Bugfix aws_ec2 inventory use_ssm_inventory (#1957) (#1958)

[PR #1957/05c262a4 backport][stable-6] Bugfix aws_ec2 inventory use_ssm_inventory

This is a backport of PR #1957 as merged into main (05c262a).
SUMMARY
Fix bug where aws_ec2 inventory plugin was failing with use_ssm_inventory: true if there are more than 40 inventories.
ISSUE TYPE

Bugfix Pull Request

COMPONENT NAME
aws_ec2
ADDITIONAL INFORMATION
Fixes #1713

Reviewed-by: Alina Buzachis

changelogs/fragments/20240129-aws_ec2-inventory-bugfix.yml

@@ -0,0 +1,3 @@
+---
+bugfixes:
+  - plugins/inventory/aws_ec2 - Fix failure when retrieving information for more than 40 instances with use_ssm_inventory (https://github.com/ansible-collections/amazon.aws/issues/1713).

plugins/inventory/aws_ec2.py

@@ -649,8 +649,8 @@ def _query(self, regions, include_filters, exclude_filters, strict_permissions,
         return {"aws_ec2": instances}
 
     def _add_ssm_information(self, connection, instances):
-        filters = [{"Key": "AWS:InstanceInformation.InstanceId", "Values": [x["InstanceId"] for x in instances]}]
-        result = _get_ssm_information(connection, filters)
+        instance_ids = [x["InstanceId"] for x in instances]
+        result = self._get_multiple_ssm_inventories(connection, instance_ids)
         for entity in result.get("Entities", []):
             for x in instances:
                 if x["InstanceId"] == entity["Id"]:
@@ -659,6 +659,19 @@ def _add_ssm_information(self, connection, instances):
                         x["SsmInventory"] = content[0]
                     break
 
+    def _get_multiple_ssm_inventories(self, connection, instance_ids):
+        result = {}
+        # SSM inventory filters Values list can contain a maximum of 40 items so we need to retrieve 40 at a time
+        # https://docs.aws.amazon.com/systems-manager/latest/APIReference/API_InventoryFilter.html
+        while len(instance_ids) > 40:
+            filters = [{"Key": "AWS:InstanceInformation.InstanceId", "Values": instance_ids[:40]}]
+            result.update(_get_ssm_information(connection, filters))
+            instance_ids = instance_ids[40:]
+        if instance_ids:
+            filters = [{"Key": "AWS:InstanceInformation.InstanceId", "Values": instance_ids}]
+            result.update(_get_ssm_information(connection, filters))
+        return result
+
     def _populate(
         self,
         groups,

tests/unit/plugins/inventory/test_aws_ec2.py

@@ -649,3 +649,39 @@ def test_inventory__add_ssm_information(m_get_ssm_information, inventory):
 
     filters = [{"Key": "AWS:InstanceInformation.InstanceId", "Values": [x["InstanceId"] for x in instances]}]
     m_get_ssm_information.assert_called_once_with(connection, filters)
+
+
+@patch("ansible_collections.amazon.aws.plugins.inventory.aws_ec2._get_ssm_information")
+def test_inventory__get_multiple_ssm_inventories(m_get_ssm_information, inventory):
+    instances = [{"InstanceId": f"i-00{i}", "Name": f"instance {i}"} for i in range(41)]
+    result = {
+        "StatusCode": 200,
+        "Entities": [
+            {
+                "Id": f"i-00{i}",
+                "Data": {
+                    "AWS:InstanceInformation": {
+                        "Content": [{"os_type": "Linux", "os_name": "Fedora", "os_version": 37}]
+                    }
+                },
+            }
+            for i in range(41)
+        ],
+    }
+    m_get_ssm_information.return_value = result
+
+    connection = MagicMock()
+
+    expected = [
+        {
+            "InstanceId": f"i-00{i}",
+            "Name": f"instance {i}",
+            "SsmInventory": {"os_type": "Linux", "os_name": "Fedora", "os_version": 37},
+        }
+        for i in range(41)
+    ]
+
+    inventory._add_ssm_information(connection, instances)
+    assert expected == instances
+
+    assert 2 == m_get_ssm_information.call_count