Configuration

Environment Variables

Backend (mpi-master / mpi-worker)

Variable	Default	Description
NODE_ROLE	master	Set to "master" or "worker" to control startup behavior
ROCKET_ADDRESS	0.0.0.0	Bind address for the HTTP server
ROCKET_PORT	8000	HTTP server port
RUST_LOG	info	Log level (trace, debug, info, warn, error)

Frontend Build Arguments

Argument	Default	Description
VITE_API_BASE	http://localhost:8000	Backend API base URL — baked into the JS bundle at build time

Build-time variable

VITE_API_BASE is baked into the JavaScript bundle during pnpm build. To change the API URL, you must rebuild the frontend image. It cannot be changed at runtime.

MPI Hostfile

The MPI hostfile (/etc/mpi/hostfile) tells the master which hosts to include in the MPI world:

172.28.1.2 slots=1    # mpi-master
172.28.1.3 slots=1    # mpi-worker

Each slots=N entry controls how many MPI ranks run on that host. With the default hostfile, the world size is 2 (1 master + 1 worker).

Rocket Configuration (Rocket.toml)

[release]
address = "0.0.0.0"
port = 8000
workers = 4
keep_alive = 5
log_level = "normal"

[release.limits]
file = "500MiB"
forms = "512MiB"

The file and forms limits control the maximum upload size. Default 500MiB handles most graph files. Adjust if you need larger uploads.

Vite Configuration

Key settings in vite.config.ts:

export default defineConfig({
  plugins: [
    react(),
    wasm(),            // vite-plugin-wasm for main bundle
    topLevelAwait(),   // required for WASM top-level await
  ],
  worker: {
    format: 'es',      // ES module format required for WASM in workers
    plugins: () => [wasm()],
  },
  server: {
    proxy: {
      '/api': {
        target: process.env.VITE_API_BASE || 'http://localhost:8000',
        changeOrigin: true,
      },
    },
  },
});

Docker Network

The mpi-network bridge uses the 172.28.1.0/24 subnet with static IPs:

Container	IP
mpi-master	172.28.1.2
mpi-worker	172.28.1.3

Static IPs are required for MPI — the master must know the worker's address at launch time to build the MPI world.

Deploying with a Different Backend URL

If deploying the frontend to a CDN or separate host:

docker build ./frontend \
  --build-arg VITE_API_BASE=https://api.yourdomain.com \
  -t distributed-graph-frontend:latest

Ensure the backend has CORS configured to allow the frontend origin. The backend's CORS handler allows all origins by default via the OPTIONS /* handler.