feat: allow to handle MsgExec instances properly (#75)

## Description
This PR adds the possibility of handling `MsgExec` inner messages. 

Currently when a `MsgExec` is executed, the inner messages are not parsed correctly by the various modules. With this PR a new `AuthzMessageModule` interface is added. Thanks to this, modules will be able to properly handle `MsgExec` inner messages and parse their data accordingly.

## Checklist
- [x] Targeted PR against correct branch.
- [ ] Linked to Github issue with discussion and accepted design OR link to spec that describes this work.
- [ ] Wrote unit tests.  
- [x] Re-reviewed `Files changed` in the Github PR explorer.

CHANGELOG.md

@@ -1,6 +1,7 @@
 ## Unreleased
 ### Changes
 - ([\#74](https://github.com/forbole/juno/pull/74)) Added database block count to prometheus to improve alert monitoring
+- ([\#75](https://github.com/forbole/juno/pull/75)) Allow modules to handle MsgExec inner messages
 
 ## v3.4.0
 ### Changes

modules/module.go

@@ -4,6 +4,8 @@ import (
 	"encoding/json"
 	"strings"
 
+	"github.com/cosmos/cosmos-sdk/x/authz"
+
 	sdk "github.com/cosmos/cosmos-sdk/types"
 	"github.com/go-co-op/gocron"
 	tmctypes "github.com/tendermint/tendermint/rpc/core/types"
@@ -91,9 +93,18 @@ type TransactionModule interface {
 
 type MessageModule interface {
 	// HandleMsg handles a single message.
-	// For convenience of usa, the index of the message inside the transaction and the transaction itself
+	// For convenience of use, the index of the message inside the transaction and the transaction itself
 	// are passed as well.
 	// NOTE. The returned error will be logged using the MsgError method. All other modules' handlers
 	// will still be called.
 	HandleMsg(index int, msg sdk.Msg, tx *types.Tx) error
 }
+
+type AuthzMessageModule interface {
+	// HandleMsgExec handles a single message that is contained within an authz.MsgExec instance.
+	// For convenience of use, the index of the message inside the transaction and the transaction itself
+	// are passed as well.
+	// NOTE. The returned error will be logged using the MsgError method. All other modules' handlers
+	// will still be called.
+	HandleMsgExec(index int, msgExec *authz.MsgExec, authzMsgIndex int, executedMsg sdk.Msg, tx *types.Tx) error
+}

parser/worker.go

@@ -5,6 +5,8 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/cosmos/cosmos-sdk/x/authz"
+
 	"github.com/forbole/juno/v3/logging"
 
 	"github.com/cosmos/cosmos-sdk/codec"
@@ -291,6 +293,7 @@ func (w Worker) handleTx(tx *types.Tx) {
 // handleMessage accepts the transaction and handles messages contained
 // inside the transaction.
 func (w Worker) handleMessage(index int, msg sdk.Msg, tx *types.Tx) {
+	// Allow modules to handle the message
 	for _, module := range w.modules {
 		if messageModule, ok := module.(modules.MessageModule); ok {
 			err := messageModule.HandleMsg(index, msg, tx)
@@ -299,6 +302,26 @@ func (w Worker) handleMessage(index int, msg sdk.Msg, tx *types.Tx) {
 			}
 		}
 	}
+
+	// If it's a MsgExecute, we need to make sure the included messages are handled as well
+	if msgExec, ok := msg.(*authz.MsgExec); ok {
+		for authzIndex, msgAny := range msgExec.Msgs {
+			var executedMsg sdk.Msg
+			err := w.codec.UnpackAny(msgAny, &executedMsg)
+			if err != nil {
+				w.logger.Error("unable to unpack MsgExec inner message", "index", authzIndex, "error", err)
+			}
+
+			for _, module := range w.modules {
+				if messageModule, ok := module.(modules.AuthzMessageModule); ok {
+					err = messageModule.HandleMsgExec(index, msgExec, authzIndex, executedMsg, tx)
+					if err != nil {
+						w.logger.MsgError(module, tx, executedMsg, err)
+					}
+				}
+			}
+		}
+	}
 }
 
 // ExportTxs accepts a slice of transactions and persists then inside the database.