Merge branch 'feature-add-file-age-rotation-to-file-output-plugin' of…

… github.com:flexd/telegraf into feature-add-file-age-rotation-to-file-output-plugin

plugins/outputs/file/file.go

@@ -58,8 +58,6 @@ func (f *File) Connect() error {
 				if err != nil {
 					return err
 				}
-				//func NewFileWriter(filename string, interval time.Duration, maxSizeInBytes int64, maxArchives int) (io.WriteCloser, error) {
-
 				// Only rotate by file age for now, keep no archives.
 				of, err = rotate.NewFileWriter(file, maxAge, 0, -1)
 			} else {

plugins/outputs/file/rotatingwriter.go

@@ -0,0 +1,94 @@
+package file
+
+// Rotating things
+import (
+	"fmt"
+	"os"
+	"sync"
+	"time"
+)
+
+// FilePerm defines the permissions that Writer will use for all
+// the files it creates.
+var FilePerm = os.FileMode(0644)
+
+// Writer implements the io.Writer interface and writes to the
+// filename specified.  When current file age exceeds max, it is
+// renamed and a new file is created.
+type Writer struct {
+	filename   string
+	current    *os.File
+	expireTime time.Time
+	max        time.Duration
+	sync.Mutex
+}
+
+// New creates a new Writer.
+func NewRotatingWriter(filename, maxAgeInput string) (*Writer, error) {
+	maxAge, err := time.ParseDuration(maxAgeInput)
+	if err != nil {
+		return nil, err
+	}
+	l := &Writer{filename: filename, max: maxAge}
+	if err := l.openCurrent(); err != nil {
+		return nil, err
+	}
+
+	return l, nil
+}
+
+// Write writes p to the current file, then checks to see if
+// rotation is necessary.
+func (r *Writer) Write(p []byte) (n int, err error) {
+	r.Lock()
+	defer r.Unlock()
+	n, err = r.current.Write(p)
+	if err != nil {
+		return n, err
+	}
+	if time.Now().After(r.expireTime) {
+		if err := r.rotate(); err != nil {
+			return n, err
+		}
+	}
+	return n, nil
+}
+
+// Close closes the current file.  Writer is unusable after this
+// is called.
+func (r *Writer) Close() error {
+	r.Lock()
+	defer r.Unlock()
+
+	// Rotate before closing
+	if err := r.rotate(); err != nil {
+		return err
+	}
+
+	if err := r.current.Close(); err != nil {
+		return err
+	}
+	r.current = nil
+	return nil
+}
+
+func (r *Writer) openCurrent() error {
+	var err error
+	r.current, err = os.OpenFile(r.filename, os.O_RDWR|os.O_CREATE|os.O_APPEND, FilePerm)
+	r.expireTime = time.Now().Add(r.max)
+	if err != nil {
+		return err
+	}
+	return nil
+}
+
+func (r *Writer) rotate() error {
+	if err := r.current.Close(); err != nil {
+		return err
+	}
+	rotatedFilename := fmt.Sprintf("%s-%d", r.filename, time.Now().UnixNano()) // UnixNano should be unique enough for this (up until a point)
+	if err := os.Rename(r.filename, rotatedFilename); err != nil {
+		return err
+	}
+	return r.openCurrent()
+}