fix: unmarshal dlq messages correctly (#37)

services/failure.go

@@ -5,6 +5,8 @@ import (
 	"encoding/json"
 	"fmt"
 
+	"github.com/google/uuid"
+
 	"github.com/ceramicnetwork/go-cas/models"
 )
 
@@ -27,26 +29,30 @@ func (f FailureHandlingService) Failure(ctx context.Context, _ string) error {
 func (f FailureHandlingService) DLQ(ctx context.Context, msgBody string) error {
 	f.metricService.Count(ctx, models.MetricName_FailureDlqMessage, 1)
 	msgType := "Unknown"
+	msgId := "Unknown"
 	// Unmarshal into one of the known message types
 	anchorReq := new(models.AnchorRequestMessage)
-	if err := json.Unmarshal([]byte(msgBody), anchorReq); err == nil {
+	if err := json.Unmarshal([]byte(msgBody), anchorReq); (err == nil) && (anchorReq.Id != uuid.Nil) {
 		msgType = "Anchor request"
+		msgId = anchorReq.Id.String()
 		f.logger.Debugw("dlq: dequeued",
 			msgType, anchorReq,
 		)
 	} else {
 		batchReq := new(models.AnchorBatchMessage)
-		if err = json.Unmarshal([]byte(msgBody), batchReq); err == nil {
+		if err = json.Unmarshal([]byte(msgBody), batchReq); (err == nil) && (batchReq.Id != uuid.Nil) {
 			msgType = "Batch request"
+			msgId = batchReq.Id.String()
 			f.logger.Debugw("dlq: dequeued",
 				msgType, batchReq,
 			)
 		}
 	}
-	text, _ := json.MarshalIndent(msgBody, "", "")
+	// Only include the message type and ID in the alert message since the message body is already logged, and Discord
+	// messages have a character limit.
 	return f.notif.SendAlert(
 		models.AlertTitle,
 		models.AlertDesc_DeadLetterQueue,
-		fmt.Sprintf(models.AlertFmt_DeadLetterQueue, msgType, text),
+		fmt.Sprintf(models.AlertFmt_DeadLetterQueue, msgType, msgId),
 	)
 }