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author | Péter Szilágyi <peterke@gmail.com> | 2015-06-22 17:00:55 +0800 |
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committer | Péter Szilágyi <peterke@gmail.com> | 2015-06-24 23:34:04 +0800 |
commit | 7bd71fa80071f86ca86ed7ef64ab51c88cabe7d4 (patch) | |
tree | 9f770d2f59ca1a3053ebf7aa7921a122aa3bc388 /Godeps/_workspace/src/github.com/rcrowley/go-metrics/meter.go | |
parent | 7f92e708c504e1c4a7382c68b5a4ed68db9c8deb (diff) | |
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godeps: pull in go-metrics
Diffstat (limited to 'Godeps/_workspace/src/github.com/rcrowley/go-metrics/meter.go')
-rw-r--r-- | Godeps/_workspace/src/github.com/rcrowley/go-metrics/meter.go | 233 |
1 files changed, 233 insertions, 0 deletions
diff --git a/Godeps/_workspace/src/github.com/rcrowley/go-metrics/meter.go b/Godeps/_workspace/src/github.com/rcrowley/go-metrics/meter.go new file mode 100644 index 000000000..0389ab0b8 --- /dev/null +++ b/Godeps/_workspace/src/github.com/rcrowley/go-metrics/meter.go @@ -0,0 +1,233 @@ +package metrics + +import ( + "sync" + "time" +) + +// Meters count events to produce exponentially-weighted moving average rates +// at one-, five-, and fifteen-minutes and a mean rate. +type Meter interface { + Count() int64 + Mark(int64) + Rate1() float64 + Rate5() float64 + Rate15() float64 + RateMean() float64 + Snapshot() Meter +} + +// GetOrRegisterMeter returns an existing Meter or constructs and registers a +// new StandardMeter. +func GetOrRegisterMeter(name string, r Registry) Meter { + if nil == r { + r = DefaultRegistry + } + return r.GetOrRegister(name, NewMeter).(Meter) +} + +// NewMeter constructs a new StandardMeter and launches a goroutine. +func NewMeter() Meter { + if UseNilMetrics { + return NilMeter{} + } + m := newStandardMeter() + arbiter.Lock() + defer arbiter.Unlock() + arbiter.meters = append(arbiter.meters, m) + if !arbiter.started { + arbiter.started = true + go arbiter.tick() + } + return m +} + +// NewMeter constructs and registers a new StandardMeter and launches a +// goroutine. +func NewRegisteredMeter(name string, r Registry) Meter { + c := NewMeter() + if nil == r { + r = DefaultRegistry + } + r.Register(name, c) + return c +} + +// MeterSnapshot is a read-only copy of another Meter. +type MeterSnapshot struct { + count int64 + rate1, rate5, rate15, rateMean float64 +} + +// Count returns the count of events at the time the snapshot was taken. +func (m *MeterSnapshot) Count() int64 { return m.count } + +// Mark panics. +func (*MeterSnapshot) Mark(n int64) { + panic("Mark called on a MeterSnapshot") +} + +// Rate1 returns the one-minute moving average rate of events per second at the +// time the snapshot was taken. +func (m *MeterSnapshot) Rate1() float64 { return m.rate1 } + +// Rate5 returns the five-minute moving average rate of events per second at +// the time the snapshot was taken. +func (m *MeterSnapshot) Rate5() float64 { return m.rate5 } + +// Rate15 returns the fifteen-minute moving average rate of events per second +// at the time the snapshot was taken. +func (m *MeterSnapshot) Rate15() float64 { return m.rate15 } + +// RateMean returns the meter's mean rate of events per second at the time the +// snapshot was taken. +func (m *MeterSnapshot) RateMean() float64 { return m.rateMean } + +// Snapshot returns the snapshot. +func (m *MeterSnapshot) Snapshot() Meter { return m } + +// NilMeter is a no-op Meter. +type NilMeter struct{} + +// Count is a no-op. +func (NilMeter) Count() int64 { return 0 } + +// Mark is a no-op. +func (NilMeter) Mark(n int64) {} + +// Rate1 is a no-op. +func (NilMeter) Rate1() float64 { return 0.0 } + +// Rate5 is a no-op. +func (NilMeter) Rate5() float64 { return 0.0 } + +// Rate15is a no-op. +func (NilMeter) Rate15() float64 { return 0.0 } + +// RateMean is a no-op. +func (NilMeter) RateMean() float64 { return 0.0 } + +// Snapshot is a no-op. +func (NilMeter) Snapshot() Meter { return NilMeter{} } + +// StandardMeter is the standard implementation of a Meter. +type StandardMeter struct { + lock sync.RWMutex + snapshot *MeterSnapshot + a1, a5, a15 EWMA + startTime time.Time +} + +func newStandardMeter() *StandardMeter { + return &StandardMeter{ + snapshot: &MeterSnapshot{}, + a1: NewEWMA1(), + a5: NewEWMA5(), + a15: NewEWMA15(), + startTime: time.Now(), + } +} + +// Count returns the number of events recorded. +func (m *StandardMeter) Count() int64 { + m.lock.RLock() + count := m.snapshot.count + m.lock.RUnlock() + return count +} + +// Mark records the occurance of n events. +func (m *StandardMeter) Mark(n int64) { + m.lock.Lock() + defer m.lock.Unlock() + m.snapshot.count += n + m.a1.Update(n) + m.a5.Update(n) + m.a15.Update(n) + m.updateSnapshot() +} + +// Rate1 returns the one-minute moving average rate of events per second. +func (m *StandardMeter) Rate1() float64 { + m.lock.RLock() + rate1 := m.snapshot.rate1 + m.lock.RUnlock() + return rate1 +} + +// Rate5 returns the five-minute moving average rate of events per second. +func (m *StandardMeter) Rate5() float64 { + m.lock.RLock() + rate5 := m.snapshot.rate5 + m.lock.RUnlock() + return rate5 +} + +// Rate15 returns the fifteen-minute moving average rate of events per second. +func (m *StandardMeter) Rate15() float64 { + m.lock.RLock() + rate15 := m.snapshot.rate15 + m.lock.RUnlock() + return rate15 +} + +// RateMean returns the meter's mean rate of events per second. +func (m *StandardMeter) RateMean() float64 { + m.lock.RLock() + rateMean := m.snapshot.rateMean + m.lock.RUnlock() + return rateMean +} + +// Snapshot returns a read-only copy of the meter. +func (m *StandardMeter) Snapshot() Meter { + m.lock.RLock() + snapshot := *m.snapshot + m.lock.RUnlock() + return &snapshot +} + +func (m *StandardMeter) updateSnapshot() { + // should run with write lock held on m.lock + snapshot := m.snapshot + snapshot.rate1 = m.a1.Rate() + snapshot.rate5 = m.a5.Rate() + snapshot.rate15 = m.a15.Rate() + snapshot.rateMean = float64(snapshot.count) / time.Since(m.startTime).Seconds() +} + +func (m *StandardMeter) tick() { + m.lock.Lock() + defer m.lock.Unlock() + m.a1.Tick() + m.a5.Tick() + m.a15.Tick() + m.updateSnapshot() +} + +type meterArbiter struct { + sync.RWMutex + started bool + meters []*StandardMeter + ticker *time.Ticker +} + +var arbiter = meterArbiter{ticker: time.NewTicker(5e9)} + +// Ticks meters on the scheduled interval +func (ma *meterArbiter) tick() { + for { + select { + case <-ma.ticker.C: + ma.tickMeters() + } + } +} + +func (ma *meterArbiter) tickMeters() { + ma.RLock() + defer ma.RUnlock() + for _, meter := range ma.meters { + meter.tick() + } +} |