AWS CDK Python: Multi-Stack + Multi-Environment + Selective Deployment

 

📁 Project Structure

📦 requirements.txt

aws-cdk-lib
constructs>=10.0.0,<11.0.0

Install dependencies:

pip install -r requirements.txt


🧠 config/dev.json
{
  "env_name": "dev",
  "region": "us-east-1",
  "account": "123456789012",
  "bucket_name": "dev-bucket-example",
  "instance_type": "t2.micro",
  "lambda_memory": 512,
  "lambda_timeout": 10,
  "alb_listener_port": 80
}

🧾 cdk.json

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

🚀 app.py

import json
from aws_cdk import App, Environment
from my_cdk_app.network_stack import NetworkStack
from my_cdk_app.compute_stack import ComputeStack
from my_cdk_app.alb_lambda_stack import AlbLambdaStack

app = App()

# Load context
env_name = app.node.try_get_context("env") or "dev"
target_stack = app.node.try_get_context("target") or "all"

# Load config file
with open(f"config/{env_name}.json") as f:
    config = json.load(f)

env = Environment(account=config["account"], region=config["region"])

# Deploy selected stacks
if target_stack in ["network", "all"]:
    network_stack = NetworkStack(app, f"NetworkStack-{env_name}", config=config, env=env)
else:
    network_stack = None

if target_stack in ["compute", "all"] and network_stack:
    ComputeStack(app, f"ComputeStack-{env_name}", config=config, vpc=network_stack.vpc, env=env)

if target_stack in ["alb", "all"] and network_stack:
    AlbLambdaStack(app, f"AlbLambdaStack-{env_name}", config=config, vpc=network_stack.vpc, env=env)

app.synth()





🧱 my_cdk_app/network_stack.py
from aws_cdk import Stack, aws_ec2 as ec2
from constructs import Construct

class NetworkStack(Stack):
    def __init__(self, scope: Construct, id: str, config: dict, **kwargs):
        super().__init__(scope, id, **kwargs)

        self.vpc = ec2.Vpc(self, "VPC", max_azs=2)


💻 my_cdk_app/compute_stack.py

from aws_cdk import Stack, aws_s3 as s3, aws_ec2 as ec2
from constructs import Construct

class ComputeStack(Stack):
    def __init__(self, scope: Construct, id: str, config: dict, vpc, **kwargs):
        super().__init__(scope, id, **kwargs)

        s3.Bucket(self, "Bucket", bucket_name=config["bucket_name"], versioned=True)

        ec2.Instance(self, "Instance",
            instance_type=ec2.InstanceType(config["instance_type"]),
            machine_image=ec2.MachineImage.latest_amazon_linux(),
            vpc=vpc
        )

🌐 my_cdk_app/alb_lambda_stack.py
from aws_cdk import (
    Stack,
    aws_lambda as _lambda,
    aws_ec2 as ec2,
    aws_elasticloadbalancingv2 as elbv2,
    aws_elasticloadbalancingv2_targets as targets
)
from constructs import Construct

class AlbLambdaStack(Stack):
    def __init__(self, scope: Construct, id: str, config: dict, vpc, **kwargs):
        super().__init__(scope, id, **kwargs)

        # Lambda Function
        fn = _lambda.Function(self, "Lambda",
            runtime=_lambda.Runtime.PYTHON_3_9,
            handler="index.handler",
            code=_lambda.Code.from_inline("def handler(event, context): return {'statusCode': 200, 'body': 'Hello from Lambda'}"),
            memory_size=config["lambda_memory"],
            timeout=config["lambda_timeout"]
        )

        # ALB
        alb = elbv2.ApplicationLoadBalancer(self, "ALB", vpc=vpc, internet_facing=True)
        listener = alb.add_listener("Listener", port=config["alb_listener_port"])
        listener.add_targets("LambdaTarget", targets=[targets.LambdaTarget(fn)])

        self.dns = alb.load_balancer_dns_name






🚀 CDK Commands
✅ Bootstrap environment (once per region/account)
cdk bootstrap
✅ Deploy single stack
cdk deploy AlbLambdaStack-dev
✅ Deploy using context filtering
cdk deploy --context env=dev --context target=alb
✅ Deploy all stacks for dev
cdk deploy --context env=dev
✅ List available stacks
cdk list
✅ Destroy stack
cdk destroy AlbLambdaStack-dev









Task
Command
Description




✅ Initialize CDK project
cdk init app --language python
Run once when starting new project


✅ Install Python deps
pip install -r requirements.txt
Required for CDK code to run


✅ Bootstrap CDK
cdk bootstrap
Sets up initial resources like CDK bucket


🛠️ Synthesize CloudFormation
cdk synth
Generates raw CloudFormation template


📦 Deploy all stacks
cdk deploy
Deploys all stacks defined in app.py


📦 Deploy single stack
cdk deploy AlbLambdaStack-dev
Deploy only the named stack


📦 Deploy with context
cdk deploy --context env=dev --context target=alb
Load environment + filter stacks


🗑️ Destroy a stack
cdk destroy AlbLambdaStack-dev
Clean up a single stack


📜 List all stacks
cdk list
Show all stacks CDK knows about


🧩 Diff template
cdk diff AlbLambdaStack-dev
Show what will change before deployment