Implemented file rotator

This commit is contained in:
Diptanu Choudhury 2016-02-19 12:55:15 -08:00
parent ef7cfb1f0b
commit 824df263aa
2 changed files with 425 additions and 0 deletions

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package logging
import (
"fmt"
"io/ioutil"
"log"
"os"
"path/filepath"
"sort"
"strconv"
"strings"
)
var (
bufSize = 32
buf = make([]byte, bufSize)
)
type FileRotator struct {
MaxFiles int
FileSize int64
path string
baseFileName string
logFileIdx int
oldestLogFileIdx int
currentFile *os.File
currentWr int64
logger *log.Logger
purgeCh chan interface{}
}
func NewFileRotator(path string, baseFile string, maxFiles int, fileSize int64, logger *log.Logger) (*FileRotator, error) {
rotator := &FileRotator{
MaxFiles: maxFiles,
FileSize: fileSize,
path: path,
baseFileName: baseFile,
logger: logger,
purgeCh: make(chan interface{}),
}
if err := rotator.lastFile(); err != nil {
return nil, err
}
go rotator.purgeOldFiles()
return rotator, nil
}
func (f *FileRotator) Write(p []byte) (n int, err error) {
n = 0
var nw int
for n < len(p) {
if f.currentWr >= f.FileSize {
f.currentFile.Close()
if err := f.nextFile(); err != nil {
return 0, err
}
}
remainingSize := f.FileSize - f.currentWr
if remainingSize < int64(len(p[n:])) {
li := int64(n) + remainingSize
nw, err = f.currentFile.Write(p[n:li])
} else {
nw, err = f.currentFile.Write(p[n:])
}
n += nw
f.currentWr += int64(n)
if err != nil {
return
}
}
return
}
func (f *FileRotator) nextFile() error {
nextFileIdx := f.logFileIdx
for {
nextFileIdx += 1
logFileName := filepath.Join(f.path, fmt.Sprintf("%s.%d", f.baseFileName, nextFileIdx))
if fi, err := os.Stat(logFileName); err == nil {
if fi.IsDir() {
nextFileIdx += 1
continue
}
if fi.Size() >= f.FileSize {
continue
}
}
f.logFileIdx = nextFileIdx
if err := f.createFile(); err != nil {
return err
}
break
}
// Purge old files if we have more files than MaxFiles
if f.logFileIdx-f.oldestLogFileIdx >= f.MaxFiles {
select {
case f.purgeCh <- new(interface{}):
default:
}
}
return nil
}
func (f *FileRotator) lastFile() error {
finfos, err := ioutil.ReadDir(f.path)
if err != nil {
return err
}
prefix := fmt.Sprintf("%s.", f.baseFileName)
for _, fi := range finfos {
if fi.IsDir() {
continue
}
if strings.HasPrefix(fi.Name(), prefix) {
fileIdx := strings.TrimPrefix(fi.Name(), prefix)
n, err := strconv.Atoi(fileIdx)
if err != nil {
continue
}
if n > f.logFileIdx {
f.logFileIdx = n
}
}
}
if err := f.createFile(); err != nil {
return err
}
return nil
}
func (f *FileRotator) createFile() error {
logFileName := filepath.Join(f.path, fmt.Sprintf("%s.%d", f.baseFileName, f.logFileIdx))
cFile, err := os.OpenFile(logFileName, os.O_RDWR|os.O_CREATE|os.O_APPEND, 0666)
if err != nil {
return err
}
f.currentFile = cFile
fi, err := f.currentFile.Stat()
if err != nil {
return err
}
f.currentWr = fi.Size()
return nil
}
// PurgeOldFiles removes older files and keeps only the last N files rotated for
// a file
func (f *FileRotator) purgeOldFiles() {
for {
select {
case <-f.purgeCh:
var fIndexes []int
files, err := ioutil.ReadDir(f.path)
if err != nil {
return
}
// Inserting all the rotated files in a slice
for _, fi := range files {
if strings.HasPrefix(fi.Name(), f.baseFileName) {
fileIdx := strings.TrimPrefix(fi.Name(), fmt.Sprintf("%s.", f.baseFileName))
n, err := strconv.Atoi(fileIdx)
if err != nil {
continue
}
fIndexes = append(fIndexes, n)
}
}
// Sorting the file indexes so that we can purge the older files and keep
// only the number of files as configured by the user
sort.Sort(sort.IntSlice(fIndexes))
var toDelete []int
toDelete = fIndexes[0 : len(fIndexes)-f.MaxFiles]
for _, fIndex := range toDelete {
fname := filepath.Join(f.path, fmt.Sprintf("%s.%d", f.baseFileName, fIndex))
os.RemoveAll(fname)
}
f.oldestLogFileIdx = fIndexes[0]
}
}
}

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package logging
import (
"io/ioutil"
"log"
"os"
"path/filepath"
"testing"
"time"
)
var (
logger = log.New(os.Stdout, "", log.LstdFlags)
pathPrefix = "logrotator"
baseFileName = "redis.stdout"
)
func TestFileRotator_IncorrectPath(t *testing.T) {
if _, err := NewFileRotator("/foo", baseFileName, 10, 10, logger); err == nil {
t.Fatalf("expected error")
}
}
func TestFileRotator_CreateNewFile(t *testing.T) {
var path string
var err error
if path, err = ioutil.TempDir("", pathPrefix); err != nil {
t.Fatalf("test setup err: %v", err)
}
defer os.RemoveAll(path)
_, err = NewFileRotator(path, baseFileName, 10, 10, logger)
if err != nil {
t.Fatalf("test setup err: %v", err)
}
if _, err := os.Stat(filepath.Join(path, "redis.stdout.0")); err != nil {
t.Fatalf("expected file")
}
}
func TestFileRotator_OpenLastFile(t *testing.T) {
var path string
var err error
if path, err = ioutil.TempDir("", pathPrefix); err != nil {
t.Fatalf("test setup err: %v", err)
}
defer os.RemoveAll(path)
fname1 := filepath.Join(path, "redis.stdout.0")
fname2 := filepath.Join(path, "redis.stdout.2")
if _, err := os.Create(fname1); err != nil {
t.Fatalf("test setup failure: %v", err)
}
if _, err := os.Create(fname2); err != nil {
t.Fatalf("test setup failure: %v", err)
}
fr, err := NewFileRotator(path, baseFileName, 10, 10, logger)
if err != nil {
t.Fatalf("test setup err: %v", err)
}
if fr.currentFile.Name() != fname2 {
t.Fatalf("expected current file: %v, got: %v", fname2, fr.currentFile.Name())
}
}
func TestFileRotator_WriteToCurrentFile(t *testing.T) {
var path string
var err error
if path, err = ioutil.TempDir("", pathPrefix); err != nil {
t.Fatalf("test setup err: %v", err)
}
defer os.RemoveAll(path)
fname1 := filepath.Join(path, "redis.stdout.0")
if _, err := os.Create(fname1); err != nil {
t.Fatalf("test setup failure: %v", err)
}
fr, err := NewFileRotator(path, baseFileName, 10, 5, logger)
if err != nil {
t.Fatalf("test setup err: %v", err)
}
fr.Write([]byte("abcde"))
fi, err := os.Stat(fname1)
if err != nil {
t.Fatalf("error getting the file info: %v", err)
}
if fi.Size() != 5 {
t.Fatalf("expected size: %v, actual: %v", 5, fi.Size())
}
}
func TestFileRotator_RotateFiles(t *testing.T) {
var path string
var err error
if path, err = ioutil.TempDir("", pathPrefix); err != nil {
t.Fatalf("test setup err: %v", err)
}
defer os.RemoveAll(path)
fr, err := NewFileRotator(path, baseFileName, 10, 5, logger)
if err != nil {
t.Fatalf("test setup err: %v", err)
}
str := "abcdefgh"
nw, err := fr.Write([]byte(str))
if err != nil {
t.Fatalf("got error while writing: %v", err)
}
if nw != len(str) {
t.Fatalf("expected %v, got %v", len(str), nw)
}
fname1 := filepath.Join(path, "redis.stdout.0")
fi, err := os.Stat(fname1)
if err != nil {
t.Fatalf("error getting the file info: %v", err)
}
if fi.Size() != 5 {
t.Fatalf("expected size: %v, actual: %v", 5, fi.Size())
}
fname2 := filepath.Join(path, "redis.stdout.1")
if _, err := os.Stat(fname2); err != nil {
t.Fatalf("expected file %v to exist", fname2)
}
if fi2, err := os.Stat(fname2); err == nil {
if fi2.Size() != 3 {
t.Fatalf("expected size: %v, actual: %v", 3, fi2.Size())
}
} else {
t.Fatalf("error getting the file info: %v", err)
}
}
func TestFileRotator_WriteRemaining(t *testing.T) {
var path string
var err error
if path, err = ioutil.TempDir("", pathPrefix); err != nil {
t.Fatalf("test setup err: %v", err)
}
defer os.RemoveAll(path)
fname1 := filepath.Join(path, "redis.stdout.0")
if f, err := os.Create(fname1); err == nil {
f.Write([]byte("abcd"))
} else {
t.Fatalf("test setup failure: %v", err)
}
fr, err := NewFileRotator(path, baseFileName, 10, 5, logger)
if err != nil {
t.Fatalf("test setup err: %v", err)
}
str := "efghijkl"
nw, err := fr.Write([]byte(str))
if err != nil {
t.Fatalf("got error while writing: %v", err)
}
if nw != len(str) {
t.Fatalf("expected %v, got %v", len(str), nw)
}
fi, err := os.Stat(fname1)
if err != nil {
t.Fatalf("error getting the file info: %v", err)
}
if fi.Size() != 5 {
t.Fatalf("expected size: %v, actual: %v", 5, fi.Size())
}
fname2 := filepath.Join(path, "redis.stdout.1")
if _, err := os.Stat(fname2); err != nil {
t.Fatalf("expected file %v to exist", fname2)
}
if fi2, err := os.Stat(fname2); err == nil {
if fi2.Size() != 5 {
t.Fatalf("expected size: %v, actual: %v", 5, fi2.Size())
}
} else {
t.Fatalf("error getting the file info: %v", err)
}
fname3 := filepath.Join(path, "redis.stdout.2")
if _, err := os.Stat(fname3); err != nil {
t.Fatalf("expected file %v to exist", fname3)
}
if fi3, err := os.Stat(fname3); err == nil {
if fi3.Size() != 2 {
t.Fatalf("expected size: %v, actual: %v", 2, fi3.Size())
}
} else {
t.Fatalf("error getting the file info: %v", err)
}
}
func TestFileRotator_PurgeOldFiles(t *testing.T) {
var path string
var err error
if path, err = ioutil.TempDir("", pathPrefix); err != nil {
t.Fatalf("test setup err: %v", err)
}
defer os.RemoveAll(path)
fr, err := NewFileRotator(path, baseFileName, 2, 2, logger)
if err != nil {
t.Fatalf("test setup err: %v", err)
}
str := "abcdeghijklmn"
nw, err := fr.Write([]byte(str))
if err != nil {
t.Fatalf("got error while writing: %v", err)
}
if nw != len(str) {
t.Fatalf("expected %v, got %v", len(str), nw)
}
time.Sleep(1 * time.Second)
f, err := ioutil.ReadDir(path)
if err != nil {
t.Fatalf("test error: %v", err)
}
if len(f) != 2 {
t.Fatalf("expected number of files: %v, got: %v", 2, len(f))
}
}