S3

The S3 module provides a simple means for an application to store and access files on AWS S3. This template is set up for deploying an S3 bucket using Terraform and provides a simple TypeScript API to work with this bucket.

Configure

In order to provide a basic configuration for an S3 bucket, we only need to know the name of the bucket you want to create.

Please note that a bucket name needs to be globally unique. However, buckets are always created in a specific AWS region. The bucket will be deployed to the AWS region you have specified.

Getting Started

Infrastructure

The first thing we recommend to do with a new module is to stand up the infrastructure for the module. For this, find the directory for this module in the packages/ folder and navigate to this folder in the command line. Then identify the name of the deployment you have defined in the Goldstack configuration tool. This can be found in the packages/[moduleName]/goldstack.json file. Look for the "deployments" property and there for the "name" of the first deployment. The name should either be dev or prod.

In order to stand up the infrastructure, now run in the command line:

yarn infra up [deploymentName]

This will be either yarn infra up dev or yarn infra up prod depending on your choice of deployment. Note that running this command can often take a while.

Development

This is how an the S3 module can be used from another module:

import { getBucketName, connect } from 'my-s3-module';

const s3 = connect();
await s3.putObject({
  BucketName: getBucketName(),
  Key: 'my-doc',
  Body: 'content',
});

The object returned from connect() is an instance of the AWS S3 client.

Note it is also possible to add additional TypeScript files in the modules src/ folder. This is a good place to put an abstraction layer on top of the S3 interface, for instance a data repository specific to the needs of your application.

Infrastructure

All infrastructure for this module is defined in Terraform. You can find the Terraform files for this module in the directory [moduleDir]/infra/aws. You can define multiple deployments for this module, for instance for deployment into a development, test and production system. The deployments and their respective configurations are defined in [moduleDir]/goldstack.json. When using the Goldstack configuration tool, there will be one deployment defined that is either dev or prod depending on whether you choose to define your initial infrastructure for a development or production system.

Infrastructure Commands

There are a number of package scripts defined for working with infrastructure. For all infrastructure scripts, we will need to define which deployment they should apply to for. This is done by referencing the deployment name as configured in goldstack.json. The following commands are supported:

yarn infra up [deploymentName]

Which will run the commands init, plan and apply to stand up the infrastructure in the specified destination. If you are new to Terraform, running yarn infra up is the easiest way to get your infrastructure up and running.

However, if you are familiar with Terraform and want more fine-grained control over the deployment of your infrastructure, the following commands are also supported:

yarn infra init [deploymentName]

Which will run terraform init to initialise the deployment.

yarn infra plan [deploymentName]

Which will run terraform plan and show the delta for the infrastructure.

yarn infra apply [deploymentName]

Which will run terraform apply and deploy the infrastructure. This requires yarn infra plan to have run successfully before.

yarn infra destroy [deploymentName]

Which will run terraform destroy and destroy all your infrastructure. Note that this will lead to loss of all the data you may be storing in datastores for this deployment, so do use this command with caution.

Customizing Terraform

Goldstack is made to make it very easy to customize the infrastructure to your specific needs. The easiest way to do this is to simply edit the *.tf files in the infra/aws folder. You can make the changes you need and then run yarn infra up [deploymentName] to apply the changes.

The infra/aws folder contains a file variables.tf that contains the variables required for your deployment; for instance the domain name for a website. The values for these variables are defined in the module's goldstack.json file in the "configuration" property. There is one global configuration property that applies for all deployments and each deployment also has their own configuration property. In order to add a new variable, add this variable to variables.tf and then add it to the configuration for your module or to the configurations for the deployments.

Note that due to JavaScript and Terraform using different conventions for naming variables, Goldstack applies a basic transformation to variable names. Camel-case variables names are converted in valid variables names for terraform by replacing every instance of a capital letter C with _c in the variable name. For instance:

myVariableName in the Goldstack configuration will translate to the Terraform variable my_variable_name as defined in variables.tf.

Terraform State

In order to manage your infrastructure, Terraform maintains a state for each deployment - to be able to calculate required changes when the infrastructure is updated and also to enable to destroy the infrastructure easily if it is no longer required. Goldstack by default will store the terraform state in the infra/aws folder as simple files.

This works well for deploying infrastructure from your local development environment but is not a good choice when building a CI/CD pipeline for the infrastructure definition. In that case, it is better to define Remote State. A popular choice many projects adopt here is to store the state in an S3 bucket. Please see the Terraform documentation for further details.

Security Hardening

The S3 bucket for this module is already configured to allow only private access to the bucket. Be careful when making the bucket public and ensure that it only has contents that can be publicly exposed. For use cases such as using a bucket for hosting content, we recommend using the Static Website module.

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