ECS: allow ecs service to transition to arbitrary running task count (#6289)

moto/ecs/models.py

@@ -2,6 +2,7 @@ import re
 from copy import copy
 from datetime import datetime, timezone
 from typing import Any, Dict, Iterator, List, Optional, Tuple
+from os import getenv
 
 from moto import settings
 from moto.core import BaseBackend, BackendDict, BaseModel, CloudFormationModel
@@ -488,6 +489,14 @@ class CapacityProviderFailure(BaseObject):
 
 
 class Service(BaseObject, CloudFormationModel):
+    """Set the environment variable MOTO_ECS_SERVICE_RUNNING to a number of running tasks you want
+    the service to transition to, ie if set to 2:
+
+    MOTO_ECS_SERVICE_RUNNING=2
+
+    then describe_services call to return runningCount of the service AND deployment to 2
+    """
+
     def __init__(
         self,
         cluster: Cluster,
@@ -507,7 +516,6 @@ class Service(BaseObject, CloudFormationModel):
         self.cluster_arn = cluster.arn
         self.name = service_name
         self.status = "ACTIVE"
-        self.running_count = 0
         self.task_definition = task_definition.arn if task_definition else None
         self.desired_count = desired_count
         self.task_sets: List[TaskSet] = []
@@ -515,6 +523,25 @@ class Service(BaseObject, CloudFormationModel):
         self.events: List[Dict[str, Any]] = []
         self.launch_type = launch_type
         self.service_registries = service_registries or []
+        self.load_balancers = load_balancers if load_balancers is not None else []
+        self.scheduling_strategy = (
+            scheduling_strategy if scheduling_strategy is not None else "REPLICA"
+        )
+        self.platform_version = platform_version
+        self.tags = tags if tags is not None else []
+        self.region_name = cluster.region_name
+        self._account_id = backend.account_id
+        self._backend = backend
+
+        try:
+            # negative running count not allowed, set to 0 if so
+            ecs_running_count = max(int(getenv("MOTO_ECS_SERVICE_RUNNING", 0)), 0)
+        except ValueError:
+            # Unable to parse value of MOTO_ECS_SERVICE_RUNNING as an integer, set to default 0
+            ecs_running_count = 0
+
+        self.running_count = ecs_running_count
+        self.pending_count = desired_count - ecs_running_count
         if self.deployment_controller["type"] == "ECS":
             self.deployments = [
                 {
@@ -522,8 +549,8 @@ class Service(BaseObject, CloudFormationModel):
                     "desiredCount": self.desired_count,
                     "id": f"ecs-svc/{mock_random.randint(0, 32**12)}",
                     "launchType": self.launch_type,
-                    "pendingCount": self.desired_count,
+                    "pendingCount": self.pending_count,
-                    "runningCount": 0,
+                    "runningCount": ecs_running_count,
                     "status": "PRIMARY",
                     "taskDefinition": self.task_definition,
                     "updatedAt": datetime.now(timezone.utc),
@@ -531,16 +558,6 @@ class Service(BaseObject, CloudFormationModel):
             ]
         else:
             self.deployments = []
-        self.load_balancers = load_balancers if load_balancers is not None else []
-        self.scheduling_strategy = (
-            scheduling_strategy if scheduling_strategy is not None else "REPLICA"
-        )
-        self.platform_version = platform_version
-        self.tags = tags if tags is not None else []
-        self.pending_count = 0
-        self.region_name = cluster.region_name
-        self._account_id = backend.account_id
-        self._backend = backend
 
     @property
     def arn(self) -> str:
@@ -1641,6 +1658,7 @@ class EC2ContainerServiceBackend(BaseBackend):
             # It is only deleted later on
             # https://boto3.amazonaws.com/v1/documentation/api/latest/reference/services/ecs.html#ECS.Client.delete_service
             service.status = "INACTIVE"
+            service.pending_count = 0
             return service
 
     def register_container_instance(

moto/s3/responses.py

@@ -2102,10 +2102,10 @@ class S3Response(BaseResponse):
         ps = minidom.parseString(body).getElementsByTagName("Part")
         prev = 0
         for p in ps:
-            pn = int(p.getElementsByTagName("PartNumber")[0].firstChild.wholeText)
+            pn = int(p.getElementsByTagName("PartNumber")[0].firstChild.wholeText)  # type: ignore[union-attr]
             if pn <= prev:
                 raise InvalidPartOrder()
-            yield (pn, p.getElementsByTagName("ETag")[0].firstChild.wholeText)
+            yield (pn, p.getElementsByTagName("ETag")[0].firstChild.wholeText)  # type: ignore[union-attr]
 
     def _key_response_post(
         self,

tests/test_ecs/test_ecs_boto3.py

@@ -589,7 +589,7 @@ def test_create_service():
     response["service"]["desiredCount"].should.equal(2)
     len(response["service"]["events"]).should.equal(0)
     len(response["service"]["loadBalancers"]).should.equal(0)
-    response["service"]["pendingCount"].should.equal(0)
+    response["service"]["pendingCount"].should.equal(2)
     response["service"]["runningCount"].should.equal(0)
     response["service"]["serviceArn"].should.equal(
         f"arn:aws:ecs:us-east-1:{ACCOUNT_ID}:service/test_ecs_cluster/test_ecs_service"
@@ -604,6 +604,77 @@ def test_create_service():
     response["service"]["platformVersion"].should.equal("2")
 
 
+@mock_ecs
+@mock_ec2
+def test_create_running_service():
+    if settings.TEST_SERVER_MODE:
+        raise SkipTest(
+            "Can't set environment variables in server mode for a single test"
+        )
+    running_service_count = 3
+    with mock.patch.dict(
+        os.environ, {"MOTO_ECS_SERVICE_RUNNING": str(running_service_count)}
+    ):
+        client = boto3.client("ecs", region_name="us-east-1")
+        ec2 = boto3.resource("ec2", region_name="us-east-1")
+        setup_ecs(client, ec2)
+
+        response = client.create_service(
+            cluster="test_ecs_cluster",
+            serviceName="test_ecs_service",
+            taskDefinition="test_ecs_task",
+            desiredCount=4,
+            platformVersion="2",
+        )
+
+        assert response["service"]["runningCount"] == running_service_count
+        assert response["service"]["pendingCount"] == 1
+
+
+@mock_ecs
+@mock_ec2
+def test_create_running_service_bad_env_var():
+    running_service_count = "ALSDHLHA;''"
+    with mock.patch.dict(
+        os.environ, {"MOTO_ECS_SERVICE_RUNNING": str(running_service_count)}
+    ):
+        client = boto3.client("ecs", region_name="us-east-1")
+        ec2 = boto3.resource("ec2", region_name="us-east-1")
+        setup_ecs(client, ec2)
+
+        response = client.create_service(
+            cluster="test_ecs_cluster",
+            serviceName="test_ecs_service",
+            taskDefinition="test_ecs_task",
+            desiredCount=2,
+            platformVersion="2",
+        )
+
+        assert response["service"]["runningCount"] == 0
+
+
+@mock_ecs
+@mock_ec2
+def test_create_running_service_negative_env_var():
+    running_service_count = "-20"
+    with mock.patch.dict(
+        os.environ, {"MOTO_ECS_SERVICE_RUNNING": str(running_service_count)}
+    ):
+        client = boto3.client("ecs", region_name="us-east-1")
+        ec2 = boto3.resource("ec2", region_name="us-east-1")
+        setup_ecs(client, ec2)
+
+        response = client.create_service(
+            cluster="test_ecs_cluster",
+            serviceName="test_ecs_service",
+            taskDefinition="test_ecs_task",
+            desiredCount=2,
+            platformVersion="2",
+        )
+
+        assert response["service"]["runningCount"] == 0
+
+
 @mock_ecs
 def test_create_service_errors():
     # given
@@ -680,7 +751,7 @@ def test_create_service_scheduling_strategy():
     response["service"]["desiredCount"].should.equal(2)
     len(response["service"]["events"]).should.equal(0)
     len(response["service"]["loadBalancers"]).should.equal(0)
-    response["service"]["pendingCount"].should.equal(0)
+    response["service"]["pendingCount"].should.equal(2)
     response["service"]["runningCount"].should.equal(0)
     response["service"]["serviceArn"].should.equal(
         f"arn:aws:ecs:us-east-1:{ACCOUNT_ID}:service/test_ecs_cluster/test_ecs_service"
@@ -870,7 +941,9 @@ def test_describe_services():
 @mock.patch.dict(os.environ, {"MOTO_ECS_NEW_ARN": "TrUe"})
 def test_describe_services_new_arn():
     if settings.TEST_SERVER_MODE:
-        raise SkipTest("Cant set environment variables in server mode")
+        raise SkipTest(
+            "Can't set environment variables in server mode for a single test"
+        )
     client = boto3.client("ecs", region_name="us-east-1")
     _ = client.create_cluster(clusterName="test_ecs_cluster")
     _ = client.register_task_definition(
@@ -1338,7 +1411,9 @@ def test_register_container_instance():
 @mock.patch.dict(os.environ, {"MOTO_ECS_NEW_ARN": "TrUe"})
 def test_register_container_instance_new_arn_format():
     if settings.TEST_SERVER_MODE:
-        raise SkipTest("Cant set environment variables in server mode")
+        raise SkipTest(
+            "Can't set environment variables in server mode for a single test"
+        )
     ecs_client = boto3.client("ecs", region_name="us-east-1")
     ec2 = boto3.resource("ec2", region_name="us-east-1")
 
@@ -1876,7 +1951,9 @@ def test_run_task_default_cluster():
 @mock.patch.dict(os.environ, {"MOTO_ECS_NEW_ARN": "TrUe"})
 def test_run_task_default_cluster_new_arn_format():
     if settings.TEST_SERVER_MODE:
-        raise SkipTest("Cant set environment variables in server mode")
+        raise SkipTest(
+            "Can't set environment variables in server mode for a single test"
+        )
     client = boto3.client("ecs", region_name="us-east-1")
     ec2 = boto3.resource("ec2", region_name="us-east-1")
 
@@ -2953,7 +3030,7 @@ def test_create_service_load_balancing():
         "test_container_name"
     )
     response["service"]["loadBalancers"][0]["containerPort"].should.equal(123)
-    response["service"]["pendingCount"].should.equal(0)
+    response["service"]["pendingCount"].should.equal(2)
     response["service"]["runningCount"].should.equal(0)
     response["service"]["serviceArn"].should.equal(
         f"arn:aws:ecs:us-east-1:{ACCOUNT_ID}:service/test_ecs_cluster/test_ecs_service"