Calling GPG method from AWS serverless

Question

I deploy my serverless function using zip method.

I'm trying to encrypt the file using the following code:

import boto3
import gnupg

def lambda_handler(event, context):
        s3=boto3.resource('s3')

        s3.meta.client.download_file('my_bucket','plain.txt','/tmp/plain.txt')
        s3.meta.client.download_file('my_bucket','public.key','/tmp/public.key')
        
        key_data = open('/tmp/public.key').read()

        gpg = gnupg.GPG('/tmp')
        priv_key = gpg.import_keys(key_data)
        
        with open('/tmp/plain.txt','rb') as a_file:
          gpg.encrypt_file(a_file,key_data,output='plain.txt.gpg')
     
        return 'ok'

but I got the following error:

  "errorMessage": "Unable to run gpg (/tmp) - it may not be available."

what's the correct way to run gpg from serverless?

How exactly are you importing the library using .zip file? What exactly is the error? What's the resulting folder structure? — gshpychka, Aug 30 '21 at 14:06
See the answer: https://stackoverflow.com/questions/66770313/lamnda-python-3-8-gpg-decryption-can-not-find-gpg-binary?answertab=active#tab-top — dpaluy, Aug 30 '21 at 18:25
How did you package the dependencies in the zip file? What is the resulting folder structure? — gshpychka, Aug 30 '21 at 19:13

score 1 · Answer 1 · answered Aug 30 '21 at 18:29

The Lambda runtime doesn't contain arbitrary executables like GPG.

Your best option is probably to use a native Python package, so that ideally you don't need an external binary, or a wrapper package such as python-gnupg.

You may need to package needed binaries with your Lambda deployment package or as part of an underlying Lambda layer.

Calling GPG method from AWS serverless

1 Answers1