Read-Only State Endpoints

[antoncxx]

Summary

Adds five read-only HTTP endpoints to the control plane server, exposing the full in-memory state to clients over the existing port 8080 server introduced in PR 1. No new logic is introduced — this is serialisation and routing only.

Endpoints

Method	Path	Description
GET	/api/services	All services: registered status, replica addresses and ports, active session counts, proxy dependencies, trigger chains, timeout, max_networks
GET	/api/nodes	Connected agent nodes: IP address and list of hosted services
GET	/api/pool	Net ID pool: total capacity, IDs in use, IDs free
GET	/api/config	Raw services.toml as text/plain
GET	/api/graph	Live topology graph as JSON (nodes + edges)

/api/graph response shape

{
  "nodes": [
    {
      "id": "color.com",
      "registered": true,
      "entry_point": true,
      "replica_count": 1,
      "active_replica_count": 1
    }
  ],
  "edges": [
    {
      "from": "color.com",
      "to": "fs.color.com",
      "net_id": 101,
      "setup_ms": 23
    },
    {
      "from": "10.0.0.50",
      "via_proxy": "10.0.0.10",
      "to": "color.com",
      "net_id": 102,
      "setup_ms": 15
    }
  ]
}

via_proxy is omitted on service-to-service edges.

Changes

http_server — split into a module

http_server.rs is replaced by http_server/ with one file per handler:

http_server/
├── mod.rs          — AppState, serve(), route table
├── health.rs       — GET /api/health (unchanged)
├── services.rs     — GET /api/services
├── nodes.rs        — GET /api/nodes
├── pool.rs         — GET /api/pool
├── config.rs       — GET /api/config
├── graph.rs        — GET /api/graph
└── static_files.rs — SPA fallback

AppState (holding Arc<RwLock<HashMap<String, ServiceInfo>>> and Orchestrator) is passed into serve() from main.rs and threaded to handlers via axum State.

graphviz.rs

• Extracts shared initiators() helper (previously inlined in render_graphviz)
• Adds render_graph_json() returning a serialisable GraphJson struct; both renderers use the same active-replica logic via the shared helper

orchestrator.rs

• connected_node_ips() — returns IPs of all nodes with an active control channel
• pool_stats() — delegates to NetIdPool::stats()

net_id_pool.rs

• stats() — returns (total_capacity, in_use, free) as a tuple
• 5 new unit tests covering fresh pool state, allocation accounting, free accounting, exhaustion, and the total == in_use + free invariant

nullnet_grpc_impl.rs

• services() and orchestrator() accessors promoted from #[cfg(test)] to always-available so main.rs can extract shared state refs before handing the struct to tonic

[GyulyVGC]

minor, not needed to fix now but IIRC IP data structures implement Copy so no need to clone them. I'm just doing a static review so no 100% sure but this may become a .copied()

[GyulyVGC]

ok for now but maybe consider computing free client-side to simplify this method's signature

[GyulyVGC]

let's try not to use any unwrap going forward. when not possible to handle error in any way, use expect.

[GyulyVGC]

@antoncxx merged but left some minor comments for you to later fix.

Another tip: to visually test if your graphs are correct, you can run tests against the service files I have in the test directory, and see if they look consistent (in their nodes / edges / labels representation) to the corresponding graphviz files, always in the test dir