Introduction

AWS Step Functions is a powerful tool for automating complex workflows. It allows you to define a series of tasks that can be executed in a specific order, and it can be used to orchestrate the execution of tasks across multiple AWS services. In this lesson, we will explore how to use Task States with AWS Step Functions. We will look at how to define a state machine, how to define tasks, and how to execute a state machine.

What are Task States?

Task States are the building blocks of AWS Step Functions. They are used to define the steps in a workflow. Each Task State is associated with an AWS service, such as Lambda, SNS, or SQS. When a Task State is executed, it will invoke the associated AWS service and execute the task.

Defining a State Machine

A State Machine is a collection of Task States that define a workflow. It is the top-level construct in AWS Step Functions. To define a State Machine, you must first create a JSON document that describes the workflow. This document is called the State Machine Definition.

The State Machine Definition contains a list of Task States and the order in which they should be executed. Each Task State must have a unique name and must specify the AWS service that should be invoked when the Task State is executed.

Defining Tasks

Once you have defined a State Machine, you must define the tasks that will be executed by each Task State. Each task must be written in a language that is supported by the AWS service that will be invoked. For example, if you are using Lambda, you must write your tasks in Node.js, Python, or Java.

When defining a task, you must specify the input and output parameters that will be used by the task. The input parameters will be used to provide data to the task, and the output parameters will be used to return data from the task.

Executing a State Machine

Once you have defined a State Machine and the tasks that will be executed by each Task State, you can execute the State Machine. To execute a State Machine, you must provide an input document that contains the data that will be used by the tasks. This document is called the Execution Input.

When you execute a State Machine, AWS Step Functions will invoke the AWS services associated with each Task State and execute the tasks. The output of each task will be stored in an Execution Output document. This document will contain the data returned by each task.

Conclusion

In this lesson, we explored how to use Task States with AWS Step Functions. We looked at how to define a State Machine, how to define tasks, and how to execute a State Machine. We also discussed how to provide an Execution Input document and how to retrieve an Execution Output document. By using Task States, you can easily create complex workflows that can be executed across multiple AWS services.