build¶

cfnrain build makes starter templates from the CloudFormation resource schemas. The schemas are in the binary, so most uses need no AWS call.

Make a template with only the required properties of a type:

cfnrain build -b AWS::SQS::Queue

AWSTemplateFormatVersion: 2010-09-09

Description: Generated by rain

Resources:
  Queue:
    Type: AWS::SQS::Queue
    Properties: {}

Without -b, the template has every property that you can set. You can give more than one type.

List the resource types that start with a prefix:

cfnrain build -l AWS::SQS

AWS::SQS::Queue
AWS::SQS::QueueInlinePolicy
AWS::SQS::QueuePolicy

Flag	What it does
`-b`, `--bare`	Only the required properties
`-j`, `--json`	JSON instead of YAML
`-s`, `--schema`	Print the registry schema of a type
`-l`, `--list`	List resource types, with an optional prefix
`-o`, `--output`	Write to a file
`--recommend`	Print a recommended template for a use case. With no more arguments, cfnrain shows a menu. `cfnrain build --recommend bucket bucket` prints the recommended bucket template.
`--pkl-class`	Print a Pkl class for a type
`--prompt`	Write a template with Amazon Bedrock from a text prompt. The default model is `claude2`, which is old. Bedrock usage costs money.
`--model`	The Bedrock model ID for `--prompt`. The short names `claude2`, `claude3haiku`, `claude3sonnet`, `claude3opus` and `claude3.5sonnet` also work.
`--prompt-lang`	What `--prompt` writes: `cfn` (CloudFormation YAML, the default), `guard` (CloudFormation Guard) or `rego` (Open Policy Agent Rego)
`--omit-patches`	Use the raw registry schema. By default, cfnrain applies its own fixes to the schemas.
`--no-cache`	Do not use the schemas in the binary. Get them from the CloudFormation registry.
`--only-cache`	Meant to use only the schemas in the binary. See the warning below.

With no arguments, build shows an interactive menu.

--only-cache does the same as --no-cache

In the code, --only-cache sets the same switch as --no-cache. Both make cfnrain skip the cached schemas. See Known issues.