Greengrass v2 components are synchronous or asynchronous in their execution?

AWS IoT Greengrass components are software modules that you deploy to Greengrass core devices. Components can represent applications, runtime installers, libraries, or any code that you would run on a device. You can define components that depend on other components. For example, you might define a component that installs Python, and then define that component as a dependency of your components that run Python applications. When you deploy your components to your fleets of devices, Greengrass deploys only the software modules that your devices require.

Components can have any number of artifacts, which are component binaries. Artifacts can include scripts, compiled code, static resources, and any other files that a component consumes. Components can also consume artifacts from component dependencies.

So within your scripts you can have your code either handle things synchronous or asynchronous based on requirements. You may also have to make your code aware of downstream services/systems with which you are interacting if they are in-turn synchronous or asynchronous

Reference : https://docs.aws.amazon.com/greengrass/v2/developerguide/develop-greengrass-components.html