feat(lokiunifi): add extra_labels config for custom Loki stream labels (#691) (#973)

Add an ExtraLabels map[string]string field to the Loki Config struct so
users can define static key=value labels that are merged into the stream
labels of every log line sent to Loki. This allows users to distinguish
streams (e.g., by environment or datacenter) without hardcoding values.

Built-in dynamic labels (application, site_name, source, etc.) always
take precedence over extra labels to preserve existing behavior.

Example config (TOML):
  [loki.extra_labels]
  environment = "production"
  datacenter  = "us-east-1"

Closes #691

Co-authored-by: Claude Sonnet 4.6 (1M context) <noreply@anthropic.com>

pkg/lokiunifi/loki.go

@@ -36,6 +36,7 @@ type Config struct {
 	TenantID  string        `json:"tenant_id"  toml:"tenant_id"  xml:"tenant_id"  yaml:"tenant_id"`
 	Interval    cnfg.Duration     `json:"interval"      toml:"interval"      xml:"interval"      yaml:"interval"`
 	Timeout     cnfg.Duration     `json:"timeout"       toml:"timeout"       xml:"timeout"       yaml:"timeout"`
+	ExtraLabels map[string]string `json:"extra_labels"  toml:"extra_labels"  xml:"extra_labels"  yaml:"extra_labels"`
 }
 
 // Loki is the main library struct. This satisfies the poller.Output interface.

pkg/lokiunifi/report.go

@@ -26,6 +26,7 @@ type Report struct {
 	Start       time.Time
 	Oldest      time.Time
 	Collect     poller.Collect
+	ExtraLabels map[string]string
 	poller.Logger
 	Counts map[string]int
 }
@@ -36,6 +37,7 @@ func (l *Loki) NewReport(start time.Time) *Report {
 		Start:       start,
 		Oldest:      l.last,
 		Collect:     l.Collect,
+		ExtraLabels: l.ExtraLabels,
 		Logger:      l,
 		Counts:      make(map[string]int),
 	}
@@ -95,3 +97,14 @@ func CleanLabels(labels map[string]string) map[string]string {
 
 	return labels
 }
+
+// MergeLabels merges extra into labels. Keys already present in labels are not overwritten.
+func MergeLabels(labels, extra map[string]string) map[string]string {
+	for k, v := range extra {
+		if _, exists := labels[k]; !exists {
+			labels[k] = v
+		}
+	}
+
+	return labels
+}

pkg/lokiunifi/report_alarm.go

@@ -26,10 +26,10 @@ func (r *Report) Alarm(event *unifi.Alarm, logs *Logs) {
 
 	logs.Streams = append(logs.Streams, LogStream{
 		Entries: [][]string{{strconv.FormatInt(event.Datetime.UnixNano(), 10), string(msg)}},
-		Labels: CleanLabels(map[string]string{
+		Labels: CleanLabels(MergeLabels(map[string]string{
 			"application": "unifi_alarm",
 			"source":      event.SourceName,
 			"site_name":   event.SiteName,
-		}),
+		}, r.ExtraLabels)),
 	})
 }

pkg/lokiunifi/report_anomaly.go

@@ -26,10 +26,10 @@ func (r *Report) Anomaly(event *unifi.Anomaly, logs *Logs) {
 
 	logs.Streams = append(logs.Streams, LogStream{
 		Entries: [][]string{{strconv.FormatInt(event.Datetime.UnixNano(), 10), string(msg)}},
-		Labels: CleanLabels(map[string]string{
+		Labels: CleanLabels(MergeLabels(map[string]string{
 			"application": "unifi_anomaly",
 			"source":      event.SourceName,
 			"site_name":   event.SiteName,
-		}),
+		}, r.ExtraLabels)),
 	})
 }

pkg/lokiunifi/report_event.go

@@ -27,11 +27,11 @@ func (r *Report) Event(event *unifi.Event, logs *Logs) {
 
 	logs.Streams = append(logs.Streams, LogStream{
 		Entries: [][]string{{strconv.FormatInt(event.Datetime.UnixNano(), 10), string(msg)}},
-		Labels: CleanLabels(map[string]string{
+		Labels: CleanLabels(MergeLabels(map[string]string{
 			"application": "unifi_event",
 			"site_name":   event.SiteName,
 			"source":      event.SourceName,
-		}),
+		}, r.ExtraLabels)),
 	})
 }
 
@@ -52,12 +52,12 @@ func (r *Report) SystemLogEvent(event *unifi.SystemLogEntry, logs *Logs) {
 
 	logs.Streams = append(logs.Streams, LogStream{
 		Entries: [][]string{{strconv.FormatInt(event.Datetime().UnixNano(), 10), string(msg)}},
-		Labels: CleanLabels(map[string]string{
+		Labels: CleanLabels(MergeLabels(map[string]string{
 			"application": "unifi_system_log",
 			"site_name":   event.SiteName,
 			"source":      event.SourceName,
 			"category":    event.Category,
 			"severity":    event.Severity,
-		}),
+		}, r.ExtraLabels)),
 	})
 }

pkg/lokiunifi/report_ids.go

@@ -26,10 +26,10 @@ func (r *Report) IDs(event *unifi.IDS, logs *Logs) {
 
 	logs.Streams = append(logs.Streams, LogStream{
 		Entries: [][]string{{strconv.FormatInt(event.Datetime.UnixNano(), 10), string(msg)}},
-		Labels: CleanLabels(map[string]string{
+		Labels: CleanLabels(MergeLabels(map[string]string{
 			"application": "unifi_ids",
 			"source":      event.SourceName,
 			"site_name":   event.SiteName,
-		}),
+		}, r.ExtraLabels)),
 	})
 }

pkg/lokiunifi/report_protect.go

@@ -34,14 +34,14 @@ func (r *Report) ProtectLogEvent(event *unifi.ProtectLogEntry, logs *Logs) {
 	// Add event log line
 	logs.Streams = append(logs.Streams, LogStream{
 		Entries: [][]string{{strconv.FormatInt(event.Datetime().UnixNano(), 10), string(msg)}},
-		Labels: CleanLabels(map[string]string{
+		Labels: CleanLabels(MergeLabels(map[string]string{
 			"application": "unifi_protect_log",
 			"source":      event.SourceName,
 			"event_type":  event.GetEventType(),
 			"category":    event.GetCategory(),
 			"severity":    event.GetSeverity(),
 			"camera":      event.Camera,
-		}),
+		}, r.ExtraLabels)),
 	})
 
 	// Add thumbnail as separate log line if present
@@ -57,12 +57,12 @@ func (r *Report) ProtectLogEvent(event *unifi.ProtectLogEntry, logs *Logs) {
 		// Use timestamp + 1 nanosecond to ensure ordering (thumbnail after event)
 		logs.Streams = append(logs.Streams, LogStream{
 			Entries: [][]string{{strconv.FormatInt(event.Datetime().UnixNano()+1, 10), string(thumbnailJSON)}},
-			Labels: CleanLabels(map[string]string{
+			Labels: CleanLabels(MergeLabels(map[string]string{
 				"application": "unifi_protect_thumbnail",
 				"source":      event.SourceName,
 				"event_id":    event.ID,
 				"camera":      event.Camera,
-			}),
+			}, r.ExtraLabels)),
 		})
 	}
 }