From d33c0cff58fa25716a21c9eb699d384aab8ca774 Mon Sep 17 00:00:00 2001
From: marbar3778 <marbar3778@yahoo.com>
Date: Thu, 25 May 2023 14:22:54 +0200
Subject: [PATCH 1/3] add base app setter for circuit breaker

---
 baseapp/baseapp.go            |  6 ++++++
 baseapp/circuit.go            | 10 ++++++++++
 baseapp/msg_service_router.go | 12 ++++++++++++
 3 files changed, 28 insertions(+)
 create mode 100644 baseapp/circuit.go

diff --git a/baseapp/baseapp.go b/baseapp/baseapp.go
index ca2fe852af6e..2cd1d577f410 100644
--- a/baseapp/baseapp.go
+++ b/baseapp/baseapp.go
@@ -229,6 +229,12 @@ 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) {
+	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) {
diff --git a/baseapp/circuit.go b/baseapp/circuit.go
new file mode 100644
index 000000000000..022ee6632c2e
--- /dev/null
+++ b/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
+}
diff --git a/baseapp/msg_service_router.go b/baseapp/msg_service_router.go
index b42fc282ec31..a6494eebc6d1 100644
--- a/baseapp/msg_service_router.go
+++ b/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)]
@@ -120,6 +125,13 @@ func (msr *MsgServiceRouter) RegisterService(sd *grpc.ServiceDesc, handler inter
 				} else {
 					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.

From 17a7571102c704da547aa39e9b5b4be0129eaa3f Mon Sep 17 00:00:00 2001
From: Julien Robert <julien@rbrt.fr>
Date: Fri, 26 May 2023 14:50:27 +0200
Subject: [PATCH 2/3] add changelog and kick ci

---
 CHANGELOG.md | 1 +
 1 file changed, 1 insertion(+)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0e1f20107ec2..838540ea883b 100644
--- a/CHANGELOG.md
+++ b/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.
 * [#16060](https://github.com/cosmos/cosmos-sdk/pull/16060) Support saving restoring snapshot locally.
 
 ### Improvements

From d87e919389412302a2e7dc3f49ab1b599389036a Mon Sep 17 00:00:00 2001
From: Julien Robert <julien@rbrt.fr>
Date: Fri, 26 May 2023 14:51:47 +0200
Subject: [PATCH 3/3] add nil check

---
 baseapp/baseapp.go | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/baseapp/baseapp.go b/baseapp/baseapp.go
index 2cd1d577f410..b42a56efca68 100644
--- a/baseapp/baseapp.go
+++ b/baseapp/baseapp.go
@@ -232,6 +232,9 @@ func (app *BaseApp) SetMsgServiceRouter(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("cannot set circuit breaker with no msg service router set")
+	}
 	app.msgServiceRouter.SetCircuit(cb)
 }