CFn: configure wait time for polling resources (localstack#13455)

simonrw · web-flow · commit fe00d2bd05fd · 2025-12-04T00:59:51.000Z
diff --git a/localstack-core/localstack/config.py b/localstack-core/localstack/config.py
@@ -1211,6 +1211,9 @@ def populate_edge_configuration(
 # EXPERIMENTAL
 CFN_IGNORE_UNSUPPORTED_RESOURCE_TYPES = is_env_not_false("CFN_IGNORE_UNSUPPORTED_RESOURCE_TYPES")
 
+# Decrease the waiting time for resource deployment
+CFN_NO_WAIT_ITERATIONS: str | int | None = os.environ.get("CFN_NO_WAIT_ITERATIONS")
+
 # bind address of local DNS server
 DNS_ADDRESS = os.environ.get("DNS_ADDRESS") or "0.0.0.0"
 # port of the local DNS server
diff --git a/localstack-core/localstack/services/cloudformation/provider.py b/localstack-core/localstack/services/cloudformation/provider.py
@@ -5,6 +5,7 @@
 from collections import defaultdict
 from copy import deepcopy
 
+from localstack import config
 from localstack.aws.api import CommonServiceException, RequestContext, handler
 from localstack.aws.api.cloudformation import (
     AlreadyExistsException,
@@ -120,6 +121,7 @@
     find_stack_by_id,
     get_cloudformation_store,
 )
+from localstack.services.plugins import ServiceLifecycleHook
 from localstack.state import StateVisitor
 from localstack.utils.collections import (
     remove_attributes,
@@ -177,7 +179,30 @@ def __init__(self, message=None):
         super().__init__("InternalFailure", status_code=500, message=message, sender_fault=False)
 
 
-class CloudformationProvider(CloudformationApi):
+class CloudformationProvider(CloudformationApi, ServiceLifecycleHook):
+    def on_before_start(self):
+        self._validate_config()
+
+    def _validate_config(self):
+        no_wait_value: int = 5
+        try:
+            no_wait_value = int(config.CFN_NO_WAIT_ITERATIONS or 5)
+        except (TypeError, ValueError):
+            LOG.warning(
+                "You have set CFN_NO_WAIT_ITERATIONS to an invalid value: '%s'. It must be an integer greater or equal to 0. Using the default of 5",
+                config.CFN_NO_WAIT_ITERATIONS,
+            )
+
+        if no_wait_value < 0:
+            LOG.warning(
+                "You have set CFN_NO_WAIT_ITERATIONS to an invalid value: '%s'. It must be an integer greater or equal to 0. Using the default of 5",
+                config.CFN_NO_WAIT_ITERATIONS,
+            )
+            no_wait_value = 5
+
+        # Set the configuration back
+        config.CFN_NO_WAIT_ITERATIONS = no_wait_value
+
     def _stack_status_is_active(self, stack_status: str) -> bool:
         return stack_status not in [StackStatus.DELETE_COMPLETE]
 
diff --git a/localstack-core/localstack/services/cloudformation/resource_provider.py b/localstack-core/localstack/services/cloudformation/resource_provider.py
@@ -430,17 +430,20 @@ def __init__(
         self.stack_name = stack_name
         self.stack_id = stack_id
 
+        # This should have been set up in the provider
+        assert isinstance(config.CFN_NO_WAIT_ITERATIONS, int)
+
     def deploy_loop(
         self,
         resource_provider: ResourceProvider,
         resource: dict,
         raw_payload: ResourceProviderPayload,
         max_timeout: int = config.CFN_PER_RESOURCE_TIMEOUT,
-        sleep_time: float = 5,
+        sleep_time: float = 1,
     ) -> ProgressEvent[Properties]:
         payload = copy.deepcopy(raw_payload)
 
-        max_iterations = max(ceil(max_timeout / sleep_time), 2)
+        max_iterations = max(ceil(max_timeout / sleep_time), 10)
 
         for current_iteration in range(max_iterations):
             resource_type = get_resource_type({"Type": raw_payload["resourceType"]})
@@ -486,10 +489,11 @@ def deploy_loop(
                     payload["requestData"]["resourceProperties"] = event.resource_model
                     resource["Properties"] = event.resource_model
 
-                    if current_iteration == 0:
-                        time.sleep(0)
+                    if current_iteration < config.CFN_NO_WAIT_ITERATIONS:
+                        pass
                     else:
                         time.sleep(sleep_time)
+
                 case OperationStatus.PENDING:
                     # come back to this resource in another iteration
                     return event
diff --git a/localstack-core/localstack/services/cloudformation/v2/provider.py b/localstack-core/localstack/services/cloudformation/v2/provider.py
@@ -222,6 +222,12 @@ def find_stack_instance(stack_set: StackSet, account: str, region: str) -> Stack
 
 class CloudformationProviderV2(CloudformationProvider, ServiceLifecycleHook):
     def on_before_start(self):
+        # TODO: make sure to bring `_validate_config` from the base class when removing it
+        # as this ensures we have a valid CFN_NO_WAIT_ITERATIONS value
+        super().on_before_start()
+        self._log_create_issue_info()
+
+    def _log_create_issue_info(self):
         base = "https://github.com/localstack/localstack/issues/new"
         query_args = {
             "template": "bug-report.yml",
