feat(baseapp): add setter for circuit breaker (backport) (cosmos#16290)

CHANGELOG.md

@@ -39,6 +39,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 
 ### Features
 
+* (baseapp) [#16290](https://github.com/cosmos/cosmos-sdk/pull/16290) Add circuit breaker setter in baseapp.
 * (x/group) [#16191](https://github.com/cosmos/cosmos-sdk/pull/16191) Add EventProposalPruned event to group module whenever a proposal is pruned.
 
 ### Improvements

baseapp/baseapp.go

@@ -231,6 +231,15 @@ func (app *BaseApp) SetMsgServiceRouter(msgServiceRouter *MsgServiceRouter) {
 	app.msgServiceRouter = msgServiceRouter
 }
 
+// SetCircuitBreaker sets the circuit breaker for the BaseApp.
+// The circuit breaker is checked on every message execution to verify if a transaction should be executed or not.
+func (app *BaseApp) SetCircuitBreaker(cb CircuitBreaker) {
+	if app.msgServiceRouter == nil {
+		panic("must be called after message server is set")
+	}
+	app.msgServiceRouter.SetCircuit(cb)
+}
+
 // MountStores mounts all IAVL or DB stores to the provided keys in the BaseApp
 // multistore.
 func (app *BaseApp) MountStores(keys ...storetypes.StoreKey) {

baseapp/circuit.go

@@ -0,0 +1,10 @@
+package baseapp
+
+import (
+	sdk "github.com/cosmos/cosmos-sdk/types"
+)
+
+// CircuitBreaker is an interface that defines the methods for a circuit breaker.
+type CircuitBreaker interface {
+	IsAllowed(ctx sdk.Context, typeURL string) bool
+}

baseapp/msg_service_router.go

@@ -17,6 +17,7 @@ import (
 type MsgServiceRouter struct {
 	interfaceRegistry codectypes.InterfaceRegistry
 	routes            map[string]MsgServiceHandler
+	circuitBreaker    CircuitBreaker
 }
 
 var _ gogogrpc.Server = &MsgServiceRouter{}
@@ -31,6 +32,10 @@ func NewMsgServiceRouter() *MsgServiceRouter {
 // MsgServiceHandler defines a function type which handles Msg service message.
 type MsgServiceHandler = func(ctx sdk.Context, req sdk.Msg) (*sdk.Result, error)
 
+func (msr *MsgServiceRouter) SetCircuit(cb CircuitBreaker) {
+	msr.circuitBreaker = cb
+}
+
 // 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)]
@@ -116,6 +121,13 @@ func (msr *MsgServiceRouter) RegisterService(sd *grpc.ServiceDesc, handler inter
 			if err := req.ValidateBasic(); err != nil {
 				return nil, err
 			}
+
+			if msr.circuitBreaker != nil {
+				msgURL := sdk.MsgTypeURL(req)
+				if !msr.circuitBreaker.IsAllowed(ctx, msgURL) {
+					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, sdk.WrapSDKContext(ctx), noopDecoder, interceptor)