Cdk on The Edge Cases

Building Docker Images on M1 Mac for Other Platforms

Sat, 19 Sep 2026 02:10:03 +0000

In order to build Docker images for Lambda functions with CDK on ARM or other non-Intel platforms, but want the Lambda to be on an x86_64 platform, use the platform parameter with the from_image_asset() function.

_lambda.DockerImage_function(
    ...
    code=_lambda.DockerImageCode.from_image_asset(  
        directory="./lambda",  
        file="./myservice/Dockerfile",  
        platform=ecr_assets.Platform.LINUX_AMD64,  
    ),
    ...
)

ecr_assets is a CDK package that also needs to be imported from the main aws_cdk package.

Including Assets from Parent Directories in Dockerized Lambda Functions with CDK

Tue, 04 Oct 2022 17:31:19 +0000

If you have a Docker based Lambda that is defined in some directory and there are assets that the Lambda needs in the parent directory, from_image_asset() takes directory and file parameters, so you can select the parent directory as well as the specific Dockerfile that describes the environment for the Lambda.

Here is an example folder structure:

CDK_infrastructure/
    lambdas/
        lambda_one.py
        lambda_two.py
        lambda_pkg/
            ...
        docker_lambda/
            Dockerfile

And here is how you would set this up in your stack definition:

CDK Deployment Troubleshooting

Tue, 07 Jun 2022 18:23:48 +0000

There are a number of avenues to explore for troubleshooting a CDK deployment.

More Than One Index Error

If you know you haven’t actually created or deleted multiple DynamoDB indexes, npx aws-cdk diff (or cdk diff if CDK was installed globally) will tell you what the differences between the synthesized template and deployed template actually are.

Source

Rebuilding Missing Resources in CDK

Mon, 14 Mar 2022 19:37:06 +0000

In AWS CDK, if a resource like a DynamoDB table is missing (maybe it was accidentally manually deleted) with a ResourceNotFound or Unable to retrieve arn error, you can recover it without tearing down the whole stack by recreating the resource with the same full name that the CDK stack/CloudFormation template is looking for.

Source

AWS docs

Passing Secrets into Lambdas in CDK

Mon, 07 Feb 2022 18:43:52 +0000

same: AWS Lambda Return Values for API Triggering, To Build a Lambda from a Dockerfile in CDK

Passing Secrets into Lambdas in CDK

Do not pass Secret Manager values via environment variables in your CDK Stack! This is a problem for two reasons:

This exposes the Secret in the generated CF templates.
This only pulls the Secret value at deploy time only if the Secrets construct or Lambda in question will be rebuilt upon deploy or synthesis. If the keys are rotated, and the constructs in the CDK stack aren’t changed, this won’t be picked up by the app.

To address this, handle Secret Manager secrets in the following way:

Install Specific CDK Version And-Or By Project

Mon, 07 Feb 2022 18:32:33 +0000

Install Specific CDK Versions And/Or By Project

You can install the CDK toolkit for a specific project by omitting -g from the npm install command then invoking it with npx aws-cdk. You can also install the toolkit for a specific version with npm install -g aws-cdk@x.yyy.z.

Install specific version for a project

Navigate to project directory
- npm install aws-cdk@x.yy.zzz
- npx aws-cdk ...

Install specific version globally

npm install -g aws-cdk@x.yyy.z
aws-cdk ...

Use the installed version

npx aws-cdk ...

AWS API Gateway Changes Break Deployment

Mon, 07 Feb 2022 15:43:47 +0000

If you try to rename a parameter in a deployed API Gateway object via CDK, deployment will break (you won’t be able to deploy the change). This seems to do with how CloudFormation diffs are applied, and it will cause a conflict during the deployment process (see here). The workaround is to comment out all the API code in the CDK stack, deploy, then uncomment and redeploy. This removes and remakes the API.

To Build a Lambda from a Dockerfile in CDK

Wed, 27 Oct 2021 19:24:41 +0000

Creating the Dockerfile

To set up a Dockerfile for a Lambda function that relies on non-AWS base images, you have to include the Python package awslambdaric in your requirements and install it. Then, do the following in the Dockerfile:

ENTRYPOINT [ "/usr/local/bin/python", "-m", "awslambdaric" ]  
CMD ["lambda_code.function_name"]

Example

ARG FUNCTION_DIR="/function"
  
FROM tensorflow/tensorflow:2.4.3 as DEV  
ARG FUNCTION_DIR  
RUN mkdir -p ${FUNCTION_DIR}
## copies python code into container's FUNCTION_DIR
COPY lambda_code.py ${FUNCTION_DIR} 
## copies lambda_requirements.txt into container's requirements.txt
COPY lambda_requirements.txt ./requirements.txt  
## copies dataset into container's FUNCTION_DIR/dataset/
COPY dataset ${FUNCTION_DIR}/dataset/  
RUN pip install --no-cache-dir --upgrade pip && \  
    pip install -r requirements.txt --target ${FUNCTION_DIR}  
WORKDIR ${FUNCTION_DIR}  
ENTRYPOINT [ "python", "-m", "awslambdaric" ]  
CMD ["lambda_code.function_name"]

Setting Up the Lambda in CDK

To create a Lambda from a Dockerfile in CDK, use cdk.aws-lambda.DockerImageFunction when defining your Lambda: