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| 1 | +// Copyright 2026 The Parca Authors |
| 2 | +// Licensed under the Apache License, Version 2.0 (the "License"); |
| 3 | +// you may not use this file except in compliance with the License. |
| 4 | +// You may obtain a copy of the License at |
| 5 | +// |
| 6 | +// http://www.apache.org/licenses/LICENSE-2.0 |
| 7 | +// |
| 8 | +// Unless required by applicable law or agreed to in writing, software |
| 9 | +// distributed under the License is distributed on an "AS IS" BASIS, |
| 10 | +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 11 | +// See the License for the specific language governing permissions and |
| 12 | +// limitations under the License. |
| 13 | + |
| 14 | +// Package metricexport provides a small OTLP metrics egress path for |
| 15 | +// parca-agent. It is deliberately generic: a Producer collects gauge/sum |
| 16 | +// metrics in the background and renders them into a pmetric.MetricSlice on |
| 17 | +// demand, and the Exporter periodically batches every producer's output into a |
| 18 | +// single OTLP ExportMetricsServiceRequest and ships it over an existing |
| 19 | +// remote-store gRPC connection (the same one used for profiles). |
| 20 | +// |
| 21 | +// The GPU metrics collector (package gpumetrics) is the first Producer, but |
| 22 | +// nothing here is GPU-specific — any subsystem that wants to emit metrics to |
| 23 | +// the remote store can register a Producer. |
| 24 | +package metricexport |
| 25 | + |
| 26 | +import ( |
| 27 | + "context" |
| 28 | + "errors" |
| 29 | + "fmt" |
| 30 | + "math/rand/v2" |
| 31 | + "time" |
| 32 | + |
| 33 | + log "github.com/sirupsen/logrus" |
| 34 | + "go.opentelemetry.io/collector/pdata/pmetric" |
| 35 | + "go.opentelemetry.io/collector/pdata/pmetric/pmetricotlp" |
| 36 | + "golang.org/x/sync/errgroup" |
| 37 | + "google.golang.org/grpc" |
| 38 | +) |
| 39 | + |
| 40 | +// Producer collects metrics in the background (Collect, blocking until ctx is |
| 41 | +// cancelled) and renders the metrics accumulated so far into ms (Produce, |
| 42 | +// called periodically by the Exporter). Implementations must be safe for |
| 43 | +// Produce and Collect to run concurrently. |
| 44 | +type Producer interface { |
| 45 | + // Produce appends the metrics collected since the last call to ms. |
| 46 | + Produce(ms pmetric.MetricSlice) error |
| 47 | + // Collect runs the background collection loop until ctx is cancelled. |
| 48 | + Collect(ctx context.Context) error |
| 49 | +} |
| 50 | + |
| 51 | +// ProducerConfig pairs a Producer with the OTLP instrumentation scope its |
| 52 | +// metrics are reported under. |
| 53 | +type ProducerConfig struct { |
| 54 | + Producer Producer |
| 55 | + ScopeName string |
| 56 | +} |
| 57 | + |
| 58 | +// Exporter periodically renders all registered producers into a single OTLP |
| 59 | +// metrics request and sends it over conn. |
| 60 | +type Exporter struct { |
| 61 | + client pmetricotlp.GRPCClient |
| 62 | + interval time.Duration |
| 63 | + producers []ProducerConfig |
| 64 | + resourceAttrs map[string]any |
| 65 | +} |
| 66 | + |
| 67 | +// NewExporter builds an Exporter that ships metrics over conn (typically the |
| 68 | +// agent's existing remote-store connection) every interval. resourceAttrs are |
| 69 | +// attached to the OTLP Resource (e.g. {"node": <node name>}). |
| 70 | +func NewExporter(conn *grpc.ClientConn, interval time.Duration, resourceAttrs map[string]any) *Exporter { |
| 71 | + return &Exporter{ |
| 72 | + client: pmetricotlp.NewGRPCClient(conn), |
| 73 | + interval: interval, |
| 74 | + resourceAttrs: resourceAttrs, |
| 75 | + } |
| 76 | +} |
| 77 | + |
| 78 | +// AddProducer registers a producer. Call before Run/Collect. |
| 79 | +func (e *Exporter) AddProducer(p ProducerConfig) { |
| 80 | + e.producers = append(e.producers, p) |
| 81 | +} |
| 82 | + |
| 83 | +func (e *Exporter) report(ctx context.Context) error { |
| 84 | + m := pmetric.NewMetrics() |
| 85 | + r := m.ResourceMetrics().AppendEmpty() |
| 86 | + if err := r.Resource().Attributes().FromRaw(e.resourceAttrs); err != nil { |
| 87 | + return err |
| 88 | + } |
| 89 | + for _, p := range e.producers { |
| 90 | + s := r.ScopeMetrics().AppendEmpty() |
| 91 | + s.Scope().SetName(p.ScopeName) |
| 92 | + if err := p.Producer.Produce(s.Metrics()); err != nil { |
| 93 | + log.WithError(err).WithField("scope", p.ScopeName).Warn("metrics producer failed to produce") |
| 94 | + } |
| 95 | + } |
| 96 | + |
| 97 | + dpc := m.DataPointCount() |
| 98 | + if dpc == 0 { |
| 99 | + return nil |
| 100 | + } |
| 101 | + |
| 102 | + req := pmetricotlp.NewExportRequestFromMetrics(m) |
| 103 | + start := time.Now() |
| 104 | + resp, err := e.client.Export(ctx, req) |
| 105 | + if err != nil { |
| 106 | + return fmt.Errorf("otlp metrics export failed: %w", err) |
| 107 | + } |
| 108 | + if ps := resp.PartialSuccess(); ps.RejectedDataPoints() > 0 || ps.ErrorMessage() != "" { |
| 109 | + log.WithFields(log.Fields{ |
| 110 | + "rejected": ps.RejectedDataPoints(), |
| 111 | + "message": ps.ErrorMessage(), |
| 112 | + }).Warn("otlp metrics partial success") |
| 113 | + } |
| 114 | + log.WithFields(log.Fields{ |
| 115 | + "data_points": dpc, |
| 116 | + "duration": time.Since(start), |
| 117 | + }).Debug("gpu metrics export succeeded") |
| 118 | + return nil |
| 119 | +} |
| 120 | + |
| 121 | +// Run starts every producer's background collection loop and the periodic |
| 122 | +// export loop, blocking until ctx is cancelled or a fatal error occurs. |
| 123 | +func (e *Exporter) Run(ctx context.Context) error { |
| 124 | + if len(e.producers) == 0 { |
| 125 | + return errors.New("metricexport: no producers configured") |
| 126 | + } |
| 127 | + log.WithField("producers", len(e.producers)).Info("starting otlp metrics exporter") |
| 128 | + |
| 129 | + g, ctx := errgroup.WithContext(ctx) |
| 130 | + |
| 131 | + // Background collection loops, one per producer. |
| 132 | + for _, p := range e.producers { |
| 133 | + g.Go(func() error { |
| 134 | + return p.Producer.Collect(ctx) |
| 135 | + }) |
| 136 | + } |
| 137 | + |
| 138 | + // Periodic export loop. |
| 139 | + g.Go(func() error { |
| 140 | + tick := time.NewTicker(e.interval) |
| 141 | + defer tick.Stop() |
| 142 | + for { |
| 143 | + select { |
| 144 | + case <-ctx.Done(): |
| 145 | + return nil |
| 146 | + case <-tick.C: |
| 147 | + if err := e.report(ctx); err != nil { |
| 148 | + // Don't tear the agent down over a transient export |
| 149 | + // failure; log and keep collecting. |
| 150 | + log.WithError(err).Warn("failed to send otlp gpu metrics") |
| 151 | + } |
| 152 | + tick.Reset(addJitter(e.interval, 0.2)) |
| 153 | + } |
| 154 | + } |
| 155 | + }) |
| 156 | + |
| 157 | + return g.Wait() |
| 158 | +} |
| 159 | + |
| 160 | +// addJitter adds +/- jitter (jitter is [0..1]) to baseDuration. |
| 161 | +// Originally copied from go.opentelemetry.io/ebpf-profiler. |
| 162 | +func addJitter(baseDuration time.Duration, jitter float64) time.Duration { |
| 163 | + if jitter < 0.0 || jitter > 1.0 { |
| 164 | + return baseDuration |
| 165 | + } |
| 166 | + //nolint:gosec |
| 167 | + return time.Duration((1 + jitter - 2*jitter*rand.Float64()) * float64(baseDuration)) |
| 168 | +} |
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