2022-02-18 18:19:35 +01:00

112 lines
3.3 KiB
Go

package task_logs
/* ***** BEGIN GPL LICENSE BLOCK *****
*
* Original Code Copyright (C) 2022 Blender Foundation.
*
* This file is part of Flamenco.
*
* Flamenco is free software: you can redistribute it and/or modify it under
* the terms of the GNU General Public License as published by the Free Software
* Foundation, either version 3 of the License, or (at your option) any later
* version.
*
* Flamenco 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 General Public License for more details.
*
* You should have received a copy of the GNU General Public License along with
* Flamenco. If not, see <https://www.gnu.org/licenses/>.
*
* ***** END GPL LICENSE BLOCK ***** */
import (
"os"
"path/filepath"
"sort"
"strconv"
"strings"
"github.com/rs/zerolog"
)
type numberedPath struct {
path string
number int
basepath string
}
// byNumber implements the sort.Interface for numberedPath objects,
// and sorts in reverse (so highest number first).
type byNumber []numberedPath
func (a byNumber) Len() int { return len(a) }
func (a byNumber) Swap(i, j int) { a[i], a[j] = a[j], a[i] }
func (a byNumber) Less(i, j int) bool { return a[i].number > a[j].number }
func createNumberedPath(path string) numberedPath {
dotIndex := strings.LastIndex(path, ".")
if dotIndex < 0 {
return numberedPath{path, -1, path}
}
asInt, err := strconv.Atoi(path[dotIndex+1:])
if err != nil {
return numberedPath{path, -1, path}
}
return numberedPath{path, asInt, path[:dotIndex]}
}
// rotateLogFile renames 'logpath' to 'logpath.1', and increases numbers for already-existing files.
// NOTE: not thread-safe when calling with the same `logpath`.
func rotateLogFile(logger zerolog.Logger, logpath string) error {
// Don't do anything if the file doesn't exist yet.
_, err := os.Stat(logpath)
if err != nil {
if os.IsNotExist(err) {
logger.Debug().Msg("log file does not exist, no need to rotate")
return nil
}
logger.Warn().Err(err).Msg("unable to stat logfile")
return err
}
// Rotate logpath.3 to logpath.2, logpath.1 to logpath.2, etc.
pattern := logpath + ".*"
existing, err := filepath.Glob(pattern)
if err != nil {
logger.Warn().Err(err).Str("glob", pattern).Msg("rotateLogFile: unable to glob")
return err
}
if existing == nil {
logger.Debug().Msg("rotateLogFile: no existing files to rotate")
} else {
// Rotate the files in reverse numerical order (so renaming n→n+1 comes after n+1→n+2)
var numbered = make(byNumber, len(existing))
for idx := range existing {
numbered[idx] = createNumberedPath(existing[idx])
}
sort.Sort(numbered)
for _, numberedPath := range numbered {
newName := numberedPath.basepath + "." + strconv.Itoa(numberedPath.number+1)
err := os.Rename(numberedPath.path, newName)
if err != nil {
logger.Error().
Str("from_path", numberedPath.path).
Str("to_path", newName).
Err(err).
Msg("rotateLogFile: unable to rename log file")
}
}
}
// Rotate the pointed-to file.
newName := logpath + ".1"
if err := os.Rename(logpath, newName); err != nil {
logger.Error().Str("new_name", newName).Err(err).Msg("rotateLogFile: unable to rename log file for rotating")
return err
}
return nil
}