Streamlining Workflows for Efficiency and Resilience: Leveraging Lambda and Step Functions.
Tags: aws, serverless, microservices
Published: 2023-09-26 14:21:53


Having recently participated in an enlightening workshop on  Building Event-Driven App moderated by [Yan Cui](https://twitter.com/theburningmonk), I gained valuable insights into how to use AWS lambda and AWS Steps functions for orchestrating serverless workflows.

In cloud-based application development, Lambda and Step Functions are two great tools provided by Amazon Web Services for managing serverless operations. 

Developers can execute code with Lambda without setting up or maintaining servers. It is perfect for doing quick, focused tasks within an application. Examples of tasks can include updating data in a DynamoDB table or executing an ETL and data transformation process in data pipelines.

In comparison, Step Functions is a service that enables the coordination of distributed applications and microservices using visual workflows. It provides a way to design, execute, and debug complex workflows, making it indispensable for managing intricate, crucial business operations.
Example of tasks where Step Functions shines includes managing multi-step approval processes in an application or orchestrating the deployment and management of cloud infrastructure, including provisioning resources, configuring services, etc.

Let's explore the unique qualities of Lambda and Step Functions below to see where each technology excels.

Using Lambda for Workflow Orchestration : 

1. Event-Driven Execution: Lambda functions are triggered in response to events, such as changes to data in an Amazon S3 bucket or updates to a DynamoDB table. This event-driven execution model ensures efficient resource utilization, as the function only runs when needed, thus minimizing costs.

2. Lambda functions have extremely low startup times, allowing near-instantaneous execution. This speed and agility make Lambda suitable for quick, responsive applications where latency and responsiveness are critical factors.

3. Scalability: Lambda automatically scales based on the number of incoming requests. This scalability allows cost optimization by avoiding over-provisioning of resources, ensuring that you pay for only what you use, especially during low-demand periods.

Using Step Functions for Workflow Orchestration: 

1. Reliability and Error Handling: Step Functions offer robust error handling and retries for each step in a workflow, enhancing reliability. The ability to define error recovery strategies at each step ensures smooth and consistent workflow execution in a scenario where failure occurs.

2. State Management: Step Functions maintain the state of each step in a workflow, making it easier to track progress and debug issues. This capability is essential for business-critical applications where tracking the status of various steps and understanding the flow of execution is crucial for successful operation.

3. Visual Representation and Debugging: The visual representation of workflows in Step Functions simplifies the debugging process. Developers can easily identify bottlenecks, optimize performance, and troubleshoot issues by visually inspecting the flow of steps, making debugging more accessible and effective.

Although Lambda and Step Functions can both work separately, a robust system architecture can be created to take advantage of both of their strengths in parallel. Step Functions can be utilized to orchestrate and manage the overall workflow process, seamlessly integrating with Lambda to handle each "stateful" step within the workflow. 

This synergistic approach ensures efficient coordination and execution of complex workflows while leveraging the capabilities of both tools for optimal performance and reliability.

![Running AWS Lambda and Step functions in parallel](https://dev-to-uploads.s3.amazonaws.com/uploads/articles/yw8b8sseizpabmaeddis.png)
Illustration of using both tools in parallel

 
**Summary:**
Lambda functions are great for attaining operational efficiency, cost optimization, and easy workflows. Step Functions, on the other hand, are perfect for handling intricate and important business procedures, maintaining dependability, and facilitating the debugging process. 

Both orchestration tools are potent instruments that meet various requirements in serverless workflow orchestration.