The AWS CDK is an open-source framework that simplifies working with cloud resources using familiar programming languages: C#, TypeScript, Java, Python, and Go (in developer preview). Within their applications, developers create and configure cloud resources using reusable types called constructs, which they use just as they would any other types in their chosen language. It’s also possible to write custom constructs, which can then be shared across your teams and organization.
With the new releases generally available today, defining your cloud resources using the CDK is now even more simple and convenient, and the Construct Hub enables sharing of open-source construct libraries within the wider cloud development community.
AWS Cloud Development Kit (AWS CDK) Version 2
Version 2 of the AWS CDK focuses on productivity improvements for developers working with CDK projects. The individual packages (libraries) used in version 1 to distribute and consume the constructs available for each AWS service have been consolidated into a single monolithic package. This simplifies dependency management in your CDK applications and when publishing construct libraries. It also makes working with CDK projects that reference constructs from multiple services more convenient, especially when those services have peer dependencies (for example, an Amazon Simple Storage Service (Amazon S3) bucket that needs to be configured with an AWS Key Management Service (KMS) key).
Version 1 of the CDK contained some APIs that were experimental. Over time, some of these were marked as deprecated in favor of other preferred approaches based on community experience and feedback. The deprecated APIs have been removed in version 2 to aid clarity for developers working with construct properties and methods. Additionally, the CDK team has adopted a new release process for creating and releasing experimental constructs without needing to include them in the monolithic GA package. From version 2 onwards, the monolithic CDK package will contain only stable APIs that customers can always rely on. Experimental APIs will be shipped in separate packages, making it easier for the team and community to revise them and ensure customers don’t incur the accidental breaking changes that caused some issues in version 1.
You can read about all the changes in version 2 of the AWS CDK, and how you can update your CDK applications to use it, in the Developer Guide.
The Construct Hub is a single home where the open-source community, AWS, and cloud technology providers can discover and share construct libraries for all CDKs. The most popular CDKs today are AWS CDK, which generates AWS CloudFormation templates; cdk8s, which generates Kubernetes manifests; and cdktf, which generates Terraform JSON files. Anyone can create a CDK, and we are open to adding other construct-based tools as they evolve!
As of this post’s publication, the Construct Hub contains over 700 CDK libraries, including core AWS CDK modules, to help customers build their cloud applications using their preferred programming languages, for their preferred use case, and with their preferred provisioning engine (CloudFormation, Terraform, or Kubernetes). For example, there are 99 libraries for working with containers, 210 libraries for serverless development, 53 libraries for websites, 65 libraries for integrations with cloud services providers like Datadog, Logz.io, Cloudflare, Snyk, and more, and dozens of additional libraries which integrate with Slack, Twitter, GitLab, Grafana, Prometheus, WordPress, Next.js, and more. Many of these were created by the open-source community.
Anyone can contribute construct libraries to the Construct Hub. New libraries that you wish to share need to be published to the npm public registry and tagged. The Construct Hub will automatically detect the published libraries and make them visible and discoverable to consumers on the hub. Consumers can search and filter for construct libraries for familiar technologies, third-party integrations, AWS services, and use cases such as compliance, monitoring, websites, containers, serverless, and more. Filters are available for publisher, language, CDK type, and keywords. In the screenshot below, I’m searching the hub for .NET and TypeScript libraries related to databases and Kubernetes across all CDKs. I could also filter to a specific CDK or a CDK version.
Publishers determine which programming languages should be supported by their packages. Construct Hub then automatically generates API references for all the supported languages and transliterates all code samples the authors provide to those supported languages. The screenshots below show an example of language-specific API documentation for the cdk-spa-deploy construct library, which you can use to deploy a single-page web application (SPA). First, the documentation for .NET developers working with the library:
The second image below shows the generated documentation for the same construct library, but this time for TypeScript developers:
All construct libraries published to the Construct Hub must be open-source. This enables users to exercise their good judgment and perform due diligence to verify that the libraries meet their security and compliance needs, just as they would with any other third-party package source consumed in their applications. Issues with a published construct library can be raised on the library’s GitHub repository using convenient links accessible from the hub entry for the library.
The Construct Hub employs a trust-through-transparency model. Users can report libraries for abuse by clicking the ‘Report abuse’ link in the hub, which will engage AWS Support teams to investigate the issue and remove the offending packages from Construct Hub listings if problems are found. Users can also send us feedback by clicking a ‘Provide feedback to Construct Hub’ link, which allows them to open an issue on our GitHub repository. And last but not least, they can click ‘Provide feedback to publisher’, which redirects to the repository the publisher provided with the package.
Just like the AWS CDK, the Construct Hub is open-source, built as a construct, and is, in fact, itself available on the Construct Hub! If you’re interested, you can see how the CDK team uses the CDK to develop the hub in their GitHub repository.
Get Started with the AWS CDK Version 2 and the Construct Hub, Today
If you’ve built CDK applications to define your cloud infrastructure using version 1 of the AWS Cloud Development Kit (AWS CDK), then I encourage you to take a look at the documented changes for version 2 and see how the new version can help simplify your project setup going forward. And, if you’re interested in sharing new constructs with the wider community, please get involved with the Construct Hub. You can find more details on how to build and share reusable construct libraries on the Construct Hub in the CDK team’s blog post on best practices.