forked from vulcand/vulcand
/
roundtrip.go
228 lines (194 loc) · 5.44 KB
/
roundtrip.go
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package memmetrics
import (
"net/http"
"time"
"github.com/mailgun/vulcand/Godeps/_workspace/src/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
histogram *RollingHDRHistogram
newCounter NewCounterFn
newHist NewRollingHistogramFn
clock timetools.TimeProvider
}
type rrOptSetter func(r *RTMetrics) error
type NewRTMetricsFn func() (*RTMetrics, error)
type NewCounterFn func() (*RollingCounter, error)
type NewRollingHistogramFn func() (*RollingHDRHistogram, error)
func RTCounter(new NewCounterFn) rrOptSetter {
return func(r *RTMetrics) error {
r.newCounter = new
return nil
}
}
func RTHistogram(new NewRollingHistogramFn) rrOptSetter {
return func(r *RTMetrics) error {
r.newHist = new
return nil
}
}
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),
}
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
}
func (m *RTMetrics) CounterWindowSize() time.Duration {
return m.total.WindowSize()
}
// GetNetworkErrorRatio calculates the amont of network errors such as time outs and dropped connection
// that occured 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())
}
// GetResponseCodeRatio 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)
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
}
func (m *RTMetrics) Append(other *RTMetrics) error {
if err := m.total.Append(other.total); err != nil {
return err
}
if err := m.netErrors.Append(other.netErrors); err != nil {
return err
}
for code, c := range other.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(other.histogram)
}
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)
}
// GetTotalCount returns total count of processed requests collected.
func (m *RTMetrics) TotalCount() int64 {
return m.total.Count()
}
// GetNetworkErrorCount returns total count of processed requests observed
func (m *RTMetrics) NetworkErrorCount() int64 {
return m.netErrors.Count()
}
// GetStatusCodesCounts returns map with counts of the response codes
func (m *RTMetrics) StatusCodesCounts() map[int]int64 {
sc := make(map[int]int64)
for k, v := range m.statusCodes {
if v.Count() != 0 {
sc[k] = v.Count()
}
}
return sc
}
// GetLatencyHistogram computes and returns resulting histogram with latencies observed.
func (m *RTMetrics) LatencyHistogram() (*HDRHistogram, error) {
return m.histogram.Merged()
}
func (m *RTMetrics) Reset() {
m.histogram.Reset()
m.total.Reset()
m.netErrors.Reset()
m.statusCodes = make(map[int]*RollingCounter)
}
func (m *RTMetrics) recordNetError() error {
m.netErrors.Inc(1)
return nil
}
func (m *RTMetrics) recordLatency(d time.Duration) error {
return m.histogram.RecordLatencies(d, 1)
}
func (m *RTMetrics) recordStatusCode(statusCode int) error {
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 // signigicant figures (1% precision)
histBuckets = 6 // number of sub-histograms in a rolling histogram
histPeriod = 10 * time.Second // roll time
)