forked from vulcand/oxy
/
roundtrip.go
302 lines (259 loc) · 7.39 KB
/
roundtrip.go
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package memmetrics
import (
"errors"
"net/http"
"sync"
"time"
"github.com/mailgun/timetools"
)
// RTMetrics provides aggregated performance metrics for HTTP requests processing
// such as round trip latency, response codes counters network error and total requests.
// all counters are collected as rolling window counters with defined precision, histograms
// are a rolling window histograms with defined precision as well.
// See RTOptions for more detail on parameters.
type RTMetrics struct {
total *RollingCounter
netErrors *RollingCounter
statusCodes map[int]*RollingCounter
statusCodesLock sync.RWMutex
histogram *RollingHDRHistogram
histogramLock sync.RWMutex
newCounter NewCounterFn
newHist NewRollingHistogramFn
clock timetools.TimeProvider
}
type rrOptSetter func(r *RTMetrics) error
// NewRTMetricsFn builder function type
type NewRTMetricsFn func() (*RTMetrics, error)
// NewCounterFn builder function type
type NewCounterFn func() (*RollingCounter, error)
// NewRollingHistogramFn builder function type
type NewRollingHistogramFn func() (*RollingHDRHistogram, error)
// RTCounter set a builder function for Counter
func RTCounter(new NewCounterFn) rrOptSetter {
return func(r *RTMetrics) error {
r.newCounter = new
return nil
}
}
// RTHistogram set a builder function for RollingHistogram
func RTHistogram(fn NewRollingHistogramFn) rrOptSetter {
return func(r *RTMetrics) error {
r.newHist = fn
return nil
}
}
// RTClock sets a clock
func RTClock(clock timetools.TimeProvider) rrOptSetter {
return func(r *RTMetrics) error {
r.clock = clock
return nil
}
}
// NewRTMetrics returns new instance of metrics collector.
func NewRTMetrics(settings ...rrOptSetter) (*RTMetrics, error) {
m := &RTMetrics{
statusCodes: make(map[int]*RollingCounter),
statusCodesLock: sync.RWMutex{},
}
for _, s := range settings {
if err := s(m); err != nil {
return nil, err
}
}
if m.clock == nil {
m.clock = &timetools.RealTime{}
}
if m.newCounter == nil {
m.newCounter = func() (*RollingCounter, error) {
return NewCounter(counterBuckets, counterResolution, CounterClock(m.clock))
}
}
if m.newHist == nil {
m.newHist = func() (*RollingHDRHistogram, error) {
return NewRollingHDRHistogram(histMin, histMax, histSignificantFigures, histPeriod, histBuckets, RollingClock(m.clock))
}
}
h, err := m.newHist()
if err != nil {
return nil, err
}
netErrors, err := m.newCounter()
if err != nil {
return nil, err
}
total, err := m.newCounter()
if err != nil {
return nil, err
}
m.histogram = h
m.netErrors = netErrors
m.total = total
return m, nil
}
// Export Returns a new RTMetrics which is a copy of the current one
func (m *RTMetrics) Export() *RTMetrics {
m.statusCodesLock.RLock()
defer m.statusCodesLock.RUnlock()
m.histogramLock.RLock()
defer m.histogramLock.RUnlock()
export := &RTMetrics{}
export.statusCodesLock = sync.RWMutex{}
export.histogramLock = sync.RWMutex{}
export.total = m.total.Clone()
export.netErrors = m.netErrors.Clone()
exportStatusCodes := map[int]*RollingCounter{}
for code, rollingCounter := range m.statusCodes {
exportStatusCodes[code] = rollingCounter.Clone()
}
export.statusCodes = exportStatusCodes
if m.histogram != nil {
export.histogram = m.histogram.Export()
}
export.newCounter = m.newCounter
export.newHist = m.newHist
export.clock = m.clock
return export
}
// CounterWindowSize gets total windows size
func (m *RTMetrics) CounterWindowSize() time.Duration {
return m.total.WindowSize()
}
// NetworkErrorRatio calculates the amont of network errors such as time outs and dropped connection
// that occurred in the given time window compared to the total requests count.
func (m *RTMetrics) NetworkErrorRatio() float64 {
if m.total.Count() == 0 {
return 0
}
return float64(m.netErrors.Count()) / float64(m.total.Count())
}
// ResponseCodeRatio calculates ratio of count(startA to endA) / count(startB to endB)
func (m *RTMetrics) ResponseCodeRatio(startA, endA, startB, endB int) float64 {
a := int64(0)
b := int64(0)
m.statusCodesLock.RLock()
defer m.statusCodesLock.RUnlock()
for code, v := range m.statusCodes {
if code < endA && code >= startA {
a += v.Count()
}
if code < endB && code >= startB {
b += v.Count()
}
}
if b != 0 {
return float64(a) / float64(b)
}
return 0
}
// Append append a metric
func (m *RTMetrics) Append(other *RTMetrics) error {
if m == other {
return errors.New("RTMetrics cannot append to self")
}
if err := m.total.Append(other.total); err != nil {
return err
}
if err := m.netErrors.Append(other.netErrors); err != nil {
return err
}
copied := other.Export()
m.statusCodesLock.Lock()
defer m.statusCodesLock.Unlock()
m.histogramLock.Lock()
defer m.histogramLock.Unlock()
for code, c := range copied.statusCodes {
o, ok := m.statusCodes[code]
if ok {
if err := o.Append(c); err != nil {
return err
}
} else {
m.statusCodes[code] = c.Clone()
}
}
return m.histogram.Append(copied.histogram)
}
// Record records a metric
func (m *RTMetrics) Record(code int, duration time.Duration) {
m.total.Inc(1)
if code == http.StatusGatewayTimeout || code == http.StatusBadGateway {
m.netErrors.Inc(1)
}
m.recordStatusCode(code)
m.recordLatency(duration)
}
// TotalCount returns total count of processed requests collected.
func (m *RTMetrics) TotalCount() int64 {
return m.total.Count()
}
// NetworkErrorCount returns total count of processed requests observed
func (m *RTMetrics) NetworkErrorCount() int64 {
return m.netErrors.Count()
}
// StatusCodesCounts returns map with counts of the response codes
func (m *RTMetrics) StatusCodesCounts() map[int]int64 {
sc := make(map[int]int64)
m.statusCodesLock.RLock()
defer m.statusCodesLock.RUnlock()
for k, v := range m.statusCodes {
if v.Count() != 0 {
sc[k] = v.Count()
}
}
return sc
}
// LatencyHistogram computes and returns resulting histogram with latencies observed.
func (m *RTMetrics) LatencyHistogram() (*HDRHistogram, error) {
m.histogramLock.Lock()
defer m.histogramLock.Unlock()
return m.histogram.Merged()
}
// Reset reset metrics
func (m *RTMetrics) Reset() {
m.statusCodesLock.Lock()
defer m.statusCodesLock.Unlock()
m.histogramLock.Lock()
defer m.histogramLock.Unlock()
m.histogram.Reset()
m.total.Reset()
m.netErrors.Reset()
m.statusCodes = make(map[int]*RollingCounter)
}
func (m *RTMetrics) recordLatency(d time.Duration) error {
m.histogramLock.Lock()
defer m.histogramLock.Unlock()
return m.histogram.RecordLatencies(d, 1)
}
func (m *RTMetrics) recordStatusCode(statusCode int) error {
m.statusCodesLock.Lock()
if c, ok := m.statusCodes[statusCode]; ok {
c.Inc(1)
m.statusCodesLock.Unlock()
return nil
}
m.statusCodesLock.Unlock()
m.statusCodesLock.Lock()
defer m.statusCodesLock.Unlock()
// Check if another goroutine has written our counter already
if c, ok := m.statusCodes[statusCode]; ok {
c.Inc(1)
return nil
}
c, err := m.newCounter()
if err != nil {
return err
}
c.Inc(1)
m.statusCodes[statusCode] = c
return nil
}
const (
counterBuckets = 10
counterResolution = time.Second
histMin = 1
histMax = 3600000000 // 1 hour in microseconds
histSignificantFigures = 2 // significant figures (1% precision)
histBuckets = 6 // number of sub-histograms in a rolling histogram
histPeriod = 10 * time.Second // roll time
)