[BLOCK-2310] Modified to catch panic from json.Marshal function (#46)

codec/abi_decoder.go

@@ -596,7 +596,7 @@ type InjectDataWrite struct {
 	InjectData
 }
 
-//ultra-andrey-bezrukov --- BLOCK-178 Dfuse cannot produce JSON data for migration
+// ultra-andrey-bezrukov --- BLOCK-178 Dfuse cannot produce JSON data for migration
 func DecodeTableInject(data []byte, abi *eos.ABI) ([]byte, error) {
 	dataRd := InjectDataRead{}
 	err := json.Unmarshal(data, &dataRd)

eosws/marshal_test.go

@@ -0,0 +1,34 @@
+package eosws
+
+import (
+	"encoding/json"
+	"fmt"
+	"testing"
+
+	"github.com/dfuse-io/dfuse-eosio/eosws/wsmsg"
+	"github.com/stretchr/testify/assert"
+)
+
+// TestMarshalOutgoingMessager is a code snippet extracted from eosws.(*WSConn).Emit() function.
+// Here, SetReqID() is called to set an invalid string, because another function for OutgoingMessager interface, SetType() is called
+// and the result is validated in Emit().
+func TestMarshalOutgoingMessager(t *testing.T) {
+	var err error
+	defer func() {
+		if r := recover(); r != nil {
+			switch v := r.(type) {
+			case error:
+				err = fmt.Errorf("unexpected error marshalling message: %w", v)
+			case string, fmt.Stringer:
+				err = fmt.Errorf("unexpected error marshalling message: %s", v)
+			default:
+				err = fmt.Errorf("unexpected error marshalling message: %v", v)
+			}
+			fmt.Printf("%s\n", err)
+			assert.Error(t, err)
+		}
+	}()
+	var msg wsmsg.OutgoingMessager
+	msg.SetReqID("")
+	_, err = json.Marshal(msg)
+}

eosws/wsconn.go

@@ -307,6 +307,21 @@ func (ws *WSConn) handleMessage(rawMsg []byte) {
 }
 
 func (ws *WSConn) Emit(ctx context.Context, msg wsmsg.OutgoingMessager) {
+	var err error
+	defer func() {
+		if r := recover(); r != nil {
+			switch v := r.(type) {
+			case error:
+				err = fmt.Errorf("unexpected error marshalling message: %w", v)
+			case string, fmt.Stringer:
+				err = fmt.Errorf("unexpected error marshalling message: %s", v)
+			default:
+				err = fmt.Errorf("unexpected error marshalling message: %v", v)
+			}
+			ws.Shutdown(err)
+		}
+	}()
+
 	zlogger := logging.Logger(ctx, zlog)
 
 	msgType, err := wsmsg.GetType(msg)