Set dedup and pushback labels on all add metrics (transparency-dev#598)

Author: AlCutter

append_lifecycle.go

@@ -334,22 +334,24 @@ func (i *integrationStats) statsDecorator(delegate AddFn) AddFn {
 			idx, err := f()
 			attr := []attribute.KeyValue{}
 			if err != nil {
-				if err == ErrPushback {
-					attr = append(attr, attribute.Bool("tessera.pushback", true))
-				} else {
+				if err != ErrPushback {
 					// Just flag that it's an errored request to avoid high cardinality of attribute values.
 					// TODO(al): We might want to bucket errors into OTel status codes in the future, though.
 					attr = append(attr, attribute.String("tessera.error.type", "_OTHER"))
 				}
 			}
-			if idx.IsDup {
-				attr = append(attr, attribute.Bool("tessera.duplicate", true))
-			} else {
-				i.sample(idx.Index)
-			}
+
+			attr = append(attr, attribute.Bool("tessera.pushback", err == ErrPushback))
+			attr = append(attr, attribute.Bool("tessera.duplicate", idx.IsDup))
+
 			appenderAddsTotal.Add(ctx, 1, metric.WithAttributes(attr...))
 			d := time.Since(start)
 			appenderAddHistogram.Record(ctx, d.Milliseconds(), metric.WithAttributes(attr...))
+
+			if !idx.IsDup {
+				i.sample(idx.Index)
+			}
+
 			return idx, err
 		}
 	}