serverless-terraform-outputs

Serverless framework plugin to reference outputs from Terraform.

At a Glance

• It allows nested attributes to be picked from objects.
• The picked attribute must be a non-null value.
• It doesn't support picking items from arrays.
• It's an ESM-only module.

Referencing Terraform outputs in Serverless Framework has been addressed multiple times using various approaches and package names. This is my attempt to solve the problem with what I believe is the fastest implementation. Additionally, I aimed to maintain it as an ESM-only module in the JavaScript Registry.

Pre-requisites

• Serverless framework v3 or higher
• Node.js version v20 or higher
• Ensure the terraform command is available in your PATH

Installation

This plugin is an ESM-only module available on the JavaScript Registry for the Node.js runtime.

npx jsr add --save-dev  @halfstack/serverless-terraform-outputs

Add the plugin to your serverless.yml configuration:

plugins:
  - '@halfstack/serverless-terraform-outputs'

Configuration

The plugin can be configured using the ServerlessTerraformOutputs option.

path

Optionally, specify the path to the Terraform files. Otherwise, the plugin assumes the current working directory. Here is the configuration if the files are located in a directory named infra:

├── project
    ├── infra
    ├── src
    └── serverless.yml

# serverless.yml

custom:
  ServerlessTerraformOutputs:
    path: './infra'

Usage

The reference in the serverless.yml file should begin with the ${TF:} prefix, followed by the path to the variable in the Terraform outputs. Here's an example:

# /infra/main.tf

output "user-uploads-bucket-name" {
  value = aws_s3_bucket.user-uploads-bucket.bucket
}

output "main" {
  value = {
    stage = "dev"
    region = "eu-west-1"
    identityPool = {
      name = "hello-world"
      url = "https://example.com"
    }
    tags = ["tag-1", "tag-2"]
  }
}

# serverless.yml

service: some-service

provider:
  name: aws
  stage: ${TF:main.stage}
  region: ${TF:main.region}

custom:
  tags: ${TF:main.tags}

functions:
  hello:
    handler: handler.hello
    environment:
      userUploadsBucket: ${TF:user-uploads-bucket-name}
      identityPoolUrl: ${TF:main.identityPool.url}

License

MIT

Credits

I read these projects, which solved the exact problem this plugin addresses, to understand their approach. However, this plugin has taken a different implementation approach.

• serverless-terraform-outputs
• serverless-terraform-variables