def _create_embedded_invalidations(appconfig: dict, stack: Stack):
"""Invalidate the cache in applications that use some of these parameters
(by restarting the application), as specified by configuration embedded
inline in the input file.
"""
invalidatable_services = appconfig.get(".ssmash-config",
{}).get("invalidations")
if not invalidatable_services:
return
clean_config = dict(appconfig)
clean_config.pop(".ssmash-config", None)
invalidated_resources = _get_invalidated_resources(clean_config)
for appname, appresources in invalidated_resources.items():
invalidator = invalidatable_services.get(appname)
if not invalidator:
# TODO this error message is a bit fragile
raise ValueError(
f"Parameter {appresources[0].Properties.Name} invalidates service {appname}, but that service is not defined."
)
stack.merge_stack(
invalidator.create_resources(appresources).with_prefixed_names(
"Invalidate" + clean_logical_name(appname)))
def test_cannot_merge_if_sam_transform_version_is_different(self):
source = Stack(Transform="123")
target = Stack(Transform="456")
# Exercise & Verify
with pytest.raises(StackMergeError) as excinfo:
target.merge_stack(source)
assert "transform version" in str(excinfo.value).lower()
def test_cannot_merge_if_template_version_is_different(self):
source = Stack(AWSTemplateFormatVersion="123")
target = Stack(AWSTemplateFormatVersion="456")
# Exercise & Verify
with pytest.raises(StackMergeError) as excinfo:
target.merge_stack(source)
assert "template version" in str(excinfo.value).lower()
def test_does_not_copy_description(self):
# Setup
source = Stack(Description="Source Description")
original_description = "Target Description"
target = Stack(Description=original_description)
# Exercise
target.merge_stack(source)
# Verify
assert target.Description == original_description
def test_item_is_added_to_the_target_stack(self, stack_attribute, item):
# Setup
item_name = "SomeChildProperty"
source = Stack()
source[stack_attribute] = {item_name: item}
target = Stack()
# Exercise
target.merge_stack(source)
# Verify
assert len(target[stack_attribute]) == 1
assert target[stack_attribute][item_name] is item
def test_does_not_copy_flying_circus_metadata(self):
# Setup
source = Stack()
source.Metadata["FlyingCircus"]["version"] = "gamma-gamma"
target = Stack()
original_fc_data = target.Metadata["FlyingCircus"]
# Exercise
target.merge_stack(source)
# Verify
assert target.Metadata["FlyingCircus"] == original_fc_data
def test_item_is_not_removed_from_source_stack(self, stack_attribute,
item):
# Setup
item_name = "SomeChildProperty"
source = Stack()
source[stack_attribute] = {item_name: item}
target = Stack()
# Exercise
target.merge_stack(source)
# Verify
assert len(source[stack_attribute]) == 1
assert source[stack_attribute][item_name] is item
def test_cannot_merge_if_two_outputs_have_the_same_export_name(self):
# Setup
export_name = "SpecialExportedValue"
source_output = Output(Value=123, Export={"Name": export_name})
source = Stack(Outputs={"SourceOutput": source_output})
target_output = Output(Value=987, Export={"Name": export_name})
target = Stack(Outputs={"TargetOutput": target_output})
# Exercise & Verify
with pytest.raises(StackMergeError) as excinfo:
target.merge_stack(source)
assert "the target stack already has exports" in str(
excinfo.value).lower()
def test_cannot_merge_if_logical_name_is_already_used_for_that_item_type(
self, stack_attribute, item):
# Setup
item_name = "SomeChildProperty"
source = Stack()
source[stack_attribute] = {item_name: item}
existing_item = copy(item)
target = Stack()
target[stack_attribute] = {item_name: existing_item}
# Exercise & Verify
with pytest.raises(StackMergeError) as excinfo:
target.merge_stack(source)
assert "in this stack already has an item with the logical name" in str(
excinfo.value)
def test_does_not_clobber_existing_items_in_target_stack(
self, stack_attribute, item):
# Setup
item_name = "SomeChildProperty"
source = Stack()
source[stack_attribute] = {item_name: item}
existing_item = copy(item)
existing_item_name = "SomeOldItem"
target = Stack()
target[stack_attribute] = {existing_item_name: existing_item}
# Exercise
target.merge_stack(source)
# Verify
assert len(target[stack_attribute]) == 2
assert target[stack_attribute][item_name] is item
assert target[stack_attribute][existing_item_name] is existing_item
def test_merge_returns_target_stack(self):
# Setup
source = Stack(Resources={"SomeResource": SimpleResource()})
target = Stack()
# Exercise
result = target.merge_stack(source)
# Verify
assert target is result
def autoscaling_group_by_cpu(low=20, high=80):
"""Create an auto-scaling group that scales based on it's CPU load."""
# TODO this is more like a recipe than a basic service
stack = Stack(
# TODO generate description by auto-breaking the line with the (not-yet-existent) reflow function instead
Description=dedent("""
Deploy an auto-scaling group that scales based on lower and upper CPU usage
thresholds.
"""),
)
launch_config = stack.Resources["LaunchConfiguration"] = LaunchConfiguration(
Properties=dict(
ImageId="ami-1a668878", # Amazon Linux 2017.09.01 in ap-southeast-2
InstanceType="t2.micro", # TODO consider making this a lookup value
# TODO KeyName would probably be helpful
),
)
asg = stack.Resources["AutoScalingGroup"] = AutoScalingGroup(
Properties=dict(
AvailabilityZones=fn.GetAZs(fn.Ref(AWS_Region)),
LaunchConfigurationName=fn.Ref(launch_config),
MinSize=1,
MaxSize=3,
),
)
stack.merge_stack(
simple_scaling_policy(
cloudwatch.Alarms.high_cpu(threshold=high), fn.Ref(asg), downscale=False,
).with_prefixed_names("ScaleUp")
).merge_stack(
simple_scaling_policy(
cloudwatch.Alarms.low_cpu(threshold=low), fn.Ref(asg), downscale=True,
).with_prefixed_names("ScaleDown")
)
return stack
def _create_ssm_parameters(appconfig: dict, stack: Stack):
"""Create SSM parameters for every item in the application configuration"""
stack.merge_stack(
convert_hierarchy_to_ssm(appconfig).with_prefixed_names("SSMParam")
)
def _create_ssm_parameters(appconfig: dict, stack: Stack):
"""Create SSM parameters for every item in the application configuration"""
clean_config = dict(appconfig)
clean_config.pop(".ssmash-config", None)
stack.merge_stack(
convert_hierarchy_to_ssm(clean_config).with_prefixed_names("SSMParam"))
