Implement Cancel and Wait commands

formica/cli.py

@@ -5,6 +5,7 @@
 import argcomplete
 import sys
 import logging
+import signal
 
 
 from . import CHANGE_SET_FORMAT, __version__
@@ -64,7 +65,17 @@ def formica():
     main(sys.argv[1:])
 
 
+def signal_handler(sig, frame):
+    logger.info('Exiting because of ctrl-c')
+    sys.exit(0)
+
+
+def add_signal_handler():
+    signal.signal(signal.SIGINT, signal_handler)
+
+
 def main(cli_args):
+    add_signal_handler()
     parser = argparse.ArgumentParser()
     parser.add_argument('--version', action='version', version='{}'.format(__version__))
     subparsers = parser.add_subparsers(title='commands',
@@ -117,6 +128,20 @@ def main(cli_args):
     add_config_file_argument(deploy_parser)
     deploy_parser.set_defaults(func=deploy)
 
+    # Cancel Command Arguments
+    cancel_parser = subparsers.add_parser('cancel', description='Cancel a Stack Update')
+    add_aws_arguments(cancel_parser)
+    add_stack_argument(cancel_parser)
+    add_config_file_argument(cancel_parser)
+    cancel_parser.set_defaults(func=cancel)
+
+    # Wait Command Arguments
+    wait_parser = subparsers.add_parser('wait', description='Wait for a Stack to be deployed or removed')
+    add_aws_arguments(wait_parser)
+    add_stack_argument(wait_parser)
+    add_config_file_argument(wait_parser)
+    wait_parser.set_defaults(func=wait)
+
     # Describe Command Arguments
     describe_parser = subparsers.add_parser('describe', description='Describe the latest change-set of the stack')
     add_aws_arguments(describe_parser)
@@ -458,27 +483,46 @@ def change(args):
     change_set.describe()
 
 
+def wait_for_stack(function):
+    def wait(args):
+        from .stack_waiter import StackWaiter
+        client = AWS.current_session().client('cloudformation')
+        stack_id = client.describe_stacks(StackName=args.stack)['Stacks'][0]['StackId']
+        last_event = client.describe_stack_events(StackName=args.stack)['StackEvents'][0]['EventId']
+        function(args, client)
+        StackWaiter(stack_id, client).wait(last_event)
+    return wait
+
+
 @requires_stack
-def deploy(args):
-    from .stack_waiter import StackWaiter
-    client = AWS.current_session().client('cloudformation')
-    last_event = client.describe_stack_events(StackName=args.stack)['StackEvents'][0]['EventId']
+@wait_for_stack
+def deploy(args, client):
+    logger.info('Deploying StackSet to {}'.format(args.stack))
     client.execute_change_set(ChangeSetName=(CHANGE_SET_FORMAT.format(stack=args.stack)), StackName=args.stack)
-    StackWaiter(args.stack, client).wait(last_event)
 
 
 @requires_stack
-def remove(args):
-    from .stack_waiter import StackWaiter
-    client = AWS.current_session().client('cloudformation')
-    stack_id = client.describe_stacks(StackName=args.stack)['Stacks'][0]['StackId']
+@wait_for_stack
+def cancel(args, client):
+    logger.info('Canceling update for stack {}'.format(args.stack))
+    client.cancel_update_stack(StackName=args.stack)
+
+
+@requires_stack
+@wait_for_stack
+def wait(args, client):
+    logger.info('Waiting for Stack {}'.format(args.stack))
+    pass
+
+
+@requires_stack
+@wait_for_stack
+def remove(args, client):
     logger.info('Removing Stack and waiting for it to be removed, ...')
-    last_event = client.describe_stack_events(StackName=args.stack)['StackEvents'][0]['EventId']
     if args.role_arn:
         client.delete_stack(StackName=args.stack, RoleARN=args.role_arn)
     else:
         client.delete_stack(StackName=args.stack)
-    StackWaiter(stack_id, client).wait(last_event)
 
 
 @requires_stack

formica/stack_waiter.py

@@ -35,7 +35,9 @@ def wait(self, last_event):
             stack_status = self.client.describe_stacks(StackName=self.stack)['Stacks'][0]['StackStatus']
             if stack_status in SUCCESSFUL_STATES:
                 finished = True
+                logger.info("Stack Change Successful: {}".format(stack_status))
             elif stack_status in FAILED_STATES:
+                logger.info("Stack Change Failed: {}".format(stack_status))
                 sys.exit(1)
 
     def __create_table(self):

tests/unit/test_cancel_wait.py

@@ -0,0 +1,40 @@
+import pytest
+from mock import Mock
+
+from formica import cli
+from tests.unit.constants import STACK, STACK_ID, EVENT_ID
+
+
+@pytest.fixture
+def logger(mocker):
+    return mocker.patch('formica.cli.logger')
+
+
+@pytest.fixture
+def stack_waiter(mocker):
+    return mocker.patch('formica.stack_waiter.StackWaiter')
+
+
+@pytest.fixture
+def session(mocker):
+    return mocker.patch('boto3.session.Session')
+
+
+@pytest.fixture
+def client(mocker, session):
+    client_mock = Mock()
+    session.return_value.client.return_value = client_mock
+    return client_mock
+
+
+def test_cancel_stack_update(client, stack_waiter):
+    client.describe_stacks.return_value = {'Stacks': [{'StackId': STACK_ID}]}
+    client.describe_stack_events.return_value = {'StackEvents': [{'EventId': EVENT_ID}]}
+    cli.main(['cancel', '--stack', STACK])
+    client.cancel_update_stack.assert_called_with(StackName=STACK)
+
+
+def test_wait(client, stack_waiter):
+    client.describe_stacks.return_value = {'Stacks': [{'StackId': STACK_ID}]}
+    client.describe_stack_events.return_value = {'StackEvents': [{'EventId': EVENT_ID}]}
+    cli.main(['wait', '--stack', STACK])

tests/unit/test_deploy.py

@@ -4,7 +4,7 @@
 from botocore.exceptions import NoCredentialsError
 
 from formica import cli
-from tests.unit.constants import STACK, PROFILE, REGION, CHANGESETNAME, EVENT_ID
+from tests.unit.constants import STACK, STACK_ID, PROFILE, REGION, CHANGESETNAME, EVENT_ID
 
 
 @pytest.fixture
@@ -49,9 +49,10 @@ def test_executes_change_set_and_waits(session, stack_waiter):
     cf_client_mock = Mock()
     session.return_value.client.return_value = cf_client_mock
     cf_client_mock.describe_stack_events.return_value = {'StackEvents': [{'EventId': EVENT_ID}]}
+    cf_client_mock.describe_stacks.return_value = {'Stacks': [{'StackId': STACK_ID}]}
 
     cli.main(['deploy', '--stack', STACK, '--profile', PROFILE, '--region', REGION])
     cf_client_mock.describe_stack_events.assert_called_with(StackName=STACK)
     cf_client_mock.execute_change_set.assert_called_with(ChangeSetName=CHANGESETNAME, StackName=STACK)
-    stack_waiter.assert_called_with(STACK, cf_client_mock)
+    stack_waiter.assert_called_with(STACK_ID, cf_client_mock)
     stack_waiter.return_value.wait.assert_called_with(EVENT_ID)