!/usr/bin/env python3

"""
CDK Stack Templates — FeatureFactory DCI Workflow

Skeleton implementations for VPC, EKS+ECR, and Route53 CDK stacks.
Copy these into your infra repo's stacks/ directory and adapt to your
project's INFRA_REQUIREMENTS.md.

Usage:
1. Copy each class to its own file in stacks/
2. Replace {project} placeholders with your project name
3. Update context values in cdk.json
4. Run make synth to verify
"""

import aws_cdk as cdk
from aws_cdk import (
Stack,
RemovalPolicy,
aws_ec2 as ec2,
aws_eks as eks,
aws_ecr as ecr,
aws_iam as iam,
aws_route53 as route53,
)
from constructs import Construct

==============================================================================

VPC Stack — stacks/vpc_stack.py

==============================================================================

class VpcStack(Stack):
"""
Network foundation: VPC with public/private subnets and NAT Gateway.

Outputs:
    self.vpc — ec2.Vpc instance (consumed by EksStack)
    self.eks_sg — Security group for EKS worker nodes
"""

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

    # VPC with 2 AZs
    self.vpc = ec2.Vpc(
        self, "Vpc",
        max_azs=2,
        nat_gateways=1,  # 1 shared for cost; set to 2 for HA in production
        subnet_configuration=[
            ec2.SubnetConfiguration(
                name="Public",
                subnet_type=ec2.SubnetType.PUBLIC,
                cidr_mask=24,
            ),
            ec2.SubnetConfiguration(
                name="Private",
                subnet_type=ec2.SubnetType.PRIVATE_WITH_EGRESS,
                cidr_mask=24,
            ),
        ],
    )

    # Security group for EKS worker nodes
    self.eks_sg = ec2.SecurityGroup(
        self, "EksNodeSg",
        vpc=self.vpc,
        description="Security group for EKS worker nodes",
        allow_all_outbound=True,
    )

    # Tag all resources
    cdk.Tags.of(self).add("managed-by", "cdk")
    cdk.Tags.of(self).add("stack", "vpc")

==============================================================================

EKS + ECR Stack — stacks/eks_stack.py

==============================================================================

class EksStack(Stack):
"""
Compute layer: EKS cluster with managed node group and ECR repository.

Requires:
    vpc — ec2.Vpc from VpcStack

Outputs:
    self.cluster — eks.Cluster instance
    self.ecr_repo — ecr.Repository instance
"""

def __init__(self, scope: Construct, id: str, vpc: ec2.Vpc, **kwargs) -> None:
    super().__init__(scope, id, **kwargs)

    # EKS Cluster
    self.cluster = eks.Cluster(
        self, "Cluster",
        vpc=vpc,
        version=eks.KubernetesVersion.V1_29,
        default_capacity=0,
        endpoint_access=eks.EndpointAccess.PUBLIC_AND_PRIVATE,
    )

    # Managed Node Group
    self.cluster.add_nodegroup_capacity(
        "WorkerNodes",
        instance_types=[ec2.InstanceType("t3.medium")],
        min_size=2,
        max_size=4,
        desired_size=2,
        disk_size=50,
        subnets=ec2.SubnetSelection(
            subnet_type=ec2.SubnetType.PRIVATE_WITH_EGRESS
        ),
    )

    # ECR Repository
    self.ecr_repo = ecr.Repository(
        self, "AppRepo",
        repository_name="{project}",  # TODO: replace with actual project name
        removal_policy=RemovalPolicy.RETAIN,
        lifecycle_rules=[
            ecr.LifecycleRule(
                max_image_count=20,
                description="Keep last 20 images",
            )
        ],
    )

    # Create blue/green namespaces
    for ns in ["blue", "green"]:
        self.cluster.add_manifest(
            f"{ns}-namespace",
            {
                "apiVersion": "v1",
                "kind": "Namespace",
                "metadata": {"name": ns},
            },
        )

    cdk.Tags.of(self).add("managed-by", "cdk")
    cdk.Tags.of(self).add("stack", "eks")

==============================================================================

DNS Stack — stacks/dns_stack.py

==============================================================================

class DnsStack(Stack):
"""
DNS layer: Route53 hosted zone for blue/green traffic switching.

Context:
    domain — Base domain (e.g., "app.example.com")

Outputs:
    self.zone — route53.HostedZone instance
"""

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

    domain = self.node.try_get_context("domain")

    # Hosted zone
    self.zone = route53.HostedZone(
        self, "Zone",
        zone_name=domain,
    )

    # Note: Weighted records for prod/idle are managed by
    # scripts/traffic_switch.py, not by CDK. CDK only creates the zone.
    # This avoids CDK drift when the switch script modifies records.

    cdk.Tags.of(self).add("managed-by", "cdk")
    cdk.Tags.of(self).add("stack", "dns")

==============================================================================

App Entry Point — app.py

==============================================================================

def create_app():
"""
CDK app entry point. Wire stacks with dependencies.

Usage in app.py:
    from cdk_stack_templates import create_app
    create_app()
"""
app = cdk.App()

env = cdk.Environment(
    account=app.node.try_get_context("account"),
    region=app.node.try_get_context("region"),
)

vpc = VpcStack(app, "VpcStack", env=env)
eks = EksStack(app, "EksStack", vpc=vpc.vpc, env=env)
dns = DnsStack(app, "DnsStack", env=env)

# Explicit dependencies
eks.add_dependency(vpc)

app.synth()

if name == "main":
create_app()