File Storage Function

A file storage function is triggered whenever a File Storage Bucket either has an item created or deleted. This annotation will create the bucket if it does not already exist within the project.

Basic Usage

A method is annotated with @FileStorageServerlessFunction which is provided with a bucketName and an event type.

Here is an example of a function which is triggered when in item is added to the bucket:

class FileStorageHandlers {
    @FileStorageServerlessFunction(bucketName = "ImageBucket", eventType = FileStorageEventType.OBJECT_CREATED)
    public void newObject(FileStorageEvent event) {
        System.out.println("New file added: " + event.getKey() + " with size " + event.getSize() + " bytes");
    }
}

The bucket name requirements are the same as they are in @FileStorageBucket.

As with all serverless functions, a file storage function must be inside of a class with a default constructor available.

It is important to note that the actual file data is not an available parameter, it must be read from the file bucket using a FileStorageClient and the file key available in the event parameter.

Method Details

Parameters

The method can have at most one parameter, a FileStorageEvent. This event class contains the key of the file which can then be accessed using a FileStorageClient. If the event is an OBJECT_DELETED event then the size of the file will be 0. The size provided by the event is in bytes.

Return Type

The return type is not used for anything and will be ignored in the deployed function. In local unit tests you can still access any returned value.

Annotation Sepecification

@FileStorageServerlessFunction

Required Parameters

• bucketName - The name of the file storage bucket in the cloud provider. In the actual cloud provider will be appended with the stage.
• eventType - What event will trigger the function, either an OBJECT_CREATED or OBJECT_DELETED

Optional Parameters

• timeout - How long the function is allowed to run for before timing out, in seconds. Defaults to 10.
• memory - The amount of memory the function runs with, in MB. Defaults to 1024.
• stages - The stages that the function is deployed to.