Attach global labels to remote storage samples

cmd/prometheus/main.go

@@ -57,6 +57,8 @@ func Main() int {
 		return 0
 	}
 
+	var reloadables []Reloadable
+
 	var (
 		memStorage     = local.NewMemorySeriesStorage(&cfg.storage)
 		remoteStorage  = remote.New(&cfg.remote)
@@ -64,6 +66,7 @@ func Main() int {
 	)
 	if remoteStorage != nil {
 		sampleAppender = append(sampleAppender, remoteStorage)
+		reloadables = append(reloadables, remoteStorage)
 	}
 
 	var (
@@ -93,7 +96,7 @@ func Main() int {
 
 	webHandler := web.New(memStorage, queryEngine, ruleManager, status, &cfg.web)
 
-	reloadables := []Reloadable{status, targetManager, ruleManager, webHandler, notificationHandler}
+	reloadables = append(reloadables, status, targetManager, ruleManager, webHandler, notificationHandler)
 
 	if !reloadConfig(cfg.configFile, reloadables...) {
 		return 1

storage/remote/remote.go

@@ -14,11 +14,13 @@
 package remote
 
 import (
+	"sync"
 	"time"
 
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/common/model"
 
+	"github.com/prometheus/prometheus/config"
 	"github.com/prometheus/prometheus/storage/remote/influxdb"
 	"github.com/prometheus/prometheus/storage/remote/opentsdb"
 )
@@ -26,6 +28,18 @@ import (
 // Storage collects multiple remote storage queues.
 type Storage struct {
 	queues       []*StorageQueueManager
+	globalLabels model.LabelSet
+	mtx          sync.RWMutex
+}
+
+// ApplyConfig updates the status state as the new config requires.
+// Returns true on success.
+func (s *Storage) ApplyConfig(conf *config.Config) bool {
+	s.mtx.Lock()
+	defer s.mtx.Unlock()
+
+	s.globalLabels = conf.GlobalConfig.Labels
+	return true
 }
 
 // New returns a new remote Storage.
@@ -70,8 +84,21 @@ func (s *Storage) Stop() {
 
 // Append implements storage.SampleAppender.
 func (s *Storage) Append(smpl *model.Sample) {
+	s.mtx.RLock()
+
+	var snew model.Sample
+	snew = *smpl
+	snew.Metric = smpl.Metric.Clone()
+
+	for ln, lv := range s.globalLabels {
+		if _, ok := smpl.Metric[ln]; !ok {
+			snew.Metric[ln] = lv
+		}
+	}
+	s.mtx.RUnlock()
+
 	for _, q := range s.queues {
-		q.Append(smpl)
+		q.Append(&snew)
 	}
 }