support series relabeling on Thanos receiver

CHANGELOG.md

@@ -17,6 +17,7 @@ We use *breaking :warning:* to mark changes that are not backward compatible (re
 ### Added
 
 - [#5352](https://github.com/thanos-io/thanos/pull/5352) Cache: Add cache metrics to groupcache.
+- [#5391](https://github.com/thanos-io/thanos/pull/5391) Receive: Add relabeling support.
 
 ### Changed
 

cmd/thanos/receive.go

@@ -22,7 +22,9 @@ import (
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/common/model"
 	"github.com/prometheus/prometheus/model/labels"
+	"github.com/prometheus/prometheus/model/relabel"
 	"github.com/prometheus/prometheus/tsdb"
+	"gopkg.in/yaml.v2"
 
 	"github.com/thanos-io/thanos/pkg/block/metadata"
 	"github.com/thanos-io/thanos/pkg/component"
@@ -173,6 +175,15 @@ func runReceive(
 		return errors.Wrapf(err, "migrate legacy storage in %v to default tenant %v", conf.dataDir, conf.defaultTenantID)
 	}
 
+	relabelContentYaml, err := conf.relabelConfigPath.Content()
+	if err != nil {
+		return errors.Wrap(err, "get content of relabel configuration")
+	}
+	var relabelConfig []*relabel.Config
+	if err := yaml.Unmarshal(relabelContentYaml, &relabelConfig); err != nil {
+		return errors.Wrap(err, "parsing relabel configuration")
+	}
+
 	dbs := receive.NewMultiTSDB(
 		conf.dataDir,
 		logger,
@@ -194,6 +205,7 @@ func runReceive(
 		DefaultTenantID:   conf.defaultTenantID,
 		ReplicaHeader:     conf.replicaHeader,
 		ReplicationFactor: conf.replicationFactor,
+		RelabelConfigs:    relabelConfig,
 		ReceiverMode:      receiveMode,
 		Tracer:            tracer,
 		TLSConfig:         rwTLSConfig,
@@ -729,7 +741,8 @@ type receiveConfig struct {
 	ignoreBlockSize       bool
 	allowOutOfOrderUpload bool
 
-	reqLogConfig *extflag.PathOrContent
+	reqLogConfig      *extflag.PathOrContent
+	relabelConfigPath *extflag.PathOrContent
 }
 
 func (rc *receiveConfig) registerFlag(cmd extkingpin.FlagClause) {
@@ -783,6 +796,8 @@ func (rc *receiveConfig) registerFlag(cmd extkingpin.FlagClause) {
 
 	rc.forwardTimeout = extkingpin.ModelDuration(cmd.Flag("receive-forward-timeout", "Timeout for each forward request.").Default("5s").Hidden())
 
+	rc.relabelConfigPath = extflag.RegisterPathOrContent(cmd, "receive.relabel-config", "YAML file that contains relabelling configuration.", extflag.WithEnvSubstitution())
+
 	rc.tsdbMinBlockDuration = extkingpin.ModelDuration(cmd.Flag("tsdb.min-block-duration", "Min duration for local TSDB blocks").Default("2h").Hidden())
 
 	rc.tsdbMaxBlockDuration = extkingpin.ModelDuration(cmd.Flag("tsdb.max-block-duration", "Max duration for local TSDB blocks").Default("2h").Hidden())

docs/components/receive.md

@@ -140,6 +140,13 @@ Flags:
                                  configuration. If it's empty AND hashring
                                  configuration was provided, it means that
                                  receive will run in RoutingOnly mode.
+      --receive.relabel-config=<content>
+                                 Alternative to 'receive.relabel-config-file'
+                                 flag (mutually exclusive). Content of YAML file
+                                 that contains relabelling configuration.
+      --receive.relabel-config-file=<file-path>
+                                 Path to YAML file that contains relabelling
+                                 configuration.
       --receive.replica-header="THANOS-REPLICA"
                                  HTTP header specifying the replica number of a
                                  write request.

pkg/receive/handler.go

@@ -28,6 +28,7 @@ import (
 	"github.com/prometheus/client_golang/prometheus"
 	"github.com/prometheus/client_golang/prometheus/promauto"
 	"github.com/prometheus/common/route"
+	"github.com/prometheus/prometheus/model/relabel"
 	"github.com/prometheus/prometheus/storage"
 	"github.com/prometheus/prometheus/tsdb"
 	"google.golang.org/grpc"
@@ -38,6 +39,7 @@ import (
 	extpromhttp "github.com/thanos-io/thanos/pkg/extprom/http"
 	"github.com/thanos-io/thanos/pkg/runutil"
 	"github.com/thanos-io/thanos/pkg/server/http/middleware"
+	"github.com/thanos-io/thanos/pkg/store/labelpb"
 	"github.com/thanos-io/thanos/pkg/store/storepb"
 	"github.com/thanos-io/thanos/pkg/store/storepb/prompb"
 	"github.com/thanos-io/thanos/pkg/tracing"
@@ -81,6 +83,7 @@ type Options struct {
 	TLSConfig         *tls.Config
 	DialOpts          []grpc.DialOption
 	ForwardTimeout    time.Duration
+	RelabelConfigs    []*relabel.Config
 }
 
 // Handler serves a Prometheus remote write receiving HTTP endpoint.
@@ -353,6 +356,13 @@ func (h *Handler) receiveHTTP(w http.ResponseWriter, r *http.Request) {
 		return
 	}
 
+	// Apply relabeling configs.
+	h.relabel(&wreq)
+	if len(wreq.Timeseries) == 0 {
+		level.Debug(tLogger).Log("msg", "remote write request dropped due to relabeling.")
+		return
+	}
+
 	err = h.handleRequest(ctx, rep, tenant, &wreq)
 	if err != nil {
 		level.Debug(tLogger).Log("msg", "failed to handle request", "err", err)
@@ -682,6 +692,22 @@ func (h *Handler) RemoteWrite(ctx context.Context, r *storepb.WriteRequest) (*st
 	}
 }
 
+// relabel relabels the time series labels in the remote write request.
+func (h *Handler) relabel(wreq *prompb.WriteRequest) {
+	if len(h.options.RelabelConfigs) > 0 {
+		timeSeries := make([]prompb.TimeSeries, 0, len(wreq.Timeseries))
+		for _, ts := range wreq.Timeseries {
+			lbls := relabel.Process(labelpb.ZLabelsToPromLabels(ts.Labels), h.options.RelabelConfigs...)
+			if lbls == nil {
+				continue
+			}
+			ts.Labels = labelpb.ZLabelsFromPromLabels(lbls)
+			timeSeries = append(timeSeries, ts)
+		}
+		wreq.Timeseries = timeSeries
+	}
+}
+
 // isConflict returns whether or not the given error represents a conflict.
 func isConflict(err error) bool {
 	if err == nil {