AWS Step Functions

AWS Step Functions is a visual workflow service that helps you build distributed applications, automate processes, orchestrate microservices, and create data and machine learning (ML) pipelines.

In the Step Functions' graphical console, you can see your application’s workflow as a series of event-driven steps.

Step Functions is based on state machines and tasks. In Step Functions, state machines are called workflows, which are a series of event-driven steps. Each step in a workflow is called a state. For example, a

Task state⁠

represents a unit of work that another AWS service performs, such as calling another AWS service or API.

With Step Functions' built-in controls, you can examine the state of each step in your workflow to make sure that your application runs in order and as expected. Depending on your use case, you can have Step Functions call AWS services, such as Lambda, to perform tasks. You can create workflows that process and publish machine learning models. You can have Step Functions control AWS services, such as AWS Glue, to create extract, transform, and load (ETL) workflows. You also can create long-running, automated workflows for applications that require human interaction.

You can quickly build and run state machines to execute the steps of your application in a reliable and scalable fashion.

How it works:

Define the steps of your workflow in the JSON-based Amazon States Language. The visual console automatically graphs each step in the order of execution.

Start an execution to visualize and verify the steps of your application are operating as intended. The console highlights the real-time status of each step and provides a detailed history of every execution.

AWS Step Functions operates and scales the steps of your application and underlying compute for you to help ensure your application executes reliably under increasing demand.

It is a managed workflow and orchestration platform.

Standard and Express workflows

Step Functions has two workflow types.

Standard workflows have exactly-once workflow execution and can run for up to one year. This means that each step in a Standard workflow will execute exactly once.

Express workflows, however, have at-least-once workflow execution and can run for up to five minutes. This means that one or more steps in an Express Workflow can potentially run more than once, while each step in the workflow executes at least once.

Executions are instances where you run your workflow to perform tasks. Standard workflows are ideal for long-running, auditable workflows, as they show execution history and visual debugging. Express workflows are ideal for high-event-rate workloads, such as streaming data processing and IoT data ingestion.