Azure Logic Apps

Azure Logic Apps is an event-triggered serverless workflow (and orchestration) service that’s provided as a cloud-hosted development PaaS. It models business processes in automated workflows.

In a nutshell, this means that it reacts to an event much like Azure Functions does, but instead of triggering code execution, Azure Logic Apps triggers a workflow. A workflow is a set of conditional task actions (operations) and can act as an integration orchestration service for these business processes.

This is classed as a designer-first (declarative) development approach; there is low code or no code, as is the case with Functions. We create the orchestration workflows by drawing out the business process as a flow diagram; we create these business processes visually using a Logic Apps designer in the Azure portal to create the workflow. We will cover this in more detail in the hands-on exercises.

Code can be still used in Logic Apps as part of the flow by using inline code or by adding Azure functions inside the Logic App’s flow.

These business process workflows are created from an extensive collection of ready-made connectors that perform the workflows tasks. An operation that performs a task is called an action and follows an if, then approach, which means that when the Logic App receives a trigger, an action (operation) can be performed.

It is possible to chain a set of functions as actions through a workflow based on an event and a trigger. An event trigger could be when a Twitter message is received when a user is added to an internal HR system or when a file is uploaded/downloaded for SharePoint, blob or file storage, other business applications, and so on.

The difference from a function is that Logic Apps is a no-code (designer-first) model; the triggers execute a workflow operation action (business process instead of code) that could send an email, post a team’s message, post a tweet, copy data to a data store, update a CRM system, call a function, and so on; there can be multiple operation actions for the workflow. This means Logic Apps acts as an automated workflow engine, an orchestrator of functions, tasks, and business processes; it allows integrations between systems, services, and data. Logic Apps workflows are created in the Azure portal through a visual designer interface; no coding is required. The following diagram visualizes the Azure Logic Apps components:

Figure 5.3 – Serverless workflow/orchestration platform

The key takeaway from the preceding diagram is that an event triggers a workflow, a set of operations known as actions; this can be contrasted with Azure Functions, where events trigger code.

The following diagram visualizes a use case scenario for serverless using Functions and Logic Apps in the solution: