Use contexts for Conn wrapper

client/client.go

 package client
 
 import (
+	"context"
 	"net"
 
 	"github.com/9seconds/mtg/config"
 )
 
 // Init defines common method for initializing client connections.
-type Init func(net.Conn, string, *config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error)
+type Init func(context.Context, context.CancelFunc, net.Conn, string,
+	*config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error)

client/direct.go

 package client
 
 import (
+	"context"
 	"net"
 	"time"
 
 
 // DirectInit initializes client connection for proxy which connects to
 // Telegram directly.
-func DirectInit(socket net.Conn, connID string, conf *config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error) {
+func DirectInit(ctx context.Context, cancel context.CancelFunc, socket net.Conn,
+	connID string, conf *config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error) {
 	tcpSocket := socket.(*net.TCPConn)
 	if err := tcpSocket.SetNoDelay(false); err != nil {
 		return nil, nil, errors.Annotate(err, "Cannot disable NO_DELAY to client socket")
 	}
 	socket.SetReadDeadline(time.Time{}) // nolint: errcheck
 
-	conn := wrappers.NewConn(socket, connID, wrappers.ConnPurposeClient, conf.PublicIPv4, conf.PublicIPv6)
+	conn := wrappers.NewConn(ctx, cancel, socket, connID, wrappers.ConnPurposeClient, conf.PublicIPv4, conf.PublicIPv6)
 	obfs2, connOpts, err := obfuscated2.ParseObfuscated2ClientFrame(conf.Secret, frame)
 	if err != nil {
 		return nil, nil, errors.Annotate(err, "Cannot parse obfuscated frame")

client/middle.go

 package client
 
 import (
+	"context"
 	"net"
 
 	"github.com/9seconds/mtg/config"
 
 // MiddleInit initializes client connection for proxy which has to
 // support promoted channels, connect to Telegram middle proxies etc.
-func MiddleInit(socket net.Conn, connID string, conf *config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error) {
-	conn, opts, err := DirectInit(socket, connID, conf)
+func MiddleInit(ctx context.Context, cancel context.CancelFunc, socket net.Conn,
+	connID string, conf *config.Config) (wrappers.Wrap, *mtproto.ConnectionOpts, error) {
+	conn, opts, err := DirectInit(ctx, cancel, socket, connID, conf)
 	if err != nil {
 		return nil, nil, err
 	}

proxy/proxy.go

 package proxy
 
 import (
+	"context"
 	"io"
 	"net"
 	"sync"
 func (p *Proxy) accept(conn net.Conn) {
 	connID := uuid.NewV4().String()
 	log := zap.S().With("connection_id", connID).Named("main")
+	ctx, cancel := context.WithCancel(context.Background())
 
 	defer func() {
 		conn.Close() // nolint: errcheck
 
 	log.Infow("Client connected", "addr", conn.RemoteAddr())
 
-	clientConn, opts, err := p.clientInit(conn, connID, p.conf)
+	clientConn, opts, err := p.clientInit(ctx, cancel, conn, connID, p.conf)
 	if err != nil {
 		log.Errorw("Cannot initialize client connection", "error", err)
 		return
 	stats.ClientConnected(opts.ConnectionType, clientConn.RemoteAddr())
 	defer stats.ClientDisconnected(opts.ConnectionType, clientConn.RemoteAddr())
 
-	serverConn, err := p.getTelegramConn(opts, connID)
+	serverConn, err := p.getTelegramConn(ctx, cancel, opts, connID)
 	if err != nil {
 		log.Errorw("Cannot initialize server connection", "error", err)
 		return
 	log.Infow("Client disconnected", "addr", conn.RemoteAddr())
 }
 
-func (p *Proxy) getTelegramConn(opts *mtproto.ConnectionOpts, connID string) (wrappers.Wrap, error) {
-	streamConn, err := p.tg.Dial(connID, opts)
+func (p *Proxy) getTelegramConn(ctx context.Context, cancel context.CancelFunc,
+	opts *mtproto.ConnectionOpts, connID string) (wrappers.Wrap, error) {
+	streamConn, err := p.tg.Dial(ctx, cancel, connID, opts)
 	if err != nil {
 		return nil, errors.Annotate(err, "Cannot dial to Telegram")
 	}

telegram/dialer.go

 package telegram
 
 import (
+	"context"
 	"net"
 	"time"
 
 	return conn, nil
 }
 
-func (t *tgDialer) dialRWC(addr, connID string) (wrappers.StreamReadWriteCloser, error) {
+func (t *tgDialer) dialRWC(ctx context.Context, cancel context.CancelFunc,
+	addr, connID string) (wrappers.StreamReadWriteCloser, error) {
 	conn, err := t.dial(addr)
 	if err != nil {
 		return nil, err
 	}
-	tgConn := wrappers.NewConn(conn, connID, wrappers.ConnPurposeTelegram, t.conf.PublicIPv4, t.conf.PublicIPv6)
+	tgConn := wrappers.NewConn(ctx, cancel, conn, connID,
+		wrappers.ConnPurposeTelegram, t.conf.PublicIPv4, t.conf.PublicIPv6)
 
 	return tgConn, nil
 }

telegram/direct.go

 package telegram
 
 import (
+	"context"
 	"net"
 
 	"github.com/juju/errors"
 	baseTelegram
 }
 
-func (t *directTelegram) Dial(connID string, connOpts *mtproto.ConnectionOpts) (wrappers.StreamReadWriteCloser, error) {
+func (t *directTelegram) Dial(ctx context.Context, cancel context.CancelFunc,
+	connID string, connOpts *mtproto.ConnectionOpts) (wrappers.StreamReadWriteCloser, error) {
 	dc := connOpts.DC
 	if dc < 0 {
 		dc = -dc
 		dc = 1
 	}
 
-	return t.baseTelegram.dial(dc-1, connID, connOpts.ConnectionProto)
+	return t.baseTelegram.dial(ctx, cancel, dc-1, connID, connOpts.ConnectionProto)
 }
 
 func (t *directTelegram) Init(connOpts *mtproto.ConnectionOpts,

telegram/middle_caller.go

 
 import (
 	"bufio"
+	"context"
 	"io/ioutil"
 	"net"
 	"net/http"
 	httpClient  *http.Client
 }
 
-func (t *middleTelegramCaller) Dial(connID string,
+func (t *middleTelegramCaller) Dial(ctx context.Context, cancel context.CancelFunc, connID string,
 	connOpts *mtproto.ConnectionOpts) (wrappers.StreamReadWriteCloser, error) {
 	dc := connOpts.DC
 	if dc == 0 {
 	t.dialerMutex.RLock()
 	defer t.dialerMutex.RUnlock()
 
-	return t.baseTelegram.dial(dc, connID, connOpts.ConnectionProto)
+	return t.baseTelegram.dial(ctx, cancel, dc, connID, connOpts.ConnectionProto)
 }
 
 func (t *middleTelegramCaller) autoUpdate() {

telegram/telegram.go

 package telegram
 
 import (
+	"context"
 	"math/rand"
 
 	"github.com/juju/errors"
 
 // Telegram is an interface for different Telegram work modes.
 type Telegram interface {
-	Dial(string, *mtproto.ConnectionOpts) (wrappers.StreamReadWriteCloser, error)
+	Dial(context.Context, context.CancelFunc, string, *mtproto.ConnectionOpts) (wrappers.StreamReadWriteCloser, error)
 	Init(*mtproto.ConnectionOpts, wrappers.StreamReadWriteCloser) (wrappers.Wrap, error)
 }
 
 	v6Addresses map[int16][]string
 }
 
-func (b *baseTelegram) dial(dcIdx int16, connID string,
+func (b *baseTelegram) dial(ctx context.Context, cancel context.CancelFunc, dcIdx int16, connID string,
 	proto mtproto.ConnectionProtocol) (wrappers.StreamReadWriteCloser, error) {
 	addrs := make([]string, 2)
 
 	}
 
 	for _, addr := range addrs {
-		if conn, err := b.dialer.dialRWC(addr, connID); err == nil {
+		if conn, err := b.dialer.dialRWC(ctx, cancel, addr, connID); err == nil {
 			return conn, err
 		}
 	}

wrappers/conn.go

 package wrappers
 
 import (
+	"context"
 	"net"
 	"time"
 
 	"go.uber.org/zap"
 
 	"github.com/9seconds/mtg/stats"
+	"github.com/juju/errors"
 )
 
 // ConnPurpose is intended to be identifier of connection purpose. We
 // Conn is a basic wrapper for net.Conn providing the most low-level
 // logic and management as possible.
 type Conn struct {
-	connID string
 	conn   net.Conn
+	ctx    context.Context
+	cancel context.CancelFunc
+	connID string
 	logger *zap.SugaredLogger
 
 	publicIPv4 net.IP
 }
 
 func (c *Conn) Write(p []byte) (int, error) {
-	c.conn.SetWriteDeadline(time.Now().Add(connTimeoutWrite)) // nolint: errcheck
-	n, err := c.conn.Write(p)
+	select {
+	case <-c.ctx.Done():
+		return 0, errors.Annotate(c.ctx.Err(), "Cannot write because context was closed")
+	default:
+		c.conn.SetWriteDeadline(time.Now().Add(connTimeoutWrite)) // nolint: errcheck
+		n, err := c.conn.Write(p)
+		if err != nil {
+			c.cancel()
+		}
 
-	c.logger.Debugw("Write to stream", "bytes", n, "error", err)
-	stats.EgressTraffic(n)
+		c.logger.Debugw("Write to stream", "bytes", n, "error", err)
+		stats.EgressTraffic(n)
 
-	return n, err
+		return n, err
+	}
 }
 
 func (c *Conn) Read(p []byte) (int, error) {
-	c.conn.SetReadDeadline(time.Now().Add(connTimeoutRead)) // nolint: errcheck
-	n, err := c.conn.Read(p)
+	select {
+	case <-c.ctx.Done():
+		return 0, errors.Annotate(c.ctx.Err(), "Cannot read because context was closed")
+	default:
+		c.conn.SetReadDeadline(time.Now().Add(connTimeoutRead)) // nolint: errcheck
+		n, err := c.conn.Read(p)
+		if err != nil {
+			c.cancel()
+		}
 
-	c.logger.Debugw("Read from stream", "bytes", n, "error", err)
-	stats.IngressTraffic(n)
+		c.logger.Debugw("Read from stream", "bytes", n, "error", err)
+		stats.IngressTraffic(n)
 
-	return n, err
+		return n, err
+	}
 }
 
 // Close closes underlying net.Conn instance.
 func (c *Conn) Close() error {
 	defer c.logger.Debugw("Close connection")
+
+	c.cancel()
 	return c.conn.Close()
 }
 
 }
 
 // NewConn initializes Conn wrapper for net.Conn.
-func NewConn(conn net.Conn, connID string, purpose ConnPurpose, publicIPv4, publicIPv6 net.IP) StreamReadWriteCloser {
+func NewConn(ctx context.Context, cancel context.CancelFunc, conn net.Conn,
+	connID string, purpose ConnPurpose, publicIPv4, publicIPv6 net.IP) StreamReadWriteCloser {
 	logger := zap.S().With(
 		"connection_id", connID,
 		"local_address", conn.LocalAddr(),
 	).Named("conn")
 
 	wrapper := Conn{
-		logger:     logger,
-		connID:     connID,
 		conn:       conn,
+		ctx:        ctx,
+		cancel:     cancel,
+		connID:     connID,
+		logger:     logger,
 		publicIPv4: publicIPv4,
 		publicIPv6: publicIPv6,
 	}