OTLP: Use optimized OTel metric translator, converting directly to Mimir format

.github/workflows/test-build-deploy.yml

@@ -30,7 +30,6 @@ jobs:
       # Determine if we will deploy (aka push) the image to the registry.
       is_deploy: ${{ (startsWith(github.ref, 'refs/tags/') || startsWith(github.ref, 'refs/heads/r')) && github.event_name == 'push' && github.repository == 'grafana/mimir' }}
 
-
   goversion:
     runs-on: ubuntu-latest
     needs: prepare
@@ -103,6 +102,8 @@ jobs:
         run: make BUILD_IN_CONTAINER=false check-license
       - name: Check Docker-Compose YAML
         run: make BUILD_IN_CONTAINER=false check-mimir-microservices-mode-docker-compose-yaml check-mimir-read-write-mode-docker-compose-yaml
+      - name: Check Generated OTLP Code
+        run: make BUILD_IN_CONTAINER=false check-generated-otlp-code
 
   doc-validator:
     runs-on: ubuntu-latest

CHANGELOG.md

@@ -42,6 +42,7 @@
 * [ENHANCEMENT] Store-gateway: improve performance when streaming chunks to queriers is enabled (`-querier.prefer-streaming-chunks-from-store-gateways=true`) and the query selects fewer than `-blocks-storage.bucket-store.batch-series-size` series (defaults to 5000 series). #8039
 * [ENHANCEMENT] Ingester: active series are now updated along with owned series. They decrease when series change ownership between ingesters. This helps provide a more accurate total of active series when ingesters are added. This is only enabled when `-ingester.track-ingester-owned-series` or `-ingester.use-ingester-owned-series-for-limits` are enabled. #8084
 * [ENHANCEMENT] Query-frontend: include route name in query stats log lines. #8191
+* [ENHANCEMENT] OTLP: Speed up conversion from OTel to Mimir format by about 8% and reduce memory consumption by about 30%. Can be disabled via `-distributor.direct-otlp-translation-enabled=false` #7957
 * [BUGFIX] Rules: improve error handling when querier is local to the ruler. #7567
 * [BUGFIX] Querier, store-gateway: Protect against panics raised during snappy encoding. #7520
 * [BUGFIX] Ingester: Prevent timely compaction of empty blocks. #7624

Makefile

@@ -231,6 +231,9 @@ images: ## Print all image names.
 PROTO_DEFS := $(shell find . $(DONT_FIND) -type f -name '*.proto' -print)
 PROTO_GOS := $(patsubst %.proto,%.pb.go,$(PROTO_DEFS))
 
+# Generating OTLP translation code is automated.
+OTLP_GOS := $(shell find ./pkg/distributor/otlp/ -type f -name '*_generated.go' -print)
+
 # Building binaries is now automated. The convention is to build a binary
 # for every directory with main.go in it.
 MAIN_GO := $(shell find . $(DONT_FIND) -type f -name 'main.go' -print)
@@ -260,7 +263,7 @@ mimir-build-image/$(UPTODATE): mimir-build-image/*
 # All the boiler plate for building golang follows:
 SUDO := $(shell docker info >/dev/null 2>&1 || echo "sudo -E")
 BUILD_IN_CONTAINER ?= true
-LATEST_BUILD_IMAGE_TAG ?= pr8107-6dc27b0894
+LATEST_BUILD_IMAGE_TAG ?= pr7957-d7652788a7
 
 # TTY is parameterized to allow Google Cloud Builder to run builds,
 # as it currently disallows TTY devices. This value needs to be overridden
@@ -771,3 +774,11 @@ test-packages: packages packaging/rpm/centos-systemd/$(UPTODATE) packaging/deb/d
 
 docs: doc
 	cd docs && $(MAKE) docs
+
+.PHONY: generate-otlp
+generate-otlp:
+	cd pkg/distributor/otlp && rm -f *_generated.go && go generate
+
+.PHONY: check-generated-otlp-code
+check-generated-otlp-code: generate-otlp
+	@./tools/find-diff-or-untracked.sh $(OTLP_GOS) || (echo "Please rebuild OTLP code by running 'generate-otlp'" && false)

cmd/mimir/config-descriptor.json

@@ -1701,6 +1701,17 @@
           "fieldFlag": "distributor.reusable-ingester-push-workers",
           "fieldType": "int",
           "fieldCategory": "advanced"
+        },
+        {
+          "kind": "field",
+          "name": "direct_otlp_translation_enabled",
+          "required": false,
+          "desc": "When enabled, OTLP write requests are directly translated to Mimir equivalents, for optimum performance.",
+          "fieldValue": null,
+          "fieldDefaultValue": true,
+          "fieldFlag": "distributor.direct-otlp-translation-enabled",
+          "fieldType": "boolean",
+          "fieldCategory": "experimental"
         }
       ],
       "fieldValue": null,

cmd/mimir/help-all.txt.tmpl

@@ -1095,6 +1095,8 @@ Usage of ./cmd/mimir/mimir:
     	Fraction of mutex contention events that are reported in the mutex profile. On average 1/rate events are reported. 0 to disable.
   -distributor.client-cleanup-period duration
     	How frequently to clean up clients for ingesters that have gone away. (default 15s)
+  -distributor.direct-otlp-translation-enabled
+    	[experimental] When enabled, OTLP write requests are directly translated to Mimir equivalents, for optimum performance. (default true)
   -distributor.drop-label string
     	This flag can be used to specify label names that to drop during sample ingestion within the distributor and can be repeated in order to drop multiple labels.
   -distributor.enable-otlp-metadata-storage

docs/sources/mimir/configure/about-versioning.md

@@ -73,6 +73,8 @@ The following features are currently experimental:
     - `-distributor.max-exemplars-per-series-per-request`
   - Enforce a maximum pool buffer size for write requests
     - `-distributor.max-request-pool-buffer-size`
+  - Enable direct translation from OTLP write requests to Mimir equivalents
+    - `-distributor.direct-otlp-translation-enabled`
 - Hash ring
   - Disabling ring heartbeat timeouts
     - `-distributor.ring.heartbeat-timeout=0`

docs/sources/mimir/configure/configuration-parameters/index.md

@@ -955,6 +955,11 @@ instance_limits:
 # limiting feature.)
 # CLI flag: -distributor.reusable-ingester-push-workers
 [reusable_ingester_push_workers: <int> | default = 2000]
+
+# (experimental) When enabled, OTLP write requests are directly translated to
+# Mimir equivalents, for optimum performance.
+# CLI flag: -distributor.direct-otlp-translation-enabled
+[direct_otlp_translation_enabled: <boolean> | default = true]
 ```
 
 ### ingester

go.mod

@@ -140,7 +140,7 @@ require (
 	github.com/bits-and-blooms/bitset v1.13.0 // indirect
 	github.com/cenkalti/backoff/v4 v4.3.0 // indirect
 	github.com/cespare/xxhash v1.1.0 // indirect
-	github.com/cespare/xxhash/v2 v2.3.0 // indirect
+	github.com/cespare/xxhash/v2 v2.3.0
 	github.com/coreos/go-semver v0.3.0 // indirect
 	github.com/coreos/go-systemd/v22 v22.5.0 // indirect
 	github.com/davecgh/go-spew v1.1.2-0.20180830191138-d8f796af33cc // indirect
@@ -237,7 +237,7 @@ require (
 	go.etcd.io/etcd/client/v3 v3.5.4 // indirect
 	go.mongodb.org/mongo-driver v1.14.0 // indirect
 	go.opencensus.io v0.24.0 // indirect
-	go.opentelemetry.io/collector/semconv v0.98.0 // indirect
+	go.opentelemetry.io/collector/semconv v0.98.0
 	go.opentelemetry.io/contrib/instrumentation/net/http/otelhttp v0.50.0 // indirect
 	go.opentelemetry.io/otel/metric v1.26.0 // indirect
 	go.uber.org/zap v1.21.0 // indirect

mimir-build-image/Dockerfile

@@ -56,6 +56,7 @@ RUN GO111MODULE=on \
 	go install github.com/google/go-jsonnet/cmd/[email protected] && \
 	go install github.com/norwoodj/helm-docs/cmd/[email protected] && \
 	go install github.com/open-policy-agent/[email protected] && \
+	go install github.com/uber-go/[email protected] && \
 	rm -rf /go/pkg /go/src /root/.cache
 
 COPY --from=helm /usr/bin/helm /usr/bin/helm

pkg/api/api.go

@@ -262,7 +262,7 @@ func (a *API) RegisterDistributor(d *distributor.Distributor, pushConfig distrib
 	distributorpb.RegisterDistributorServer(a.server.GRPC, d)
 
 	a.RegisterRoute(PrometheusPushEndpoint, distributor.Handler(pushConfig.MaxRecvMsgSize, d.RequestBufferPool, a.sourceIPs, a.cfg.SkipLabelNameValidationHeader, limits, pushConfig.RetryConfig, d.PushWithMiddlewares, d.PushMetrics, a.logger), true, false, "POST")
-	a.RegisterRoute(OTLPPushEndpoint, distributor.OTLPHandler(pushConfig.MaxRecvMsgSize, d.RequestBufferPool, a.sourceIPs, a.cfg.SkipLabelNameValidationHeader, a.cfg.EnableOtelMetadataStorage, limits, pushConfig.RetryConfig, d.PushWithMiddlewares, d.PushMetrics, reg, a.logger), true, false, "POST")
+	a.RegisterRoute(OTLPPushEndpoint, distributor.OTLPHandler(pushConfig.MaxRecvMsgSize, d.RequestBufferPool, a.sourceIPs, a.cfg.SkipLabelNameValidationHeader, a.cfg.EnableOtelMetadataStorage, limits, pushConfig.RetryConfig, d.PushWithMiddlewares, d.PushMetrics, reg, a.logger, pushConfig.DirectOTLPTranslationEnabled), true, false, "POST")
 
 	a.indexPage.AddLinks(defaultWeight, "Distributor", []IndexPageLink{
 		{Desc: "Ring status", Path: "/distributor/ring"},

pkg/distributor/distributor.go

@@ -219,6 +219,9 @@ type Config struct {
 	WriteRequestsBufferPoolingEnabled           bool `yaml:"write_requests_buffer_pooling_enabled" category:"experimental"`
 	LimitInflightRequestsUsingGrpcMethodLimiter bool `yaml:"limit_inflight_requests_using_grpc_method_limiter" category:"deprecated"` // TODO Remove the configuration option in Mimir 2.14, keeping the same behavior as if it's enabled
 	ReusableIngesterPushWorkers                 int  `yaml:"reusable_ingester_push_workers" category:"advanced"`
+
+	// DirectOTLPTranslationEnabled allows reverting to the older way of translating from OTLP write requests via Prometheus, in case of problems.
+	DirectOTLPTranslationEnabled bool `yaml:"direct_otlp_translation_enabled" category:"experimental"`
 }
 
 // PushWrapper wraps around a push. It is similar to middleware.Interface.
@@ -237,6 +240,7 @@ func (cfg *Config) RegisterFlags(f *flag.FlagSet, logger log.Logger) {
 	f.BoolVar(&cfg.WriteRequestsBufferPoolingEnabled, "distributor.write-requests-buffer-pooling-enabled", true, "Enable pooling of buffers used for marshaling write requests.")
 	f.BoolVar(&cfg.LimitInflightRequestsUsingGrpcMethodLimiter, "distributor.limit-inflight-requests-using-grpc-method-limiter", true, "When enabled, in-flight write requests limit is checked as soon as the gRPC request is received, before the request is decoded and parsed.")
 	f.IntVar(&cfg.ReusableIngesterPushWorkers, "distributor.reusable-ingester-push-workers", 2000, "Number of pre-allocated workers used to forward push requests to the ingesters. If 0, no workers will be used and a new goroutine will be spawned for each ingester push request. If not enough workers available, new goroutine will be spawned. (Note: this is a performance optimization, not a limiting feature.)")
+	f.BoolVar(&cfg.DirectOTLPTranslationEnabled, "distributor.direct-otlp-translation-enabled", true, "When enabled, OTLP write requests are directly translated to Mimir equivalents, for optimum performance.")
 
 	cfg.DefaultLimits.RegisterFlags(f)
 }

pkg/distributor/otel.go

@@ -26,6 +26,7 @@ import (
 	"go.opentelemetry.io/collector/pdata/pmetric/pmetricotlp"
 	"go.uber.org/multierr"
 
+	"github.com/grafana/mimir/pkg/distributor/otlp"
 	"github.com/grafana/mimir/pkg/mimirpb"
 	"github.com/grafana/mimir/pkg/util"
 	"github.com/grafana/mimir/pkg/util/spanlogger"
@@ -53,6 +54,7 @@ func OTLPHandler(
 	pushMetrics *PushMetrics,
 	reg prometheus.Registerer,
 	logger log.Logger,
+	directTranslation bool,
 ) http.Handler {
 	discardedDueToOtelParseError := validation.DiscardedSamplesCounter(reg, otelParseError)
 
@@ -154,9 +156,17 @@ func OTLPHandler(
 		pushMetrics.IncOTLPRequest(tenantID)
 		pushMetrics.ObserveUncompressedBodySize(tenantID, float64(uncompressedBodySize))
 
-		metrics, err := otelMetricsToTimeseries(tenantID, addSuffixes, discardedDueToOtelParseError, logger, otlpReq.Metrics())
-		if err != nil {
-			return err
+		var metrics []mimirpb.PreallocTimeseries
+		if directTranslation {
+			metrics, err = otelMetricsToTimeseries(tenantID, addSuffixes, discardedDueToOtelParseError, logger, otlpReq.Metrics())
+			if err != nil {
+				return err
+			}
+		} else {
+			metrics, err = otelMetricsToTimeseriesOld(tenantID, addSuffixes, discardedDueToOtelParseError, logger, otlpReq.Metrics())
+			if err != nil {
+				return err
+			}
 		}
 
 		metricCount := len(metrics)
@@ -259,6 +269,32 @@ func otelMetricsToMetadata(addSuffixes bool, md pmetric.Metrics) []*mimirpb.Metr
 }
 
 func otelMetricsToTimeseries(tenantID string, addSuffixes bool, discardedDueToOtelParseError *prometheus.CounterVec, logger log.Logger, md pmetric.Metrics) ([]mimirpb.PreallocTimeseries, error) {
+	converter := otlp.NewMimirConverter()
+	errs := converter.FromMetrics(md, otlp.Settings{
+		AddMetricSuffixes: addSuffixes,
+	})
+	mimirTS := converter.TimeSeries()
+	if errs != nil {
+		dropped := len(multierr.Errors(errs))
+		discardedDueToOtelParseError.WithLabelValues(tenantID, "").Add(float64(dropped)) // Group is empty here as metrics couldn't be parsed
+
+		parseErrs := errs.Error()
+		if len(parseErrs) > maxErrMsgLen {
+			parseErrs = parseErrs[:maxErrMsgLen]
+		}
+
+		if len(mimirTS) == 0 {
+			return nil, errors.New(parseErrs)
+		}
+
+		level.Warn(logger).Log("msg", "OTLP parse error", "err", parseErrs)
+	}
+
+	return mimirTS, nil
+}
+
+// Old, less efficient, version of otelMetricsToTimeseries.
+func otelMetricsToTimeseriesOld(tenantID string, addSuffixes bool, discardedDueToOtelParseError *prometheus.CounterVec, logger log.Logger, md pmetric.Metrics) ([]mimirpb.PreallocTimeseries, error) {
 	converter := prometheusremotewrite.NewPrometheusConverter()
 	errs := converter.FromMetrics(md, prometheusremotewrite.Settings{
 		AddMetricSuffixes: addSuffixes,

pkg/distributor/otel_test.go

@@ -66,7 +66,7 @@ func BenchmarkOTLPHandler(b *testing.B) {
 		validation.NewMockTenantLimits(map[string]*validation.Limits{}),
 	)
 	require.NoError(b, err)
-	handler := OTLPHandler(100000, nil, nil, false, true, limits, RetryConfig{}, pushFunc, nil, nil, log.NewNopLogger())
+	handler := OTLPHandler(100000, nil, nil, false, true, limits, RetryConfig{}, pushFunc, nil, nil, log.NewNopLogger(), true)
 
 	b.Run("protobuf", func(b *testing.B) {
 		req := createOTLPProtoRequest(b, exportReq, false)

pkg/distributor/otlp/generate.sh

@@ -0,0 +1,26 @@
+#!/bin/bash
+# SPDX-License-Identifier: AGPL-3.0-only
+
+set -euo pipefail
+
+# Use GNU sed on MacOS falling back to `sed` everywhere else
+SED=$(which gsed || which sed)
+
+FILES=$(find ../../../vendor/github.com/prometheus/prometheus/storage/remote/otlptranslator/prometheusremotewrite -name '*.go' ! -name timeseries.go ! -name "*_test.go")
+
+for SRC in $FILES
+do
+  BASENAME=$(basename "$SRC")
+  DST="${BASENAME%%.go}_generated.go"
+
+  rm -f "$DST"
+  echo "Processing $SRC to $DST"
+  printf "// Code generated from Prometheus sources - DO NOT EDIT.\n\n" >"$DST"
+  cat "$SRC" >> "$DST"
+
+  gopatch -p mimirpb.patch "$DST"
+
+  $SED -i "s/PrometheusConverter/MimirConverter/g" "$DST"
+  $SED -i "s/Prometheus remote write format/Mimir remote write format/g" "$DST"
+  goimports -w -local github.com/grafana/mimir "$DST"
+done