feat(idempotency): makeHandlerIdempotent middy middleware

[dreamorosi]

Description of your changes

This PR introduces a new Middy middleware that allows to wrap a Lambda handler and make it idempotent.

The middleware can be used like this:

import {
  makeHandlerIdempotent,
  DynamoDBPersistenceLayer,
} from '@aws-lambda-powertools/idempotency';
import middy from '@middy/core';

const dynamoDBPersistenceLayer = new DynamoDBPersistenceLayer({
  tableName: 'idempotencyTable',
});

const lambdaHandler = async (_event: unknown, _context: unknown) => {
  //...
};

export const handler = middy(lambdaHandler)
  .use(makeHandlerIdempotent({ persistenceStore: dynamoDBPersistenceLayer }));

Implementation details

The first detail to notice is that contrary to the function wrapper and the class method decorator, this middleware doesn't leverage fully the IdempotencyHandler class. The reason for this is that Middy has a specific lifecycle when it comes to logic running before, after, and in case of error thrown by the handler. The current implementation of the IdempotencyHandler groups certain actions together and expects certain signatures and a class instantiation and as such it's not possible for the middleware to use the same method all the time.

As a result, the middleware interacts with the persistence store directly and is in charge of handling/throwing the errors. This allows the middleware to follow its own patterns, however moving forward we will need to make sure we keep the two implementations in sync.

Related issues, RFCs

Issue number: #1293

Checklist

• My changes meet the tenets criteria
• I have performed a self-review of my own code
• I have commented my code where necessary, particularly in areas that should be flagged with a TODO, or hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my change is effective and works
• The PR title follows the conventional commit semantics

Breaking change checklist

Is it a breaking change?: NO

• I have documented the migration process
• I have added, implemented necessary warnings (if it can live side by side)

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