Generate S3 Presigned URL with 7 Day Expiry via Lambda

Question

Trying to find a way to generate a presigned URL via Lambda to get an S3 object. Need to be able to set the expiry for up to 10 days. I see that it is possible to do this via SDK using the signature v4 signing process, but don't believe that this can be done via Lambda. Is this possible?

Accepted Answer

This can be accomplished using Lambda up to a maximum of 7 days. 10 days is beyond the maximum valid expiration period for any pre-signed url scenario using Sig V4. To have a pre-signed URL be valid for the entire 7 days you need to use valid credentials for an IAM User to generate the URL. To do this in Lamdba you'd need to give the Lambda access to long-lived IAM User credentials and and use them to generate the pre-signed URL w/ Sig v4.

You could do this with encrypted ENV Variables or Secrets Manager for example. Then configure your lambda to use these credentials, and not a the Lambda's execution role credentials when generating the pre-signed urls.

You could do this with encrypted ENV Variables or Secrets Manager for example.  Then configure your lambda to use these credentials, and not a the Lambda's execution role credentials when generating the pre-signed urls.

Answer

This is related to a topic located here: https://repost.aws/questions/QUN4e24VL5QM6ygP99mEydUA/generate-presigned-url-for-s-3-object-lambda.

To see an updated guide for how to build presigned URLs and set the expiration date, this guide is pretty helpful: https://howtocloud.io/generate-s3-presigned-urls-with-boto3/.

Generate S3 Presigned URL with 7 Day Expiry via Lambda

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