// Copyright 2018 The go-ethereum Authors
// This file is part of the go-ethereum library.
//
// The go-ethereum library is free software: you can redistribute it and/or modify
// it under the terms of the GNU Lesser General Public License as published by
// the Free Software Foundation, either version 3 of the License, or
// (at your option) any later version.
//
// The go-ethereum library is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
// GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with the go-ethereum library. If not, see <http://www.gnu.org/licenses/>.
package dashboard
import (
"bytes"
"encoding/json"
"io/ioutil"
"os"
"path/filepath"
"regexp"
"sort"
"time"
"github.com/ethereum/go-ethereum/log"
"github.com/mohae/deepcopy"
"github.com/rjeczalik/notify"
)
var emptyChunk = json.RawMessage("[]")
// prepLogs creates a JSON array from the given log record buffer.
// Returns the prepared array and the position of the last '\n'
// character in the original buffer, or -1 if it doesn't contain any.
func prepLogs(buf []byte) (json.RawMessage, int) {
b := make(json.RawMessage, 1, len(buf)+1)
b[0] = '['
b = append(b, buf...)
last := -1
for i := 1; i < len(b); i++ {
if b[i] == '\n' {
b[i] = ','
last = i
}
}
if last < 0 {
return emptyChunk, -1
}
b[last] = ']'
return b[:last+1], last - 1
}
// handleLogRequest searches for the log file specified by the timestamp of the
// request, creates a JSON array out of it and sends it to the requesting client.
func (db *Dashboard) handleLogRequest(r *LogsRequest, c *client) {
files, err := ioutil.ReadDir(db.logdir)
if err != nil {
log.Warn("Failed to open logdir", "path", db.logdir, "err", err)
return
}
re := regexp.MustCompile(`\.log$`)
fileNames := make([]string, 0, len(files))
for _, f := range files {
if f.Mode().IsRegular() && re.MatchString(f.Name()) {
fileNames = append(fileNames, f.Name())
}
}
if len(fileNames) < 1 {
log.Warn("No log files in logdir", "path", db.logdir)
return
}
idx := sort.Search(len(fileNames), func(idx int) bool {
// Returns the smallest index such as fileNames[idx] >= r.Name,
// if there is no such index, returns n.
return fileNames[idx] >= r.Name
})
switch {
case idx < 0:
return
case idx == 0 && r.Past:
return
case idx >= len(fileNames):
return
case r.Past:
idx--
case idx == len(fileNames)-1 && fileNames[idx] == r.Name:
return
case idx == len(fileNames)-1 || (idx == len(fileNames)-2 && fileNames[idx] == r.Name):
// The last file is continuously updated, and its chunks are streamed,
// so in order to avoid log record duplication on the client side, it is
// handled differently. Its actual content is always saved in the history.
db.lock.Lock()
if db.history.Logs != nil {
c.msg <- &Message{
Logs: db.history.Logs,
}
}
db.lock.Unlock()
return
case fileNames[idx] == r.Name:
idx++
}
path := filepath.Join(db.logdir, fileNames[idx])
var buf []byte
if buf, err = ioutil.ReadFile(path); err != nil {
log.Warn("Failed to read file", "path", path, "err", err)
return
}
chunk, end := prepLogs(buf)
if end < 0 {
log.Warn("The file doesn't contain valid logs", "path", path)
return
}
c.msg <- &Message{
Logs: &LogsMessage{
Source: &LogFile{
Name: fileNames[idx],
Last: r.Past && idx == 0,
},
Chunk: chunk,
},
}
}
// streamLogs watches the file system, and when the logger writes
// the new log records into the files, picks them up, then makes
// JSON array out of them and sends them to the clients.
func (db *Dashboard) streamLogs() {
defer db.wg.Done()
var (
err error
errc chan error
)
defer func() {
if errc == nil {
errc = <-db.quit
}
errc <- err
}()
files, err := ioutil.ReadDir(db.logdir)
if err != nil {
log.Warn("Failed to open logdir", "path", db.logdir, "err", err)
return
}
var (
opened *os.File // File descriptor for the opened active log file.
buf []byte // Contains the recently written log chunks, which are not sent to the clients yet.
)
// The log records are always written into the last file in alphabetical order, because of the timestamp.
re := regexp.MustCompile(`\.log$`)
i := len(files) - 1
for i >= 0 && (!files[i].Mode().IsRegular() || !re.MatchString(files[i].Name())) {
i--
}
if i < 0 {
log.Warn("No log files in logdir", "path", db.logdir)
return
}
if opened, err = os.OpenFile(filepath.Join(db.logdir, files[i].Name()), os.O_RDONLY, 0600); err != nil {
log.Warn("Failed to open file", "name", files[i].Name(), "err", err)
return
}
defer opened.Close() // Close the lastly opened file.
fi, err := opened.Stat()
if err != nil {
log.Warn("Problem with file", "name", opened.Name(), "err", err)
return
}
db.lock.Lock()
db.history.Logs = &LogsMessage{
Source: &LogFile{
Name: fi.Name(),
Last: true,
},
Chunk: emptyChunk,
}
db.lock.Unlock()
watcher := make(chan notify.EventInfo, 10)
if err := notify.Watch(db.logdir, watcher, notify.Create); err != nil {
log.Warn("Failed to create file system watcher", "err", err)
return
}
defer notify.Stop(watcher)
ticker := time.NewTicker(db.config.Refresh)
defer ticker.Stop()
loop:
for err == nil || errc == nil {
select {
case event := <-watcher:
// Make sure that new log file was created.
if !re.Match([]byte(event.Path())) {
break
}
if opened == nil {
log.Warn("The last log file is not opened")
break loop
}
// The new log file's name is always greater,
// because it is created using the actual log record's time.
if opened.Name() >= event.Path() {
break
}
// Read the rest of the previously opened file.
chunk, err := ioutil.ReadAll(opened)
if err != nil {
log.Warn("Failed to read file", "name", opened.Name(), "err", err)
break loop
}
buf = append(buf, chunk...)
opened.Close()
if chunk, last := prepLogs(buf); last >= 0 {
// Send the rest of the previously opened file.
db.sendToAll(&Message{
Logs: &LogsMessage{
Chunk: chunk,
},
})
}
if opened, err = os.OpenFile(event.Path(), os.O_RDONLY, 0644); err != nil {
log.Warn("Failed to open file", "name", event.Path(), "err", err)
break loop
}
buf = buf[:0]
// Change the last file in the history.
fi, err := opened.Stat()
if err != nil {
log.Warn("Problem with file", "name", opened.Name(), "err", err)
break loop
}
db.lock.Lock()
db.history.Logs.Source.Name = fi.Name()
db.history.Logs.Chunk = emptyChunk
db.lock.Unlock()
case <-ticker.C: // Send log updates to the client.
if opened == nil {
log.Warn("The last log file is not opened")
break loop
}
// Read the new logs created since the last read.
chunk, err := ioutil.ReadAll(opened)
if err != nil {
log.Warn("Failed to read file", "name", opened.Name(), "err", err)
break loop
}
b := append(buf, chunk...)
chunk, last := prepLogs(b)
if last < 0 {
break
}
// Only keep the invalid part of the buffer, which can be valid after the next read.
buf = b[last+1:]
var l *LogsMessage
// Update the history.
db.lock.Lock()
if bytes.Equal(db.history.Logs.Chunk, emptyChunk) {
db.history.Logs.Chunk = chunk
l = deepcopy.Copy(db.history.Logs).(*LogsMessage)
} else {
b = make([]byte, len(db.history.Logs.Chunk)+len(chunk)-1)
copy(b, db.history.Logs.Chunk)
b[len(db.history.Logs.Chunk)-1] = ','
copy(b[len(db.history.Logs.Chunk):], chunk[1:])
db.history.Logs.Chunk = b
l = &LogsMessage{Chunk: chunk}
}
db.lock.Unlock()
db.sendToAll(&Message{Logs: l})
case errc = <-db.quit:
break loop
}
}
}
