[FIXED] AWS CDK with Python - basics of creating VPCs

Issue

I have started learning AWS CDK and have a problem with below code sample copied from CDK reference page for Python: https://docs.aws.amazon.com/cdk/api/latest/python/aws_cdk.aws_ec2.README.html#vpc. It's my first attempt to write something better than just copying tutorials and I can't find where I made a mistake. Many thanks for helping me.

Configuration:

source .env/bin/activate
pip3 install -r requirements.txt
pip3 install aws_cdk.aws_ec2

My code:

from aws_cdk import (
    aws_ec2 as ec2,
    core
)


class CdkStack(core.Stack):

    def __init__(self, scope: core.Construct, id: str, **kwargs) -> None:
        super().__init__(scope, id, **kwargs)

        vpc = ec2.Vpc(self, "VPC",
            cidr="10.100.0.0/16",
            max_azs=3,
            subnet_configuration=[{
                "subnet_type": ec2.SubnetType.PUBLIC,
                "name": "public1",
                "cidr_mask": 24
            }, {
                "cidr_mask": 24,
                "name": "private1",
                "subnet_type": ec2.SubnetType.PRIVATE
            }
            ]
        )

Error message thrown by "cdk synth" command:

(.env) [robert@fedora1 cdk]$ cdk synth
jsii.errors.JavaScriptError: 
  Error: Missing required properties for @aws-cdk/aws-ec2.SubnetConfiguration: subnetType
      at validateRequiredProps (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7161:15)
      at Object.deserialize (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:6835:21)
      at Kernel._toSandbox (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:8111:61)
      at /home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:6731:40
      at Array.map (<anonymous>)
      at Object.deserialize (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:6731:26)
      at Kernel._toSandbox (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:8111:61)
      at /home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:6841:29
      at mapValues (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7101:27)
      at Kernel._wrapSandboxCode (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:8205:19)
      at Kernel._create (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7749:26)
      at Kernel.create (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7503:21)
      at KernelHost.processRequest (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7293:28)
      at KernelHost.run (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7233:14)
      at Immediate._onImmediate (/home/robert/Documents/local/cdk/.env/lib/python3.7/site-packages/jsii/_embedded/jsii/jsii-runtime.js:7236:37)
      at processImmediate (internal/timers.js:439:21)

The above exception was the direct cause of the following exception:

Traceback (most recent call last):
  File "app.py", line 9, in <module>
    CdkStack(app, "cdk")
  File "/home/robert/Documents/local/cdk/.env/lib64/python3.7/site-packages/jsii/_runtime.py", line 66, in __call__
    inst = super().__call__(*args, **kwargs)
  File "/home/robert/Documents/local/cdk/cdk/cdk_stack.py", line 22, in __init__
    "subnet_type": ec2.SubnetType.PRIVATE
  File "/home/robert/Documents/local/cdk/.env/lib64/python3.7/site-packages/jsii/_runtime.py", line 66, in __call__
    inst = super().__call__(*args, **kwargs)
  File "/home/robert/Documents/local/cdk/.env/lib64/python3.7/site-packages/aws_cdk/aws_ec2/__init__.py", line 23226, in __init__
    jsii.create(Vpc, self, [scope, id, props])
  File "/home/robert/Documents/local/cdk/.env/lib64/python3.7/site-packages/jsii/_kernel/__init__.py", line 223, in create
    interfaces=[iface.__jsii_type__ for iface in getattr(klass, "__jsii_ifaces__", [])],
  File "/home/robert/Documents/local/cdk/.env/lib64/python3.7/site-packages/jsii/_kernel/providers/process.py", line 333, in create
    return self._process.send(request, CreateResponse)
  File "/home/robert/Documents/local/cdk/.env/lib64/python3.7/site-packages/jsii/_kernel/providers/process.py", line 318, in send
    raise JSIIError(resp.error) from JavaScriptError(resp.stack)
jsii.errors.JSIIError: Missing required properties for @aws-cdk/aws-ec2.SubnetConfiguration: subnetType
Subprocess exited with error 1

Solution

You provided a list of dictionaries, but it expects a list of SubnetConfiguration objects.

subnet_configuration (Optional[List[SubnetConfiguration]])

subnet_configuration=[
    ec2.SubnetConfiguration(
        cidr_mask=24,
        name='public1',
        subnet_type=ec2.SubnetType.PUBLIC
    ),
    ec2.SubnetConfiguration(
        cidr_mask=24,
        name='private1',
        subnet_type=ec2.SubnetType.PRIVATE
    )

]

Answered By - Vikyol