Common types of triggers
Let's understand first how a trigger works and get acquainted with the different types of triggers available in Azure Functions.
The architecture of a trigger and how it works is shown in the following figure:
![](https://static.packt-cdn.com/products/9781787122932/graphics/eda77c48-0841-4c08-ac84-0f92ae476a45.jpg)
The preceding diagram shows the event that fires the trigger and once the trigger is fired, it runs the Azure Function associated with it.
We need to note a very important point here: one function must have exactly one trigger; in other words, one function can't have multiple triggers.
Now let's see the different types of trigger available in Azure:
- TimerTrigger: This trigger is called on a predefined schedule. We can set the time for execution of the Azure Function using this trigger.
- BlobTrigger: This trigger will get fired when a new or updated blob is detected. The blob contents are provided as input to the function.
- EventHubTrigger: This trigger is used for the application instrumentation, the user experience, workflow processing, and in the Internet of Things...