I needed to find the specific version of packages available by default in AWS Lambda. I did so with a mashup of ideas from this page. I'm sharing it for posterity.

import pkgutil __version__ = '0.1.1' def get_ver(name): try: return str(__import__(name).__version__) except: return None def lambda_handler(event, context): return { 'statusCode': 200, 'body': [{ 'path': m.module_finder.path, 'name': m.name, 'version': get_ver(m.name), } for m in list(pkgutil.iter_modules()) #if m.module_finder.path == "/var/runtime" # Uncomment this if you only care about a certain path ], } 

What I discovered is that the provided boto3 library was way out of date and it wasn't my fault that my code was failing. I just needed to add boto3 and botocore to my project. But without this I would have been banging my head thinking my code was bad.

{ "statusCode": 200, "body": [ { "path": "/var/task", "name": "lambda_function", "version": "0.1.1" }, { "path": "/var/runtime", "name": "bootstrap", "version": null }, { "path": "/var/runtime", "name": "boto3", "version": "1.9.42" }, { "path": "/var/runtime", "name": "botocore", "version": "1.12.42" }, { "path": "/var/runtime", "name": "dateutil", "version": "2.7.5" }, { "path": "/var/runtime", "name": "docutils", "version": "0.14" }, { "path": "/var/runtime", "name": "jmespath", "version": "0.9.3" }, { "path": "/var/runtime", "name": "lambda_runtime_client", "version": null }, { "path": "/var/runtime", "name": "lambda_runtime_exception", "version": null }, { "path": "/var/runtime", "name": "lambda_runtime_marshaller", "version": null }, { "path": "/var/runtime", "name": "s3transfer", "version": "0.1.13" }, { "path": "/var/runtime", "name": "six", "version": "1.11.0" }, { "path": "/var/runtime", "name": "test_bootstrap", "version": null }, { "path": "/var/runtime", "name": "test_lambda_runtime_client", "version": null }, { "path": "/var/runtime", "name": "test_lambda_runtime_marshaller", "version": null }, { "path": "/var/runtime", "name": "urllib3", "version": "1.24.1" }, { "path": "/var/lang/lib/python3.7", "name": "__future__", "version": null }, ...