Custom manifests

While Crustomize mimics kustomize with overlays and Helm Charts with its template rendering support, the generate command is a bit different.

It enables you to define a DSL like manifest format that results in a generated AWS CloudFormation template. For example, you could have a manifest YAML file similar to this:

# mydb.yml
type: rds/postgres
name: MyPostgresDB
def:
  cluster: production
  size: small

When you run the crustomize generate mydb.yml -R repo_path command it would output a CloudFormation template for bringing up that resource. This allows you to define standard resources in a DevEx friendly way.

How it works

The generate command would locate the repository folder and use the value of the type property to find the proper overlay. In the above example, the repo is located at ./repo_path and the value of the type property is rds/postgres. Crustomize would then look for a ./repo_path/rds/postgres folder. That folder should have at minimum two files: schema.json and crustomize.yml.in. The JSON schema is used to validate the correctness of the mydb.yml manifest. If successful Crustomize will then pre-render the crustomize.yml.in file using all the properties of the mydb.yml file. Once that step is complete, Crustomize will then apply the overlay as usual.

Note that in order to deploy the generated template, you must use the AWS CLI.

Repo

The repo is just a collection of folders and files and can be located on the file system or in an S3 bucket. The --repo/-R switch should always point to the root of the repo, in order for the paths contained in the type property to be located.

If you use an S3 bucket, Crustomize will download the repo to a .repo folder in the working directory. This folder will be synced every time you run the command.

Repo and custom helpers

If you have custom helpers for a repo, you can store these in a folder in the repo and then point to these using the --helpers/-H cli flag.

For example, if you repo is in an S3 bucket, and you point to it like this: --repo s3://bucket/ecs/v3 and your helpers are located at s3://bucket/ecs/v3/helpers the repo will be synced to: ./.repo/ecs/v3. Thus, your helpers will be located at: ./.repo/ecs/v3/helpers.

Example usage

crustomize generate <definition.yml> --repo <repo-path> [options]

See the example under examples/repo for a working setup:

crustomize generate examples/repo/examples/example.yml \
  --repo examples/repo/repo --output ./build