What is the basic difference between AWS step functions vs lambda?

 In the context of AWS, here are the differences given between both:-

AWS Step functions

You can use the step functions if the workflow involves multiple state transitions, conditional logic, error handling, and coordination between different AWS services or custom codes.

You can define the workflow as a state machine by using an AWS step functions JSON-based state language.

Here is the example given of a step functions state machine definition in JSON:-

{
  “Comment”: “Order Processing Workflow”,
  “StartAt”: “ValidateOrder”,
  “States”: {
    “ValidateOrder”: {
      “Type”: “Task”,
      “Resource”: “arn:aws:lambda:us-east-1:123456789012:function:ValidateOrderFunction”,
      “Next”: “CheckInventory”,
      “Retry”: [
        {
          “ErrorEquals”: [“ValidationError”],
          “IntervalSeconds”: 5,
          “MaxAttempts”: 3,
          “BackoffRate”: 1.5
        }
      ],
      “Catch”: [
        {
          “ErrorEquals”: [“InvalidInputError”],
          “Next”: “HandleInvalidInput”
        }
      ]
    },
    “CheckInventory”: {
      “Type”: “Task”,
      “Resource”: “arn:aws:lambda:us-east-1:123456789012:function:CheckInventoryFunction”,
      “Next”: “SendNotifications”
    },
    “SendNotifications”: {
      “Type”: “Task”,
      “Resource”: “arn:aws:lambda:us-east-1:123456789012:function:SendNotificationsFunction”,
      “Next”: “UpdateDatabase”
    },
    “UpdateDatabase”: {
      “Type”: “Task”,
      “Resource”: “arn:aws:lambda:us-east-1:123456789012:function:UpdateDatabaseFunction”,
      “End”: true
    },
    “HandleInvalidInput”: {
      “Type”: “Fail”,
      “Cause”: “Invalid input provided”,
      “Error”: “InvalidInputError”
    }
  }
}

AWS lambda

You can use the lambda function for individual, stateless tasks that can run independently and don’t require complex coordination.

Here is the example given of a Lambda function for processing orders:-

Import json
Def lambda_handler(event, context):
    Order = event[‘order’]
    # Validate the order
    Validated_order = validate_order(order)
    # Check inventory
    Inventory_check_result = check_inventory(validated_order)
    # Send notifications
    Send_notifications(inventory_check_result)
    # Update database
    Update_database(inventory_check_result)
    Return {
        ‘statusCode’: 200,
        ‘body’: json.dumps(‘Order processed successfully’)
    }
Def validate_order(order):
    # Perform validation logic
    If not order:
        Raise Exception(‘ValidationError’, ‘Order is empty’)
    Return order
Def check_inventory(order):
    # Perform inventory check logic
    # Simulated result
    Return {‘item’: ‘Product A’, ‘available’: True, ‘quantity’: 10}
Def send_notifications(inventory_result):
    # Perform notification sending logic
    Notification_message = f”Product {inventory_result[‘item’]} is available!”
    Print(notification_message)
Def update_database(inventory_result):
    # Perform database update logic
    # Simulated update
    Print(f”Updating database with inventory result: {inventory_result}”)