webdelve - Online Go Compiler & Debugger

webdelve is a web service that provides an online debugging environment for Go programs. It allows to run and debug Go code directly from browser using the delve server running in isolated docker containers.

Demo

demo.mp4

Features

• web-based debugging - debug go code from any browser
• prometheus metrics - monitor performance and usage
• websocket communication - real-time debugger interaction
• code formatting - automatic go code formatting

Supported debug Commands

Command	Description	Arguments
continue	Resume execution	-
next	Step over	-
step	Step into	-
stepout	Step out	-
break	Set breakpoint	file, line
clear	Remove breakpoint	id
stack	Show stack trace	goroutineId, depth
locals	Show local variables	goroutineId, frame
goroutines	List all goroutines	-
state	Get debugger state	-
restart	Restart program	-

Prerequisites

• Docker with gVisor runtime (runsc)
• Make (optional)

Usage

Option 1: Docker (recommended)

Builds both images (for sandbox and service), then runs everything in containers.

make docker-run

Service will be available at address specified in config.yaml.
Stop with make docker-stop.

Option 2: Local development (service on host, sandbox in Docker)

Requires the sandbox Docker image to be built once.

# Build the sandbox image
docker build -f Dockerfile.sandbox -t webdelve-sandbox:latest .

# Build and run the service binary locally
make run

The service will use your local Docker daemon to create sandbox containers from the webdelve-sandbox:latest image.

API Usage

Start a debugging session

curl -X POST http://localhost:8080/build \
  -H "Content-Type: application/json" \
  -d '{"code": "package main\n\nfunc main() {\n    println(\"Hello\")\n}"}'

Response:

{
  "session_id": "550e8400-e29b-41d4-a716-446655440000",
  "formatted": "package main\n\nfunc main() {\n\tprintln(\"Hello\")\n}\n"
}

Connect via WebSocket

const ws = new WebSocket("ws://localhost:8080/ws/550e8400...");

ws.send(JSON.stringify({ command: "continue" }));
ws.send(JSON.stringify({ command: "break", args: { file: "main.go", line: 4 } }));

Metrics

Prometheus metrics available at http://localhost:8080/metrics:

• http_requests_total
• build_duration_seconds
• build_errors_total
• sandbox_idle
• active_sessions
• debug_command_duration_seconds

Future Improvements

• Multi‑file programs – Allow uploading multiple .go files. (or txtar format).
• Rate limiting – Per‑IP limits on build requests and debug commands.
• Improved frontend - Current frontend uses pure js and therefore hard to mantain