Do we need Lambda extensions for accessing AWS Secrets Manager ?

Question

Do we need Lambda extensions for accessing AWS Secrets Manager ? 
I explored Vault, Lambda provides vault extensions, which can optimize the secrets fetching - 
https://www.hashicorp.com/blog/aws-lambda-extensions-for-hashicorp-vault

> The extension can retrieve multiple secrets from Vault, if configured to do so, and writes the full JSON response from HashiCorp Vault to the configured destination.
Before a Lambda function is invoked, extensions are initialized and given the opportunity to perform tasks before signaling their readiness

Do we need similar setup in AWS Secrets Manager ? Or Fetching secrets from AWS Secret Manager already optimised for Lambda ?

Answer

In order to access secrets manager you only need to define the security policy in your lambda and it should then be able to access it from your code.

More info [here](https://bobbyhadz.com/blog/aws-grant-lambda-access-to-secrets-manager#:~:text=In%20order%20to%20grant%20a,to%20perform%20on%20the%20secrets.)

Answer

You do not need a Lambda extension to retrieve a secret from AWS Secrets Manager in a serverless workload. You should retrieve the secret as a global variable, not in the handler, to maximize performance. To learn more, see https://aws.amazon.com/blogs/networking-and-content-delivery/securing-and-accessing-secrets-from-lambdaedge-using-aws-secrets-manager.

Answer

This link -https://docs.aws.amazon.com/prescriptive-guidance/latest/patterns/cache-secrets-using-aws-lambda-extensions.html provides a way to run local host to cache the secrets.

This setup is not necessary at all the times.  Accessing Secrets Manager from Lambda can be done via the boto3 API, but the pattern above is considered best practice as it prevent cold start, increase speed of retrieval and keep the costs for Secrets Manager access low (in cases where you expect a lot of invocations).

Do we need Lambda extensions for accessing AWS Secrets Manager ?

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