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author | Christopher Speller <crspeller@gmail.com> | 2017-05-17 16:51:25 -0400 |
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committer | GitHub <noreply@github.com> | 2017-05-17 16:51:25 -0400 |
commit | d103ed6ca97ca5a2669f6cf5fe4b3d2a9c945f26 (patch) | |
tree | dbde13123c6add150448f7b75753ac022d862475 /vendor/github.com/armon/go-metrics/inmem.go | |
parent | cd23b8139a9463b67e3096744321f6f4eb0ca40a (diff) | |
download | chat-d103ed6ca97ca5a2669f6cf5fe4b3d2a9c945f26.tar.gz chat-d103ed6ca97ca5a2669f6cf5fe4b3d2a9c945f26.tar.bz2 chat-d103ed6ca97ca5a2669f6cf5fe4b3d2a9c945f26.zip |
Upgrading server dependancies (#6431)
Diffstat (limited to 'vendor/github.com/armon/go-metrics/inmem.go')
-rw-r--r-- | vendor/github.com/armon/go-metrics/inmem.go | 247 |
1 files changed, 247 insertions, 0 deletions
diff --git a/vendor/github.com/armon/go-metrics/inmem.go b/vendor/github.com/armon/go-metrics/inmem.go new file mode 100644 index 000000000..83fb6bba0 --- /dev/null +++ b/vendor/github.com/armon/go-metrics/inmem.go @@ -0,0 +1,247 @@ +package metrics + +import ( + "fmt" + "math" + "strings" + "sync" + "time" +) + +// InmemSink provides a MetricSink that does in-memory aggregation +// without sending metrics over a network. It can be embedded within +// an application to provide profiling information. +type InmemSink struct { + // How long is each aggregation interval + interval time.Duration + + // Retain controls how many metrics interval we keep + retain time.Duration + + // maxIntervals is the maximum length of intervals. + // It is retain / interval. + maxIntervals int + + // intervals is a slice of the retained intervals + intervals []*IntervalMetrics + intervalLock sync.RWMutex + + rateDenom float64 +} + +// IntervalMetrics stores the aggregated metrics +// for a specific interval +type IntervalMetrics struct { + sync.RWMutex + + // The start time of the interval + Interval time.Time + + // Gauges maps the key to the last set value + Gauges map[string]float32 + + // Points maps the string to the list of emitted values + // from EmitKey + Points map[string][]float32 + + // Counters maps the string key to a sum of the counter + // values + Counters map[string]*AggregateSample + + // Samples maps the key to an AggregateSample, + // which has the rolled up view of a sample + Samples map[string]*AggregateSample +} + +// NewIntervalMetrics creates a new IntervalMetrics for a given interval +func NewIntervalMetrics(intv time.Time) *IntervalMetrics { + return &IntervalMetrics{ + Interval: intv, + Gauges: make(map[string]float32), + Points: make(map[string][]float32), + Counters: make(map[string]*AggregateSample), + Samples: make(map[string]*AggregateSample), + } +} + +// AggregateSample is used to hold aggregate metrics +// about a sample +type AggregateSample struct { + Count int // The count of emitted pairs + Rate float64 // The count of emitted pairs per time unit (usually 1 second) + Sum float64 // The sum of values + SumSq float64 // The sum of squared values + Min float64 // Minimum value + Max float64 // Maximum value + LastUpdated time.Time // When value was last updated +} + +// Computes a Stddev of the values +func (a *AggregateSample) Stddev() float64 { + num := (float64(a.Count) * a.SumSq) - math.Pow(a.Sum, 2) + div := float64(a.Count * (a.Count - 1)) + if div == 0 { + return 0 + } + return math.Sqrt(num / div) +} + +// Computes a mean of the values +func (a *AggregateSample) Mean() float64 { + if a.Count == 0 { + return 0 + } + return a.Sum / float64(a.Count) +} + +// Ingest is used to update a sample +func (a *AggregateSample) Ingest(v float64, rateDenom float64) { + a.Count++ + a.Sum += v + a.SumSq += (v * v) + if v < a.Min || a.Count == 1 { + a.Min = v + } + if v > a.Max || a.Count == 1 { + a.Max = v + } + a.Rate = float64(a.Count)/rateDenom + a.LastUpdated = time.Now() +} + +func (a *AggregateSample) String() string { + if a.Count == 0 { + return "Count: 0" + } else if a.Stddev() == 0 { + return fmt.Sprintf("Count: %d Sum: %0.3f LastUpdated: %s", a.Count, a.Sum, a.LastUpdated) + } else { + return fmt.Sprintf("Count: %d Min: %0.3f Mean: %0.3f Max: %0.3f Stddev: %0.3f Sum: %0.3f LastUpdated: %s", + a.Count, a.Min, a.Mean(), a.Max, a.Stddev(), a.Sum, a.LastUpdated) + } +} + +// NewInmemSink is used to construct a new in-memory sink. +// Uses an aggregation interval and maximum retention period. +func NewInmemSink(interval, retain time.Duration) *InmemSink { + rateTimeUnit := time.Second + i := &InmemSink{ + interval: interval, + retain: retain, + maxIntervals: int(retain / interval), + rateDenom: float64(interval.Nanoseconds()) / float64(rateTimeUnit.Nanoseconds()), + } + i.intervals = make([]*IntervalMetrics, 0, i.maxIntervals) + return i +} + +func (i *InmemSink) SetGauge(key []string, val float32) { + k := i.flattenKey(key) + intv := i.getInterval() + + intv.Lock() + defer intv.Unlock() + intv.Gauges[k] = val +} + +func (i *InmemSink) EmitKey(key []string, val float32) { + k := i.flattenKey(key) + intv := i.getInterval() + + intv.Lock() + defer intv.Unlock() + vals := intv.Points[k] + intv.Points[k] = append(vals, val) +} + +func (i *InmemSink) IncrCounter(key []string, val float32) { + k := i.flattenKey(key) + intv := i.getInterval() + + intv.Lock() + defer intv.Unlock() + + agg := intv.Counters[k] + if agg == nil { + agg = &AggregateSample{} + intv.Counters[k] = agg + } + agg.Ingest(float64(val), i.rateDenom) +} + +func (i *InmemSink) AddSample(key []string, val float32) { + k := i.flattenKey(key) + intv := i.getInterval() + + intv.Lock() + defer intv.Unlock() + + agg := intv.Samples[k] + if agg == nil { + agg = &AggregateSample{} + intv.Samples[k] = agg + } + agg.Ingest(float64(val), i.rateDenom) +} + +// Data is used to retrieve all the aggregated metrics +// Intervals may be in use, and a read lock should be acquired +func (i *InmemSink) Data() []*IntervalMetrics { + // Get the current interval, forces creation + i.getInterval() + + i.intervalLock.RLock() + defer i.intervalLock.RUnlock() + + intervals := make([]*IntervalMetrics, len(i.intervals)) + copy(intervals, i.intervals) + return intervals +} + +func (i *InmemSink) getExistingInterval(intv time.Time) *IntervalMetrics { + i.intervalLock.RLock() + defer i.intervalLock.RUnlock() + + n := len(i.intervals) + if n > 0 && i.intervals[n-1].Interval == intv { + return i.intervals[n-1] + } + return nil +} + +func (i *InmemSink) createInterval(intv time.Time) *IntervalMetrics { + i.intervalLock.Lock() + defer i.intervalLock.Unlock() + + // Check for an existing interval + n := len(i.intervals) + if n > 0 && i.intervals[n-1].Interval == intv { + return i.intervals[n-1] + } + + // Add the current interval + current := NewIntervalMetrics(intv) + i.intervals = append(i.intervals, current) + n++ + + // Truncate the intervals if they are too long + if n >= i.maxIntervals { + copy(i.intervals[0:], i.intervals[n-i.maxIntervals:]) + i.intervals = i.intervals[:i.maxIntervals] + } + return current +} + +// getInterval returns the current interval to write to +func (i *InmemSink) getInterval() *IntervalMetrics { + intv := time.Now().Truncate(i.interval) + if m := i.getExistingInterval(intv); m != nil { + return m + } + return i.createInterval(intv) +} + +// Flattens the key for formatting, removes spaces +func (i *InmemSink) flattenKey(parts []string) string { + joined := strings.Join(parts, ".") + return strings.Replace(joined, " ", "_", -1) +} |