feat(crons): Add max-workers option (#70261)

Follow up to GH-64825

src/sentry/consumers/__init__.py

@@ -124,6 +124,12 @@ def ingest_monitors_options() -> list[click.Option]:
             default=1,
             help="Maximum time spent batching check-ins to batch before processing in parallel.",
         ),
+        click.Option(
+            ["--max-workers", "max_workers"],
+            type=int,
+            default=None,
+            help="The maximum number of threads to spawn in parallel mode.",
+        ),
     ]
     return options
 

src/sentry/monitors/consumers/monitor_consumer.py

@@ -929,6 +929,11 @@ class StoreMonitorCheckInStrategyFactory(ProcessingStrategyFactory[KafkaPayload]
     Does the consumer process unrelated check-ins in parallel?
     """
 
+    max_workers: int | None = None
+    """
+    Number of Executor workers to use when running in parallel
+    """
+
     max_batch_size = 500
     """
     How many messages will be batched at once when in parallel mode.
@@ -944,6 +949,7 @@ def __init__(
         mode: Literal["parallel", "serial"] | None = None,
         max_batch_size: int | None = None,
         max_batch_time: int | None = None,
+        max_workers: int | None = None,
     ) -> None:
         if mode == "parallel":
             self.parallel = True
@@ -952,13 +958,15 @@ def __init__(
             self.max_batch_size = max_batch_size
         if max_batch_time is not None:
             self.max_batch_time = max_batch_time
+        if max_workers is not None:
+            self.max_workers = max_workers
 
     def shutdown(self) -> None:
         if self.parallel_executor:
             self.parallel_executor.shutdown()
 
-    def create_paralell_worker(self, commit: Commit) -> ProcessingStrategy[KafkaPayload]:
-        self.parallel_executor = ThreadPoolExecutor()
+    def create_parallel_worker(self, commit: Commit) -> ProcessingStrategy[KafkaPayload]:
+        self.parallel_executor = ThreadPoolExecutor(max_workers=self.max_workers)
 
         batch_processor = RunTask(
             function=partial(process_batch, self.parallel_executor),
@@ -982,6 +990,6 @@ def create_with_partitions(
         partitions: Mapping[Partition, int],
     ) -> ProcessingStrategy[KafkaPayload]:
         if self.parallel:
-            return self.create_paralell_worker(commit)
+            return self.create_parallel_worker(commit)
         else:
             return self.create_synchronous_worker(commit)

tests/sentry/monitors/consumers/test_monitor_consumer.py

@@ -164,7 +164,11 @@ def test_parallel(self, process_checkin_group) -> None:
         Validates that the consumer in parallel mode correctly groups check-ins
         into groups by their monitor slug / environment
         """
-        factory = StoreMonitorCheckInStrategyFactory(mode="parallel", max_batch_size=4)
+        factory = StoreMonitorCheckInStrategyFactory(
+            mode="parallel",
+            max_batch_size=4,
+            max_workers=1,
+        )
         commit = mock.Mock()
         consumer = factory.create_with_partitions(commit, {self.partition: 0})