feat: Implement multi-node support with MQTT and mDNS for service discovery and coordination

castle-api/src/castle_api/nodes.py

@@ -0,0 +1,115 @@
+"""Nodes router — discover and inspect mesh nodes."""
+
+from __future__ import annotations
+
+from fastapi import APIRouter, HTTPException, Request, status
+
+from castle_api.config import get_registry, settings
+from castle_api.mesh import mesh_state
+from castle_api.models import ComponentSummary, MeshStatus, NodeDetail, NodeSummary
+
+router = APIRouter(tags=["nodes"])
+
+
+def _local_node_summary(registry: object) -> NodeSummary:
+    """Build a NodeSummary for the local node from the registry."""
+    return NodeSummary(
+        hostname=registry.node.hostname,
+        gateway_port=registry.node.gateway_port,
+        deployed_count=len(registry.deployed),
+        service_count=sum(1 for d in registry.deployed.values() if d.port is not None),
+        is_local=True,
+        online=True,
+        is_stale=False,
+    )
+
+
+def _remote_node_summary(hostname: str, remote: object) -> NodeSummary:
+    """Build a NodeSummary from a RemoteNode."""
+    reg = remote.registry
+    return NodeSummary(
+        hostname=hostname,
+        gateway_port=reg.node.gateway_port,
+        deployed_count=len(reg.deployed),
+        service_count=sum(1 for d in reg.deployed.values() if d.port is not None),
+        is_local=False,
+        online=remote.online,
+        is_stale=remote.is_stale,
+        last_seen=remote.last_seen,
+    )
+
+
+def _deployed_to_summaries(registry: object, hostname: str) -> list[ComponentSummary]:
+    """Convert deployed components from a registry into ComponentSummary list."""
+    summaries = []
+    for name, d in registry.deployed.items():
+        summaries.append(
+            ComponentSummary(
+                id=name,
+                description=d.description,
+                category=d.category,
+                runner=d.runner,
+                port=d.port,
+                health_path=d.health_path,
+                proxy_path=d.proxy_path,
+                managed=d.managed,
+                schedule=d.schedule,
+                node=hostname,
+            )
+        )
+    return summaries
+
+
+@router.get("/mesh/status", response_model=MeshStatus)
+def get_mesh_status(request: Request) -> MeshStatus:
+    """Get the current state of the mesh coordination layer."""
+    mqtt_client = getattr(request.app.state, "mqtt_client", None)
+    mdns = getattr(request.app.state, "mdns", None)
+
+    peers = list(mesh_state.all_nodes(include_stale=True).keys())
+
+    return MeshStatus(
+        enabled=settings.mqtt_enabled,
+        mqtt_connected=mqtt_client.connected if mqtt_client else False,
+        mqtt_broker_host=mqtt_client.broker_host if mqtt_client else None,
+        mqtt_broker_port=mqtt_client.broker_port if mqtt_client else None,
+        mdns_enabled=settings.mdns_enabled,
+        peer_count=len(peers),
+        peers=peers,
+    )
+
+
+@router.get("/nodes", response_model=list[NodeSummary])
+def list_nodes() -> list[NodeSummary]:
+    """List all known nodes (local + discovered remote)."""
+    registry = get_registry()
+    nodes = [_local_node_summary(registry)]
+
+    for hostname, remote in mesh_state.all_nodes(include_stale=True).items():
+        nodes.append(_remote_node_summary(hostname, remote))
+
+    return nodes
+
+
+@router.get("/nodes/{hostname}", response_model=NodeDetail)
+def get_node(hostname: str) -> NodeDetail:
+    """Get detailed info for a specific node."""
+    registry = get_registry()
+
+    # Local node
+    if hostname == registry.node.hostname:
+        summary = _local_node_summary(registry)
+        deployed = _deployed_to_summaries(registry, hostname)
+        return NodeDetail(**summary.model_dump(), deployed=deployed)
+
+    # Remote node
+    remote = mesh_state.get_node(hostname)
+    if remote is None:
+        raise HTTPException(
+            status_code=status.HTTP_404_NOT_FOUND,
+            detail=f"Node '{hostname}' not found",
+        )
+
+    summary = _remote_node_summary(hostname, remote)
+    deployed = _deployed_to_summaries(remote.registry, hostname)
+    return NodeDetail(**summary.model_dump(), deployed=deployed)