udondan
aws-cloudformation-custom-resource
Helper for managing custom AWS CloudFormation resources in a Lambda function.
Usage
You can find a complete example in the test directory.
The use of generics is optional. If no ResourceProperties is passed to the Event and CustomResource, the default type is Records<string, string>.
Basic usage:
import {
Callback,
Context,
CustomResource,
Event,
Logger,
} from 'aws-cloudformation-custom-resource';
export interface ResourceProperties {
name: string;
}
export const handler = function (
event: Event<ResourceProperties>,
context: Context,
callback: Callback,
) {
new CustomResource<ResourceProperties>(
event,
context,
callback,
createResource,
updateResource,
deleteResource,
);
};
function createResource(
resource: CustomResource<ResourceProperties>,
log: Logger,
): Promise<void> {
return new Promise(function (resolve, reject) {
log.log('Hello from create');
// Every custom resource requires a physical ID.
// Either you can pass a `name` parameter to the lambda function
// (accessed via `resource.properties.name`)
// or you can manually set the ID:
resource.setPhysicalResourceId('some-physical-resource-id');
// you can return values from the Lambda function:
resource.addResponseValue('Foo', 'bar');
doSomethingWith(resource.properties.name.value).then(resolve).catch(reject);
});
}
function updateResource(
resource: CustomResource<ResourceProperties>,
log: Logger,
): Promise<void> {
log.log('Hello from update');
return new Promise(function (resolve, reject) {
resource.addResponseValue('Foo', 'bar');
if (resource.properties.name.changed) {
doSomethingWith(resource.properties.name.value)
.then(resolve)
.catch(reject);
} else {
resolve();
}
});
}
function deleteResource(
resource: CustomResource<ResourceProperties>,
log: Logger,
): Promise<void> {
log.log('Hello from delete');
return new Promise(function (resolve, reject) {
// do stuff
resolve();
});
}By default only errors are logged. You can change the log level or use another logging library:
import {
Callback,
Context,
CustomResource,
Event,
LogLevel,
StandardLogger,
} from 'aws-cloudformation-custom-resource';
const logger = new StandardLogger(LogLevel.debug);
const resource = new CustomResource(
event,
context,
callback,
createResource,
updateResource,
deleteResource,
);
resource.setLogger(logger);