AdGuardHome/coredns_plugin/coredns_stats.go

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