Merge remote-tracking branch 'origin/master' into stable

Dockerfile

     curl \
     git \
     make \
-    upx \
-  && update-ca-certificates
+    upx
 
 COPY . /go/src/github.com/9seconds/mtg/
 
 
 FROM scratch
 
-ENTRYPOINT ["/usr/local/bin/mtg"]
+ENTRYPOINT ["/mtg"]
 ENV MTG_IP=0.0.0.0 \
     MTG_PORT=3128 \
     MTG_STATS_IP=0.0.0.0 \
 EXPOSE 3128 3129
 
 COPY --from=0 /etc/ssl/certs/ca-certificates.crt /etc/ssl/certs/ca-certificates.crt
-COPY --from=0 /go/src/github.com/9seconds/mtg/mtg /usr/local/bin/mtg
+COPY --from=0 /go/src/github.com/9seconds/mtg/mtg /mtg

README.md

 Bullshit-free MTPROTO proxy for Telegram
 
 [![Build Status](https://travis-ci.org/9seconds/mtg.svg?branch=master)](https://travis-ci.org/9seconds/mtg)
+[![Go Report Card](https://goreportcard.com/badge/github.com/9seconds/mtg)](https://goreportcard.com/report/github.com/9seconds/mtg)
 [![Docker Build Status](https://img.shields.io/docker/build/nineseconds/mtg.svg)](https://hub.docker.com/r/nineseconds/mtg/)
 
 # Rationale
   software. I also believe that in case of throwout proxies, this feature
   is useless luxury.
 * **Minimum docker image size**
-  Official image is less than 2.5 megabytes. Literally.
+  Official image is less than 3 megabytes. Literally.
 * **No management WebUI**
   This is an implementation of simple lightweight proxy. I won't do that.
 
 | `MTG_STATSD_PREFIX`      | `--statsd-prefix`      | `mtg`                             | Which bucket prefix we should use. For example, if you set `mtg`, then metric `traffic.ingress` would be send as `mtg.traffic.ingress`.                                                                                                                                    |
 | `MTG_STATSD_TAGS_FORMAT` | `--statsd-tags-format` |                                   | Which tags format we should use. By default, we are using default vanilla statsd tags format but if you want to send directly to InfluxDB or Datadog, please specify it there. Possible options are `influxdb` and `datadog`.                                              |
 | `MTG_STATSD_TAGS`        | `--statsd-tags`        |                                   | Which tags should we send to statsd with our metrics. Please specify them as `key=value` pairs.                                                                                                                                                                            |
+| `MTG_PROMETHEUS_PREFIX`  | `--prometheus-prefix`  | `mtg`                             | Which namespace should be used for prometheus metrics.                                                                                                                                                                                                                     |
 | `MTG_BUFFER_WRITE`       | `-w`, `--write-buffer` | `65536`                           | The size of TCP write buffer in bytes. Write buffer is the buffer for messages which are going from client to Telegram.                                                                                                                                                    |
 | `MTG_BUFFER_READ`        | `-r`, `--read-buffer`  | `131072`                          | The size of TCP read buffer in bytes. Read buffer is the buffer for messages from Telegram to client.                                                                                                                                                                      |
 | `MTG_SECURE_ONLY`        | `-s`, `--secure-only`  | `false`                           | Support only clients with secure mode (i.e only clients with dd-secrets).                                                                                                                                                                                                  |
 All metrics are prefixed with given prefix. Default prefix is `mtg`.
 With such prefix metric name `traffic.ingress`, for example, would be
 `mtg.traffic.ingress`.
+
+
+# Prometheus integration
+
+[Prometheus](https://prometheus.io) integration comes out of
+the box, you do not need to setup anything special. Prometheus
+scrape endpoint lives on the same IP/port where generic stats
+service (`http://${MTG_STATS_IP}:${MTG_STATS_PORT}`) but on
+`/prometheus` path. So, if you access http stats service as `curl
+http://localhost:3129/`, then your prometheus endpoint is `curl
+http://localhost:3129/prometheus/`.

config/config.go

 		TagsFormat statsd.TagFormat
 		Enabled    bool
 	}
+	Prometheus struct {
+		Prefix string
+	}
 
 	Secret []byte
 	AdTag  []byte
 	bindIP, publicIPv4, publicIPv6, statsIP net.IP,
 	bindPort, publicIPv4Port, publicIPv6Port, statsPort, statsdPort uint16,
 	statsdIP, statsdNetwork, statsdPrefix, statsdTagsFormat string,
-	statsdTags map[string]string,
+	statsdTags map[string]string, prometheusPrefix string,
 	secureOnly bool,
 	secret, adtag []byte) (*Config, error) {
 	secureMode := secureOnly
 		ReadBufferSize:  int(readBufferSize),
 		WriteBufferSize: int(writeBufferSize),
 	}
+	conf.Prometheus.Prefix = prometheusPrefix
 
 	if statsdIP != "" {
 		conf.StatsD.Enabled = true

go.mod

 	github.com/alecthomas/template v0.0.0-20160405071501-a0175ee3bccc // indirect
 	github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf // indirect
 	github.com/beevik/ntp v0.2.0
+	github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 // indirect
 	github.com/davecgh/go-spew v1.1.1 // indirect
-	github.com/dustin/go-humanize v0.0.0-20180713052910-9f541cc9db5d
+	github.com/dustin/go-humanize v1.0.0
 	github.com/gofrs/uuid v3.1.0+incompatible
-	github.com/juju/errors v0.0.0-20180806074554-22422dad46e1
+	github.com/gogo/protobuf v1.1.1 // indirect
+	github.com/golang/protobuf v1.2.0 // indirect
+	github.com/juju/errors v0.0.0-20181012004132-a4583d0a56ea
 	github.com/juju/loggo v0.0.0-20180524022052-584905176618 // indirect
 	github.com/juju/testing v0.0.0-20180920084828-472a3e8b2073 // indirect
 	github.com/kr/pretty v0.1.0 // indirect
+	github.com/matttproud/golang_protobuf_extensions v1.0.1 // indirect
 	github.com/pkg/errors v0.8.0 // indirect
 	github.com/pmezard/go-difflib v1.0.0 // indirect
+	github.com/prometheus/client_golang v0.9.0
+	github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910 // indirect
+	github.com/prometheus/common v0.0.0-20181015124227-bcb74de08d37 // indirect
+	github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d // indirect
 	github.com/stretchr/testify v1.2.2
 	go.uber.org/atomic v1.3.2 // indirect
 	go.uber.org/multierr v1.1.0 // indirect
 	go.uber.org/zap v1.9.1
-	golang.org/x/net v0.0.0-20180921000356-2f5d2388922f // indirect
+	golang.org/x/net v0.0.0-20181011144130-49bb7cea24b1 // indirect
+	golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f // indirect
 	gopkg.in/alecthomas/kingpin.v2 v2.2.6
 	gopkg.in/alexcesaro/statsd.v2 v2.0.0
 	gopkg.in/check.v1 v1.0.0-20180628173108-788fd7840127 // indirect

go.sum

 github.com/alecthomas/units v0.0.0-20151022065526-2efee857e7cf/go.mod h1:ybxpYRFXyAe+OPACYpWeL0wqObRcbAqCMya13uyzqw0=
 github.com/beevik/ntp v0.2.0 h1:sGsd+kAXzT0bfVfzJfce04g+dSRfrs+tbQW8lweuYgw=
 github.com/beevik/ntp v0.2.0/go.mod h1:hIHWr+l3+/clUnF44zdK+CWW7fO8dR5cIylAQ76NRpg=
+github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973 h1:xJ4a3vCFaGF/jqvzLMYoU8P317H5OQ+Via4RmuPwCS0=
+github.com/beorn7/perks v0.0.0-20180321164747-3a771d992973/go.mod h1:Dwedo/Wpr24TaqPxmxbtue+5NUziq4I4S80YR8gNf3Q=
 github.com/davecgh/go-spew v1.1.1 h1:vj9j/u1bqnvCEfJOwUhtlOARqs3+rkHYY13jYWTU97c=
 github.com/davecgh/go-spew v1.1.1/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38=
-github.com/dustin/go-humanize v0.0.0-20180713052910-9f541cc9db5d h1:lDrio3iIdNb0Gw9CgH7cQF+iuB5mOOjdJ9ERNJCBgb4=
-github.com/dustin/go-humanize v0.0.0-20180713052910-9f541cc9db5d/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
+github.com/dustin/go-humanize v1.0.0 h1:VSnTsYCnlFHaM2/igO1h6X3HA71jcobQuxemgkq4zYo=
+github.com/dustin/go-humanize v1.0.0/go.mod h1:HtrtbFcZ19U5GC7JDqmcUSB87Iq5E25KnS6fMYU6eOk=
 github.com/gofrs/uuid v3.1.0+incompatible h1:q2rtkjaKT4YEr6E1kamy0Ha4RtepWlQBedyHx0uzKwA=
 github.com/gofrs/uuid v3.1.0+incompatible/go.mod h1:b2aQJv3Z4Fp6yNu3cdSllBxTCLRxnplIgP/c0N/04lM=
-github.com/juju/errors v0.0.0-20180806074554-22422dad46e1 h1:wnhMXidtb70kDZCeLt/EfsVtkXS5c8zLnE9y/6DIRAU=
-github.com/juju/errors v0.0.0-20180806074554-22422dad46e1/go.mod h1:W54LbzXuIE0boCoNJfwqpmkKJ1O4TCTZMetAt6jGk7Q=
+github.com/gogo/protobuf v1.1.1 h1:72R+M5VuhED/KujmZVcIquuo8mBgX4oVda//DQb3PXo=
+github.com/gogo/protobuf v1.1.1/go.mod h1:r8qH/GZQm5c6nD/R0oafs1akxWv10x8SbQlK7atdtwQ=
+github.com/golang/protobuf v1.2.0 h1:P3YflyNX/ehuJFLhxviNdFxQPkGK5cDcApsge1SqnvM=
+github.com/golang/protobuf v1.2.0/go.mod h1:6lQm79b+lXiMfvg/cZm0SGofjICqVBUtrP5yJMmIC1U=
+github.com/juju/errors v0.0.0-20181012004132-a4583d0a56ea h1:g2k+8WR7cHch4g0tBDhfiEvAp7fXxTNBiD1oC1Oxj3E=
+github.com/juju/errors v0.0.0-20181012004132-a4583d0a56ea/go.mod h1:W54LbzXuIE0boCoNJfwqpmkKJ1O4TCTZMetAt6jGk7Q=
 github.com/juju/loggo v0.0.0-20180524022052-584905176618 h1:MK144iBQF9hTSwBW/9eJm034bVoG30IshVm688T2hi8=
 github.com/juju/loggo v0.0.0-20180524022052-584905176618/go.mod h1:vgyd7OREkbtVEN/8IXZe5Ooef3LQePvuBm9UWj6ZL8U=
 github.com/juju/testing v0.0.0-20180920084828-472a3e8b2073 h1:WQM1NildKThwdP7qWrNAFGzp4ijNLw8RlgENkaI4MJs=
 github.com/kr/pty v1.1.1/go.mod h1:pFQYn66WHrOpPYNljwOMqo10TkYh1fy3cYio2l3bCsQ=
 github.com/kr/text v0.1.0 h1:45sCR5RtlFHMR4UwH9sdQ5TC8v0qDQCHnXt+kaKSTVE=
 github.com/kr/text v0.1.0/go.mod h1:4Jbv+DJW3UT/LiOwJeYQe1efqtUx/iVham/4vfdArNI=
+github.com/matttproud/golang_protobuf_extensions v1.0.1 h1:4hp9jkHxhMHkqkrB3Ix0jegS5sx/RkqARlsWZ6pIwiU=
+github.com/matttproud/golang_protobuf_extensions v1.0.1/go.mod h1:D8He9yQNgCq6Z5Ld7szi9bcBfOoFv/3dc6xSMkL2PC0=
 github.com/pkg/errors v0.8.0 h1:WdK/asTD0HN+q6hsWO3/vpuAkAr+tw6aNJNDFFf0+qw=
 github.com/pkg/errors v0.8.0/go.mod h1:bwawxfHBFNV+L2hUp1rHADufV3IMtnDRdf1r5NINEl0=
 github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM=
 github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4=
+github.com/prometheus/client_golang v0.9.0 h1:tXuTFVHC03mW0D+Ua1Q2d1EAVqLTuggX50V0VLICCzY=
+github.com/prometheus/client_golang v0.9.0/go.mod h1:7SWBe2y4D6OKWSNQJUaRYU/AaXPKyh/dDVn+NZz0KFw=
+github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910 h1:idejC8f05m9MGOsuEi1ATq9shN03HrxNkD/luQvxCv8=
+github.com/prometheus/client_model v0.0.0-20180712105110-5c3871d89910/go.mod h1:MbSGuTsp3dbXC40dX6PRTWyKYBIrTGTE9sqQNg2J8bo=
+github.com/prometheus/common v0.0.0-20181015124227-bcb74de08d37 h1:Y7YdJ9Xb3MoQOzAWXnDunAJYpvhVwZdTirNfGUgPKaA=
+github.com/prometheus/common v0.0.0-20181015124227-bcb74de08d37/go.mod h1:daVV7qP5qjZbuso7PdcryaAu0sAZbrN9i7WWcTMWvro=
+github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d h1:GoAlyOgbOEIFdaDqxJVlbOQ1DtGmZWs/Qau0hIlk+WQ=
+github.com/prometheus/procfs v0.0.0-20181005140218-185b4288413d/go.mod h1:c3At6R/oaqEKCNdg8wHV1ftS6bRYblBhIjjI8uT2IGk=
 github.com/stretchr/testify v1.2.2 h1:bSDNvY7ZPG5RlJ8otE/7V6gMiyenm9RtJ7IUVIAoJ1w=
 github.com/stretchr/testify v1.2.2/go.mod h1:a8OnRcib4nhh0OaRAV+Yts87kKdq0PP7pXfy6kDkUVs=
 go.uber.org/atomic v1.3.2 h1:2Oa65PReHzfn29GpvgsYwloV9AVFHPDk8tYxt2c2tr4=
 go.uber.org/multierr v1.1.0/go.mod h1:wR5kodmAFQ0UK8QlbwjlSNy0Z68gJhDJUG5sjR94q/0=
 go.uber.org/zap v1.9.1 h1:XCJQEf3W6eZaVwhRBof6ImoYGJSITeKWsyeh3HFu/5o=
 go.uber.org/zap v1.9.1/go.mod h1:vwi/ZaCAaUcBkycHslxD9B2zi4UTXhF60s6SWpuDF0Q=
-golang.org/x/net v0.0.0-20180921000356-2f5d2388922f h1:QM2QVxvDoW9PFSPp/zy9FgxJLfaWTZlS61KEPtBwacM=
-golang.org/x/net v0.0.0-20180921000356-2f5d2388922f/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/net v0.0.0-20181011144130-49bb7cea24b1 h1:Y/KGZSOdz/2r0WJ9Mkmz6NJBusp0kiNx1Cn82lzJQ6w=
+golang.org/x/net v0.0.0-20181011144130-49bb7cea24b1/go.mod h1:mL1N/T3taQHkDXs73rZJwtUhF3w3ftmwwsq0BUmARs4=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f h1:wMNYb4v58l5UBM7MYRLPG6ZhfOqbKu7X5eyFl8ZhKvA=
+golang.org/x/sync v0.0.0-20180314180146-1d60e4601c6f/go.mod h1:RxMgew5VJxzue5/jJTE5uejpjVlOe/izrB70Jof72aM=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6 h1:jMFz6MfLP0/4fUyZle81rXUoxOBFi19VUFKVDOQfozc=
 gopkg.in/alecthomas/kingpin.v2 v2.2.6/go.mod h1:FMv+mEhP44yOT+4EoQTLFTRgOQ1FBLkstjWtayDeSgw=
 gopkg.in/alexcesaro/statsd.v2 v2.0.0 h1:FXkZSCZIH17vLCO5sO2UucTHsH9pc+17F6pl3JVCwMc=

main.go

 		Envar("MTG_STATSD_TAGS").
 		StringMap()
 
+	prometheusPrefix = app.Flag("prometheus-prefix",
+		"Which namespace to use to send stats to Prometheus.").
+		Envar("MTG_PROMETHEUS_PREFIX").
+		Default("mtg").
+		String()
+
 	writeBufferSize = app.Flag("write-buffer",
 		"Write buffer size in bytes. You can think about it as a buffer from client to Telegram.").
 		Short('w').
 		*bindIP, *publicIPv4, *publicIPv6, *statsIP,
 		*bindPort, *publicIPv4Port, *publicIPv6Port, *statsPort, *statsdPort,
 		*statsdIP, *statsdNetwork, *statsdPrefix, *statsdTagsFormat,
-		*statsdTags, *secureOnly,
+		*statsdTags, *prometheusPrefix, *secureOnly,
 		*secret, *adtag,
 	)
 	if err != nil {
 		zap.S().Infow("Use direct connection to Telegram")
 	}
 
-	if err := stats.Start(conf); err != nil {
+	if err := stats.Init(conf); err != nil {
 		panic(err)
 	}
 

proxy/proxy.go

 		clientPacket := clientConn.(wrappers.PacketReadWriteCloser)
 		serverPacket := serverConn.(wrappers.PacketReadWriteCloser)
 		go p.middlePipe(clientPacket, serverPacket, wait, &opts.ReadHacks)
-		go p.middlePipe(serverPacket, clientPacket, wait, &opts.WriteHacks)
+		p.middlePipe(serverPacket, clientPacket, wait, &opts.WriteHacks)
 	} else {
 		clientStream := clientConn.(wrappers.StreamReadWriteCloser)
 		serverStream := serverConn.(wrappers.StreamReadWriteCloser)
 		go p.directPipe(clientStream, serverStream, wait, p.conf.ReadBufferSize)
-		go p.directPipe(serverStream, clientStream, wait, p.conf.WriteBufferSize)
+		p.directPipe(serverStream, clientStream, wait, p.conf.WriteBufferSize)
 	}
 
 	wait.Wait()
 	return packetConn, nil
 }
 
-func (p *Proxy) middlePipe(src wrappers.PacketReadCloser, dst io.WriteCloser,
-	wait *sync.WaitGroup, hacks *mtproto.Hacks) {
-	defer func() {
-		src.Close() // nolint: errcheck, gosec
-		dst.Close() // nolint: errcheck, gosec
-		wait.Done()
-	}()
+func (p *Proxy) middlePipe(src wrappers.PacketReadCloser, dst io.Writer, wait *sync.WaitGroup, hacks *mtproto.Hacks) {
+	defer wait.Done()
 
 	for {
 		hacks.SimpleAck = false
 	}
 }
 
-func (p *Proxy) directPipe(src wrappers.StreamReadCloser, dst io.WriteCloser,
-	wait *sync.WaitGroup, bufferSize int) {
-	defer func() {
-		src.Close() // nolint: errcheck, gosec
-		dst.Close() // nolint: errcheck, gosec
-		wait.Done()
-	}()
+func (p *Proxy) directPipe(src wrappers.StreamReadCloser, dst io.Writer, wait *sync.WaitGroup, bufferSize int) {
+	defer wait.Done()
 
 	buffer := make([]byte, bufferSize)
 	if _, err := io.CopyBuffer(dst, src, buffer); err != nil {

stats/channels.go

 
 import (
 	"net"
-	"time"
 
 	"github.com/9seconds/mtg/mtproto"
 )
 
 const (
-	crashesChanLength     = 1
-	connectionsChanLength = 20
-	trafficChanLength     = 5000
+	connectionsChanLength = 10
+	trafficChanLength     = 10
 )
 
 var (
-	crashesChan     = make(chan struct{}, crashesChanLength)
-	connectionsChan = make(chan *connectionData, connectionsChanLength)
-	trafficChan     = make(chan *trafficData, trafficChanLength)
+	crashesChan     = make(chan struct{})
+	statsChan       = make(chan chan<- Stats)
+	connectionsChan = make(chan connectionData, connectionsChanLength)
+	trafficChan     = make(chan trafficData, trafficChanLength)
 )
 
 type connectionData struct {
 	ingress bool
 }
 
-func crashManager() {
-	for range crashesChan {
-		instance.mutex.RLock()
-
-		instance.Crashes++
-
-		instance.mutex.RUnlock()
-	}
-}
-
-func connectionManager() {
-	for event := range connectionsChan {
-		instance.mutex.RLock()
-
-		isIPv4 := event.addr.IP.To4() != nil
-		var inc uint32 = 1
-		if !event.connected {
-			inc = ^uint32(0)
-		}
-
-		switch event.connectionType {
-		case mtproto.ConnectionTypeAbridged:
-			if isIPv4 {
-				instance.Connections.Abridged.IPv4 += inc
-			} else {
-				instance.Connections.Abridged.IPv6 += inc
-			}
-		case mtproto.ConnectionTypeSecure:
-			if isIPv4 {
-				instance.Connections.Secure.IPv4 += inc
-			} else {
-				instance.Connections.Secure.IPv6 += inc
-			}
-		default:
-			if isIPv4 {
-				instance.Connections.Intermediate.IPv4 += inc
-			} else {
-				instance.Connections.Intermediate.IPv6 += inc
-			}
-		}
-
-		instance.mutex.RUnlock()
-	}
-}
-
-func trafficManager() {
-	speedChan := time.Tick(time.Second)
-
-	for {
-		select {
-		case event := <-trafficChan:
-			instance.mutex.RLock()
-
-			if event.ingress {
-				instance.Traffic.Ingress += trafficValue(event.traffic)
-				instance.speedCurrent.Ingress += trafficSpeedValue(event.traffic)
-			} else {
-				instance.Traffic.Egress += trafficValue(event.traffic)
-				instance.speedCurrent.Egress += trafficSpeedValue(event.traffic)
-			}
-
-			instance.mutex.RUnlock()
-		case <-speedChan:
-			instance.mutex.RLock()
-
-			instance.Speed.Ingress = instance.speedCurrent.Ingress
-			instance.Speed.Egress = instance.speedCurrent.Egress
-			instance.speedCurrent.Ingress = trafficSpeedValue(0)
-			instance.speedCurrent.Egress = trafficSpeedValue(0)
-
-			instance.mutex.RUnlock()
-		}
-	}
-}
-
 // NewCrash indicates new crash.
 func NewCrash() {
 	crashesChan <- struct{}{}
 
 // ClientConnected indicates that new client was connected.
 func ClientConnected(connectionType mtproto.ConnectionType, addr *net.TCPAddr) {
-	connectionsChan <- &connectionData{
+	connectionsChan <- connectionData{
 		connectionType: connectionType,
 		addr:           addr,
 		connected:      true,
 
 // ClientDisconnected indicates that client was disconnected.
 func ClientDisconnected(connectionType mtproto.ConnectionType, addr *net.TCPAddr) {
-	connectionsChan <- &connectionData{
+	connectionsChan <- connectionData{
 		connectionType: connectionType,
 		addr:           addr,
 		connected:      false,
 
 // IngressTraffic accounts new ingress traffic.
 func IngressTraffic(traffic int) {
-	trafficChan <- &trafficData{
+	trafficChan <- trafficData{
 		traffic: traffic,
 		ingress: true,
 	}
 
 // EgressTraffic accounts new ingress traffic.
 func EgressTraffic(traffic int) {
-	trafficChan <- &trafficData{
+	trafficChan <- trafficData{
 		traffic: traffic,
 		ingress: false,
 	}
 }
+
+// GetStats returns a snapshot of Stats instance.
+func GetStats() Stats {
+	rpcChan := make(chan Stats)
+	statsChan <- rpcChan
+	return <-rpcChan
+}

stats/init.go

+package stats
+
+import (
+	"github.com/juju/errors"
+
+	"github.com/9seconds/mtg/config"
+)
+
+// Init initializes stats subsystem.
+func Init(conf *config.Config) error {
+	if conf.StatsD.Enabled {
+		client, err := newStatsd(conf)
+		if err != nil {
+			return errors.Annotate(err, "Cannot initialize statsd client")
+		}
+		go client.run()
+	}
+	prometheus, err := newPrometheus(conf)
+	if err != nil {
+		return errors.Annotate(err, "Cannot initialize prometheus client")
+	}
+	go prometheus.run()
+
+	go NewStats(conf).start()
+	go startServer(conf)
+
+	return nil
+}

stats/prometheus.go

+package stats
+
+import (
+	"time"
+
+	"github.com/juju/errors"
+	"github.com/prometheus/client_golang/prometheus"
+
+	"github.com/9seconds/mtg/config"
+)
+
+const prometheusPollTime = time.Second
+
+type prometheusExporter struct {
+	connections *prometheus.GaugeVec
+	traffic     *prometheus.GaugeVec
+	speed       *prometheus.GaugeVec
+	crashes     prometheus.Gauge
+}
+
+func (p *prometheusExporter) run() {
+	for range time.Tick(prometheusPollTime) {
+		instance := GetStats()
+
+		p.connections.WithLabelValues("abridged", "v4").Set(float64(instance.Connections.Abridged.IPv4))
+		p.connections.WithLabelValues("abridged", "v6").Set(float64(instance.Connections.Abridged.IPv6))
+		p.connections.WithLabelValues("intermediate", "v4").Set(float64(instance.Connections.Intermediate.IPv4))
+		p.connections.WithLabelValues("intermediate", "v6").Set(float64(instance.Connections.Intermediate.IPv6))
+		p.connections.WithLabelValues("secure", "v4").Set(float64(instance.Connections.Secure.IPv4))
+		p.connections.WithLabelValues("secure", "v6").Set(float64(instance.Connections.Secure.IPv6))
+		p.traffic.WithLabelValues("ingress").Set(float64(instance.Traffic.ingress))
+		p.traffic.WithLabelValues("egress").Set(float64(instance.Traffic.egress))
+		p.speed.WithLabelValues("ingress").Set(float64(instance.Speed.ingress))
+		p.speed.WithLabelValues("egress").Set(float64(instance.Speed.egress))
+		p.crashes.Set(float64(instance.Crashes))
+	}
+}
+
+func newPrometheus(conf *config.Config) (*prometheusExporter, error) {
+	connections := prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: conf.Prometheus.Prefix,
+		Name:      "connections",
+		Help:      "Current number of connections to the proxy.",
+	}, []string{"type", "protocol"})
+	traffic := prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: conf.Prometheus.Prefix,
+		Name:      "traffic",
+		Help:      "Traffic passed through the proxy in bytes.",
+	}, []string{"direction"})
+	speed := prometheus.NewGaugeVec(prometheus.GaugeOpts{
+		Namespace: conf.Prometheus.Prefix,
+		Name:      "speed",
+		Help:      "Current throughput in bytes per second.",
+	}, []string{"direction"})
+	crashes := prometheus.NewGauge(prometheus.GaugeOpts{
+		Namespace: conf.Prometheus.Prefix,
+		Name:      "crashes",
+		Help:      "How many crashes happened.",
+	})
+
+	if err := prometheus.Register(connections); err != nil {
+		return nil, errors.Annotate(err, "Cannot register connections collector")
+	}
+	if err := prometheus.Register(traffic); err != nil {
+		return nil, errors.Annotate(err, "cannot register traffic collector")
+	}
+	if err := prometheus.Register(speed); err != nil {
+		return nil, errors.Annotate(err, "cannot register speed collector")
+	}
+	if err := prometheus.Register(crashes); err != nil {
+		return nil, errors.Annotate(err, "cannot register crashes collector")
+	}
+
+	return &prometheusExporter{
+		connections: connections,
+		traffic:     traffic,
+		speed:       speed,
+		crashes:     crashes,
+	}, nil
+}

stats/server.go

 import (
 	"encoding/json"
 	"net/http"
-	"sync"
-	"time"
 
+	"github.com/prometheus/client_golang/prometheus/promhttp"
 	"go.uber.org/zap"
 
 	"github.com/9seconds/mtg/config"
 )
 
-var instance *stats
-
-// Start starts new statistics server.
-func Start(conf *config.Config) error {
+func startServer(conf *config.Config) {
 	log := zap.S().Named("stats")
 
-	instance = &stats{
-		URLs:   conf.GetURLs(),
-		Uptime: uptime(time.Now()),
-		mutex:  &sync.RWMutex{},
-	}
-
-	if conf.StatsD.Enabled {
-		client, err := newStatsd(conf)
-		if err != nil {
-			return err
-		}
-		go client.run()
-	}
-
-	go crashManager()
-	go connectionManager()
-	go trafficManager()
-
 	http.HandleFunc("/", func(w http.ResponseWriter, r *http.Request) {
 		w.Header().Set("Content-Type", "application/json")
 
-		instance.mutex.Lock()
-		first, err := json.Marshal(instance)
-		instance.mutex.Unlock()
-
+		first, err := json.Marshal(GetStats())
 		if err != nil {
 			log.Errorw("Cannot encode json", "error", err)
 			http.Error(w, "Internal server error", 500)
 			return
 		}
 
-		interm := map[string]interface{}{}
-		json.Unmarshal(first, &interm) // nolint: errcheck, gosec
+		interim := map[string]interface{}{}
+		json.Unmarshal(first, &interim) // nolint: errcheck, gosec
 
 		encoder := json.NewEncoder(w)
 		encoder.SetEscapeHTML(false)
 		encoder.SetIndent("", "  ")
-		if err = encoder.Encode(interm); err != nil {
+		if err = encoder.Encode(interim); err != nil {
 			log.Errorw("Cannot encode json", "error", err)
 		}
 	})
+	http.Handle("/prometheus/", promhttp.Handler())
 
-	go func() {
-		if err := http.ListenAndServe(conf.StatAddr(), nil); err != nil {
-			log.Fatalw("Stats server has been stopped", "error", err)
-		}
-	}()
-
-	return nil
+	if err := http.ListenAndServe(conf.StatAddr(), nil); err != nil {
+		log.Fatalw("Stats server has been stopped", "error", err)
+	}
 }

stats/stats.go

 	"encoding/json"
 	"fmt"
 	"strconv"
-	"sync"
 	"time"
 
 	humanize "github.com/dustin/go-humanize"
 
 	"github.com/9seconds/mtg/config"
+	"github.com/9seconds/mtg/mtproto"
 )
 
 type uptime time.Time
 	return json.Marshal(value)
 }
 
-type trafficValue uint64
-
-func (t trafficValue) MarshalJSON() ([]byte, error) {
-	tv := uint64(t)
-	value := map[string]interface{}{
-		"bytes": tv,
-		"human": humanize.Bytes(tv),
-	}
-
-	return json.Marshal(value)
-}
-
-type trafficSpeedValue uint64
-
-func (t trafficSpeedValue) MarshalJSON() ([]byte, error) {
-	speed := uint64(t)
-	value := map[string]interface{}{
-		"bytes/s": speed,
-		"human":   fmt.Sprintf("%s/S", humanize.Bytes(speed)),
-	}
-
-	return json.Marshal(value)
+type connectionType struct {
+	IPv6 uint32 `json:"ipv6"`
+	IPv4 uint32 `json:"ipv4"`
 }
 
-type connections struct {
+type baseConnections struct {
 	All          connectionType `json:"all"`
 	Abridged     connectionType `json:"abridged"`
 	Intermediate connectionType `json:"intermediate"`
 	Secure       connectionType `json:"secure"`
 }
 
+type connections struct {
+	baseConnections
+}
+
 func (c connections) MarshalJSON() ([]byte, error) {
 	c.All.IPv4 = c.Abridged.IPv4 + c.Intermediate.IPv4 + c.Secure.IPv4
 	c.All.IPv6 = c.Abridged.IPv6 + c.Intermediate.IPv6 + c.Secure.IPv6
 
-	value := struct {
-		All          connectionType `json:"all"`
-		Abridged     connectionType `json:"abridged"`
-		Intermediate connectionType `json:"intermediate"`
-		Secure       connectionType `json:"secure"`
-	}{
-		All:          c.All,
-		Abridged:     c.Abridged,
-		Intermediate: c.Intermediate,
-		Secure:       c.Secure,
+	return json.Marshal(c.baseConnections)
+}
+
+type traffic struct {
+	ingress uint64
+	egress  uint64
+}
+
+func (t *traffic) dumpValue(value uint64) map[string]interface{} {
+	return map[string]interface{}{
+		"bytes": value,
+		"human": humanize.Bytes(value),
+	}
+}
+
+func (t traffic) MarshalJSON() ([]byte, error) {
+	value := map[string]map[string]interface{}{
+		"ingress": t.dumpValue(t.ingress),
+		"egress":  t.dumpValue(t.egress),
 	}
 
 	return json.Marshal(value)
 }
 
-type connectionType struct {
-	IPv6 uint32 `json:"ipv6"`
-	IPv4 uint32 `json:"ipv4"`
+type speed struct {
+	ingress uint64
+	egress  uint64
 }
 
-type traffic struct {
-	Ingress trafficValue `json:"ingress"`
-	Egress  trafficValue `json:"egress"`
+func (s *speed) dumpValue(value uint64) map[string]interface{} {
+	return map[string]interface{}{
+		"bytes/s": value,
+		"human":   fmt.Sprintf("%s/s", humanize.Bytes(value)),
+	}
 }
 
-type speed struct {
-	Ingress trafficSpeedValue `json:"ingress"`
-	Egress  trafficSpeedValue `json:"egress"`
+func (s speed) MarshalJSON() ([]byte, error) {
+	value := map[string]map[string]interface{}{
+		"ingress": s.dumpValue(s.ingress),
+		"egress":  s.dumpValue(s.egress),
+	}
+
+	return json.Marshal(value)
 }
 
-type stats struct {
+// Stats represents a statistics of the proxy.
+type Stats struct {
 	URLs        config.IPURLs `json:"urls"`
 	Connections connections   `json:"connections"`
 	Traffic     traffic       `json:"traffic"`
 	Uptime      uptime        `json:"uptime"`
 	Crashes     uint32        `json:"crashes"`
 
-	speedCurrent speed
-	mutex        *sync.RWMutex
+	previousTraffic traffic
+}
+
+func (s *Stats) start() {
+	speedChan := time.Tick(time.Second)
+
+	for {
+		select {
+		case <-speedChan:
+			s.handleSpeed()
+		case event := <-trafficChan:
+			s.handleTraffic(event)
+		case event := <-connectionsChan:
+			s.handleConnection(event)
+		case getStatsChan := <-statsChan:
+			s.handleGetStats(getStatsChan)
+		case <-crashesChan:
+			s.handleCrash()
+		}
+	}
+}
+
+func (s *Stats) handleTraffic(evt trafficData) {
+	if evt.ingress {
+		s.Traffic.ingress += uint64(evt.traffic)
+	} else {
+		s.Traffic.egress += uint64(evt.traffic)
+	}
+}
+
+func (s *Stats) handleSpeed() {
+	s.Speed.ingress = s.Traffic.ingress - s.previousTraffic.ingress
+	s.Speed.egress = s.Traffic.egress - s.previousTraffic.egress
+	s.previousTraffic.ingress = s.Traffic.ingress
+	s.previousTraffic.egress = s.Traffic.egress
+}
+
+func (s *Stats) handleConnection(evt connectionData) {
+	var inc uint32 = 1
+	if !evt.connected {
+		inc = ^uint32(0)
+	}
+
+	var conn *connectionType
+	switch evt.connectionType {
+	case mtproto.ConnectionTypeAbridged:
+		conn = &s.Connections.Abridged
+	case mtproto.ConnectionTypeSecure:
+		conn = &s.Connections.Secure
+	default:
+		conn = &s.Connections.Intermediate
+	}
+
+	if evt.addr.IP.To4() != nil {
+		conn.IPv4 += inc
+	} else {
+		conn.IPv6 += inc
+	}
+}
+
+func (s *Stats) handleGetStats(getStatsChan chan<- Stats) {
+	getStatsChan <- *s
+}
+
+func (s *Stats) handleCrash() {
+	s.Crashes++
+}
+
+// NewStats creates a new instance of Stats structure.
+func NewStats(conf *config.Config) *Stats {
+	return &Stats{
+		URLs:   conf.GetURLs(),
+		Uptime: uptime(time.Now()),
+	}
 }

stats/statsd.go

 
 func (s *statsdExporter) run() {
 	for range time.Tick(statsdPollTime) {
-		instance.mutex.Lock()
+		instance := GetStats()
 
 		s.client.Gauge(statsdConnectionsAbridgedV4, instance.Connections.Abridged.IPv4)
 		s.client.Gauge(statsdConnectionsAbridgedV6, instance.Connections.Abridged.IPv6)
 		s.client.Gauge(statsdConnectionsIntermediateV6, instance.Connections.Intermediate.IPv6)
 		s.client.Gauge(statsdConnectionsSecureV4, instance.Connections.Secure.IPv4)
 		s.client.Gauge(statsdConnectionsSecureV6, instance.Connections.Secure.IPv6)
-		s.client.Gauge(statsdTrafficIngress, uint64(instance.Traffic.Ingress))
-		s.client.Gauge(statsdTrafficEgress, uint64(instance.Traffic.Egress))
-		s.client.Gauge(statsdSpeedIngress, uint64(instance.Speed.Ingress))
-		s.client.Gauge(statsdSpeedEgress, uint64(instance.Speed.Egress))
+		s.client.Gauge(statsdTrafficIngress, instance.Traffic.ingress)
+		s.client.Gauge(statsdTrafficEgress, instance.Traffic.egress)
+		s.client.Gauge(statsdSpeedIngress, instance.Speed.ingress)
+		s.client.Gauge(statsdSpeedEgress, instance.Speed.egress)
 		s.client.Gauge(statsdCrashes, instance.Crashes)
-
-		instance.mutex.Unlock()
 	}
 }
 

wrappers/conn.go

 	connTimeoutWrite = 2 * time.Minute
 )
 
-type ioResult struct {
-	n   int
-	err error
-}
-
-type ioFunc func([]byte) (int, error)
-
 // Conn is a basic wrapper for net.Conn providing the most low-level
 // logic and management as possible.
 type Conn struct {
 func (c *Conn) Write(p []byte) (int, error) {
 	select {
 	case <-c.ctx.Done():
+		c.Close() // nolint: gosec
 		return 0, errors.Annotate(c.ctx.Err(), "Cannot write because context was closed")
 	default:
-		n, err := c.doIO(c.conn.Write, p, connTimeoutWrite)
+		if err := c.conn.SetWriteDeadline(time.Now().Add(connTimeoutWrite)); err != nil {
+			c.Close() // nolint: gosec
+			return 0, errors.Annotate(err, "Cannot set write deadline to the socket")
+		}
 
+		n, err := c.conn.Write(p)
 		c.logger.Debugw("Write to stream", "bytes", n, "error", err)
 		stats.EgressTraffic(n)
+		if err != nil {
+			c.Close() // nolint: gosec
+		}
 
 		return n, err
 	}
 func (c *Conn) Read(p []byte) (int, error) {
 	select {
 	case <-c.ctx.Done():
+		c.Close() // nolint: gosec
 		return 0, errors.Annotate(c.ctx.Err(), "Cannot read because context was closed")
 	default:
-		n, err := c.doIO(c.conn.Read, p, connTimeoutRead)
+		if err := c.conn.SetReadDeadline(time.Now().Add(connTimeoutRead)); err != nil {
+			c.Close() // nolint: gosec
+			return 0, errors.Annotate(err, "Cannot set read deadline to the socket")
+		}
 
+		n, err := c.conn.Read(p)
 		c.logger.Debugw("Read from stream", "bytes", n, "error", err)
 		stats.IngressTraffic(n)
-
-		return n, err
-	}
-}
-
-func (c *Conn) doIO(callback ioFunc, p []byte, timeout time.Duration) (int, error) {
-	resChan := make(chan ioResult, 1)
-	timer := time.NewTimer(timeout)
-
-	go func() {
-		n, err := callback(p)
-		resChan <- ioResult{n: n, err: err}
-	}()
-
-	select {
-	case res := <-resChan:
-		timer.Stop()
-		if res.err != nil {
+		if err != nil {
 			c.Close() // nolint: gosec
 		}
-		return res.n, res.err
-	case <-c.ctx.Done():
-		timer.Stop()
-		c.Close() // nolint: gosec
-		return 0, errors.Annotate(c.ctx.Err(), "Cannot do IO because context is closed")
-	case <-timer.C:
-		c.Close() // nolint: gosec
-		return 0, errors.Annotate(c.ctx.Err(), "Timeout on IO operation")
+
+		return n, err
 	}
 }
 
 // Close closes underlying net.Conn instance.
 func (c *Conn) Close() error {
-	defer c.logger.Debugw("Close connection")
-
+	c.logger.Debugw("Close connection")
 	c.cancel()
+
 	return c.conn.Close()
 }