576 lines
15 KiB
Go
576 lines
15 KiB
Go
package metrics
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import (
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"bytes"
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"fmt"
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"io"
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"sort"
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"sync"
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"time"
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)
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// Set is a set of metrics.
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//
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// Metrics belonging to a set are exported separately from global metrics.
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//
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// Set.WritePrometheus must be called for exporting metrics from the set.
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type Set struct {
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mu sync.Mutex
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a []*namedMetric
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m map[string]*namedMetric
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summaries []*Summary
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metricsWriters []func(w io.Writer)
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}
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// NewSet creates new set of metrics.
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//
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// Pass the set to RegisterSet() function in order to export its metrics via global WritePrometheus() call.
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func NewSet() *Set {
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return &Set{
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m: make(map[string]*namedMetric),
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}
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}
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// WritePrometheus writes all the metrics from s to w in Prometheus format.
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func (s *Set) WritePrometheus(w io.Writer) {
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// Collect all the metrics in in-memory buffer in order to prevent from long locking due to slow w.
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var bb bytes.Buffer
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lessFunc := func(i, j int) bool {
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return s.a[i].name < s.a[j].name
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}
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s.mu.Lock()
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for _, sm := range s.summaries {
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sm.updateQuantiles()
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}
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if !sort.SliceIsSorted(s.a, lessFunc) {
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sort.Slice(s.a, lessFunc)
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}
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sa := append([]*namedMetric(nil), s.a...)
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metricsWriters := s.metricsWriters
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s.mu.Unlock()
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prevMetricFamily := ""
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for _, nm := range sa {
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metricFamily := getMetricFamily(nm.name)
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if metricFamily != prevMetricFamily {
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// write meta info only once per metric family
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metricType := nm.metric.metricType()
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WriteMetadataIfNeeded(&bb, nm.name, metricType)
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prevMetricFamily = metricFamily
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}
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// Call marshalTo without the global lock, since certain metric types such as Gauge
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// can call a callback, which, in turn, can try calling s.mu.Lock again.
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nm.metric.marshalTo(nm.name, &bb)
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}
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w.Write(bb.Bytes())
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for _, writeMetrics := range metricsWriters {
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writeMetrics(w)
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}
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}
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// NewHistogram creates and returns new histogram in s with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned histogram is safe to use from concurrent goroutines.
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func (s *Set) NewHistogram(name string) *Histogram {
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h := &Histogram{}
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s.registerMetric(name, h)
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return h
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}
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// GetOrCreateHistogram returns registered histogram in s with the given name
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// or creates new histogram if s doesn't contain histogram with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned histogram is safe to use from concurrent goroutines.
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//
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// Performance tip: prefer NewHistogram instead of GetOrCreateHistogram.
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func (s *Set) GetOrCreateHistogram(name string) *Histogram {
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s.mu.Lock()
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nm := s.m[name]
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s.mu.Unlock()
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if nm == nil {
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// Slow path - create and register missing histogram.
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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nmNew := &namedMetric{
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name: name,
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metric: &Histogram{},
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}
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s.mu.Lock()
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nm = s.m[name]
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if nm == nil {
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nm = nmNew
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s.m[name] = nm
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s.a = append(s.a, nm)
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}
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s.mu.Unlock()
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}
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h, ok := nm.metric.(*Histogram)
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if !ok {
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panic(fmt.Errorf("BUG: metric %q isn't a Histogram. It is %T", name, nm.metric))
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}
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return h
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}
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// NewCounter registers and returns new counter with the given name in the s.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned counter is safe to use from concurrent goroutines.
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func (s *Set) NewCounter(name string) *Counter {
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c := &Counter{}
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s.registerMetric(name, c)
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return c
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}
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// GetOrCreateCounter returns registered counter in s with the given name
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// or creates new counter if s doesn't contain counter with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned counter is safe to use from concurrent goroutines.
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//
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// Performance tip: prefer NewCounter instead of GetOrCreateCounter.
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func (s *Set) GetOrCreateCounter(name string) *Counter {
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s.mu.Lock()
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nm := s.m[name]
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s.mu.Unlock()
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if nm == nil {
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// Slow path - create and register missing counter.
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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nmNew := &namedMetric{
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name: name,
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metric: &Counter{},
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}
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s.mu.Lock()
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nm = s.m[name]
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if nm == nil {
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nm = nmNew
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s.m[name] = nm
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s.a = append(s.a, nm)
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}
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s.mu.Unlock()
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}
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c, ok := nm.metric.(*Counter)
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if !ok {
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panic(fmt.Errorf("BUG: metric %q isn't a Counter. It is %T", name, nm.metric))
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}
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return c
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}
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// NewFloatCounter registers and returns new FloatCounter with the given name in the s.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned FloatCounter is safe to use from concurrent goroutines.
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func (s *Set) NewFloatCounter(name string) *FloatCounter {
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c := &FloatCounter{}
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s.registerMetric(name, c)
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return c
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}
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// GetOrCreateFloatCounter returns registered FloatCounter in s with the given name
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// or creates new FloatCounter if s doesn't contain FloatCounter with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned FloatCounter is safe to use from concurrent goroutines.
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//
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// Performance tip: prefer NewFloatCounter instead of GetOrCreateFloatCounter.
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func (s *Set) GetOrCreateFloatCounter(name string) *FloatCounter {
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s.mu.Lock()
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nm := s.m[name]
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s.mu.Unlock()
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if nm == nil {
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// Slow path - create and register missing counter.
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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nmNew := &namedMetric{
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name: name,
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metric: &FloatCounter{},
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}
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s.mu.Lock()
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nm = s.m[name]
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if nm == nil {
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nm = nmNew
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s.m[name] = nm
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s.a = append(s.a, nm)
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}
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s.mu.Unlock()
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}
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c, ok := nm.metric.(*FloatCounter)
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if !ok {
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panic(fmt.Errorf("BUG: metric %q isn't a Counter. It is %T", name, nm.metric))
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}
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return c
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}
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// NewGauge registers and returns gauge with the given name in s, which calls f
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// to obtain gauge value.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// f must be safe for concurrent calls.
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//
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// The returned gauge is safe to use from concurrent goroutines.
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func (s *Set) NewGauge(name string, f func() float64) *Gauge {
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g := &Gauge{
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f: f,
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}
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s.registerMetric(name, g)
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return g
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}
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// GetOrCreateGauge returns registered gauge with the given name in s
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// or creates new gauge if s doesn't contain gauge with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned gauge is safe to use from concurrent goroutines.
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//
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// Performance tip: prefer NewGauge instead of GetOrCreateGauge.
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func (s *Set) GetOrCreateGauge(name string, f func() float64) *Gauge {
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s.mu.Lock()
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nm := s.m[name]
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s.mu.Unlock()
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if nm == nil {
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// Slow path - create and register missing gauge.
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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nmNew := &namedMetric{
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name: name,
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metric: &Gauge{
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f: f,
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},
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}
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s.mu.Lock()
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nm = s.m[name]
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if nm == nil {
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nm = nmNew
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s.m[name] = nm
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s.a = append(s.a, nm)
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}
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s.mu.Unlock()
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}
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g, ok := nm.metric.(*Gauge)
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if !ok {
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panic(fmt.Errorf("BUG: metric %q isn't a Gauge. It is %T", name, nm.metric))
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}
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return g
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}
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// NewSummary creates and returns new summary with the given name in s.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned summary is safe to use from concurrent goroutines.
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func (s *Set) NewSummary(name string) *Summary {
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return s.NewSummaryExt(name, defaultSummaryWindow, defaultSummaryQuantiles)
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}
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// NewSummaryExt creates and returns new summary in s with the given name,
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// window and quantiles.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned summary is safe to use from concurrent goroutines.
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func (s *Set) NewSummaryExt(name string, window time.Duration, quantiles []float64) *Summary {
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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sm := newSummary(window, quantiles)
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s.mu.Lock()
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// defer will unlock in case of panic
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// checks in tests
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defer s.mu.Unlock()
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s.mustRegisterLocked(name, sm, false)
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registerSummaryLocked(sm)
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s.registerSummaryQuantilesLocked(name, sm)
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s.summaries = append(s.summaries, sm)
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return sm
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}
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// GetOrCreateSummary returns registered summary with the given name in s
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// or creates new summary if s doesn't contain summary with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned summary is safe to use from concurrent goroutines.
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//
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// Performance tip: prefer NewSummary instead of GetOrCreateSummary.
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func (s *Set) GetOrCreateSummary(name string) *Summary {
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return s.GetOrCreateSummaryExt(name, defaultSummaryWindow, defaultSummaryQuantiles)
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}
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// GetOrCreateSummaryExt returns registered summary with the given name,
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// window and quantiles in s or creates new summary if s doesn't
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// contain summary with the given name.
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//
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// name must be valid Prometheus-compatible metric with possible labels.
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// For instance,
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//
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// - foo
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// - foo{bar="baz"}
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// - foo{bar="baz",aaa="b"}
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//
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// The returned summary is safe to use from concurrent goroutines.
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//
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// Performance tip: prefer NewSummaryExt instead of GetOrCreateSummaryExt.
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func (s *Set) GetOrCreateSummaryExt(name string, window time.Duration, quantiles []float64) *Summary {
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s.mu.Lock()
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nm := s.m[name]
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s.mu.Unlock()
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if nm == nil {
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// Slow path - create and register missing summary.
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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sm := newSummary(window, quantiles)
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nmNew := &namedMetric{
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name: name,
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metric: sm,
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}
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s.mu.Lock()
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nm = s.m[name]
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if nm == nil {
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nm = nmNew
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s.m[name] = nm
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s.a = append(s.a, nm)
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registerSummaryLocked(sm)
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s.registerSummaryQuantilesLocked(name, sm)
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}
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s.summaries = append(s.summaries, sm)
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s.mu.Unlock()
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}
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sm, ok := nm.metric.(*Summary)
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if !ok {
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panic(fmt.Errorf("BUG: metric %q isn't a Summary. It is %T", name, nm.metric))
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}
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if sm.window != window {
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panic(fmt.Errorf("BUG: invalid window requested for the summary %q; requested %s; need %s", name, window, sm.window))
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}
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if !isEqualQuantiles(sm.quantiles, quantiles) {
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panic(fmt.Errorf("BUG: invalid quantiles requested from the summary %q; requested %v; need %v", name, quantiles, sm.quantiles))
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}
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return sm
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}
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func (s *Set) registerSummaryQuantilesLocked(name string, sm *Summary) {
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for i, q := range sm.quantiles {
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quantileValueName := addTag(name, fmt.Sprintf(`quantile="%g"`, q))
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qv := &quantileValue{
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sm: sm,
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idx: i,
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}
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s.mustRegisterLocked(quantileValueName, qv, true)
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}
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}
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func (s *Set) registerMetric(name string, m metric) {
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if err := validateMetric(name); err != nil {
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panic(fmt.Errorf("BUG: invalid metric name %q: %s", name, err))
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}
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s.mu.Lock()
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// defer will unlock in case of panic
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// checks in test
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defer s.mu.Unlock()
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s.mustRegisterLocked(name, m, false)
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}
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// mustRegisterLocked registers given metric with the given name.
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//
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// Panics if the given name was already registered before.
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func (s *Set) mustRegisterLocked(name string, m metric, isAux bool) {
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nm, ok := s.m[name]
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if !ok {
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nm = &namedMetric{
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name: name,
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metric: m,
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isAux: isAux,
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}
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s.m[name] = nm
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s.a = append(s.a, nm)
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}
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if ok {
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panic(fmt.Errorf("BUG: metric %q is already registered", name))
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}
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}
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// UnregisterMetric removes metric with the given name from s.
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//
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// True is returned if the metric has been removed.
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// False is returned if the given metric is missing in s.
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func (s *Set) UnregisterMetric(name string) bool {
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s.mu.Lock()
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defer s.mu.Unlock()
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nm, ok := s.m[name]
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if !ok {
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return false
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}
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if nm.isAux {
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// Do not allow deleting auxiliary metrics such as summary_metric{quantile="..."}
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// Such metrics must be deleted via parent metric name, e.g. summary_metric .
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return false
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}
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return s.unregisterMetricLocked(nm)
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}
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func (s *Set) unregisterMetricLocked(nm *namedMetric) bool {
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name := nm.name
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delete(s.m, name)
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deleteFromList := func(metricName string) {
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for i, nm := range s.a {
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if nm.name == metricName {
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s.a = append(s.a[:i], s.a[i+1:]...)
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return
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}
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}
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panic(fmt.Errorf("BUG: cannot find metric %q in the list of registered metrics", name))
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}
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// remove metric from s.a
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deleteFromList(name)
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sm, ok := nm.metric.(*Summary)
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if !ok {
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// There is no need in cleaning up non-summary metrics.
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return true
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}
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// cleanup registry from per-quantile metrics
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for _, q := range sm.quantiles {
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quantileValueName := addTag(name, fmt.Sprintf(`quantile="%g"`, q))
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delete(s.m, quantileValueName)
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deleteFromList(quantileValueName)
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}
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// Remove sm from s.summaries
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found := false
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for i, xsm := range s.summaries {
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if xsm == sm {
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s.summaries = append(s.summaries[:i], s.summaries[i+1:]...)
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found = true
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break
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}
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}
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if !found {
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panic(fmt.Errorf("BUG: cannot find summary %q in the list of registered summaries", name))
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}
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unregisterSummary(sm)
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return true
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}
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// UnregisterAllMetrics de-registers all metrics registered in s.
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//
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// It also de-registers writeMetrics callbacks passed to RegisterMetricsWriter.
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func (s *Set) UnregisterAllMetrics() {
|
|
metricNames := s.ListMetricNames()
|
|
for _, name := range metricNames {
|
|
s.UnregisterMetric(name)
|
|
}
|
|
|
|
s.mu.Lock()
|
|
s.metricsWriters = nil
|
|
s.mu.Unlock()
|
|
}
|
|
|
|
// ListMetricNames returns sorted list of all the metrics in s.
|
|
//
|
|
// The returned list doesn't include metrics generated by metricsWriter passed to RegisterMetricsWriter.
|
|
func (s *Set) ListMetricNames() []string {
|
|
s.mu.Lock()
|
|
defer s.mu.Unlock()
|
|
metricNames := make([]string, 0, len(s.m))
|
|
for _, nm := range s.m {
|
|
if nm.isAux {
|
|
continue
|
|
}
|
|
metricNames = append(metricNames, nm.name)
|
|
}
|
|
sort.Strings(metricNames)
|
|
return metricNames
|
|
}
|
|
|
|
// RegisterMetricsWriter registers writeMetrics callback for including metrics in the output generated by s.WritePrometheus.
|
|
//
|
|
// The writeMetrics callback must write metrics to w in Prometheus text exposition format without timestamps and trailing comments.
|
|
// The last line generated by writeMetrics must end with \n.
|
|
// See https://github.com/prometheus/docs/blob/main/content/docs/instrumenting/exposition_formats.md#text-based-format
|
|
//
|
|
// It is OK to reguster multiple writeMetrics callbacks - all of them will be called sequentially for gererating the output at s.WritePrometheus.
|
|
func (s *Set) RegisterMetricsWriter(writeMetrics func(w io.Writer)) {
|
|
s.mu.Lock()
|
|
defer s.mu.Unlock()
|
|
|
|
s.metricsWriters = append(s.metricsWriters, writeMetrics)
|
|
}
|