---
id: aws-cdk-custom-resources
version: "1.204.0"
license: Apache-2.0
license_treatment: permissive
maintenance: active
---

# aws-cdk.custom-resources — Constructs for implementing CDK custom resources

License: permissive · Maintenance: active · Downloads: 155.3K/mo

## What it is and what it does

This package provides a Provider construct that acts as a mini-framework for building AWS CloudFormation custom resources within AWS CDK. It wraps Lambda functions as handlers for CloudFormation lifecycle events (Create, Update, Delete), managing the request/response protocol, error handling, and response submission back to CloudFormation. The framework supports both synchronous handlers (onEvent) that complete immediately and asynchronous handlers (isComplete) that poll until a resource reaches a stable state, useful for operations exceeding Lambda's timeout window.

The package depends on aws-cdk.core, aws-cdk.aws-lambda, aws-cdk.aws-iam, aws-cdk.aws-logs, and several other CDK modules to construct and manage the underlying infrastructure. However, it is important to note that AWS CDK v1 reached end-of-support on 2023-06-01, and this package is no longer being updated. Users should plan migration to AWS CDK v2 rather than starting new projects with this version.

Use it for:

- Implement a custom CloudFormation resource that provisions third-party infrastructure not natively supported by CloudFormation.
- Create a long-running provisioning operation (e.g., database initialization) that requires polling until completion rather than immediate return.
- Build a wrapper around an external API to make it deployable as a CloudFormation custom resource within CDK stacks.
- Handle resource lifecycle events (creation, updates, deletion) with custom business logic before or after standard AWS operations.
- Validate and transform resource properties during CloudFormation deployment using Lambda-based custom logic.

## Worth the install?

AI-flagged interpretation of the facts above — verify before relying.

Provides a framework for implementing AWS CloudFormation custom resources using AWS CDK, handling lifecycle events and asynchronous operations through Lambda functions.

No — do not install for new projects. This package is end-of-support (AWS CDK v1 reached end-of-support 2023-06-01) and users are explicitly directed to migrate to AWS CDK v2. Only use if maintaining an existing CDK v1 codebase with no migration path; otherwise, adopt the v2 equivalent to receive updates and security patches.

## Install

pip install aws-cdk-custom-resources
uv add aws-cdk-custom-resources
poetry add aws-cdk-custom-resources

## Installing aws-cdk.custom-resources

Before you install: Low install friction with 11 runtime dependencies. Package is in active maintenance but marked as inactive (Development Status 7) — AWS CDK v1 reached end-of-support on 2023-06-01 and users are advised to migrate to AWS CDK v2.

License in practice: Licensed under Apache-2.0 (permissive), allowing commercial and private use with minimal restrictions beyond attribution and liability disclaimers.

Quickstart:

from aws_cdk import custom_resources as cr
from aws_cdk import aws_lambda as lambda_
from aws_cdk import aws_iam as iam
from aws_cdk import aws_logs as logs

provider = cr.Provider(self, "MyProvider",
    on_event_handler=on_event_function,
    is_complete_handler=is_complete_function,
    log_retention=logs.RetentionDays.ONE_DAY,
    role=my_role
)

Requires AWS CDK v1 runtime environment; package is end-of-support as of 2023-06-01 and migration to AWS CDK v2 is recommended.

Verify before relying:

- Whether AWS CDK v2 has a direct replacement for this custom resources module or if migration requires architectural changes.
- Performance characteristics and timeout limits for asynchronous handlers under typical workloads.
- Security implications of Step Functions execution history exposure mentioned in the description for your threat model.

## Package facts

- License: Apache-2.0 (permissive)
- Python support: supports_current
- Install friction: low
- Maintenance: active
- Downloads: 155.3K/month (top 15,000 on PyPI)
- Known vulnerabilities: none known

## Tags

cloudformation custom resources, aws cdk custom resources, cdk provider framework, lambda cloudformation integration, cdk lifecycle handlers, custom resource provisioning, asynchronous resource handlers, aws-cdk, cloudformation, end-of-support

[View on SkillFed](https://skillfed.io/packages/aws-cdk-custom-resources) · [View on PyPI](https://pypi.org/project/aws-cdk-custom-resources/)