401 lines
11 KiB
Go
401 lines
11 KiB
Go
package dnsfilter
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import (
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"encoding/json"
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"fmt"
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"log"
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"net/http"
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"sync"
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"time"
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"github.com/coredns/coredns/plugin"
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"github.com/prometheus/client_golang/prometheus"
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)
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var (
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requests = newDNSCounter("requests_total", "Count of requests seen by dnsfilter.")
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filtered = newDNSCounter("filtered_total", "Count of requests filtered by dnsfilter.")
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filteredLists = newDNSCounter("filtered_lists_total", "Count of requests filtered by dnsfilter using lists.")
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filteredSafebrowsing = newDNSCounter("filtered_safebrowsing_total", "Count of requests filtered by dnsfilter using safebrowsing.")
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filteredParental = newDNSCounter("filtered_parental_total", "Count of requests filtered by dnsfilter using parental.")
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filteredInvalid = newDNSCounter("filtered_invalid_total", "Count of requests filtered by dnsfilter because they were invalid.")
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whitelisted = newDNSCounter("whitelisted_total", "Count of requests not filtered by dnsfilter because they are whitelisted.")
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safesearch = newDNSCounter("safesearch_total", "Count of requests replaced by dnsfilter safesearch.")
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errorsTotal = newDNSCounter("errors_total", "Count of requests that dnsfilter couldn't process because of transitive errors.")
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elapsedTime = newDNSHistogram("request_duration", "Histogram of the time (in seconds) each request took.")
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)
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// entries for single time period (for example all per-second entries)
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type statsEntries map[string][statsHistoryElements]float64
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// how far back to keep the stats
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const statsHistoryElements = 60 + 1 // +1 for calculating delta
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// each periodic stat is a map of arrays
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type periodicStats struct {
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Entries statsEntries
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period time.Duration // how long one entry lasts
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LastRotate time.Time // last time this data was rotated
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sync.RWMutex
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}
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type stats struct {
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PerSecond periodicStats
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PerMinute periodicStats
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PerHour periodicStats
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PerDay periodicStats
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}
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// per-second/per-minute/per-hour/per-day stats
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var statistics stats
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func initPeriodicStats(periodic *periodicStats, period time.Duration) {
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periodic.Entries = statsEntries{}
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periodic.LastRotate = time.Now()
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periodic.period = period
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}
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func init() {
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purgeStats()
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}
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func purgeStats() {
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initPeriodicStats(&statistics.PerSecond, time.Second)
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initPeriodicStats(&statistics.PerMinute, time.Minute)
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initPeriodicStats(&statistics.PerHour, time.Hour)
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initPeriodicStats(&statistics.PerDay, time.Hour*24)
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}
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func (p *periodicStats) Inc(name string, when time.Time) {
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// calculate how many periods ago this happened
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elapsed := int64(time.Since(when) / p.period)
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// trace("%s: %v as %v -> [%v]", name, time.Since(when), p.period, elapsed)
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if elapsed >= statsHistoryElements {
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return // outside of our timeframe
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}
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p.Lock()
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currentValues := p.Entries[name]
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currentValues[elapsed]++
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p.Entries[name] = currentValues
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p.Unlock()
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}
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func (p *periodicStats) Observe(name string, when time.Time, value float64) {
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// calculate how many periods ago this happened
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elapsed := int64(time.Since(when) / p.period)
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// trace("%s: %v as %v -> [%v]", name, time.Since(when), p.period, elapsed)
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if elapsed >= statsHistoryElements {
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return // outside of our timeframe
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}
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p.Lock()
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{
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countname := name + "_count"
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currentValues := p.Entries[countname]
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value := currentValues[elapsed]
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// trace("Will change p.Entries[%s][%d] from %v to %v", countname, elapsed, value, value+1)
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value += 1
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currentValues[elapsed] = value
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p.Entries[countname] = currentValues
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}
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{
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totalname := name + "_sum"
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currentValues := p.Entries[totalname]
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currentValues[elapsed] += value
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p.Entries[totalname] = currentValues
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}
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p.Unlock()
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}
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func (p *periodicStats) statsRotate(now time.Time) {
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p.Lock()
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rotations := int64(now.Sub(p.LastRotate) / p.period)
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if rotations > statsHistoryElements {
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rotations = statsHistoryElements
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}
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// calculate how many times we should rotate
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for r := int64(0); r < rotations; r++ {
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for key, values := range p.Entries {
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newValues := [statsHistoryElements]float64{}
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for i := 1; i < len(values); i++ {
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newValues[i] = values[i-1]
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}
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p.Entries[key] = newValues
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}
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}
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if rotations > 0 {
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p.LastRotate = now
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}
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p.Unlock()
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}
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func statsRotator() {
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for range time.Tick(time.Second) {
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now := time.Now()
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statistics.PerSecond.statsRotate(now)
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statistics.PerMinute.statsRotate(now)
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statistics.PerHour.statsRotate(now)
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statistics.PerDay.statsRotate(now)
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}
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}
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// counter that wraps around prometheus Counter but also adds to periodic stats
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type counter struct {
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name string // used as key in periodic stats
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value int64
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prom prometheus.Counter
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}
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func newDNSCounter(name string, help string) *counter {
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// trace("called")
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c := &counter{}
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c.prom = prometheus.NewCounter(prometheus.CounterOpts{
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Namespace: plugin.Namespace,
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Subsystem: "dnsfilter",
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Name: name,
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Help: help,
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})
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c.name = name
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return c
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}
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func (c *counter) IncWithTime(when time.Time) {
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statistics.PerSecond.Inc(c.name, when)
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statistics.PerMinute.Inc(c.name, when)
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statistics.PerHour.Inc(c.name, when)
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statistics.PerDay.Inc(c.name, when)
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c.value++
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c.prom.Inc()
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}
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func (c *counter) Inc() {
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c.IncWithTime(time.Now())
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}
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func (c *counter) Describe(ch chan<- *prometheus.Desc) {
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c.prom.Describe(ch)
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}
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func (c *counter) Collect(ch chan<- prometheus.Metric) {
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c.prom.Collect(ch)
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}
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type histogram struct {
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name string // used as key in periodic stats
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count int64
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total float64
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prom prometheus.Histogram
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}
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func newDNSHistogram(name string, help string) *histogram {
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// trace("called")
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h := &histogram{}
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h.prom = prometheus.NewHistogram(prometheus.HistogramOpts{
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Namespace: plugin.Namespace,
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Subsystem: "dnsfilter",
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Name: name,
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Help: help,
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})
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h.name = name
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return h
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}
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func (h *histogram) ObserveWithTime(value float64, when time.Time) {
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statistics.PerSecond.Observe(h.name, when, value)
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statistics.PerMinute.Observe(h.name, when, value)
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statistics.PerHour.Observe(h.name, when, value)
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statistics.PerDay.Observe(h.name, when, value)
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h.count++
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h.total += value
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h.prom.Observe(value)
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}
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func (h *histogram) Observe(value float64) {
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h.ObserveWithTime(value, time.Now())
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}
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func (h *histogram) Describe(ch chan<- *prometheus.Desc) {
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h.prom.Describe(ch)
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}
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func (h *histogram) Collect(ch chan<- prometheus.Metric) {
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h.prom.Collect(ch)
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}
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// -----
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// stats
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// -----
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func handleStats(w http.ResponseWriter, r *http.Request) {
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const numHours = 24
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histrical := generateMapFromStats(&statistics.PerHour, 0, numHours)
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// sum them up
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summed := map[string]interface{}{}
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for key, values := range histrical {
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summedValue := 0.0
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floats, ok := values.([]float64)
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if !ok {
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continue
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}
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for _, v := range floats {
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summedValue += v
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}
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summed[key] = summedValue
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}
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// don't forget to divide by number of elements in returned slice
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if val, ok := summed["avg_processing_time"]; ok {
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if flval, flok := val.(float64); flok {
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flval /= numHours
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summed["avg_processing_time"] = flval
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}
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}
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summed["stats_period"] = "24 hours"
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json, err := json.Marshal(summed)
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if err != nil {
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errortext := fmt.Sprintf("Unable to marshal status json: %s", err)
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log.Println(errortext)
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http.Error(w, errortext, 500)
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return
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}
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w.Header().Set("Content-Type", "application/json")
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_, err = w.Write(json)
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if err != nil {
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errortext := fmt.Sprintf("Unable to write response json: %s", err)
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log.Println(errortext)
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http.Error(w, errortext, 500)
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return
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}
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}
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func generateMapFromStats(stats *periodicStats, start int, end int) map[string]interface{} {
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// clamp
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start = clamp(start, 0, statsHistoryElements)
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end = clamp(end, 0, statsHistoryElements)
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avgProcessingTime := make([]float64, 0)
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count := getReversedSlice(stats.Entries[elapsedTime.name+"_count"], start, end)
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sum := getReversedSlice(stats.Entries[elapsedTime.name+"_sum"], start, end)
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for i := 0; i < len(count); i++ {
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var avg float64
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if count[i] != 0 {
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avg = sum[i] / count[i]
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avg *= 1000
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}
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avgProcessingTime = append(avgProcessingTime, avg)
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}
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result := map[string]interface{}{
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"dns_queries": getReversedSlice(stats.Entries[requests.name], start, end),
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"blocked_filtering": getReversedSlice(stats.Entries[filtered.name], start, end),
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"replaced_safebrowsing": getReversedSlice(stats.Entries[filteredSafebrowsing.name], start, end),
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"replaced_safesearch": getReversedSlice(stats.Entries[safesearch.name], start, end),
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"replaced_parental": getReversedSlice(stats.Entries[filteredParental.name], start, end),
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"avg_processing_time": avgProcessingTime,
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}
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return result
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}
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func handleStatsHistory(w http.ResponseWriter, r *http.Request) {
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// handle time unit and prepare our time window size
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now := time.Now()
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timeUnitString := r.URL.Query().Get("time_unit")
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var stats *periodicStats
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var timeUnit time.Duration
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switch timeUnitString {
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case "seconds":
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timeUnit = time.Second
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stats = &statistics.PerSecond
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case "minutes":
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timeUnit = time.Minute
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stats = &statistics.PerMinute
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case "hours":
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timeUnit = time.Hour
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stats = &statistics.PerHour
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case "days":
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timeUnit = time.Hour * 24
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stats = &statistics.PerDay
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default:
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http.Error(w, "Must specify valid time_unit parameter", 400)
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return
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}
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// parse start and end time
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startTime, err := time.Parse(time.RFC3339, r.URL.Query().Get("start_time"))
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if err != nil {
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errortext := fmt.Sprintf("Must specify valid start_time parameter: %s", err)
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log.Println(errortext)
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http.Error(w, errortext, 400)
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return
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}
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endTime, err := time.Parse(time.RFC3339, r.URL.Query().Get("end_time"))
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if err != nil {
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errortext := fmt.Sprintf("Must specify valid end_time parameter: %s", err)
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log.Println(errortext)
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http.Error(w, errortext, 400)
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return
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}
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// check if start and time times are within supported time range
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timeRange := timeUnit * statsHistoryElements
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if startTime.Add(timeRange).Before(now) {
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http.Error(w, "start_time parameter is outside of supported range", 501)
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return
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}
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if endTime.Add(timeRange).Before(now) {
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http.Error(w, "end_time parameter is outside of supported range", 501)
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return
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}
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// calculate start and end of our array
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// basically it's how many hours/minutes/etc have passed since now
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start := int(now.Sub(endTime) / timeUnit)
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end := int(now.Sub(startTime) / timeUnit)
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// swap them around if they're inverted
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if start > end {
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start, end = end, start
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}
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data := generateMapFromStats(stats, start, end)
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json, err := json.Marshal(data)
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if err != nil {
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errortext := fmt.Sprintf("Unable to marshal status json: %s", err)
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log.Println(errortext)
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http.Error(w, errortext, 500)
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return
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}
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w.Header().Set("Content-Type", "application/json")
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_, err = w.Write(json)
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if err != nil {
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errortext := fmt.Sprintf("Unable to write response json: %s", err)
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log.Println(errortext)
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http.Error(w, errortext, 500)
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return
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}
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}
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func clamp(value, low, high int) int {
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if value < low {
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return low
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}
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if value > high {
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return high
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}
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return value
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}
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// --------------------------
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// helper functions for stats
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// --------------------------
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func getReversedSlice(input [statsHistoryElements]float64, start int, end int) []float64 {
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output := make([]float64, 0)
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for i := start; i <= end; i++ {
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output = append([]float64{input[i]}, output...)
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}
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return output
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}
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