Automating your workflow using AWS Step Functions

Posted on by Panther

Introduction

As more and more companies are moving towards the cloud to host their applications and services, the need for automation has become increasingly important to reduce human error and improve efficiency. AWS Step Functions is a powerful service provided by Amazon Web Services (AWS) that enables you to build serverless workflows that orchestrate AWS services, third-party services, and your own application code.

In this tutorial, we will explore how to automate workflows using AWS Step Functions. Specifically, we will go through the process of creating a simple workflow that retrieves data from a database, processes it using a AWS Lambda function, and updates the database with the result. We will be using the AWS Console to perform the steps, but the same process can also be done using the AWS CLI or SDKs.

Prerequisites

Before we begin, you will need an AWS account and some basic knowledge of AWS services, including AWS Lambda, AWS Step Functions, and Amazon Relational Database Service (Amazon RDS). Additionally, you will need to have created a MySQL database instance on Amazon RDS and have the connection details available.

Step 1: Create the Lambda Function

The first step in our workflow is to create a Lambda function that will be used to process our data. In the AWS Console, navigate to the Lambda service and click on “Create Function”. From there, select “Author from scratch” and give your function a name. For the runtime, select “Python 3.8” (or any other runtime of your choice).

Once your function is created, paste in the following code:

import json

def lambda_handler(event, context):
    # Your processing code here
    return {
        'statusCode': 200,
        'body': json.dumps('Hello from Lambda!')
    }

This is just a simple function that returns a JSON response, but you can replace it with any code that processes your data. Click on “Deploy” to save your function.

Step 2: Create the Step Function

Now that we have our Lambda function, we can create a Step Function that will orchestrate our workflow. In the AWS Console, navigate to the Step Functions service and click on “Create state machine”.

In the state machine designer, we will define the steps in our workflow. Our workflow will have three states:
1. Retrieve data from the database
2. Invoke the Lambda function to process the data
3. Update the database with the result

To define each state, drag and drop the corresponding state from the left menu onto the designer. For the first state, select “AWS Lambda” and choose the IAM role that your Lambda function will use. For the second state, select “Lambda Function” and choose your function.

For the third state, we will use an Amazon RDS query to update the database. Drag and drop a new state onto the designer and select “Service”, then choose “Amazon RDS”. In the “Service Integration” section, select your database instance and enter a SQL query to update the table with the processed data. For example:

UPDATE mytable SET result = 'processed_data' WHERE id = 'myid'

Save your state machine and take note of the ARN (Amazon Resource Name) for it.

Step 3: Test the Workflow

Now that we have our Lambda function and Step Function defined, we can test our workflow. In the Step Functions console, select your state machine and click on “New Execution”.

In the input field, we will pass the ID of the row in our database that we want to process. In this example, we will assume that our database schema has a table called “mytable” with columns “id” and “data”. We want to process the row with “id” equal to “myid”. Our input will look like this:

{
    "id": "myid"
}

Click on “Start Execution” to begin the workflow execution. You should see the individual states being executed one by one and eventually completing successfully.

Step 4: Schedule the Workflow

Now that we have a working workflow, we can schedule it using the AWS CloudWatch Events service. In the AWS Console, navigate to the CloudWatch service and click on “Rules”.

Click on “Create rule” and select the “Schedule” event source. Set the schedule to “Fixed rate” and choose a rate of your choice (e.g. every 5 minutes).

In the “Targets” section, select “Step Functions state machine” and choose your state machine. Enter the same input as before, with the ID of the row to process.

Click on “Create rule” to schedule the workflow. Your workflow will now execute automatically at the schedule you specified.

Conclusion

In this tutorial, we explored how to automate workflows using AWS Step Functions. We went through the process of creating a simple workflow that retrieves data from a database, processes it using a AWS Lambda function, and updates the database with the result. We also scheduled the workflow to run automatically at a fixed rate using AWS CloudWatch Events.

AWS Step Functions provides a powerful way to orchestrate your AWS services and third-party services, making it easy to automate your workflows and reduce error-prone manual processes. With a little bit of setup, you can have powerful workflows running on the cloud in no time.

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