/
server.go
210 lines (194 loc) · 4.23 KB
/
server.go
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package main
import (
"context"
"encoding/base64"
"flag"
"fmt"
"io"
"log"
"net"
"os"
"strings"
"sync"
"github.com/algorand/graphtrace/graphtrace"
)
var verbose bool = false
func debug(format string, args ...interface{}) {
if verbose == false {
return
}
log.Printf(format, args...)
}
type server struct {
addr string
ln net.Listener
ctx context.Context
cf func()
out io.Writer
lock sync.Mutex
}
func (s *server) Run() {
defer s.cf()
lc := net.ListenConfig{}
var err error
s.ln, err = lc.Listen(s.ctx, "tcp", s.addr)
if err != nil {
log.Printf("%s: listen, %s", s.addr, err)
return
}
for {
conn, err := s.ln.Accept()
if err != nil {
log.Printf("%s: accept, %s", s.addr, err)
return
}
cl := &client{
conn: conn.(*net.TCPConn),
ctx: s.ctx,
s: s,
}
go cl.Run()
}
}
func (s *server) trace(addr *net.TCPAddr, t int64, m []byte) {
msg := fmt.Sprintf("%d\t%s\t%d\t%s\n", t, addr.IP.String(), addr.Port, base64.StdEncoding.EncodeToString(m))
s.lock.Lock()
defer s.lock.Unlock()
_, err := s.out.Write([]byte(msg))
if err != nil {
log.Printf("record log err: %s", err)
s.cf()
}
}
type client struct {
conn *net.TCPConn
ctx context.Context
// their time + offset == our time
// offset = (our time) - (their time)
offset int64
s *server
}
func (c *client) Run() {
buf := make([]byte, graphtrace.MaxRecordLength)
for {
select {
case <-c.ctx.Done():
c.Close()
return
default:
}
blen, err := c.conn.Read(buf)
if err != nil {
if err != io.EOF {
log.Printf("%s: read %s", c.conn.RemoteAddr(), err)
}
c.Close()
return
}
rb := buf[:blen]
switch rb[0] {
case graphtrace.MessagePing:
err = c.handlePing(rb)
if err != nil {
log.Printf("%s: bad ping %s", c.conn.RemoteAddr(), err)
c.Close()
return
}
case graphtrace.MessageTrace:
err = c.handleTrace(rb)
if err != nil {
log.Printf("%s: bad trace %s", c.conn.RemoteAddr(), err)
c.Close()
return
}
default:
log.Printf("%s: bad msg 0x%x", c.conn.RemoteAddr(), rb[0])
c.Close()
return
}
}
}
func (c *client) handlePing(rb []byte) error {
now := graphtrace.EpochMicroseconds()
theirTime, myTime, err := graphtrace.ParsePing(rb)
if err != nil {
return err
}
if myTime == 0 {
c.offset = int64(now) - int64(theirTime)
msg := graphtrace.BuildPing(now, theirTime)
_, err = c.conn.Write(msg)
if err != nil {
return err
}
} else {
roundTripMicros := now - myTime
c.offset = int64(now) - int64(theirTime+(roundTripMicros/2))
debug("%s rtt=%d µs, offset=%d µs", c.conn.RemoteAddr(), roundTripMicros, c.offset)
}
return nil
}
func (c *client) handleTrace(rb []byte) error {
now := int64(graphtrace.EpochMicroseconds())
theirTime, msg, err := graphtrace.ParseTrace(rb)
if err != nil {
return err
}
adjTime := int64(theirTime) + c.offset
if adjTime < now {
adjTime = now
}
c.s.trace(c.conn.RemoteAddr().(*net.TCPAddr), adjTime, msg)
return nil
}
func (c *client) Close() {
if c.conn == nil {
return
}
c.conn.Close()
c.conn = nil
}
// math package only has min/max values for explicitly sized int
var m1 = -1
var maxInt = int(uint64(m1) >> 1)
func main() {
var serveAddr string
var dataPath string
var rotateSize int
var archivePath string
flag.StringVar(&serveAddr, "addr", ":6525", ":port or host:port to serve on")
flag.StringVar(&dataPath, "out", "-", "path to write data to, \"-\" for stdout (default)")
flag.IntVar(&rotateSize, "rotateSize", maxInt, "number of bytes of main output file after which to rotate the output file")
flag.StringVar(&archivePath, "outArchive", "", "path to move old files to. {{s}} for unix seconds")
flag.BoolVar(&verbose, "verbose", false, "verbose logging")
flag.Parse()
var out io.Writer
if dataPath == "-" {
out = os.Stdout
} else {
lw := &LogWriter{
BreakSize: rotateSize,
OutPath: dataPath,
ArchiveFormat: archivePath,
}
if strings.HasSuffix(archivePath, ".gz") {
lw.Gzip = true
}
out = lw
}
ctx, cf := context.WithCancel(context.Background())
s := server{
addr: serveAddr,
ctx: ctx,
cf: cf,
out: out,
}
s.Run()
}
func maybeFail(err error, errfmt string, params ...interface{}) {
if err == nil {
return
}
fmt.Fprintf(os.Stderr, errfmt, params...)
os.Exit(1)
}