otel: add support for per tenant configuration for mapping otlp data …

…to loki format (grafana#11143)

**What this PR does / why we need it**:
In OTEL, we pick select Resource Attributes to identify the streams and
store all the other attributes as Structured Metadata, as explained
here. The problem however is that the list of Resource Attributes that
are picked as Stream labels are hardcoded, and there is no way to drop
unwanted data. This PR adds support for configuring how data is mapped
from OTEL to Loki format per tenant. It also adds support for dropping
unwanted data. We decided to make the config look similar to
Prometheus's relabling config to make it familiar.

**Special notes for your reviewer**:
Opening a draft PR to get some initial feedback. I will add
documentation in a separate PR.

**Checklist**
- [x] Tests updated
- [x] `CHANGELOG.md` updated

CHANGELOG.md

@@ -51,6 +51,7 @@
 * [11654](https://github.com/grafana/loki/pull/11654) **dannykopping** Cache: atomically check background cache size limit correctly.
 * [11682](https://github.com/grafana/loki/pull/11682) **ashwanthgoli** Metadata cache: Adds `frontend.max-metadata-cache-freshness` to configure the time window for which metadata results are not cached. This helps avoid returning inaccurate results by not caching recent results.
 * [11679](https://github.com/grafana/loki/pull/11679) **dannykopping** Cache: extending #11535 to align custom ingester query split with cache keys for correct caching of results.
+* [11143](https://github.com/grafana/loki/pull/11143) **sandeepsukhani** otel: Add support for per tenant configuration for mapping otlp data to loki format
 * [11499](https://github.com/grafana/loki/pull/11284) **jmichalek132** Config: Adds `frontend.log-query-request-headers` to enable logging of request headers in query logs.
 
 ##### Fixes

clients/pkg/promtail/targets/lokipush/pushtarget.go

@@ -111,7 +111,7 @@ func (t *PushTarget) run() error {
 func (t *PushTarget) handleLoki(w http.ResponseWriter, r *http.Request) {
 	logger := util_log.WithContext(r.Context(), util_log.Logger)
 	userID, _ := tenant.TenantID(r.Context())
-	req, err := push.ParseRequest(logger, userID, r, nil, push.ParseLokiRequest)
+	req, err := push.ParseRequest(logger, userID, r, nil, nil, push.ParseLokiRequest)
 	if err != nil {
 		level.Warn(t.logger).Log("msg", "failed to parse incoming push request", "err", err.Error())
 		http.Error(w, err.Error(), http.StatusBadRequest)

docs/sources/configure/_index.md

@@ -3140,6 +3140,17 @@ shard_streams:
 # Maximum number of structured metadata entries per log line.
 # CLI flag: -limits.max-structured-metadata-entries-count
 [max_structured_metadata_entries_count: <int> | default = 128]
+
+# OTLP log ingestion configurations
+otlp_config:
+  resource_attributes:
+    [ignore_defaults: <boolean>]
+
+    [attributes: <list of AttributesConfigs>]
+
+  [scope_attributes: <list of AttributesConfigs>]
+
+  [log_attributes: <list of AttributesConfigs>]
 ```
 
 ### frontend_worker

pkg/distributor/http.go

@@ -34,7 +34,7 @@ func (d *Distributor) pushHandler(w http.ResponseWriter, r *http.Request, pushRe
 		http.Error(w, err.Error(), http.StatusBadRequest)
 		return
 	}
-	req, err := push.ParseRequest(logger, tenantID, r, d.tenantsRetention, pushRequestParser)
+	req, err := push.ParseRequest(logger, tenantID, r, d.tenantsRetention, d.validator.Limits, pushRequestParser)
 	if err != nil {
 		if d.tenantConfigs.LogPushRequest(tenantID) {
 			level.Debug(logger).Log(

pkg/distributor/limits.go

@@ -5,6 +5,7 @@ import (
 
 	"github.com/grafana/loki/pkg/compactor/retention"
 	"github.com/grafana/loki/pkg/distributor/shardstreams"
+	"github.com/grafana/loki/pkg/loghttp/push"
 )
 
 // Limits is an interface for distributor limits/related configs
@@ -29,4 +30,5 @@ type Limits interface {
 	AllowStructuredMetadata(userID string) bool
 	MaxStructuredMetadataSize(userID string) int
 	MaxStructuredMetadataCount(userID string) int
+	OTLPConfig(userID string) push.OTLPConfig
 }

pkg/loghttp/push/otlp.go

@@ -25,28 +25,9 @@ import (
 const (
 	pbContentType       = "application/x-protobuf"
 	gzipContentEncoding = "gzip"
+	attrServiceName     = "service.name"
 )
 
-var blessedAttributes = []string{
-	"service.name",
-	"service.namespace",
-	"service.instance.id",
-	"deployment.environment",
-	"cloud.region",
-	"cloud.availability_zone",
-	"k8s.cluster.name",
-	"k8s.namespace.name",
-	"k8s.pod.name",
-	"k8s.container.name",
-	"container.name",
-	"k8s.replicaset.name",
-	"k8s.deployment.name",
-	"k8s.statefulset.name",
-	"k8s.daemonset.name",
-	"k8s.cronjob.name",
-	"k8s.job.name",
-}
-
 var blessedAttributesNormalized = make([]string, len(blessedAttributes))
 
 func init() {
@@ -62,14 +43,14 @@ func newPushStats() *Stats {
 	}
 }
 
-func ParseOTLPRequest(userID string, r *http.Request, tenantsRetention TenantsRetention) (*logproto.PushRequest, *Stats, error) {
+func ParseOTLPRequest(userID string, r *http.Request, tenantsRetention TenantsRetention, limits Limits) (*logproto.PushRequest, *Stats, error) {
 	stats := newPushStats()
 	otlpLogs, err := extractLogs(r, stats)
 	if err != nil {
 		return nil, nil, err
 	}
 
-	req := otlpToLokiPushRequest(otlpLogs, userID, tenantsRetention, stats)
+	req := otlpToLokiPushRequest(otlpLogs, userID, tenantsRetention, limits.OTLPConfig(userID), stats)
 	return req, stats, nil
 }
 
@@ -120,7 +101,7 @@ func extractLogs(r *http.Request, pushStats *Stats) (plog.Logs, error) {
 	return req.Logs(), nil
 }
 
-func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention TenantsRetention, stats *Stats) *logproto.PushRequest {
+func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention TenantsRetention, otlpConfig OTLPConfig, stats *Stats) *logproto.PushRequest {
 	if ld.LogRecordCount() == 0 {
 		return &logproto.PushRequest{}
 	}
@@ -131,39 +112,38 @@ func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention Tenants
 	for i := 0; i < rls.Len(); i++ {
 		sls := rls.At(i).ScopeLogs()
 		res := rls.At(i).Resource()
+		resAttrs := res.Attributes()
 
-		flattenedResourceAttributes := labels.NewBuilder(logproto.FromLabelAdaptersToLabels(attributesToLabels(res.Attributes(), "")))
-		// service.name is a required Resource Attribute. If it is not present, we will set it to "unknown_service".
-		if flattenedResourceAttributes.Get("service_name") == "" {
-			flattenedResourceAttributes = flattenedResourceAttributes.Set("service_name", "unknown_service")
+		if v, _ := resAttrs.Get(attrServiceName); v.AsString() == "" {
+			resAttrs.PutStr(attrServiceName, "unknown_service")
 		}
+		resourceAttributesAsStructuredMetadata := make(push.LabelsAdapter, 0, resAttrs.Len())
+		streamLabels := make(model.LabelSet, len(blessedAttributesNormalized))
 
-		if dac := res.DroppedAttributesCount(); dac != 0 {
-			flattenedResourceAttributes = flattenedResourceAttributes.Set("resource_dropped_attributes_count", fmt.Sprintf("%d", dac))
-		}
+		resAttrs.Range(func(k string, v pcommon.Value) bool {
+			action := otlpConfig.ActionForResourceAttribute(k)
+			if action == Drop {
+				return true
+			}
 
-		// copy blessed attributes to stream labels
-		streamLabels := make(model.LabelSet, len(blessedAttributesNormalized))
-		for _, ba := range blessedAttributesNormalized {
-			v := flattenedResourceAttributes.Get(ba)
-			if v == "" {
-				continue
+			attributeAsLabels := attributeToLabels(k, v, "")
+			if action == IndexLabel {
+				for _, lbl := range attributeAsLabels {
+					streamLabels[model.LabelName(lbl.Name)] = model.LabelValue(lbl.Value)
+				}
+			} else if action == StructuredMetadata {
+				resourceAttributesAsStructuredMetadata = append(resourceAttributesAsStructuredMetadata, attributeAsLabels...)
 			}
-			streamLabels[model.LabelName(ba)] = model.LabelValue(v)
 
-			// remove the blessed attributes copied to stream labels
-			flattenedResourceAttributes.Del(ba)
-		}
+			return true
+		})
 
 		if err := streamLabels.Validate(); err != nil {
 			stats.errs = append(stats.errs, fmt.Errorf("invalid labels: %w", err))
 			continue
 		}
 		labelsStr := streamLabels.String()
 
-		// convert the remaining resource attributes to structured metadata
-		resourceAttributesAsStructuredMetadata := logproto.FromLabelsToLabelAdapters(flattenedResourceAttributes.Labels())
-
 		lbs := modelLabelsSetToLabelsList(streamLabels)
 		if _, ok := pushRequestsByStream[labelsStr]; !ok {
 			pushRequestsByStream[labelsStr] = logproto.Stream{
@@ -178,6 +158,7 @@ func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention Tenants
 		for j := 0; j < sls.Len(); j++ {
 			scope := sls.At(j).Scope()
 			logs := sls.At(j).LogRecords()
+			scopeAttrs := scope.Attributes()
 
 			// it would be rare to have multiple scopes so if the entries slice is empty, pre-allocate it for the number of log entries
 			if cap(pushRequestsByStream[labelsStr].Entries) == 0 {
@@ -187,7 +168,20 @@ func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention Tenants
 			}
 
 			// use fields and attributes from scope as structured metadata
-			scopeAttributesAsStructuredMetadata := attributesToLabels(scope.Attributes(), "")
+			scopeAttributesAsStructuredMetadata := make(push.LabelsAdapter, 0, scopeAttrs.Len()+3)
+			scopeAttrs.Range(func(k string, v pcommon.Value) bool {
+				action := otlpConfig.ActionForScopeAttribute(k)
+				if action == Drop {
+					return true
+				}
+
+				attributeAsLabels := attributeToLabels(k, v, "")
+				if action == StructuredMetadata {
+					scopeAttributesAsStructuredMetadata = append(scopeAttributesAsStructuredMetadata, attributeAsLabels...)
+				}
+
+				return true
+			})
 
 			if scopeName := scope.Name(); scopeName != "" {
 				scopeAttributesAsStructuredMetadata = append(scopeAttributesAsStructuredMetadata, push.LabelAdapter{
@@ -213,7 +207,7 @@ func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention Tenants
 			for k := 0; k < logs.Len(); k++ {
 				log := logs.At(k)
 
-				entry := otlpLogToPushEntry(log)
+				entry := otlpLogToPushEntry(log, otlpConfig)
 
 				// if entry.StructuredMetadata doesn't have capacity to add resource and scope attributes, make a new slice with enough capacity
 				attributesAsStructuredMetadataLen := len(resourceAttributesAsStructuredMetadata) + len(scopeAttributesAsStructuredMetadata)
@@ -251,9 +245,23 @@ func otlpToLokiPushRequest(ld plog.Logs, userID string, tenantsRetention Tenants
 }
 
 // otlpLogToPushEntry converts an OTLP log record to a Loki push.Entry.
-func otlpLogToPushEntry(log plog.LogRecord) push.Entry {
+func otlpLogToPushEntry(log plog.LogRecord, otlpConfig OTLPConfig) push.Entry {
 	// copy log attributes and all the fields from log(except log.Body) to structured metadata
-	structuredMetadata := attributesToLabels(log.Attributes(), "")
+	logAttrs := log.Attributes()
+	structuredMetadata := make(push.LabelsAdapter, 0, logAttrs.Len()+7)
+	logAttrs.Range(func(k string, v pcommon.Value) bool {
+		action := otlpConfig.ActionForLogAttribute(k)
+		if action == Drop {
+			return true
+		}
+
+		attributeAsLabels := attributeToLabels(k, v, "")
+		if action == StructuredMetadata {
+			structuredMetadata = append(structuredMetadata, attributeAsLabels...)
+		}
+
+		return true
+	})
 
 	// if log.Timestamp() is 0, we would have already stored log.ObservedTimestamp as log timestamp so no need to store again in structured metadata
 	if log.Timestamp() != 0 && log.ObservedTimestamp() != 0 {
@@ -316,25 +324,39 @@ func attributesToLabels(attrs pcommon.Map, prefix string) push.LabelsAdapter {
 	}
 
 	attrs.Range(func(k string, v pcommon.Value) bool {
-		keyWithPrefix := k
-		if prefix != "" {
-			keyWithPrefix = prefix + "_" + k
-		}
-		keyWithPrefix = prometheustranslator.NormalizeLabel(keyWithPrefix)
-
-		typ := v.Type()
-		if typ == pcommon.ValueTypeMap {
-			labelsAdapter = append(labelsAdapter, attributesToLabels(v.Map(), keyWithPrefix)...)
-		} else {
-			labelsAdapter = append(labelsAdapter, push.LabelAdapter{Name: keyWithPrefix, Value: v.AsString()})
-		}
-
+		labelsAdapter = append(labelsAdapter, attributeToLabels(k, v, prefix)...)
 		return true
 	})
 
 	return labelsAdapter
 }
 
+func attributeToLabels(k string, v pcommon.Value, prefix string) push.LabelsAdapter {
+	var labelsAdapter push.LabelsAdapter
+
+	keyWithPrefix := k
+	if prefix != "" {
+		keyWithPrefix = prefix + "_" + k
+	}
+	keyWithPrefix = prometheustranslator.NormalizeLabel(keyWithPrefix)
+
+	typ := v.Type()
+	if typ == pcommon.ValueTypeMap {
+		mv := v.Map()
+		labelsAdapter = make(push.LabelsAdapter, 0, mv.Len())
+		mv.Range(func(k string, v pcommon.Value) bool {
+			labelsAdapter = append(labelsAdapter, attributeToLabels(k, v, keyWithPrefix)...)
+			return true
+		})
+	} else {
+		labelsAdapter = push.LabelsAdapter{
+			push.LabelAdapter{Name: keyWithPrefix, Value: v.AsString()},
+		}
+	}
+
+	return labelsAdapter
+}
+
 func timestampFromLogRecord(lr plog.LogRecord) time.Time {
 	if lr.Timestamp() != 0 {
 		return time.Unix(0, int64(lr.Timestamp()))