/
parser.go
179 lines (149 loc) · 3.44 KB
/
parser.go
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package parser
import (
"bytes"
"compress/zlib"
"encoding/binary"
"fmt"
"io"
"log"
"net"
"strconv"
"time"
"github.com/hailocab/logslam/buffer"
)
const (
ack = "ACKMSG"
maxKeyLen = 100 * 1024 * 1024 // 100 mb
maxValueLen = 250 * 1024 * 1024 // 250 mb
)
type Receiver interface {
Send(*buffer.Event)
}
type Parser struct {
Conn net.Conn
Recv Receiver
wlen, plen uint32
buffer io.Reader
}
func New(c net.Conn, r Receiver) *Parser {
return &Parser{
Conn: c,
Recv: r,
}
}
// ack acknowledges that the payload was received successfully
func (p *Parser) ack() error {
if _, err := p.Conn.Write([]byte(ack)); err != nil {
return err
}
return nil
}
// readKV parses key value pairs from within the payload
func (p *Parser) readKV() ([]byte, []byte, error) {
var klen, vlen uint32
// Read key len
binary.Read(p.buffer, binary.BigEndian, &klen)
if klen > maxKeyLen {
return nil, nil, fmt.Errorf("key exceeds max len %d, got %d bytes", maxKeyLen, klen)
}
// Read key
key := make([]byte, klen)
_, err := p.buffer.Read(key)
if err != nil {
return nil, nil, err
}
// Read value len
binary.Read(p.buffer, binary.BigEndian, &vlen)
if vlen > maxValueLen {
return nil, nil, fmt.Errorf("value exceeds max len %d, got %d bytes", maxValueLen, vlen)
}
// Read value
value := make([]byte, vlen)
_, err = p.buffer.Read(value)
if err != nil {
return nil, nil, err
}
return key, value, nil
}
// read parses the compressed data frame
func (p *Parser) read() error {
var s, f uint32
var k, v []byte
var err error
r, err := zlib.NewReader(p.Conn)
if err != nil {
return err
}
defer r.Close()
// Decompress
buff := new(bytes.Buffer)
io.Copy(buff, r)
p.buffer = buff
b := make([]byte, 2)
for i := uint32(0); i < p.wlen; i++ {
n, err := buff.Read(b)
if err == io.EOF {
return err
}
if n == 0 {
continue
}
switch string(b) {
case "1D": // window size
binary.Read(buff, binary.BigEndian, &s)
binary.Read(buff, binary.BigEndian, &f)
var ev buffer.Event
fields := make(map[string]string)
fields["timestamp"] = time.Now().Format(time.RFC3339Nano)
for j := uint32(0); j < f; j++ {
if k, v, err = p.readKV(); err != nil {
return err
}
fields[string(k)] = string(v)
}
ev.Source = fmt.Sprintf("lumberjack://%s%s", fields["host"], fields["file"])
ev.Offset, _ = strconv.ParseInt(fields["offset"], 10, 64)
ev.Line = uint64(s)
t := fields["line"]
ev.Text = &t
ev.Fields = &fields
// Send to the receiver which is a buffer. We block because...
p.Recv.Send(&ev)
default:
return fmt.Errorf("unknown type")
}
}
return nil
}
// Parse initialises the read loop and begins parsing the incoming request
func (p *Parser) Parse() {
b := make([]byte, 2)
Read:
for {
n, err := p.Conn.Read(b)
switch {
case err == io.EOF:
break Read
case n == 0:
goto Read
}
switch string(b) {
case "1W": // window length
binary.Read(p.Conn, binary.BigEndian, &p.wlen)
case "1C": // frame length
binary.Read(p.Conn, binary.BigEndian, &p.plen)
if err := p.read(); err != nil {
log.Printf("[%s] error parsing %v", p.Conn.RemoteAddr().String(), err)
break Read
}
if err := p.ack(); err != nil {
log.Printf("[%s] error acking %v", p.Conn.RemoteAddr().String(), err)
break Read
}
default:
// This really shouldn't happen
log.Printf("[%s] Received unknown type", p.Conn.RemoteAddr().String(), err)
break Read
}
}
}