How to pass Python objects (that are not JSON serializable) from one (AWS) lambda function to another?

One option:

• Create an encoded string representation of the object and pass it, using a function like this:

  def native_object_encoded(x): x = pickle.dumps(x) x = zlib.compress(x) x = base64.b64encode(x).decode() return x 

• In the second lambda function, perform the same steps in reverse to get back the original object:

  def native_object_decoded(s): s = base64.b64decode(s) s = zlib.decompress(s) s = pickle.loads(s) return s 

Usage:

# lambda 1 (the caller) a = {66, 99, 35} # set: not serializable payload = { 'a': native_object_encoded(a), } response = client.invoke( ... ) # lambda 2 (the one being invoked) a = native_object_decoded(event['a']) 

Notes:

• If the object is of custom type, that type must be defined in the second lambda function too.
• If the object is part of some other library (standard or third-party), that library should be imported in the second lambda function.
• The compression step is optional.