No Code Synthesis

[iliapolo]

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• Hit the like (👍) or dislike (👎) button to let us know what you think about this feature.
• Feel free to ask any clarifying questions or suggest enhancements.
• This is just a proposal doc and intentionally doesn’t focus on technical details but rather on customer experience. If the proposal is accepted we will publish a detailed RFC where you’ll get a chance to provide more feedback.

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With cdk8s, customers can create reusable and customizable constructs that synthesize into a Kubernetes manifest to be deployed at a future date. These constructs can then be published to standard package managers in the form of code libraries. This allows creating abstractions that reduce complexity and enforce best practices.

Currently, the way to consume those libraries (i.e produce a Kubernetes manifest out of them) is as follows:

1. cdk8s init
2. Install dependencies
3. Edit the main file.
4. cdk8s synth (possibly compile before as well, depending on the language)

In cases where a cdk8s application consists solely of instantiating a single construct, we feel this workflow can be a bit tedious, and introduces a maintenance burden that can be avoided. For example, say that we want to deploy a redis cluster using the cdk8s-redis library. We would have to create a cdk8s application and write code similar to this:

import { Redis } from 'cdk8s-redis';

new Redis(this, 'my-redis', {
  replicas: 4
});

This type of work is undifferentiated, and can be automated. We propose to simplify these use cases by allowing the cdk8s synth command to accept a package URL and an arguments file:

cdk8s synth --package https://www.npmjs.com/package/cdk8s-redis/v/0.1.536 --args args.yaml

Where the args.yaml file will (most likely) contain:

replicas: 4

Running the above command will produce the desired manifest. This command can then be easily integrated into scripts or workflows that simply want to utilize a cdk8s library.

Combine this feature with #1196, and we will have a single line command that can create a helm chart from a remote cdk8s library:

cdk8s synth --format helm --package <package-url> --args args.yaml

Some limitations will most likely exist:

• To consume a library in this way, it may only contain a single construct.
• The constructor may only accept pure data types, not classes or enums.