feat: labels map en config (role) → extra_label en métricas + stream labels en logs

config.go

@@ -16,6 +16,9 @@ type Config struct {
 	User        string `json:"user"`         // basic-auth user, shared by metrics and logs (empty disables auth)
 	Pass        string `json:"pass"`         // basic-auth password
 	IntervalSec int    `json:"interval_sec"` // metrics push period in seconds (default 15)
+	// Extra labels attached to every metric series and log stream of this node,
+	// e.g. {"role": "vps"}. Enables filtering in Grafana (per-role dashboards).
+	Labels map[string]string `json:"labels"`
 	// Android/Termux exec workaround: the standard Go binary cannot exec
 	// subprocesses there (seccomp blocks pidfd_open with SIGSYS). When set, the
 	// agent reads battery JSON from this file (written by a shell helper) instead
@@ -81,3 +84,17 @@ func loadConfig(path string) (Config, error) {
 	}
 	return cfg, nil
 }
+
+// extraLabels returns the labels attached to every series/stream: the node's
+// instance plus any custom labels (e.g. role). The optional extra map is merged
+// last (used to add per-stream labels like job/unit for logs).
+func (cfg Config) extraLabels(extra map[string]string) map[string]string {
+	m := map[string]string{"instance": cfg.Node}
+	for k, v := range cfg.Labels {
+		m[k] = v
+	}
+	for k, v := range extra {
+		m[k] = v
+	}
+	return m
+}