AWS-CDK cannot import core in Python

Question

I have recently been asked to learn the AWS-CDK module in Python to handle deployments and following the examples on in the AWS-CDK documentation I am getting an error that indicates it cannot import 'core'

I have created a virtual environment that is using Python 3.6.6 and am running CDK version 1.16.2 (build 5893301) all running on a Windows 10 64-bit machine in VSCode

from aws_cdk import core

I would expect this to just load the constructor but it just returns the error:

Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
ImportError: cannot import name 'core'

I have searched and searched and I cannot seem to find what I am doing wrong or anything that contradicts the documentation on the CDK site. Any insight would be appreciated.

Answer 1

This worked for me. Might be related to conda / venv interactions.

pip3 install -r requirements.txt --user

Answer 2

Is aws_cdk.core installed in your environment? I have this:

pip list|grep core
aws-cdk.core                        1.68.0

Answer 3

I noticed that the cdk.json "app" value can also generate this error.
Example of the cdk.json file which used to generate the error:

{
  "app": "python3 app.py",
  "context": {
    ...
  }
}

Changing the app value from python3 to python resolved the problem for me. Like this:

{
  "app": "python app.py",
  "context": {
    ...
  }
}

I am not entirely sure why this happens as I am using python 3.8 and I can see a python.exe in the python path/environment variables. If I deactivate the virtual env, and I have cdk installed globally, this problem goes away regardless of whether I use python or python3 for the app value. Therefore, I suspect it's got to do something with environment paths.

Answer 4

aws-cdk-lib==2.34.0
constructs>=10.0.0,<11.0.0
aws-cdk.aws-kinesisfirehose-alpha
aws_cdk.aws-kinesisfirehose-destinations-alpha
aws_cdk.core

pip list|grep core