AWS Step Functions Overview

Introduction

AWS Step Functions allows the creation of workflows with fixed or dynamic sequences.
They enable modeling applications as independent units that interact with AWS resources (DynamoDB, SNS, Lambda, etc.).

Orchestration: Step Functions act as an orchestration for application workflows.
Built-in Retry Functionality: Customizable retry policies (e.g., number of retries, exponential back-off).
Native AWS Integrations: Easy interaction with AWS services using a JSON-like ADSL language.
Auditing: Feature-rich GUI to track application flow, inputs, and outputs.
Scalability and Cost: Highly scalable and low cost ($0.025 per 1,000 state transitions).

Without Step Functions:
- Traditional server processing logic (EC2, Lambda).
- Manages multiple service interactions (e.g., PIN authorization, transaction commit, notifications).
- Handling fail-resubmission, complex retry logic not efficient.
Using Step Functions:
- State Machine Setup: Input parameters include customer ID, amount, credit card number, and PIN.
- First Step: Store History:
  - Define task as state to put an item in DynamoDB.
  - Example parameters: Table name, transaction ID, timestamp.
  - Customizable retry policy (e.g., 3 attempts, 1-second intervals).
- Second Step: PIN Authorization:
  - Interaction with authorization service for PIN validation.
  - Handle outcomes (accept, reject, exception) effectively.
- Third Step: Transaction Commit:
  - Commit transaction with credit card authority service.
  - Use Lambda for service calls.
- Final Step: Broadcast Notification:
  - Use SNS to notify other systems if successful.

DynamoDB Interaction: Define state, resource, and parameters for item storage.
Lambda Integration: Define state and map to Lambda function ARN.

Highlights the simplicity and power of Step Functions for managing and integrating multiple AWS services without complex code.
Teaser for next video: End-to-end setup tutorial using real resources (DynamoDB tables, Lambdas, SNS topics).