From 628ae67b7def027553c287cfd71f840570469bce Mon Sep 17 00:00:00 2001
From: Damocles <damocles@darkest.space>
Date: Thu, 7 May 2026 21:36:58 +0200
Subject: [PATCH] systemd: hm-module systemd.machines option + warn on fetch
 failures

---
 nix/hm-module.nix             | 20 ++++++++++++++++++++
 plugin/src/systemd_service.rs | 14 +++++++++++---
 2 files changed, 31 insertions(+), 3 deletions(-)

diff --git a/nix/hm-module.nix b/nix/hm-module.nix
index 51758cf..b73bdc4 100644
--- a/nix/hm-module.nix
+++ b/nix/hm-module.nix
@@ -240,6 +240,26 @@ in
             };
           };
         };
+        systemd = moduleOpt "systemd" (
+          (intervalOpt 15000)
+          // {
+            machines = lib.mkOption {
+              type = lib.types.listOf lib.types.str;
+              default = [ ];
+              example = [
+                "muede-pc2"
+                "monitoring@server.example.com"
+              ];
+              description = ''
+                SSH targets to query via `busctl --host=<target>` for the
+                systemd applet's cross-machine tree. May include `localhost` /
+                the local hostname; duplicates are deduped at runtime. SSH
+                auth (keys, known_hosts, ssh config aliases) is the user's
+                responsibility - nova-shell only spawns busctl.
+              '';
+            };
+          }
+        );
         statsDaemon = lib.mkOption {
           default = { };
           description = "Configuration for the nova-stats daemon.";
diff --git a/plugin/src/systemd_service.rs b/plugin/src/systemd_service.rs
index 4b55cb0..1479b56 100644
--- a/plugin/src/systemd_service.rs
+++ b/plugin/src/systemd_service.rs
@@ -486,8 +486,12 @@ impl qobject::SystemdService {
             local_container_names
                 .iter()
                 .map(|(name, _, _)| {
-                    fetch_via_busctl(name, &["--machine", name], false, "")
-                        .unwrap_or_else(|(k, r)| MachineJson::errored(name.clone(), k, r, 0))
+                    fetch_via_busctl(name, &["--machine", name], false, "").unwrap_or_else(
+                        |(k, r)| {
+                            tracing::warn!(target: "nova_plugin::systemd", machine = %name, kind = k, error = %r, "local container fetch failed");
+                            MachineJson::errored(name.clone(), k, r, 0)
+                        },
+                    )
                 })
                 .collect()
         } else {
@@ -555,12 +559,16 @@ impl qobject::SystemdService {
                                     false,
                                     "",
                                 )
-                                .unwrap_or_else(|(k, r)| MachineJson::errored(cn.clone(), k, r, 0))
+                                .unwrap_or_else(|(k, r)| {
+                                    tracing::warn!(target: "nova_plugin::systemd", host = %target, machine = %cn, kind = k, error = %r, "remote container fetch failed");
+                                    MachineJson::errored(cn.clone(), k, r, 0)
+                                })
                             })
                             .collect();
                         m
                     }
                     Err((kind, reason)) => {
+                        tracing::warn!(target: "nova_plugin::systemd", host = %target, kind = kind, error = %reason, "remote host fetch failed");
                         MachineJson::errored(target.clone(), kind, reason, prev_last_seen)
                     }
                 };