package baseapp
import (
"context"
"fmt"
gogogrpc "github.com/cosmos/gogoproto/grpc"
"github.com/cosmos/gogoproto/proto"
"google.golang.org/grpc"
"google.golang.org/protobuf/runtime/protoiface"
errorsmod "cosmossdk.io/errors"
"github.com/cosmos/cosmos-sdk/baseapp/internal/protocompat"
"github.com/cosmos/cosmos-sdk/codec"
codectypes "github.com/cosmos/cosmos-sdk/codec/types"
sdk "github.com/cosmos/cosmos-sdk/types"
sdkerrors "github.com/cosmos/cosmos-sdk/types/errors"
)
/ MessageRouter ADR 031 request type routing
/ https://github.com/cosmos/cosmos-sdk/blob/main/docs/architecture/adr-031-msg-service.md
type MessageRouter interface {
Handler(msg sdk.Msg)
MsgServiceHandler
HandlerByTypeURL(typeURL string)
MsgServiceHandler
}
/ MsgServiceRouter routes fully-qualified Msg service methods to their handler.
type MsgServiceRouter struct {
interfaceRegistry codectypes.InterfaceRegistry
routes map[string]MsgServiceHandler
hybridHandlers map[string]func(ctx context.Context, req, resp protoiface.MessageV1)
error
circuitBreaker CircuitBreaker
}
var _ gogogrpc.Server = &MsgServiceRouter{
}
/ NewMsgServiceRouter creates a new MsgServiceRouter.
func NewMsgServiceRouter() *MsgServiceRouter {
return &MsgServiceRouter{
routes: map[string]MsgServiceHandler{
},
hybridHandlers: map[string]func(ctx context.Context, req, resp protoiface.MessageV1)
error{
},
}
}
func (msr *MsgServiceRouter)
SetCircuit(cb CircuitBreaker) {
msr.circuitBreaker = cb
}
/ MsgServiceHandler defines a function type which handles Msg service message.
type MsgServiceHandler = func(ctx sdk.Context, req sdk.Msg) (*sdk.Result, error)
/ Handler returns the MsgServiceHandler for a given msg or nil if not found.
func (msr *MsgServiceRouter)
Handler(msg sdk.Msg)
MsgServiceHandler {
return msr.routes[sdk.MsgTypeURL(msg)]
}
/ HandlerByTypeURL returns the MsgServiceHandler for a given query route path or nil
/ if not found.
func (msr *MsgServiceRouter)
HandlerByTypeURL(typeURL string)
MsgServiceHandler {
return msr.routes[typeURL]
}
/ RegisterService implements the gRPC Server.RegisterService method. sd is a gRPC
/ service description, handler is an object which implements that gRPC service.
/
/ This function PANICs:
/ - if it is called before the service `Msg`s have been registered using
/ RegisterInterfaces,
/ - or if a service is being registered twice.
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 {
err := msr.registerMsgServiceHandler(sd, method, handler)
if err != nil {
panic(err)
}
err = msr.registerHybridHandler(sd, method, handler)
if err != nil {
panic(err)
}
}
}
func (msr *MsgServiceRouter)
HybridHandlerByMsgName(msgName string)
func(ctx context.Context, req, resp protoiface.MessageV1)
error {
return msr.hybridHandlers[msgName]
}
func (msr *MsgServiceRouter)
registerHybridHandler(sd *grpc.ServiceDesc, method grpc.MethodDesc, handler interface{
})
error {
inputName, err := protocompat.RequestFullNameFromMethodDesc(sd, method)
if err != nil {
return err
}
cdc := codec.NewProtoCodec(msr.interfaceRegistry)
hybridHandler, err := protocompat.MakeHybridHandler(cdc, sd, method, handler)
if err != nil {
return err
}
/ if circuit breaker is not nil, then we decorate the hybrid handler with the circuit breaker
if msr.circuitBreaker == nil {
msr.hybridHandlers[string(inputName)] = hybridHandler
return nil
}
/ decorate the hybrid handler with the circuit breaker
circuitBreakerHybridHandler := func(ctx context.Context, req, resp protoiface.MessageV1)
error {
messageName := codectypes.MsgTypeURL(req)
allowed, err := msr.circuitBreaker.IsAllowed(ctx, messageName)
if err != nil {
return err
}
if !allowed {
return fmt.Errorf("circuit breaker disallows execution of message %s", messageName)
}
return hybridHandler(ctx, req, resp)
}
msr.hybridHandlers[string(inputName)] = circuitBreakerHybridHandler
return nil
}
func (msr *MsgServiceRouter)
registerMsgServiceHandler(sd *grpc.ServiceDesc, method grpc.MethodDesc, handler interface{
})
error {
fqMethod := fmt.Sprintf("/%s/%s", sd.ServiceName, method.MethodName)
methodHandler := method.Handler
var requestTypeName string
/ 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.(sdk.Msg)
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("unable to register service method %s: %T does not implement sdk.Msg", fqMethod, i))
}
requestTypeName = sdk.MsgTypeURL(msg)
return nil
}, noopInterceptor)
/ Check that the service Msg fully-qualified method name has already
/ been registered (via RegisterInterfaces). If the user registers a
/ service without registering according service Msg type, there might be
/ some unexpected behavior down the road. Since we can't return an error
/ (`Server.RegisterService` interface restriction)
we panic (at startup).
reqType, err := msr.interfaceRegistry.Resolve(requestTypeName)
if err != nil || reqType == nil {
return fmt.Errorf(
"type_url %s has not been registered yet. "+
"Before calling RegisterService, you must register all interfaces by calling the `RegisterInterfaces` "+
"method on module.BasicManager. Each module should call `msgservice.RegisterMsgServiceDesc` inside its "+
"`RegisterInterfaces` method with the `_Msg_serviceDesc` generated by proto-gen",
requestTypeName,
)
}
/ Check that each service is only registered once. If a service is
/ registered more than once, then we should error. Since we can't
/ return an error (`Server.RegisterService` interface restriction)
we
/ panic (at startup).
_, found := msr.routes[requestTypeName]
if found {
return fmt.Errorf(
"msg service %s has already been registered. Please make sure to only register each service once. "+
"This usually means that there are conflicting modules registering the same msg service",
fqMethod,
)
}
msr.routes[requestTypeName] = func(ctx sdk.Context, msg sdk.Msg) (*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, msg)
}
if m, ok := msg.(sdk.HasValidateBasic); ok {
if err := m.ValidateBasic(); err != nil {
return nil, err
}
}
if msr.circuitBreaker != nil {
msgURL := sdk.MsgTypeURL(msg)
isAllowed, err := msr.circuitBreaker.IsAllowed(ctx, msgURL)
if err != nil {
return nil, err
}
if !isAllowed {
return nil, fmt.Errorf("circuit breaker disables execution of this message: %s", msgURL)
}
}
/ 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, ctx, noopDecoder, interceptor)
if err != nil {
return nil, err
}
resMsg, ok := res.(proto.Message)
if !ok {
return nil, errorsmod.Wrapf(sdkerrors.ErrInvalidType, "Expecting proto.Message, got %T", resMsg)
}
return sdk.WrapServiceResult(ctx, resMsg, err)
}
return nil
}
/ SetInterfaceRegistry sets the interface registry for the router.
func (msr *MsgServiceRouter)
SetInterfaceRegistry(interfaceRegistry codectypes.InterfaceRegistry) {
msr.interfaceRegistry = interfaceRegistry
}
func noopDecoder(_ interface{
})
error {
return nil
}
func noopInterceptor(_ context.Context, _ interface{
}, _ *grpc.UnaryServerInfo, _ grpc.UnaryHandler) (interface{
}, error) {
return nil, nil
}
