Pre-empt in-progress nested stack updates on new update

If the parent resource of a nested stack is locked due to an IN_PROGRESS
update, cancel the nested stack update (which will result in the parent
resource being marked FAILED and releasing the lock so that the new
traversal can begin acting on it). This also cancels all descendants of
the nested stack.

This means that a concurrent update no longer gets blocked at a nested
stack boundary until the previous update has finished.

Change-Id: I5f14453ebab75d89672c6eea12de46d48a5147f3
Task: 17760

1 files changed, 83 insertions, 0 deletions

diff --git a/heat_integrationtests/functional/test_simultaneous_update.py b/heat_integrationtests/functional/test_simultaneous_update.py
index 0c562c075..004145d3b 100644
--- a/heat_integrationtests/functional/test_simultaneous_update.py
+++ b/heat_integrationtests/functional/test_simultaneous_update.py
@@ -12,6 +12,7 @@
 
 
 import copy
+import json
 import time
 
 from heat_integrationtests.common import test
@@ -91,3 +92,85 @@ class SimultaneousUpdateStackTest(functional_base.FunctionalTestsBase):
         time.sleep(50)
 
         self.update_stack(stack_id, after)
+
+
+input_param = 'input'
+preempt_nested_stack_type = 'preempt.yaml'
+preempt_root_rsrcs = {
+    'nested_stack': {
+        'type': preempt_nested_stack_type,
+        'properties': {
+            'input': {'get_param': input_param},
+        },
+    }
+}
+preempt_root_out = {'get_attr': ['nested_stack', 'delay_stack']}
+preempt_delay_stack_type = 'delay.yaml'
+preempt_nested_rsrcs = {
+    'delay_stack': {
+        'type': preempt_delay_stack_type,
+        'properties': {
+            'input': {'get_param': input_param},
+        },
+    }
+}
+preempt_nested_out = {'get_resource': 'delay_stack'}
+preempt_delay_rsrcs = {
+    'delay_resource': {
+        'type': 'OS::Heat::TestResource',
+        'properties': {
+            'action_wait_secs': {
+                'update': 6000,
+            },
+            'value': {'get_param': input_param},
+        },
+    }
+}
+
+
+def _tmpl_with_rsrcs(rsrcs, output_value=None):
+    tmpl = {
+        'heat_template_version': 'queens',
+        'parameters': {
+            input_param: {
+                'type': 'string',
+            },
+        },
+        'resources': rsrcs,
+    }
+    if output_value is not None:
+        outputs = {'delay_stack': {'value': output_value}}
+        tmpl['outputs'] = outputs
+    return json.dumps(tmpl)
+
+
+class SimultaneousUpdateNestedStackTest(functional_base.FunctionalTestsBase):
+    @test.requires_convergence
+    def test_nested_preemption(self):
+        root_tmpl = _tmpl_with_rsrcs(preempt_root_rsrcs,
+                                     preempt_root_out)
+        files = {
+            preempt_nested_stack_type: _tmpl_with_rsrcs(preempt_nested_rsrcs,
+                                                        preempt_nested_out),
+            preempt_delay_stack_type: _tmpl_with_rsrcs(preempt_delay_rsrcs),
+        }
+        stack_id = self.stack_create(template=root_tmpl, files=files,
+                                     parameters={input_param: 'foo'})
+        delay_stack_uuid = self.get_stack_output(stack_id, 'delay_stack')
+
+        # Start an update that includes a long delay in the second nested stack
+        self.update_stack(stack_id, template=root_tmpl, files=files,
+                          parameters={input_param: 'bar'},
+                          expected_status='UPDATE_IN_PROGRESS')
+        self._wait_for_resource_status(delay_stack_uuid, 'delay_resource',
+                                       'UPDATE_IN_PROGRESS')
+
+        # Update again to check that we preempt update of the first nested
+        # stack. This will delete the second nested stack, after preempting the
+        # update of that stack as well, which will cause the delay resource
+        # within to be cancelled.
+        empty_nest_files = {
+            preempt_nested_stack_type: _tmpl_with_rsrcs({}),
+        }
+        self.update_stack(stack_id, template=root_tmpl, files=empty_nest_files,
+                          parameters={input_param: 'baz'})