Add queue_clear management command

Author: lirsacc

django_lightweight_queue/management/commands/queue_clear.py

@@ -0,0 +1,51 @@
+import argparse
+
+from django.core.management.base import BaseCommand, CommandError
+
+from ...types import QueueName
+from ...utils import get_backend
+from ...backends.base import BackendWithClear
+
+
+class Command(BaseCommand):
+    help = """
+    Command to clear work on a redis-backed queue.
+
+    All pending jobs will be deleted from the queue. In flight jobs won't be
+    affected.
+    """  # noqa:A003 # inherited name
+
+    def add_arguments(self, parser: argparse.ArgumentParser) -> None:
+        parser.add_argument(
+            'queue',
+            action='store',
+            help="The queue to pause.",
+        )
+
+        parser.add_argument(
+            '--yes',
+            'skip_prompt',
+            action='store_true',
+            help="Skip confirmation prompt.",
+        )
+
+    def handle(self, queue: QueueName, skip_prompt: bool = False, **options: object) -> None:
+
+        backend = get_backend(queue)
+
+        if not isinstance(backend, BackendWithClear):
+            raise CommandError(
+                "Configured backend '{}.{}' doesn't support clearing".format(
+                    type(backend).__module__,
+                    type(backend).__name__,
+                ),
+            )
+
+        if not skip_prompt:
+            prompt = "Clear all jobs from queue {}) [y/N] ".format(queue)
+            choice = input(prompt).lower()
+
+            if choice != "y":
+                raise CommandError("Aborting")
+
+        backend.clear(queue)