Template directives¶

Directives are YAML tags that start with !Rain::. cfnrain processes them when it packages a template, and replaces each one with a plain value. CloudFormation never sees them.

See Packaging for which commands package a template. Run cfnrain pkg to see the packaged template before you deploy it.

Directive	What it inserts	Needs AWS
`!Rain::Embed <path>`	The contents of a file, as a string	No
`!Rain::Include <path>`	A YAML or JSON file, as an object	No
`!Rain::Env <name>`	The value of an environment variable, as a string	No
`!Rain::S3 <path>`	The S3 URI of an uploaded file, or an object with the bucket and key	Yes
`!Rain::S3Http <path>`	The HTTPS URL of an uploaded file	Yes
`!Rain::Constant <name>`	The value of a constant from the `Rain:` section	No
`!Rain::Module <uri>`	The resources of a module. This is the older module system and needs `--experimental`.	No

cfnrain also uploads local files for some resource properties without a directive, like aws cloudformation package does. See Implicit uploads.

Paths¶

A path in a directive is relative to the template file that contains it. See Paths.

Long form¶

The YAML tag is a short form. The long form is a map with one key, and it also works in JSON templates:

{
  "Code": {
    "ZipFile": { "Rain::Embed": "handler.py" }
  }
}

Examples come from tests¶

The examples on these pages are test files in cft/pkg/tmpl/docs. go test ./cft/pkg/ packages each -template.yaml file and compares the result with its -expect.yaml file. If cfnrain changes how a directive works, the test fails. The S3 directives need AWS, so their examples are illustrative and not tested.