When working with Azure Logic Apps, I like to have each Logic App do a single piece of work, as this allows us to mix and match these Logic Apps in various flows. For this demo, we will be using a very simple representation of this, where we have one Logic App which receives the message and send back a response to the original caller, another Logic App which does transformation of the message, and finally a Logic App which calls a backend system. To decouple these Logic Apps we will be using Azure Service Bus topics, providing us with routing capabilities and allowing us to handle downtime more easily.
Architecture
Now the challenge we were running into, is that we needed to give the response which we received from the backend, back as a response to the client.
Requested architecture
Of course, since we have implemented communication between the Logic Apps asynchronously and decoupled by using Service Bus in between, we don’t have a return channel on which we can send the response. In this post, I will show how we can solve this by using Service Bus sessions.
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