fix: Change retry logic to extract next run from traceback

celery_progress/backend.py

@@ -1,5 +1,6 @@
 import datetime
 import logging
+import re
 from abc import ABCMeta, abstractmethod
 from decimal import Decimal
 
@@ -76,9 +77,29 @@ def get_info(self):
         elif state in ['RETRY', 'REVOKED']:
             if state == 'RETRY':
                 retry = info
-                when = str(retry.when) if isinstance(retry.when, datetime.datetime) else str(
-                        datetime.datetime.now() + datetime.timedelta(seconds=retry.when))
-                result = {'when': when, 'message': retry.message or str(retry.exc)}
+                try:
+                    iter(retry)
+                    when = (
+                        str(retry.when)
+                        if isinstance(retry.when, datetime.datetime)
+                        else str(
+                            datetime.datetime.now()
+                            + datetime.timedelta(seconds=retry.when)
+                        )
+                    )
+                    result = {"when": when, "message": retry.message or str(retry.exc)}
+                except:
+                    traceback = task_meta.get("traceback")
+                    seconds = re.search("\d{1,10}s", traceback)
+                    if seconds:
+                        when = str(
+                            task_meta["date_done"]
+                            + datetime.timedelta(seconds=int(seconds.group()[:-1]))
+                        )
+                    else:
+                        when = "Unknown"  # Can't find the retry time
+
+                    result = {"when": when, "message": f"{str(task_meta['result'])[0:50]}..."}
             else:
                 result = 'Task ' + str(info)
             response.update({

celery_progress/static/celery_progress/celery_progress.js

@@ -65,7 +65,8 @@ class CeleryProgressBar {
     onRetryDefault(progressBarElement, progressBarMessageElement, excMessage, retryWhen) {
         retryWhen = new Date(retryWhen);
         let message = 'Retrying in ' + Math.round((retryWhen.getTime() - Date.now())/1000) + 's: ' + excMessage;
-        this.onError(progressBarElement, progressBarMessageElement, message);
+        progressBarElement.style.backgroundColor = this.barColors.error;
+        progressBarMessageElement.textContent =  message;
     }
 
     onIgnoredDefault(progressBarElement, progressBarMessageElement, result) {
@@ -163,7 +164,7 @@ class CeleryProgressBar {
             this.onHttpError(this.progressBarElement, this.progressBarMessageElement, "HTTP Code " + response.status, response);
         }
     }
-    
+
     static getBarColorsDefault() {
         return {
             success: '#76ce60',