snapshot of https://github.com/ThreeDotsLabs/watermill.git (master, 2026-09-15; blobs > 131072B omitted)

components/metrics/labels.go

@@ -0,0 +1,75 @@
+package metrics
+
+import (
+	"context"
+
+	"github.com/ThreeDotsLabs/watermill/message"
+
+	"github.com/prometheus/client_golang/prometheus"
+)
+
+const (
+	labelKeyHandlerName    = "handler_name"
+	labelKeyPublisherName  = "publisher_name"
+	labelKeySubscriberName = "subscriber_name"
+	labelSuccess           = "success"
+	labelAcked             = "acked"
+
+	labelValueNoHandler = "<no handler>"
+)
+
+var (
+	labelGetters = map[string]func(context.Context) string{
+		labelKeyHandlerName:    message.HandlerNameFromCtx,
+		labelKeyPublisherName:  message.PublisherNameFromCtx,
+		labelKeySubscriberName: message.SubscriberNameFromCtx,
+	}
+)
+
+func labelsFromCtx(ctx context.Context, labels ...string) prometheus.Labels {
+	ctxLabels := map[string]string{}
+
+	for _, l := range labels {
+		k := l
+		ctxLabels[l] = ""
+
+		getter, ok := labelGetters[k]
+		if !ok {
+			continue
+		}
+
+		v := getter(ctx)
+		if v != "" {
+			ctxLabels[l] = v
+		}
+	}
+
+	return ctxLabels
+}
+
+type LabelComputeValueFn func(msgCtx context.Context) string
+
+type MetricLabel struct {
+	Label          string
+	ComputeValueFn LabelComputeValueFn
+}
+
+func toLabelsSlice(baseLabels []string, customs []MetricLabel) []string {
+	labels := make([]string, len(baseLabels), len(baseLabels)+len(customs))
+	copy(labels, baseLabels)
+	for _, label := range customs {
+		//Check if the additional label is already in the base labels. We cannot have duplicate labels
+		//If it's in the base, just skip it as the compute function is going to overwrite the default value
+		contains := false
+		for _, baseLabel := range baseLabels {
+			if baseLabel == label.Label {
+				contains = true
+				break
+			}
+		}
+		if !contains {
+			labels = append(labels, label.Label)
+		}
+	}
+	return labels
+}