http4kbox - http4k app deployed in multiple modes

This is a simple Dropbox clone built with http4k which uses S3 as a backing store, implemented in ~70 lines of code (when imports are excluded). It is designed to demo that http4k apps run identically in the following modes:

1. As a Kotlin function with SunHttp dev server for tests - see app
2. In a deployed local Undertow server + Apache HTTP client - see local
3. To Heroku as a cloud-based Apache server (with Java HTTP client) deployed through a fully CD pipeline run on Travis - see heroku
4. Into a Kubernetes cluster - see k8s
5. As a pure Kotlin function deployed in a Serverless environment (AWS Lambda) - see serverless
6. As a native Apache server binary running in GraalVM - see native

Apart from the switchable server backends and clients, the core app uses the following http4k modules and features:

• http4k-core <-- main HTTP library
• http4k-cloudnative <-- for 12-factor configuration via environmental properties
• http4k-aws <-- replaces the Java AWS SDK
• http4k-template-handlebars <-- for templating
• http4k-multipart <-- multipart form uploads
• http4k-testing-hamkrest <-- for test assertions

In action: