forked from jeromer/syslogparser
/
rfc3164.go
244 lines (192 loc) · 4.05 KB
/
rfc3164.go
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package rfc3164
import (
"bytes"
"github.com/deis/syslogparser"
"time"
)
type Parser struct {
buff []byte
cursor int
l int
priority syslogparser.Priority
version int
header header
message rfc3164message
}
type header struct {
timestamp time.Time
hostname string
}
type rfc3164message struct {
tag string
content string
}
func NewParser(buff []byte) *Parser {
return &Parser{
buff: buff,
cursor: 0,
l: len(buff),
}
}
func (p *Parser) Parse() error {
pri := syslogparser.Priority{}
if p.buff[0] == '<' {
priority, err := p.parsePriority()
if err != nil {
return err
}
pri = priority
}
hdr, err := p.parseHeader()
if err != nil {
return err
}
p.cursor++
msg, err := p.parsemessage()
if err != syslogparser.ErrEOL {
return err
}
p.priority = pri
p.version = syslogparser.NO_VERSION
p.header = hdr
p.message = msg
return nil
}
func (p *Parser) Dump() syslogparser.LogParts {
return syslogparser.LogParts{
"timestamp": p.header.timestamp,
"hostname": p.header.hostname,
"tag": p.message.tag,
"content": p.message.content,
"priority": p.priority.P,
"facility": p.priority.F.Value,
"severity": p.priority.S.Value,
}
}
func (p *Parser) parsePriority() (syslogparser.Priority, error) {
return syslogparser.ParsePriority(p.buff, &p.cursor, p.l)
}
func (p *Parser) parseHeader() (header, error) {
hdr := header{}
var err error
ts, err := p.parseTimestamp()
if err != nil {
return hdr, err
}
hostname, err := p.parseHostname()
if err != nil {
return hdr, err
}
hdr.timestamp = ts
hdr.hostname = hostname
return hdr, nil
}
func (p *Parser) parsemessage() (rfc3164message, error) {
msg := rfc3164message{}
var err error
tag, err := p.parseTag()
if err != nil {
return msg, err
}
content, err := p.parseContent()
if err != syslogparser.ErrEOL {
return msg, err
}
msg.tag = tag
msg.content = content
return msg, err
}
// https://tools.ietf.org/html/rfc3164#section-4.1.2
func (p *Parser) parseTimestamp() (time.Time, error) {
var ts time.Time
var err error
var tsFmtLen int
var sub []byte
tsFmts := []string{
"Jan 02 15:04:05",
"Jan 2 15:04:05",
"2006-01-02 15:04:05",
}
found := false
for _, tsFmt := range tsFmts {
tsFmtLen = len(tsFmt)
if p.cursor+tsFmtLen > p.l {
continue
}
sub = p.buff[p.cursor : tsFmtLen+p.cursor]
ts, err = time.Parse(tsFmt, string(sub))
if err == nil {
found = true
break
}
}
if !found {
p.cursor = tsFmtLen
// XXX : If the timestamp is invalid we try to push the cursor one byte
// XXX : further, in case it is a space
if (p.cursor < p.l) && (p.buff[p.cursor] == ' ') {
p.cursor++
}
return ts, syslogparser.ErrTimestampUnknownFormat
}
fixTimestampIfNeeded(&ts)
p.cursor += tsFmtLen
if (p.cursor < p.l) && (p.buff[p.cursor] == ' ') {
p.cursor++
}
return ts, nil
}
func (p *Parser) parseHostname() (string, error) {
return syslogparser.ParseHostname(p.buff, &p.cursor, p.l)
}
// http://tools.ietf.org/html/rfc3164#section-4.1.3
func (p *Parser) parseTag() (string, error) {
var b byte
var endOfTag bool
var bracketOpen bool
var tag []byte
var err error
var found bool
from := p.cursor
for {
b = p.buff[p.cursor]
bracketOpen = (b == '[')
endOfTag = (b == ':' || b == ' ')
// XXX : parse PID ?
if bracketOpen {
tag = p.buff[from:p.cursor]
found = true
}
if endOfTag {
if !found {
tag = p.buff[from:p.cursor]
found = true
}
p.cursor++
break
}
p.cursor++
}
if (p.cursor < p.l) && (p.buff[p.cursor] == ' ') {
p.cursor++
}
return string(tag), err
}
func (p *Parser) parseContent() (string, error) {
if p.cursor > p.l {
return "", syslogparser.ErrEOL
}
content := bytes.Trim(p.buff[p.cursor:p.l], " ")
p.cursor += len(content)
return string(content), syslogparser.ErrEOL
}
func fixTimestampIfNeeded(ts *time.Time) {
now := time.Now()
y := ts.Year()
if ts.Year() == 0 {
y = now.Year()
}
newTs := time.Date(y, ts.Month(), ts.Day(), ts.Hour(), ts.Minute(),
ts.Second(), ts.Nanosecond(), ts.Location())
*ts = newTs
}