grpcreflect

Documentation

Overview

Package grpcreflect provides GRPC-specific extensions to protobuf reflection. This includes a way to access rich service descriptors for all services that a GRPC server exports.

Also included is an easy-to-use client for the GRPC reflection service (https://goo.gl/2ILAHf). This client makes it easy to ask a server (that supports the reflection service) for metadata on its exported services, which could be used to construct a dynamic client. (See the grpcdynamic package in this same repo for more on that.)

Index

• func IsElementNotFoundError(err error) bool
• func LoadServiceDescriptor(svc *grpc.ServiceDesc) (*desc.ServiceDescriptor, error)
• func LoadServiceDescriptors(s GRPCServer) (map[string]*desc.ServiceDescriptor, error)
• type Client
  • func NewClient(ctx context.Context, stub refv1alpha.ServerReflectionClient) *Client
  • func NewClientAuto(ctx context.Context, cc grpc.ClientConnInterface) *Client
  • func NewClientV1(ctx context.Context, stub refv1.ServerReflectionClient) *Client
  • func NewClientV1Alpha(ctx context.Context, stub refv1alpha.ServerReflectionClient) *Client
  • func (cr *Client) AllExtensionNumbersForType(extendedMessageName string) ([]int32, error)
  • func (cr *Client) AllowFallbackResolver(descriptors protodesc.Resolver, exts protoregistry.ExtensionTypeResolver)
  • func (cr *Client) AllowMissingFileDescriptors()
  • func (cr *Client) FileByFilename(filename string) (*desc.FileDescriptor, error)
  • func (cr *Client) FileContainingExtension(extendedMessageName string, extensionNumber int32) (*desc.FileDescriptor, error)
  • func (cr *Client) FileContainingSymbol(symbol string) (*desc.FileDescriptor, error)
  • func (cr *Client) ListServices() ([]string, error)
  • func (cr *Client) Reset()
  • func (cr *Client) ResolveEnum(enumName string) (*desc.EnumDescriptor, error)
  • func (cr *Client) ResolveEnumValues(enumName string) (map[string]int32, error)
  • func (cr *Client) ResolveExtension(extendedType string, extensionNumber int32) (*desc.FieldDescriptor, error)
  • func (cr *Client) ResolveMessage(messageName string) (*desc.MessageDescriptor, error)
  • func (cr *Client) ResolveService(serviceName string) (*desc.ServiceDescriptor, error)
• type GRPCServer
• type ProtocolError
  • func (p ProtocolError) Error() string

Functions

func IsElementNotFoundError

func IsElementNotFoundError(err error) bool

IsElementNotFoundError determines if the given error indicates that a file name, symbol name, or extension field was could not be found by the server.

func LoadServiceDescriptor

func LoadServiceDescriptor(svc *grpc.ServiceDesc) (*desc.ServiceDescriptor, error)

LoadServiceDescriptor loads a rich descriptor for a given service description generated by protoc-gen-go. Generated code contains an unexported symbol with a name like "_<Service>_serviceDesc" which is the service's description. It is used internally to register a service implementation with a GRPC server. But it can also be used by this package to retrieve the rich descriptor for the service.

func LoadServiceDescriptors

func LoadServiceDescriptors(s GRPCServer) (map[string]*desc.ServiceDescriptor, error)

LoadServiceDescriptors loads the service descriptors for all services exposed by the given GRPC server.

Types

type Client

type Client struct {
	// contains filtered or unexported fields
}

Client is a client connection to a server for performing reflection calls and resolving remote symbols.

func NewClient

func NewClient(ctx context.Context, stub refv1alpha.ServerReflectionClient) *Client

NewClient creates a new Client with the given root context and using the given RPC stub for talking to the server.

Deprecated: Use NewClientV1Alpha if you are intentionally pinning the v1alpha version of the reflection service. Otherwise, use NewClientAuto instead.

func NewClientAuto

func NewClientAuto(ctx context.Context, cc grpc.ClientConnInterface) *Client

NewClientAuto creates a new Client that will use either v1 or v1alpha version of reflection (based on what the server supports) with the given root context and using the given client connection.

It will first the v1 version of the reflection service. If it gets back an "Unimplemented" error, it will fall back to using the v1alpha version. It will remember which version the server supports for any subsequent operations that need to re-invoke the streaming RPC. But, if it's a very long-lived client, it will periodically retry the v1 version (in case the server is updated to support it also). The period for these retries is every hour.

func NewClientV1

func NewClientV1(ctx context.Context, stub refv1.ServerReflectionClient) *Client

NewClientV1 creates a new Client using the v1 version of reflection with the given root context and using the given RPC stub for talking to the server.

func NewClientV1Alpha

func NewClientV1Alpha(ctx context.Context, stub refv1alpha.ServerReflectionClient) *Client

NewClientV1Alpha creates a new Client using the v1alpha version of reflection with the given root context and using the given RPC stub for talking to the server.

func (*Client) AllExtensionNumbersForType

func (cr *Client) AllExtensionNumbersForType(extendedMessageName string) ([]int32, error)

AllExtensionNumbersForType asks the server for all known extension numbers for the given fully-qualified message name.

func (*Client) AllowFallbackResolver

func (cr *Client) AllowFallbackResolver(descriptors protodesc.Resolver, exts protoregistry.ExtensionTypeResolver)

AllowFallbackResolver configures the client to allow falling back to the given resolvers if the server is unable to supply descriptors for a particular query. This allows working around issues where servers' reflection service provides an incomplete set of descriptors, but the client has knowledge of the missing descriptors from another source. It is usually most appropriate to pass protoregistry.GlobalFiles and protoregistry.GlobalTypes as the resolver values.

The first value is used as a fallback for FileByFilename and FileContainingSymbol queries. The second value is used as a fallback for FileContainingExtension. It can also be used as a fallback for AllExtensionNumbersForType if it provides a method with the following signature (which *protoregistry.Types provides):

RangeExtensionsByMessage(message protoreflect.FullName, f func(protoreflect.ExtensionType) bool)

func (*Client) AllowMissingFileDescriptors

func (cr *Client) AllowMissingFileDescriptors()

AllowMissingFileDescriptors configures the client to allow missing files when building descriptors when possible. Missing files are often fatal errors, but with this option they can sometimes be worked around. Building a schema can only succeed with some files missing if the files in question only provide custom options and/or other unused types.

func (*Client) FileByFilename

func (cr *Client) FileByFilename(filename string) (*desc.FileDescriptor, error)

FileByFilename asks the server for a file descriptor for the proto file with the given name.

func (*Client) FileContainingExtension

func (cr *Client) FileContainingExtension(extendedMessageName string, extensionNumber int32) (*desc.FileDescriptor, error)

FileContainingExtension asks the server for a file descriptor for the proto file that declares an extension with the given number for the given fully-qualified message name.

func (*Client) FileContainingSymbol

func (cr *Client) FileContainingSymbol(symbol string) (*desc.FileDescriptor, error)

FileContainingSymbol asks the server for a file descriptor for the proto file that declares the given fully-qualified symbol.

func (*Client) ListServices

func (cr *Client) ListServices() ([]string, error)

ListServices asks the server for the fully-qualified names of all exposed services.

func (*Client) Reset

func (cr *Client) Reset()

Reset ensures that any active stream with the server is closed, releasing any resources.

func (*Client) ResolveEnum

func (cr *Client) ResolveEnum(enumName string) (*desc.EnumDescriptor, error)

ResolveEnum asks the server to resolve the given fully-qualified enum name into an enum descriptor.

func (*Client) ResolveEnumValues

func (cr *Client) ResolveEnumValues(enumName string) (map[string]int32, error)

ResolveEnumValues asks the server to resolve the given fully-qualified enum name into a map of names to numbers that represents the enum's values.

func (*Client) ResolveExtension

func (cr *Client) ResolveExtension(extendedType string, extensionNumber int32) (*desc.FieldDescriptor, error)

ResolveExtension asks the server to resolve the given extension number and fully-qualified message name into a field descriptor.

func (*Client) ResolveMessage

func (cr *Client) ResolveMessage(messageName string) (*desc.MessageDescriptor, error)

ResolveMessage asks the server to resolve the given fully-qualified message name into a message descriptor.

func (*Client) ResolveService

func (cr *Client) ResolveService(serviceName string) (*desc.ServiceDescriptor, error)

ResolveService asks the server to resolve the given fully-qualified service name into a service descriptor.

type GRPCServer

type GRPCServer = reflection.GRPCServer

GRPCServer is the interface provided by a gRPC server. In addition to being a service registrar (for registering services and handlers), it also has an accessor for retrieving metadata about all registered services.

type ProtocolError

type ProtocolError struct {
	// contains filtered or unexported fields
}

ProtocolError is an error returned when the server sends a response of the wrong type.

func (ProtocolError) Error

func (p ProtocolError) Error() string