Setting up AWS CDK CLI

Reference guide by AWS: https://docs.aws.amazon.com/cdk/v2/guide/hello_world.html

Using local Node.js

Install NVM as described in https://github.com/nvm-sh/nvm?#installing-and-updating

In your Makefile:

clean:
	rm -rf cdk
	rm -rf node_modules

cdk:
	. ~/.nvm/nvm.sh \
	  && nvm install 20 \
	  && npm install -g npm@latest \
	  && npm install aws-cdk
	echo '#!/usr/bin/env bash\n. ~/.nvm/nvm.sh\nnvm use 20' > cdk
	echo '$$(dirname "$${BASH_SOURCE[0]}")/node_modules/aws-cdk/bin/cdk $$*' >> cdk
	chmod +x cdk

Using Docker image

Create Dockerfile:

FROM node:20-alpine
RUN apk add --no-cache python3 py3-pip
RUN npm install -g aws-cdk

Make cdk binary running cdk image:

cdk:
	docker build -t aws-cdk .
	export sh='#!/usr/bin/env bash\n' \
	  && echo $${sh}'docker run --rm -it -v "$$(pwd):/home" -w /home aws-cdk "$$@"' > cdk_run \
	  && echo $${sh}'"$${BASH_SOURCE[0]}_run" cdk "$$@"' > cdk
	chmod +x cdk cdk_run
	./cdk --version

Shell setup

Add a similar line to your shell profile so that cdk is found globally:

export PATH="/Users/andrei/Projects/AWS-CDK-CLI:$PATH"

Testing

Check version:

$ cd .. && cdk --version
2.131.0 (build 92b912d)

Init a new stack:

# 1. Init stack
mkdir -p demo && cd demo
cdk init app --language python

# 2a. Install dependencies created using local Node cdk
.venv/bin/pip install -U pip
.venv/bin/pip install -r requirements.txt

# 2b. or using Docker
cdk_run python -m venv .venv
cdk_run .venv/bin/pip install -U pip
cdk_run .venv/bin/pip install -r requirements.txt

# 3. Patch config
echo "$(yq -Moj '.app = ".venv/bin/python app.py"' cdk.json)" > cdk.json

# 4. Synth CloudFormation template
cdk synth | yq -P

AWS session

In order to call AWS API we need to pass AWS session to the container.

aws-vault allows creating a metadata service server on port 9099 so for standard AWS CLI we could add -p 9099:9099 to the docker run parameters but CDK CLI does not support it and honestly, the service is too implicit to be considered safe when working with multiple accounts.

Instead, we can pass all environmental variables with names starting with AWS_ prefix:

--env-file <(env | grep ^AWS_)

so that our run command in cdk_run file will look like:

docker run --rm -it -v "$(pwd):/home" -w /home --env-file <(env | grep ^AWS_) aws-cdk "$@"

and we can run cdk deploy the following way:

aws-vault exec my-profile -- cdk deploy