server

README

dockbox

Welcome! This is the backend for dockbox, an application that gets you started quickly with on-the-go coding environments. Ever wanted to try out a library quickly before trying it out in your project? Have you ever stressed about having a lot of unwanted resources tied up on your machine? dockbox aims to solve these problems.

Server

The server is written in Go using the Gin framework. It supports and manages websocket connections from various client, and proxies websocket connections to the docker server

Prerequisites

The environment variables are loaded from utils/config.go. These values need to be defined in the local file before starting the server; otherwise, an error will be thrown.

Currently, the following values are required in a .env file in the root directory:

type configType struct {
	ENVIRONMENT        string
	PORT               string
	DOCKER_SERVER_HOST string
	DATABASE_NAME      string
	DATABASE_HOST      string
	DATABASE_PORT      string
	DATABASE_USER      string
	DATABASE_PASSWORD  string
	MOUNT_POINT        string
}

Note: the mount point is where the user data will be stored.

To set up for production, the set up EC2 script can be used.

Architecture

Currently, these are the components in the architecture of the server:

• Docker server(s)
• Go server(s)
• Mounted shared file system for each server
• Database

The specifics of the architecture is implemented with AWS resources.

• Servers: EC2 machines running Ubuntu 20.0.2
• File System: EFS (Elastic File System)
• Database: RDS (PostgreSQL)

Along with the above, the resources are running in a single VPC and spans multiple AZ in us-east-1 (North Virginia). An Application Load Balancer (ALB) is used for load balancing and terminates SSL. An ALB instead of a classic Load Balancer was used since it supports WebSockets.

Functions

Currently, there is support for creating, retrieving, and connecting to a dockbox. A dockbox is an environment for your project, and contains details about the source repository; its ID can be used to connect a live websocket to it. From the UI, a dockbox would be a terminal window for the user.

To prevent the server from being overloaded, active containers need to managed properly. The ConnectionManager object takes care of the specifics, and is thread-safe. The server keeps track of the number of connections for each container, and once the number of connections for a specific container reaches 0, a new goroutine is spawned and the container is added to the deletion queue. Once the container is in the deletion queue for 1 minute, the container is stopped.

Credits

• https://github.com/koding/websocketproxy
• https://github.com/gin-gonic/gin