cosmos-sdk/baseapp/msg_service_router.go

98 lines
3.7 KiB
Go

package baseapp
import (
"context"
"fmt"
gogogrpc "github.com/gogo/protobuf/grpc"
"github.com/gogo/protobuf/proto"
"google.golang.org/grpc"
codectypes "github.com/cosmos/cosmos-sdk/codec/types"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
)
// MsgServiceRouter routes fully-qualified Msg service methods to their handler.
type MsgServiceRouter struct {
interfaceRegistry codectypes.InterfaceRegistry
routes map[string]MsgServiceHandler
}
var _ gogogrpc.Server = &MsgServiceRouter{}
// NewMsgServiceRouter creates a new MsgServiceRouter.
func NewMsgServiceRouter() *MsgServiceRouter {
return &MsgServiceRouter{
routes: map[string]MsgServiceHandler{},
}
}
// MsgServiceHandler defines a function type which handles Msg service message.
type MsgServiceHandler = func(ctx sdk.Context, req sdk.MsgRequest) (*sdk.Result, error)
// Handler returns the MsgServiceHandler for a given query route path or nil
// if not found.
func (msr *MsgServiceRouter) Handler(methodName string) MsgServiceHandler {
return msr.routes[methodName]
}
// RegisterService implements the gRPC Server.RegisterService method. sd is a gRPC
// service description, handler is an object which implements that gRPC service.
func (msr *MsgServiceRouter) RegisterService(sd *grpc.ServiceDesc, handler interface{}) {
// Adds a top-level query handler based on the gRPC service name.
for _, method := range sd.Methods {
fqMethod := fmt.Sprintf("/%s/%s", sd.ServiceName, method.MethodName)
methodHandler := method.Handler
// NOTE: This is how we pull the concrete request type for each handler for registering in the InterfaceRegistry.
// This approach is maybe a bit hacky, but less hacky than reflecting on the handler object itself.
// We use a no-op interceptor to avoid actually calling into the handler itself.
_, _ = methodHandler(nil, context.Background(), func(i interface{}) error {
msg, ok := i.(proto.Message)
if !ok {
// We panic here because there is no other alternative and the app cannot be initialized correctly
// this should only happen if there is a problem with code generation in which case the app won't
// work correctly anyway.
panic(fmt.Errorf("can't register request type %T for service method %s", i, fqMethod))
}
msr.interfaceRegistry.RegisterCustomTypeURL((*sdk.MsgRequest)(nil), fqMethod, msg)
return nil
}, noopInterceptor)
msr.routes[fqMethod] = func(ctx sdk.Context, req sdk.MsgRequest) (*sdk.Result, error) {
ctx = ctx.WithEventManager(sdk.NewEventManager())
interceptor := func(goCtx context.Context, _ interface{}, _ *grpc.UnaryServerInfo, handler grpc.UnaryHandler) (interface{}, error) {
goCtx = context.WithValue(goCtx, sdk.SdkContextKey, ctx)
return handler(goCtx, req)
}
// Call the method handler from the service description with the handler object.
// We don't do any decoding here because the decoding was already done.
res, err := methodHandler(handler, sdk.WrapSDKContext(ctx), noopDecoder, interceptor)
if err != nil {
return nil, err
}
resMsg, ok := res.(proto.Message)
if !ok {
return nil, sdkerrors.Wrapf(sdkerrors.ErrInvalidType, "Expecting proto.Message, got %T", resMsg)
}
return sdk.WrapServiceResult(ctx, resMsg, err)
}
}
}
// SetInterfaceRegistry sets the interface registry for the router.
func (msr *MsgServiceRouter) SetInterfaceRegistry(interfaceRegistry codectypes.InterfaceRegistry) {
msr.interfaceRegistry = interfaceRegistry
}
// gRPC NOOP interceptor
func noopInterceptor(_ context.Context, _ interface{}, _ *grpc.UnaryServerInfo, _ grpc.UnaryHandler) (interface{}, error) {
return nil, nil
}
func noopDecoder(_ interface{}) error { return nil }