From ad9466db4b880baf399077d87031ef7e4a5197fc Mon Sep 17 00:00:00 2001
From: Thomas Steinacher <tom@eggdrop.ch>
Date: Thu, 7 Dec 2023 14:21:46 +0000
Subject: [PATCH] Purge errored tasks even if task object is not found (#310)

---
 tasktiger/task.py      | 44 ++++++++++++++++++++++++++++++------------
 tasktiger/tasktiger.py |  7 ++++++-
 tests/test_base.py     | 11 +++++++++++
 3 files changed, 49 insertions(+), 13 deletions(-)

diff --git a/tasktiger/task.py b/tasktiger/task.py
index 4f7b83c2..db034a6a 100644
--- a/tasktiger/task.py
+++ b/tasktiger/task.py
@@ -492,14 +492,24 @@ def tasks_from_queue(
         skip: int = 0,
         limit: int = 1000,
         load_executions: int = 0,
+        include_not_found: bool = False,
     ) -> Tuple[int, List["Task"]]:
         """
-        Returns a tuple with the following information:
-        * total items in the queue
-        * tasks from the given queue in the given state, latest first.
-
-        An integer may be passed in the load_executions parameter to indicate
-        how many executions should be loaded (starting from the latest).
+        Return tasks from a queue.
+
+        Args:
+            tiger: TaskTiger instance.
+            queue: Name of the queue.
+            state: State of the task (QUEUED, ACTIVE, SCHEDULED, ERROR).
+            limit: Maximum number of tasks to return.
+            load_executions: Maximum number of executions to load for each task
+                (starting from the latest).
+            include_not_found: Whether to include tasks that cannot be loaded.
+
+        Returns:
+            Tuple with the following information:
+            * total items in the queue
+            * tasks from the given queue in the given state, latest first.
         """
 
         key = tiger._key(state, queue)
@@ -525,10 +535,14 @@ def tasks_from_queue(
                     )
                 results = pipeline.execute()
 
-                for serialized_data, serialized_executions, ts in zip(
-                    results[0], results[1:], tss
+                for idx, serialized_data, serialized_executions, ts in zip(
+                    range(len(items)), results[0], results[1:], tss
                 ):
-                    data = json.loads(serialized_data)
+                    if serialized_data is None and include_not_found:
+                        data = {"id": items[idx][0]}
+                    else:
+                        data = json.loads(serialized_data)
+
                     executions = [
                         json.loads(e) for e in serialized_executions if e
                     ]
@@ -544,11 +558,17 @@ def tasks_from_queue(
 
                     tasks.append(task)
             else:
-                data = tiger.connection.mget(
+                result = tiger.connection.mget(
                     [tiger._key("task", item[0]) for item in items]
                 )
-                for serialized_data, ts in zip(data, tss):
-                    data = json.loads(serialized_data)
+                for idx, serialized_data, ts in zip(
+                    range(len(items)), result, tss
+                ):
+                    if serialized_data is None and include_not_found:
+                        data = {"id": items[idx][0]}
+                    else:
+                        data = json.loads(serialized_data)
+
                     task = Task(
                         tiger, queue=queue, _data=data, _state=state, _ts=ts
                     )
diff --git a/tasktiger/tasktiger.py b/tasktiger/tasktiger.py
index 943ccbb5..54f6c251 100644
--- a/tasktiger/tasktiger.py
+++ b/tasktiger/tasktiger.py
@@ -611,7 +611,12 @@ def errored_tasks() -> Iterable[Task]:
                 task_limit = 5000
                 while total_tasks is None or skip < total_tasks:
                     total_tasks, tasks = Task.tasks_from_queue(
-                        self, queue, ERROR, skip=skip, limit=task_limit
+                        self,
+                        queue,
+                        ERROR,
+                        skip=skip,
+                        limit=task_limit,
+                        include_not_found=True,
                     )
                     for task in tasks:
                         if (
diff --git a/tests/test_base.py b/tests/test_base.py
index d6d04b41..c8774999 100644
--- a/tests/test_base.py
+++ b/tests/test_base.py
@@ -965,6 +965,17 @@ def test_purge_errored_tasks_only_errored_unique_task(self):
         assert 1 == self.tiger.purge_errored_tasks()
         self._ensure_queues(queued={"default": 1}, error={"default": 0})
 
+    def test_purge_errored_tasks_if_task_not_found(self):
+        task = self.tiger.delay(exception_task)
+
+        Worker(self.tiger).run(once=True)
+        self._ensure_queues(error={"default": 1})
+
+        self.tiger.connection.delete(self.tiger._key("task", task.id))
+
+        self.tiger.purge_errored_tasks()
+        self._ensure_queues(error={"default": 0})
+
 
 class TestTasks(BaseTestCase):
     """