Added a checker that will detect dead sockets before the timeout (Lin…

…ux only)

Signed-off-by: Juanjo Alvarez <juanjo@sourced.tech>

go.mod

@@ -1,6 +1,7 @@
 module github.com/src-d/go-mysql-server
 
 require (
+	github.com/StackExchange/wmi v0.0.0-20190523213315-cbe66965904d // indirect
 	github.com/VividCortex/gohistogram v1.0.0 // indirect
 	github.com/go-kit/kit v0.8.0
 	github.com/go-ole/go-ole v1.2.4 // indirect
@@ -12,18 +13,16 @@ require (
 	github.com/mitchellh/hashstructure v1.0.0
 	github.com/oliveagle/jsonpath v0.0.0-20180606110733-2e52cf6e6852
 	github.com/opentracing/opentracing-go v1.0.2
-	github.com/pbnjay/memory v0.0.0-20190104145345-974d429e7ae4
 	github.com/pilosa/pilosa v1.3.0
 	github.com/sanity-io/litter v1.1.0
+	github.com/shirou/w32 v0.0.0-20160930032740-bb4de0191aa4 // indirect
 	github.com/sirupsen/logrus v1.3.0
 	github.com/spf13/cast v1.3.0
 	github.com/src-d/go-oniguruma v1.0.0
 	github.com/stretchr/testify v1.3.0
 	go.etcd.io/bbolt v1.3.2
 	google.golang.org/grpc v1.19.0 // indirect
 	gopkg.in/src-d/go-errors.v1 v1.0.0
-	gopkg.in/src-d/go-git.v4 v4.13.1
-	gopkg.in/src-d/go-mysql-server.v0 v0.5.1
 	gopkg.in/yaml.v2 v2.2.2
 	vitess.io/vitess v3.0.0-rc.3.0.20190602171040-12bfde34629c+incompatible
 )

internal/sockstate/netstat.go

@@ -0,0 +1,82 @@
+package sockstate
+
+import (
+	"fmt"
+	"net"
+)
+
+// OS independent part of the netstat_[OS].go modules
+// Taken (simplified, privatized and with utility functions added) from:
+// https://github.com/cakturk/go-netstat
+
+// skState type represents socket connection state
+type skState uint8
+
+func (s skState) String() string {
+	return skStates[s]
+}
+
+// Socket states
+const (
+	Established skState = 0x01
+	SynSent             = 0x02
+	SynRecv             = 0x03
+	FinWait1            = 0x04
+	FinWait2            = 0x05
+	TimeWait            = 0x06
+	Close               = 0x07
+	CloseWait           = 0x08
+	LastAck             = 0x09
+	Listen              = 0x0a
+	Closing             = 0x0b
+)
+
+var skStates = [...]string{
+	"UNKNOWN",
+	"ESTABLISHED",
+	"SYN_SENT",
+	"SYN_RECV",
+	"FIN_WAIT1",
+	"FIN_WAIT2",
+	"TIME_WAIT",
+	"", // CLOSE
+	"CLOSE_WAIT",
+	"LAST_ACK",
+	"LISTEN",
+	"CLOSING",
+}
+
+// sockAddr represents an ip:port pair
+type sockAddr struct {
+	IP   net.IP
+	Port uint16
+}
+
+func (s *sockAddr) String() string {
+	return fmt.Sprintf("%v:%d", s.IP, s.Port)
+}
+
+// sockTabEntry type represents each line of the /proc/net/tcp
+type sockTabEntry struct {
+	Ino        string
+	LocalAddr  *sockAddr
+	RemoteAddr *sockAddr
+	State      skState
+	UID        uint32
+	Process    *process
+}
+
+// process holds the PID and process name to which each socket belongs
+type process struct {
+	pid  int
+	name string
+}
+
+func (p *process) String() string {
+	return fmt.Sprintf("%d/%s", p.pid, p.name)
+}
+
+// AcceptFn is used to filter socket entries. The value returned indicates
+// whether the element is to be appended to the socket list.
+type AcceptFn func(*sockTabEntry) bool
+

internal/sockstate/netstat_darwin.go

@@ -0,0 +1,11 @@
+package sockstate
+
+import "github.com/sirupsen/logrus"
+
+// tcpSocks returns a slice of active TCP sockets containing only those
+// elements that satisfy the accept function
+func tcpSocks(accept AcceptFn) ([]sockTabEntry, error) {
+	// (juanjux) TODO: not implemented
+	logrus.Info("Connection checking not implemented for Darwin")
+	return []sockTabEntry{}, nil
+}

internal/sockstate/netstat_linux.go

@@ -0,0 +1,206 @@
+package sockstate
+
+// Taken (simplified and with utility functions added) from https://github.com/cakturk/go-netstat
+
+import (
+	"bufio"
+	"bytes"
+	"encoding/binary"
+	"fmt"
+	"io"
+	"io/ioutil"
+	"log"
+	"net"
+	"os"
+	"path"
+	"strconv"
+	"strings"
+)
+
+const (
+	pathTCPTab = "/proc/net/tcp"
+	ipv4StrLen = 8
+)
+
+type procFd struct {
+	base  string
+	pid   int
+	sktab []sockTabEntry
+	p     *process
+}
+
+const sockPrefix = "socket:["
+
+func getProcName(s []byte) string {
+	i := bytes.Index(s, []byte("("))
+	if i < 0 {
+		return ""
+	}
+	j := bytes.LastIndex(s, []byte(")"))
+	if i < 0 {
+		return ""
+	}
+	if i > j {
+		return ""
+	}
+	return string(s[i+1 : j])
+}
+
+func (p *procFd) iterFdDir() {
+	// link name is of the form socket:[5860846]
+	fddir := path.Join(p.base, "/fd")
+	fi, err := ioutil.ReadDir(fddir)
+	if err != nil {
+		return
+	}
+	var buf [128]byte
+
+	for _, file := range fi {
+		fd := path.Join(fddir, file.Name())
+		lname, err := os.Readlink(fd)
+		if err != nil {
+			continue
+		}
+
+		for i := range p.sktab {
+			sk := &p.sktab[i]
+			ss := sockPrefix + sk.Ino + "]"
+			if ss != lname {
+				continue
+			}
+			if p.p == nil {
+				stat, err := os.Open(path.Join(p.base, "stat"))
+				if err != nil {
+					return
+				}
+				n, err := stat.Read(buf[:])
+				_ = stat.Close()
+				if err != nil {
+					return
+				}
+				z := bytes.SplitN(buf[:n], []byte(" "), 3)
+				name := getProcName(z[1])
+				p.p = &process{p.pid, name}
+			}
+			sk.Process = p.p
+		}
+	}
+}
+
+func extractProcInfo(sktab []sockTabEntry) {
+	const basedir = "/proc"
+	fi, err := ioutil.ReadDir(basedir)
+	if err != nil {
+		return
+	}
+
+	for _, file := range fi {
+		if !file.IsDir() {
+			continue
+		}
+		pid, err := strconv.Atoi(file.Name())
+		if err != nil {
+			continue
+		}
+		base := path.Join(basedir, file.Name())
+		proc := procFd{base: base, pid: pid, sktab: sktab}
+		proc.iterFdDir()
+	}
+}
+
+func parseIPv4(s string) (net.IP, error) {
+	v, err := strconv.ParseUint(s, 16, 32)
+	if err != nil {
+		return nil, err
+	}
+	ip := make(net.IP, net.IPv4len)
+	binary.LittleEndian.PutUint32(ip, uint32(v))
+	return ip, nil
+}
+
+func parseAddr(s string) (*sockAddr, error) {
+	fields := strings.Split(s, ":")
+	if len(fields) < 2 {
+		return nil, fmt.Errorf("sockstate: not enough fields: %v", s)
+	}
+	var ip net.IP
+	var err error
+	switch len(fields[0]) {
+	case ipv4StrLen:
+		ip, err = parseIPv4(fields[0])
+	default:
+		log.Fatal("Bad formatted string")
+	}
+	if err != nil {
+		return nil, err
+	}
+	v, err := strconv.ParseUint(fields[1], 16, 16)
+	if err != nil {
+		return nil, err
+	}
+	return &sockAddr{IP: ip, Port: uint16(v)}, nil
+}
+
+func parseSocktab(r io.Reader, accept AcceptFn) ([]sockTabEntry, error) {
+	br := bufio.NewScanner(r)
+	tab := make([]sockTabEntry, 0, 4)
+
+	// Discard title
+	br.Scan()
+
+	for br.Scan() {
+		var e sockTabEntry
+		line := br.Text()
+		// Skip comments
+		if i := strings.Index(line, "#"); i >= 0 {
+			line = line[:i]
+		}
+		fields := strings.Fields(line)
+		if len(fields) < 12 {
+			return nil, fmt.Errorf("sockstate: not enough fields: %v, %v", len(fields), fields)
+		}
+		addr, err := parseAddr(fields[1])
+		if err != nil {
+			return nil, err
+		}
+		e.LocalAddr = addr
+		addr, err = parseAddr(fields[2])
+		if err != nil {
+			return nil, err
+		}
+		e.RemoteAddr = addr
+		u, err := strconv.ParseUint(fields[3], 16, 8)
+		if err != nil {
+			return nil, err
+		}
+		e.State = skState(u)
+		u, err = strconv.ParseUint(fields[7], 10, 32)
+		if err != nil {
+			return nil, err
+		}
+		e.UID = uint32(u)
+		e.Ino = fields[9]
+		if accept(&e) {
+			tab = append(tab, e)
+		}
+	}
+	return tab, br.Err()
+}
+
+// tcpSocks returns a slice of active TCP sockets containing only those
+// elements that satisfy the accept function
+func tcpSocks(accept AcceptFn) ([]sockTabEntry, error) {
+	f, err := os.Open(pathTCPTab)
+	defer f.Close()
+	if err != nil {
+		return nil, err
+	}
+
+	tabs, err := parseSocktab(f, accept)
+	if err != nil {
+		return nil, err
+	}
+
+	extractProcInfo(tabs)
+	return tabs, nil
+}

internal/sockstate/netstat_windows.go

@@ -0,0 +1,11 @@
+package sockstate
+
+import "github.com/sirupsen/logrus"
+
+// tcpSocks returns a slice of active TCP sockets containing only those
+// elements that satisfy the accept function
+func tcpSocks(accept AcceptFn) ([]sockTabEntry, error) {
+	// (juanjux) TODO: not implemented
+	logrus.Info("Connection checking not implemented for Windows")
+	return []sockTabEntry{}, nil
+}