diff options
Diffstat (limited to 'vendor/go.opentelemetry.io/otel/exporters/prometheus/exporter.go')
| -rw-r--r-- | vendor/go.opentelemetry.io/otel/exporters/prometheus/exporter.go | 536 |
1 files changed, 536 insertions, 0 deletions
diff --git a/vendor/go.opentelemetry.io/otel/exporters/prometheus/exporter.go b/vendor/go.opentelemetry.io/otel/exporters/prometheus/exporter.go new file mode 100644 index 000000000..92651c38c --- /dev/null +++ b/vendor/go.opentelemetry.io/otel/exporters/prometheus/exporter.go @@ -0,0 +1,536 @@ +// Copyright The OpenTelemetry Authors +// +// Licensed under the Apache License, Version 2.0 (the "License"); +// you may not use this file except in compliance with the License. +// You may obtain a copy of the License at +// +// http://www.apache.org/licenses/LICENSE-2.0 +// +// Unless required by applicable law or agreed to in writing, software +// distributed under the License is distributed on an "AS IS" BASIS, +// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. +// See the License for the specific language governing permissions and +// limitations under the License. + +package prometheus // import "go.opentelemetry.io/otel/exporters/prometheus" + +import ( + "context" + "errors" + "fmt" + "sort" + "strings" + "sync" + "unicode" + "unicode/utf8" + + "github.com/prometheus/client_golang/prometheus" + dto "github.com/prometheus/client_model/go" + "google.golang.org/protobuf/proto" + + "go.opentelemetry.io/otel" + "go.opentelemetry.io/otel/attribute" + "go.opentelemetry.io/otel/internal/global" + "go.opentelemetry.io/otel/sdk/instrumentation" + "go.opentelemetry.io/otel/sdk/metric" + "go.opentelemetry.io/otel/sdk/metric/metricdata" + "go.opentelemetry.io/otel/sdk/resource" +) + +const ( + targetInfoMetricName = "target_info" + targetInfoDescription = "Target metadata" + + scopeInfoMetricName = "otel_scope_info" + scopeInfoDescription = "Instrumentation Scope metadata" +) + +var ( + scopeInfoKeys = [2]string{"otel_scope_name", "otel_scope_version"} + + errScopeInvalid = errors.New("invalid scope") +) + +// Exporter is a Prometheus Exporter that embeds the OTel metric.Reader +// interface for easy instantiation with a MeterProvider. +type Exporter struct { + metric.Reader +} + +// MarshalLog returns logging data about the Exporter. +func (e *Exporter) MarshalLog() interface{} { + const t = "Prometheus exporter" + + if r, ok := e.Reader.(*metric.ManualReader); ok { + under := r.MarshalLog() + if data, ok := under.(struct { + Type string + Registered bool + Shutdown bool + }); ok { + data.Type = t + return data + } + } + + return struct{ Type string }{Type: t} +} + +var _ metric.Reader = &Exporter{} + +// collector is used to implement prometheus.Collector. +type collector struct { + reader metric.Reader + + withoutUnits bool + withoutCounterSuffixes bool + disableScopeInfo bool + namespace string + + mu sync.Mutex // mu protects all members below from the concurrent access. + disableTargetInfo bool + targetInfo prometheus.Metric + scopeInfos map[instrumentation.Scope]prometheus.Metric + scopeInfosInvalid map[instrumentation.Scope]struct{} + metricFamilies map[string]*dto.MetricFamily +} + +// prometheus counters MUST have a _total suffix by default: +// https://github.com/open-telemetry/opentelemetry-specification/blob/v1.20.0/specification/compatibility/prometheus_and_openmetrics.md +const counterSuffix = "_total" + +// New returns a Prometheus Exporter. +func New(opts ...Option) (*Exporter, error) { + cfg := newConfig(opts...) + + // this assumes that the default temporality selector will always return cumulative. + // we only support cumulative temporality, so building our own reader enforces this. + // TODO (#3244): Enable some way to configure the reader, but not change temporality. + reader := metric.NewManualReader(cfg.readerOpts...) + + collector := &collector{ + reader: reader, + disableTargetInfo: cfg.disableTargetInfo, + withoutUnits: cfg.withoutUnits, + withoutCounterSuffixes: cfg.withoutCounterSuffixes, + disableScopeInfo: cfg.disableScopeInfo, + scopeInfos: make(map[instrumentation.Scope]prometheus.Metric), + scopeInfosInvalid: make(map[instrumentation.Scope]struct{}), + metricFamilies: make(map[string]*dto.MetricFamily), + namespace: cfg.namespace, + } + + if err := cfg.registerer.Register(collector); err != nil { + return nil, fmt.Errorf("cannot register the collector: %w", err) + } + + e := &Exporter{ + Reader: reader, + } + + return e, nil +} + +// Describe implements prometheus.Collector. +func (c *collector) Describe(ch chan<- *prometheus.Desc) { + // The Opentelemetry SDK doesn't have information on which will exist when the collector + // is registered. By returning nothing we are an "unchecked" collector in Prometheus, + // and assume responsibility for consistency of the metrics produced. + // + // See https://pkg.go.dev/github.com/prometheus/client_golang@v1.13.0/prometheus#hdr-Custom_Collectors_and_constant_Metrics +} + +// Collect implements prometheus.Collector. +// +// This method is safe to call concurrently. +func (c *collector) Collect(ch chan<- prometheus.Metric) { + // TODO (#3047): Use a sync.Pool instead of allocating metrics every Collect. + metrics := metricdata.ResourceMetrics{} + err := c.reader.Collect(context.TODO(), &metrics) + if err != nil { + if errors.Is(err, metric.ErrReaderShutdown) { + return + } + otel.Handle(err) + if errors.Is(err, metric.ErrReaderNotRegistered) { + return + } + } + + global.Debug("Prometheus exporter export", "Data", metrics) + + // Initialize (once) targetInfo and disableTargetInfo. + func() { + c.mu.Lock() + defer c.mu.Unlock() + + if c.targetInfo == nil && !c.disableTargetInfo { + targetInfo, err := createInfoMetric(targetInfoMetricName, targetInfoDescription, metrics.Resource) + if err != nil { + // If the target info metric is invalid, disable sending it. + c.disableTargetInfo = true + otel.Handle(err) + return + } + + c.targetInfo = targetInfo + } + }() + + if !c.disableTargetInfo { + ch <- c.targetInfo + } + + for _, scopeMetrics := range metrics.ScopeMetrics { + var keys, values [2]string + + if !c.disableScopeInfo { + scopeInfo, err := c.scopeInfo(scopeMetrics.Scope) + if err == errScopeInvalid { + // Do not report the same error multiple times. + continue + } + if err != nil { + otel.Handle(err) + continue + } + + ch <- scopeInfo + + keys = scopeInfoKeys + values = [2]string{scopeMetrics.Scope.Name, scopeMetrics.Scope.Version} + } + + for _, m := range scopeMetrics.Metrics { + typ := c.metricType(m) + if typ == nil { + continue + } + name := c.getName(m, typ) + + drop, help := c.validateMetrics(name, m.Description, typ) + if drop { + continue + } + + if help != "" { + m.Description = help + } + + switch v := m.Data.(type) { + case metricdata.Histogram[int64]: + addHistogramMetric(ch, v, m, keys, values, name) + case metricdata.Histogram[float64]: + addHistogramMetric(ch, v, m, keys, values, name) + case metricdata.Sum[int64]: + addSumMetric(ch, v, m, keys, values, name) + case metricdata.Sum[float64]: + addSumMetric(ch, v, m, keys, values, name) + case metricdata.Gauge[int64]: + addGaugeMetric(ch, v, m, keys, values, name) + case metricdata.Gauge[float64]: + addGaugeMetric(ch, v, m, keys, values, name) + } + } + } +} + +func addHistogramMetric[N int64 | float64](ch chan<- prometheus.Metric, histogram metricdata.Histogram[N], m metricdata.Metrics, ks, vs [2]string, name string) { + // TODO(https://github.com/open-telemetry/opentelemetry-go/issues/3163): support exemplars + for _, dp := range histogram.DataPoints { + keys, values := getAttrs(dp.Attributes, ks, vs) + + desc := prometheus.NewDesc(name, m.Description, keys, nil) + buckets := make(map[float64]uint64, len(dp.Bounds)) + + cumulativeCount := uint64(0) + for i, bound := range dp.Bounds { + cumulativeCount += dp.BucketCounts[i] + buckets[bound] = cumulativeCount + } + m, err := prometheus.NewConstHistogram(desc, dp.Count, float64(dp.Sum), buckets, values...) + if err != nil { + otel.Handle(err) + continue + } + ch <- m + } +} + +func addSumMetric[N int64 | float64](ch chan<- prometheus.Metric, sum metricdata.Sum[N], m metricdata.Metrics, ks, vs [2]string, name string) { + valueType := prometheus.CounterValue + if !sum.IsMonotonic { + valueType = prometheus.GaugeValue + } + + for _, dp := range sum.DataPoints { + keys, values := getAttrs(dp.Attributes, ks, vs) + + desc := prometheus.NewDesc(name, m.Description, keys, nil) + m, err := prometheus.NewConstMetric(desc, valueType, float64(dp.Value), values...) + if err != nil { + otel.Handle(err) + continue + } + ch <- m + } +} + +func addGaugeMetric[N int64 | float64](ch chan<- prometheus.Metric, gauge metricdata.Gauge[N], m metricdata.Metrics, ks, vs [2]string, name string) { + for _, dp := range gauge.DataPoints { + keys, values := getAttrs(dp.Attributes, ks, vs) + + desc := prometheus.NewDesc(name, m.Description, keys, nil) + m, err := prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(dp.Value), values...) + if err != nil { + otel.Handle(err) + continue + } + ch <- m + } +} + +// getAttrs parses the attribute.Set to two lists of matching Prometheus-style +// keys and values. It sanitizes invalid characters and handles duplicate keys +// (due to sanitization) by sorting and concatenating the values following the spec. +func getAttrs(attrs attribute.Set, ks, vs [2]string) ([]string, []string) { + keysMap := make(map[string][]string) + itr := attrs.Iter() + for itr.Next() { + kv := itr.Attribute() + key := strings.Map(sanitizeRune, string(kv.Key)) + if _, ok := keysMap[key]; !ok { + keysMap[key] = []string{kv.Value.Emit()} + } else { + // if the sanitized key is a duplicate, append to the list of keys + keysMap[key] = append(keysMap[key], kv.Value.Emit()) + } + } + + keys := make([]string, 0, attrs.Len()) + values := make([]string, 0, attrs.Len()) + for key, vals := range keysMap { + keys = append(keys, key) + sort.Slice(vals, func(i, j int) bool { + return i < j + }) + values = append(values, strings.Join(vals, ";")) + } + + if ks[0] != "" { + keys = append(keys, ks[:]...) + values = append(values, vs[:]...) + } + return keys, values +} + +func createInfoMetric(name, description string, res *resource.Resource) (prometheus.Metric, error) { + keys, values := getAttrs(*res.Set(), [2]string{}, [2]string{}) + desc := prometheus.NewDesc(name, description, keys, nil) + return prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(1), values...) +} + +func createScopeInfoMetric(scope instrumentation.Scope) (prometheus.Metric, error) { + keys := scopeInfoKeys[:] + desc := prometheus.NewDesc(scopeInfoMetricName, scopeInfoDescription, keys, nil) + return prometheus.NewConstMetric(desc, prometheus.GaugeValue, float64(1), scope.Name, scope.Version) +} + +func sanitizeRune(r rune) rune { + if unicode.IsLetter(r) || unicode.IsDigit(r) || r == ':' || r == '_' { + return r + } + return '_' +} + +var unitSuffixes = map[string]string{ + // Time + "d": "_days", + "h": "_hours", + "min": "_minutes", + "s": "_seconds", + "ms": "_milliseconds", + "us": "_microseconds", + "ns": "_nanoseconds", + + // Bytes + "By": "_bytes", + "KiBy": "_kibibytes", + "MiBy": "_mebibytes", + "GiBy": "_gibibytes", + "TiBy": "_tibibytes", + "KBy": "_kilobytes", + "MBy": "_megabytes", + "GBy": "_gigabytes", + "TBy": "_terabytes", + + // SI + "m": "_meters", + "V": "_volts", + "A": "_amperes", + "J": "_joules", + "W": "_watts", + "g": "_grams", + + // Misc + "Cel": "_celsius", + "Hz": "_hertz", + "1": "_ratio", + "%": "_percent", +} + +// getName returns the sanitized name, prefixed with the namespace and suffixed with unit. +func (c *collector) getName(m metricdata.Metrics, typ *dto.MetricType) string { + name := sanitizeName(m.Name) + addCounterSuffix := !c.withoutCounterSuffixes && *typ == dto.MetricType_COUNTER + if addCounterSuffix { + // Remove the _total suffix here, as we will re-add the total suffix + // later, and it needs to come after the unit suffix. + name = strings.TrimSuffix(name, counterSuffix) + } + if c.namespace != "" { + name = c.namespace + name + } + if suffix, ok := unitSuffixes[m.Unit]; ok && !c.withoutUnits && !strings.HasSuffix(name, suffix) { + name += suffix + } + if addCounterSuffix { + name += counterSuffix + } + return name +} + +func sanitizeName(n string) string { + // This algorithm is based on strings.Map from Go 1.19. + const replacement = '_' + + valid := func(i int, r rune) bool { + // Taken from + // https://github.com/prometheus/common/blob/dfbc25bd00225c70aca0d94c3c4bb7744f28ace0/model/metric.go#L92-L102 + if (r >= 'a' && r <= 'z') || (r >= 'A' && r <= 'Z') || r == '_' || r == ':' || (r >= '0' && r <= '9' && i > 0) { + return true + } + return false + } + + // This output buffer b is initialized on demand, the first time a + // character needs to be replaced. + var b strings.Builder + for i, c := range n { + if valid(i, c) { + continue + } + + if i == 0 && c >= '0' && c <= '9' { + // Prefix leading number with replacement character. + b.Grow(len(n) + 1) + _ = b.WriteByte(byte(replacement)) + break + } + b.Grow(len(n)) + _, _ = b.WriteString(n[:i]) + _ = b.WriteByte(byte(replacement)) + width := utf8.RuneLen(c) + n = n[i+width:] + break + } + + // Fast path for unchanged input. + if b.Cap() == 0 { // b.Grow was not called above. + return n + } + + for _, c := range n { + // Due to inlining, it is more performant to invoke WriteByte rather then + // WriteRune. + if valid(1, c) { // We are guaranteed to not be at the start. + _ = b.WriteByte(byte(c)) + } else { + _ = b.WriteByte(byte(replacement)) + } + } + + return b.String() +} + +func (c *collector) metricType(m metricdata.Metrics) *dto.MetricType { + switch v := m.Data.(type) { + case metricdata.Histogram[int64], metricdata.Histogram[float64]: + return dto.MetricType_HISTOGRAM.Enum() + case metricdata.Sum[float64]: + if v.IsMonotonic { + return dto.MetricType_COUNTER.Enum() + } + return dto.MetricType_GAUGE.Enum() + case metricdata.Sum[int64]: + if v.IsMonotonic { + return dto.MetricType_COUNTER.Enum() + } + return dto.MetricType_GAUGE.Enum() + case metricdata.Gauge[int64], metricdata.Gauge[float64]: + return dto.MetricType_GAUGE.Enum() + } + return nil +} + +func (c *collector) scopeInfo(scope instrumentation.Scope) (prometheus.Metric, error) { + c.mu.Lock() + defer c.mu.Unlock() + + scopeInfo, ok := c.scopeInfos[scope] + if ok { + return scopeInfo, nil + } + + if _, ok := c.scopeInfosInvalid[scope]; ok { + return nil, errScopeInvalid + } + + scopeInfo, err := createScopeInfoMetric(scope) + if err != nil { + c.scopeInfosInvalid[scope] = struct{}{} + return nil, fmt.Errorf("cannot create scope info metric: %w", err) + } + + c.scopeInfos[scope] = scopeInfo + + return scopeInfo, nil +} + +func (c *collector) validateMetrics(name, description string, metricType *dto.MetricType) (drop bool, help string) { + c.mu.Lock() + defer c.mu.Unlock() + + emf, exist := c.metricFamilies[name] + + if !exist { + c.metricFamilies[name] = &dto.MetricFamily{ + Name: proto.String(name), + Help: proto.String(description), + Type: metricType, + } + return false, "" + } + + if emf.GetType() != *metricType { + global.Error( + errors.New("instrument type conflict"), + "Using existing type definition.", + "instrument", name, + "existing", emf.GetType(), + "dropped", *metricType, + ) + return true, "" + } + if emf.GetHelp() != description { + global.Info( + "Instrument description conflict, using existing", + "instrument", name, + "existing", emf.GetHelp(), + "dropped", description, + ) + return false, emf.GetHelp() + } + + return false, "" +} |