cloudform

TypeScript-based imperative way to define AWS CloudFormation templates

Read the introductory blog post

Installation

npm install --save-dev cloudform

Usage

1. Define your AWS CloudFormation template in a TypeScript file, for example template.ts:

import cloudform, {Fn, Refs, EC2, StringParameter, ResourceTag} from "cloudform"

export default cloudform({
    Description: 'My template',
    Parameters: {
        DeployEnv: new StringParameter({
            Description: 'Deploy environment name',
            AllowedValues: ['stage', 'production']
        })
    },
    Mappings: {
        DeploymentConfig: {
            stage: {
                InstanceType: 't2.small'
            },
            production: {
                InstanceType: 't2.large'
            }
        }
    },
    Resources: {
        VPC: new EC2.VPC({
            CidrBlock: NetworkingConfig.VPC.CIDR,
            EnableDnsHostnames: true,
            Tags: [
                new ResourceTag('Application', Refs.StackName),
                new ResourceTag('Network', 'Public'),
                new ResourceTag('Name', Fn.Join('-', [Refs.StackId, 'VPC']))
            ]
        }),
        Instance: new EC2.Instance({
            InstanceType: Fn.FindInMap('DeploymentConfig', Fn.Ref('DeployEnv'), 'InstanceType'),
            ImageId: 'ami-a85480c7'
        }).dependsOn('VPC')
    }
})

See also example/example.ts.

2. Run cloudform path/to/your/template.ts to generate the CloudFormation template as JSON.

It makes sense to define it in your npm scripts and run within your build or deployment pipeline, for example:

"scripts"
  // ...
  "generate-cloudformation-template": "cloudform path/to/your/template > template.aws"
}

Use cloudform --minify path/to/your/template.ts if you want CloudForm to output minified JSON instead of formatted. It might be useful if you reach CloudFormation template body size limitation.

API

The types are generated automatically from the AWS-provided schema file throughout all the regions, so cloudform supports all the types available in AWS CloudFormation.

The simple convention is used – all the AWS types’ namespaces are available directly as exports from the cloudform package. All the resources within this package are available inside. This way EC2.VPC object from our example translates into AWS::EC2::VPC type we can find in CloudFormation documentation. All the properties also match one-to-one, including casing.

All Intrinsic Functions are available within Fn namespace:

Fn.Base64(value: Value<string>)
Fn.FindInMap(mapName: Value<string>, topLevelKey: Value<string>, secondLevelKey: Value<string>)
Fn.GetAtt(logicalNameOfResource: Value<string>, attributeName: Value<string>)
Fn.GetAZs(region?: Value<string>)
Fn.ImportValue(sharedValueToImport: Value<any>)
Fn.Join(delimiter: Value<string>, values: List<any>)
Fn.Select(index: Value<number>, listOfObjects: List<any>)
Fn.Split(delimiter: Value<string>, sourceString: Value<string>)
Fn.Sub(string: Value<string>, vars [key: string]: Value<any> })
Fn.Ref(logicalName: Value<string>)

// condition functions
Fn.And(condition: List<Condition>)
Fn.Equals(left: any, right: any)
Fn.If(conditionName: Value<string>, valueIfTrue: any, valueIfFalse: any)
Fn.Not(condition: Condition)
Fn.Or(condition: List<Condition>)

All the Pseudo Parameters are there, too:

Ref.AccountId
Ref.NotificationARNs
Ref.NoValue
Ref.Partition
Ref.Region
Ref.StackId
Ref.StackName
Ref.URLSuffix

Licence

MIT