Mathieu Virbel
da3a2ac3a4
Rebrand the project from Fence to Greywall, the sandboxing layer of the GreyHaven platform. This updates: - Go module path to gitea.app.monadical.io/monadical/greywall - Binary name, CLI help text, and all usage examples - Config paths (~/.config/greywall/greywall.json), env vars (GREYWALL_*) - Log prefixes ([greywall:*]), temp file prefixes (greywall-*) - All documentation, scripts, CI workflows, and example files - README rewritten with GreyHaven branding and Fence attribution Directory/file renames: cmd/fence → cmd/greywall, pkg/fence → pkg/greywall, docs/why-fence.md → docs/why-greywall.md, example JSON files, and banner.
2.3 KiB
Dev Server + Redis Demo
This demo shows how greywall controls network access: allowing specific external domains while blocking (or allowing) localhost connections.
Prerequisites
You need Redis running on localhost:6379:
docker run -p 6379:6379 redis:alpine
Install
npm install
Demo 1: Localhost allowed, external blocked
This shows that requests to Redis (local service) works, but external requests are blocked.
greywall -p 3000 --settings greywall-external-blocked.json npm start
Test it:
# Works - localhost outbound to Redis allowed
curl http://localhost:3000/api/users
# Blocked - no domains whitelisted for external requests
curl http://localhost:3000/api/external
Demo 2: External Allowed, Localhost Blocked
This shows the opposite: whitelisted external domains work, but Redis (localhost) is blocked.
greywall -p 3000 --settings greywall-external-only.json npm start
You will immediately notice that Redis connection is blocked on app startup:
[app] Redis connection failed: connect EPERM 127.0.0.1:6379 - Local (0.0.0.0:0)
Test it:
# Works - httpbin.org is in the allowlist
curl http://localhost:3000/api/external
# Blocked - localhost outbound to Redis not allowed
curl http://localhost:3000/api/users
Summary
| Config | Redis (localhost) | External (httpbin.org) |
|---|---|---|
greywall-external-blocked.json |
✓ Allowed | ✗ Blocked |
greywall-external-only.json |
✗ Blocked | ✓ Allowed |
Key Settings
| Setting | Purpose |
|---|---|
allowLocalBinding |
Server can listen on ports |
allowLocalOutbound |
App can connect to localhost services |
allowedDomains |
Whitelist of external domains |
Note: Node.js Proxy Support
Node.js's native http/https modules don't respect proxy environment variables. This demo uses undici with ProxyAgent to route requests through greywall's proxy:
import { ProxyAgent, fetch } from "undici";
const proxyUrl = process.env.HTTPS_PROXY;
const response = await fetch(url, {
dispatcher: new ProxyAgent(proxyUrl),
});
Without this, external HTTP requests would fail with connection errors (the sandbox blocks them) rather than going through greywall's proxy.