fix: improve baseapp event emission (backport #1075)

CHANGELOG.md

@@ -51,6 +51,7 @@ Ref: https://keepachangelog.com/en/1.0.0/
 ### Bug Fixes
 * (ledger) [\#1040](https://github.com/Finschia/finschia-sdk/pull/1040) fix a bug(unable to connect nano S plus ledger on ubuntu)
 * (x/foundation) [\#1053](https://github.com/Finschia/finschia-sdk/pull/1053) Make x/foundation MsgExec propagate events
+* (baseapp) [\#1091](https://github.com/cosmos/cosmos-sdk/pull/1091) Add `events.GetAttributes` and `event.GetAttribute` methods to simplify the retrieval of an attribute from event(s) (backport #1075)
 
 ### Removed
 

baseapp/baseapp.go

@@ -814,7 +814,7 @@ func (app *BaseApp) runMsgs(ctx sdk.Context, msgs []sdk.Msg) (*sdk.Result, error
 		}
 
 		// create message events
-		msgEvents := createEvents(msg).AppendEvents(msgResult.GetEvents())
+		msgEvents := createEvents(msgResult.GetEvents(), msg)
 
 		// append message events, data and logs
 		//
@@ -838,7 +838,7 @@ func (app *BaseApp) runMsgs(ctx sdk.Context, msgs []sdk.Msg) (*sdk.Result, error
 	}, nil
 }
 
-func createEvents(msg sdk.Msg) sdk.Events {
+func createEvents(events sdk.Events, msg sdk.Msg) sdk.Events {
 	eventMsgName := sdk.MsgTypeURL(msg)
 	msgEvent := sdk.NewEvent(sdk.EventTypeMessage, sdk.NewAttribute(sdk.AttributeKeyAction, eventMsgName))
 
@@ -847,12 +847,15 @@ func createEvents(msg sdk.Msg) sdk.Events {
 		msgEvent = msgEvent.AppendAttributes(sdk.NewAttribute(sdk.AttributeKeySender, msg.GetSigners()[0].String()))
 	}
 
-	// here we assume that routes module name is the second element of the route
-	// e.g. "cosmos.bank.v1beta1.MsgSend" => "bank"
-	moduleName := strings.Split(eventMsgName, ".")
-	if len(moduleName) > 1 {
-		msgEvent = msgEvent.AppendAttributes(sdk.NewAttribute(sdk.AttributeKeyModule, moduleName[1]))
+	// verify that events have no module attribute set
+	if _, found := events.GetAttributes(sdk.AttributeKeyModule); !found {
+		// here we assume that routes module name is the second element of the route
+		// e.g. "cosmos.bank.v1beta1.MsgSend" => "bank"
+		moduleName := strings.Split(eventMsgName, ".")
+		if len(moduleName) > 1 {
+			msgEvent = msgEvent.AppendAttributes(sdk.NewAttribute(sdk.AttributeKeyModule, moduleName[1]))
+		}
 	}
 
-	return sdk.Events{msgEvent}
+	return sdk.Events{msgEvent}.AppendEvents(events)
 }

types/events.go

@@ -197,6 +197,17 @@ func (e Event) AppendAttributes(attrs ...Attribute) Event {
 	return e
 }
 
+// GetAttribute returns an attribute for a given key present in an event.
+// If the key is not found, the boolean value will be false.
+func (e Event) GetAttribute(key string) (Attribute, bool) {
+	for _, attr := range e.Attributes {
+		if string(attr.Key) == key {
+			return Attribute{Key: string(attr.Key), Value: string(attr.Value)}, true
+		}
+	}
+	return Attribute{}, false
+}
+
 // AppendEvent adds an Event to a slice of events.
 func (e Events) AppendEvent(event Event) Events {
 	return append(e, event)
@@ -229,6 +240,19 @@ func toBytes(i interface{}) []byte {
 	}
 }
 
+// GetAttributes returns all attributes matching a given key present in events.
+// If the key is not found, the boolean value will be false.
+func (e Events) GetAttributes(key string) ([]Attribute, bool) {
+	attrs := make([]Attribute, 0)
+	for _, event := range e {
+		if attr, found := event.GetAttribute(key); found {
+			attrs = append(attrs, attr)
+		}
+	}
+
+	return attrs, len(attrs) > 0
+}
+
 // Common event types and attribute keys
 var (
 	EventTypeTx = "tx"

types/events_test.go

@@ -43,6 +43,25 @@ func (s *eventsTestSuite) TestAppendAttributes() {
 	s.Require().Equal(e, sdk.NewEvent("transfer", sdk.NewAttribute("sender", "foo"), sdk.NewAttribute("recipient", "bar")))
 }
 
+func (s *eventsTestSuite) TestGetAttributes() {
+	e := sdk.NewEvent("transfer", sdk.NewAttribute("sender", "foo"))
+	e = e.AppendAttributes(sdk.NewAttribute("recipient", "bar"))
+	attr, found := e.GetAttribute("recipient")
+	s.Require().True(found)
+	s.Require().Equal(attr, sdk.NewAttribute("recipient", "bar"))
+	_, found = e.GetAttribute("foo")
+	s.Require().False(found)
+
+	events := sdk.Events{e}.AppendEvent(sdk.NewEvent("message", sdk.NewAttribute("sender", "bar")))
+	attrs, found := events.GetAttributes("sender")
+	s.Require().True(found)
+	s.Require().Len(attrs, 2)
+	s.Require().Equal(attrs[0], sdk.NewAttribute("sender", "foo"))
+	s.Require().Equal(attrs[1], sdk.NewAttribute("sender", "bar"))
+	_, found = events.GetAttributes("foo")
+	s.Require().False(found)
+}
+
 func (s *eventsTestSuite) TestEmptyEvents() {
 	s.Require().Equal(sdk.EmptyEvents(), sdk.Events{})
 }