Harden dashboard IPC socket path with parent dir creation and demo-friendly defaults

- Ensure parent directory exists before binding dashboard IPC listener
- Switch demo config socket paths from /run/rust-supervisor/ to /tmp/rust-supervisor-demo/
- Change bind_mode from create_new to replace_stale for demo resilience

Author: developerworks

examples/config/supervisor.template.yaml

@@ -31,12 +31,12 @@ observability:
 ipc:
   enabled: false
   target_id: example-target
-  path: /run/rust-supervisor/example-target.sock
+  path: /tmp/rust-supervisor-demo/example-target.sock
   permissions: "0600"
-  bind_mode: create_new
+  bind_mode: replace_stale
   registration:
     enabled: false
-    relay_registration_path: /run/rust-supervisor/dashboard-relay-registration.sock
+    relay_registration_path: /tmp/rust-supervisor-demo/dashboard-relay-registration.sock
     display_name: "example target"
     lease_seconds: 30
     registration_heartbeat_interval_seconds: 15

examples/config/supervisor.yaml

@@ -20,12 +20,12 @@ observability:
 ipc:
   enabled: true
   target_id: payments-worker-a
-  path: /run/rust-supervisor/payments-worker-a.sock
+  path: /tmp/rust-supervisor-demo/payments-worker-a.sock
   permissions: "0600"
-  bind_mode: create_new
+  bind_mode: replace_stale
   registration:
     enabled: true
-    relay_registration_path: /run/rust-supervisor/dashboard-relay-registration.sock
+    relay_registration_path: /tmp/rust-supervisor-demo/dashboard-relay-registration.sock
     display_name: "payments worker a"
     lease_seconds: 30
     registration_heartbeat_interval_seconds: 15

src/dashboard/ipc_server.rs

@@ -465,6 +465,18 @@ pub fn bind_dashboard_listener(
     config: &ValidatedDashboardIpcConfig,
 ) -> Result<UnixListener, DashboardError> {
     prepare_socket_path(config)?;
+    // Ensure the parent directory exists before binding.
+    if let Some(parent) = config.path.parent() {
+        std::fs::create_dir_all(parent).map_err(|error| {
+            DashboardError::new(
+                "ipc_parent_dir_creation_failed",
+                "ipc_bind",
+                Some(config.target_id.clone()),
+                format!("failed to create IPC parent directory: {error}"),
+                false,
+            )
+        })?;
+    }
     UnixListener::bind(&config.path).map_err(|error| {
         DashboardError::new(
             "ipc_bind_failed",