aws-cdk

What this skill does

# AWS CDK

## Overview

Domain expertise for CDK construct authoring, deployment workflows, compliance, drift, importing resources, safe refactoring, and troubleshooting CDK CLI / CloudFormation errors.

**When NOT to use:** Raw CloudFormation YAML/JSON. SAM. Terraform/Pulumi. CI/CD beyond CDK Pipelines. Use builtin knowledge or specialized skills for these.

## Critical Warnings

**Deadly embrace**: Removing a cross-stack reference deadlocks deployment. Two-deploy fix required: (1) remove consumer import + add `this.exportValue()` on producer, deploy; (2) remove `exportValue()`, deploy again. See [troubleshooting-deployment](references/troubleshooting-deployment.md).

**Construct ID changes cause replacement**: Renaming/moving a construct changes its logical ID → CloudFormation replaces the resource (data loss for stateful resources). Always `cdk diff` before deploy. See [refactor-and-prevent-replacement](references/refactor-and-prevent-replacement.md).

**UPDATE_ROLLBACK_FAILED**: Stack is stuck. Fix with `cdk rollback $STACK` or `cdk rollback $STACK --orphan <LogicalId>`. See [troubleshooting-deployment](references/troubleshooting-deployment.md).

**Non-empty S3 buckets persist after destroy**: You MUST set both `removalPolicy: DESTROY` and `autoDeleteObjects: true`. Versioned buckets are worse — delete markers persist even after apparent deletion.

## Common Workflows

| Task | Quick Command | Details |
|------|--------------|---------|
| Bootstrap | `cdk bootstrap aws://$ACCOUNT/$REGION` | [bootstrap-and-project-setup](references/bootstrap-and-project-setup.md) |
| New TS project | `cdk init app --language typescript` — use `tsx`, `eslint-plugin-awscdk` | [bootstrap-and-project-setup](references/bootstrap-and-project-setup.md) |
| New Python project | `cdk init app --language python` — pin deps, use virtualenv | [bootstrap-and-project-setup](references/bootstrap-and-project-setup.md) |
| Deploy | `cdk synth --strict` → `cdk diff` → `cdk deploy` | Always diff before deploy to prod |
| cdk-nag | `Aspects.of(app).add(new AwsSolutionsChecks())` | [compliance-and-drift](references/compliance-and-drift.md) |
| Drift | `cdk drift $STACK` (use `--fail` in CI) | [compliance-and-drift](references/compliance-and-drift.md) |
| Import resource | `cdk import` (interactive or `--resource-mapping` for CI), `cdk deploy --import-existing-resources` | [import-and-migrate](references/import-and-migrate.md) |
| Refactor safely | `cdk refactor --unstable=refactor` — no property changes in same deploy | [refactor-and-prevent-replacement](references/refactor-and-prevent-replacement.md) |

## Troubleshooting

| Error | Cause → Fix |
|-------|------------|
| **DeployFailed / DeploymentError** | CDK error is not root cause. Check CFN events: `aws cloudformation describe-stack-events --stack-name $STACK --query "StackEvents[?contains(ResourceStatus,'FAILED')]"`. [Details](references/troubleshooting-deployment.md) |
| **NoCredentials / ExpiredToken / AssumeRoleFailed** | `aws sts get-caller-identity` + `cdk doctor`. Expired SSO, missing `env`, missing `sts:AssumeRole`. [Details](references/troubleshooting-credentials.md) |
| **Asset errors** (CannotFindAsset, FailedToBundleAsset, AssetBuildFailed, AssetPublishFailed) | Path wrong, Docker not running, or bootstrap bucket perms. Use `path.join(__dirname, ...)`. [Details](references/troubleshooting-synth.md) |
| **AppRequired** | Add `"app": "npx tsx bin/my-app.ts"` to `cdk.json`. [Details](references/troubleshooting-synth.md) |
| **AnnotationErrors** | Fix the underlying issue; suppress with `NagSuppressions` only as last resort. [Details](references/troubleshooting-synth.md) |
| **ConcurrentReadLock / ConcurrentWriteLock** | `rm -rf cdk.out` then re-run. Parallel CI: `--output ./cdk.out.$BUILD_ID`. [Details](references/troubleshooting-synth.md) |
| **BootstrapVersionValidation** | Re-bootstrap. Match `--qualifier` everywhere. [Details](references/troubleshooting-credentials.md) |
| **DependencyCycle** | Extract shared resource into third stack or use SSM for late-binding. [Details](references/troubleshooting-synth.md) |
| **UnresolvedAccount** | Set explicit `env: { account, region }` on stack. Commit `cdk.context.json`. [Details](references/troubleshooting-credentials.md) |
| **NoStacksMatched** | CDK uses logical ID (2nd constructor arg), not CFN name. `cdk list` to find IDs. [Details](references/troubleshooting-synth.md) |
| **Cannot find module** (synth time) | Run `npx tsc --noEmit`, check `cdk.json` app path matches `tsconfig.json` `outDir`, delete stale `.js` files. Python: activate venv. [Details](references/troubleshooting-synth.md) |
| **V1 import paths / duplicate aws-cdk-lib** | V1 `@aws-cdk/*` imports, wrong `Construct` import, duplicate lib copies in monorepos. [Details](references/v1-to-v2-migration.md) |
| **Lambda Cannot find module** (runtime) | Wrong handler value, missing SDK v3 migration, Python deps not bundled. [Details](references/troubleshooting-deployment.md) |
| **API Gateway multi-stage conflicts** | Set `deploy: false` on `RestApi`, create `Deployment` and `Stage` explicitly. [Details](references/troubleshooting-deployment.md) |

## Construct Patterns

Prefer L2. Use L1 with Mixins/Facades when L2 lacks a property. Escape hatches: `node.defaultChild` → `addPropertyOverride`. See [construct-patterns](references/construct-patterns.md).

## Additional Resources

- Search AWS documentation for "CDK Developer Guide", "CDK API Reference" and "CDK Pipelines" respectively

## Security Considerations

- OIDC for CI/CD credentials (no static keys)
- `--custom-permissions-boundary` on bootstrap
- `grant*()` for inter-resource IAM
- `cdk-nag` + `--strict` in CI
- Stateful resources in own stack with `terminationProtection: true`
- Commit `cdk.context.json`