This is my first program written in Go which compiles C# code (as a proof of concept) on a docker 'mono' image in a docker sandboxed container. The http server exposes "/"" which is a simple text area to demonstrate the capability. /compile is where the magic happens. I was curious how to build such a system and found CompileBox which is pretty cool! Decided to write one myself with a few borrowed ideas.

This is not production ready and a bunch of features should be implemented before using it in production (see later).

• create N docker containers to reduce latency of container creation time in compilation step
• each container has /home/temp which is mounted to ./runs/TEMP where the user posted code is saved
• http server listens to default port 8000 for compile requests

• get handle of an available container and defer concurrent requests to destroy this container and create new, the requester waits until a container is available
• source code POSTed is copied to a temporary folder in ./runs/ (already mounted on the container)
• code compilation and execution are executed on the container
• stdout and stderr are captured and returned to client as JSON response (Output and ErrorString fields)
• timeout can be set and in case of a timeout Timeout: true is returned as part of JSON response

{"Output":"Sum: 499500\nCode Execution: 23 ms\n",
"LatencyInMS":582,
"ErrorString":"",
"Timeout":false}

• Install Go 1.4+
• Install docker (Mac is OK, use boot2docker)
• Install docker image 'mono:latest'
• Create new a directory 'runs' with write access
• Edit config.go and set configuration options
• go build -o webcompile *.go (will need to "go get" a few packages)
• ./webcompile

http://localhost:8000/

• use stdin to send code to container. Avoids temporary path, mounting, copying and delete
• use web security libraries to enable throttling
• dump logs to disk
• use go docker client library for 'create' and 'exec'
• better error handling
• support more languages. v0.1 only supports C# as a proof of concept
• optimize container properties (limit memory?)
• fault tolerance to recover after errors creating docker containers
• add tests, do scale testing
• use bocker instead of docker? :)
• time out if cannot acquire container
• if client cancels request, cancel wait/execution gracefully
• collect stats and optionally expose them on /stats