A trigger is an event used to trigger your function code. Previously, we have defined functions triggered by HTTP requests. A variety of other triggers are available, and we will give examples of the most popular ones in this chapter.
Each function is limited to a single trigger. The function trigger must be defined in a binding in function.json, or through a trigger attribute in the function's signature in the Visual Studio functions project.
The function trigger must be selected from the supported list (the current list is provided further in the chapter). Defining custom triggers may become available in the future.