There are nine types of output bindings:
- HTTP (REST or Webhook): The Azure Function can produce an output as HTTP (REST or Webhook). For example, the output of the Azure Function can be linked to Webhook or can be HTTP REST.
- Blob storage: The Azure Function can use blob storage for output binding. For example, we have the Azure Function, which processes the image and compresses the size of image. After the image is compressed, we want it to be stored in blob storage. For this, we need output binding for the Azure Function with blob storage.
- Events: An event can also be bound as output from the Azure Function. We will see an example of an event as output binding to the Azure Function later in this chapter.
- Queues and topics: Queues and topics can also be an output from the Azure Function. We will see an example for Service Bus queues and topics as output binding to the Azure Function later in this chapter.
- Storage tables: Storage tables can also be bound as output to the Azure Function. Storage tables can be used as input or output to the Azure Function. For example, the Azure Function can take input from the storage table, process the data, and after processing again, store data in the storage table.
- SQL tables: SQL table can be used as input or output to the Azure Function. The Azure Function can read or take input from the SQL table and after processing again, can store data to the SQL table.
- NoSQL DB: No-SQL tables can also be used as input or output to the Azure Function. The Azure Function can read data from NoSQL DB and process it. Once the data is processed, it can be stored in NoSQL DB.
- Push notifications: Push notifications can be used as output binding for the Azure Function. For example, consider a scenario where we want to send a push notification with a confirmation message to all users who have registered for some marathon. For this, we will create the Azure Function and process the form of all the users and send the push notification to those users whose registration is confirmed. In this scenario, we need to use push notification as output binding to the Azure Function.
- SendGrid email: SendGrid email is used as output to the Azure Function. This is used when we want to send an email after execution of the Azure Function.
So, in this section, we have given a brief overview of input and output bindings. For more details and examples, you can refer to https://docs.microsoft.com/en-us/azure/azure-functions/functions-triggers-bindings#overview.
In the next section, we will discuss Event Bus and Service Bus.