&sendWrapper{handler: desc.Handler, i: i}).Handler()
+		return streamer(ctx, desc, cc, method)
+	}
+}
+
+type recvWrapper struct {
+	i interceptor
+	grpc.ServerStream
+}
+
+func (s *recvWrapper) RecvMsg(m interface{}) error {
+	if err := s.ServerStream.RecvMsg(m); err != nil {
+		return err
+	}
+
+	if err := s.i.validate(m); err != nil {
+		return err
+	}
+
+	return nil
+}
+
+type sendWrapper struct {
+	i interceptor
+	grpc.ServerStream
+	handler grpc.StreamHandler
+}
+
+func (s *sendWrapper) Handler() grpc.StreamHandler {
+	return func(srv interface{}, stream grpc.ServerStream) error {
+		return s.handler(srv, s)
+	}
+}
+
+func (s *sendWrapper) SendMsg(m interface{}) error {
+	if err := s.i.validate(m); err != nil {
+		return err
+	}
+	return s.ServerStream.SendMsg(m)
+}