Resource Bindings

Abstract

So far, I have shown you how to interface with other services within your microservices-based application. This chapter will be about integrating with various external services. The communication typically happens in two ways – either an external service creates an event that a local Dapr service listens for or a local Dapr application makes a request to an external system. Dapr has a building block for talking to external systems, which logically can be split into two groups from a logical perspective – input and output bindings. I will enumerate the various systems that the Resource Bindings building block integrates with and whether it is for input or output or it is bidirectional. Then I will explain what the API of the Resource Bindings building block looks like. To demonstrate how things work, I will walk you through implementing a solution that monitors an Azure Blob Storage container for newly uploaded photos using Azure Event Grid; it performs object detection, then sends the recognized and tagged images to the same storage account, and also persists the objects identified to a state store.