AWS.Lambda.Powertools.Idempotency

AWS Lambda Idempotency for .NET

The idempotency package provides a simple solution to convert your Lambda functions into idempotent operations which are safe to retry.

Terminology

The property of idempotency means that an operation does not cause additional side effects if it is called more than once with the same input parameters.

Idempotent operations will return the same result when they are called multiple times with the same parameters. This makes idempotent operations safe to retry. Read more about idempotency.

Idempotency key is a hash representation of either the entire event or a specific configured subset of the event, and invocation results are JSON serialized and stored in your persistence storage layer.

Key features

• Prevent Lambda handler function from executing more than once on the same event payload during a time window
• Ensure Lambda handler returns the same result when called with the same payload
• Select a subset of the event as the idempotency key using JMESPath expressions
• Set a time window in which records with the same payload should be considered duplicates
• Expires in-progress executions if the Lambda function times out halfway through

Read the docs

For a full list of features go to docs.aws.amazon.com/powertools/dotnet/utilities/idempotency/

GitHub: https://github.com/aws-powertools/powertools-lambda-dotnet/

Installation

You should install with NuGet:

Install-Package Amazon.Lambda.PowerTools.Idempotency

Or via the .NET Core command line interface:

dotnet add package Amazon.Lambda.PowerTools.Idempotency

Sample Function

public class Function
{
    public Function()
    {
        Idempotency.Configure(builder => builder.UseDynamoDb("idempotency_table"));
    }

    [Idempotent]
    public Task<string> FunctionHandler(string input, ILambdaContext context)
    {
        return Task.FromResult(input.ToUpper());
    }
}