Introduction

This is a sample implementation of the request-response message bus pattern using Azure Functions and Azure Service Bus. In this sample, one queue each for both requests and replies (instead of a temporary queue per request/reply) will be used together with some Durable Functions functionality.

• .NET Core 3.1
• Azure Functions v3

Getting Started

Setup environment (or local.settings.json) values:

Name	Description
AzureWebJobsServiceBus	Connection string/SAS with read/write rights to a ServiceBus namespace
RequestQueueName	Name of an existing queue in the above namespace, which will be used for sending the request
ReplyQueueName	Name of an existing queue in the above namespace, which will be used for sending the reply

There will be an HTTP trigger function at http://localhost:7071/api/input that will accept a simple POST with a payload:

{ "name": "string" }

The API starts a new Durable Functions instance, which will asynchronously handle the request/reply pattern. On success, the API will respond with

{
    "id": "8d7f914cebda4b86aa74db135077b7ec",
    "statusQueryGetUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/8d7f914cebda4b86aa74db135077b7ec?taskHub=TestHubName&connection=Storage&code=qncc7CfyyYK7u4T5AM6d6TyLa6JFj3e6D1Jxbw9IgYE2Grgq7/i8fA==",
    "sendEventPostUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/8d7f914cebda4b86aa74db135077b7ec/raiseEvent/{eventName}?taskHub=TestHubName&connection=Storage&code=qncc7CfyyYK7u4T5AM6d6TyLa6JFj3e6D1Jxbw9IgYE2Grgq7/i8fA==",
    "terminatePostUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/8d7f914cebda4b86aa74db135077b7ec/terminate?reason={text}&taskHub=TestHubName&connection=Storage&code=qncc7CfyyYK7u4T5AM6d6TyLa6JFj3e6D1Jxbw9IgYE2Grgq7/i8fA==",
    "purgeHistoryDeleteUri": "http://localhost:7071/runtime/webhooks/durabletask/instances/8d7f914cebda4b86aa74db135077b7ec?taskHub=TestHubName&connection=Storage&code=qncc7CfyyYK7u4T5AM6d6TyLa6JFj3e6D1Jxbw9IgYE2Grgq7/i8fA=="
}

To see progress, use URI provided in property statusQueryGetUri. It will return a response something like this:

{
	"name": "HandleRequest",
	"instanceId": "8d7f914cebda4b86aa74db135077b7ec",
	"runtimeStatus": "Completed",
	"input": {
		"Name": "<name given in API request>"
	},
	"customStatus": null,
	"output": {
		"OrchestrationId": "8d7f914cebda4b86aa74db135077b7ec",
		"Name": "<name given in API request>",
		"Timestamp": "2020-11-27T19:05:13.9803949Z",
		"Id": "3a34be4f-77b1-4546-ba82-854cd92fb38c",
		"Success": true
	},
	"createdTime": "2020-11-27T19:05:13Z",
	"lastUpdatedTime": "2020-11-27T19:05:14Z"
}