AUTH-2596 added new logger package and replaced logrus

logger/file_writer.go

@@ -0,0 +1,105 @@
+package logger
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+)
+
+// FileRollingWriter maintains a set of log files numbered in order
+// to keep a subset of log data to ensure it doesn't grow pass defined limits
+type FileRollingWriter struct {
+	baseFileName string
+	directory    string
+	maxFileSize  int64
+	maxFileCount uint
+	fileHandle   *os.File
+}
+
+// NewFileRollingWriter creates a new rolling file writer.
+// directory is the working directory for the files
+// baseFileName is the log file name. This writer appends .log to the name for the file name
+// maxFileSize is the size in bytes of how large each file can be. Not a hard limit, general limit based after each write
+// maxFileCount is the number of rolled files to keep.
+func NewFileRollingWriter(directory, baseFileName string, maxFileSize int64, maxFileCount uint) *FileRollingWriter {
+	return &FileRollingWriter{
+		directory:    directory,
+		baseFileName: baseFileName,
+		maxFileSize:  maxFileSize,
+		maxFileCount: maxFileCount,
+	}
+}
+
+// Write is an implementation of io.writer the rolls the file once it reaches its max size
+// It is expected the caller to Write is doing so in a thread safe manner (as WriteManager does).
+func (w *FileRollingWriter) Write(p []byte) (n int, err error) {
+	logFile := buildPath(w.directory, w.baseFileName)
+	if w.fileHandle == nil {
+		h, err := os.OpenFile(logFile, os.O_APPEND|os.O_CREATE|os.O_WRONLY, 0664)
+		if err != nil {
+			return 0, err
+		}
+		w.fileHandle = h
+	}
+
+	// get size for rolling check
+	info, err := w.fileHandle.Stat()
+	if err != nil {
+		// failed to stat the file. Close the file handle and attempt to open a new handle on the next write
+		w.Close()
+		w.fileHandle = nil
+		return 0, err
+	}
+
+	// write to the file
+	written, err := w.fileHandle.Write(p)
+
+	// check if the file needs to be rolled
+	if err == nil && info.Size()+int64(written) > w.maxFileSize {
+		// close the file handle than do the renaming. A new one will be opened on the next write
+		w.Close()
+		w.rename(logFile, 1)
+	}
+
+	return written, err
+}
+
+// Close closes the file handle if it is open
+func (w *FileRollingWriter) Close() {
+	if w.fileHandle != nil {
+		w.fileHandle.Close()
+		w.fileHandle = nil
+	}
+}
+
+// rename is how the files are rolled. It works recursively to move the base log file to the rolled ones
+// e.g. cloudflared.log -> cloudflared-1.log,
+// but if cloudflared-1.log already exists, it is renamed to cloudflared-2.log,
+// then the other files move in to their postion
+func (w *FileRollingWriter) rename(sourcePath string, index uint) {
+	destinationPath := buildPath(w.directory, fmt.Sprintf("%s-%d", w.baseFileName, index))
+
+	// rolled to the max amount of files allowed on disk
+	if index >= w.maxFileCount {
+		os.Remove(destinationPath)
+	}
+
+	// if the rolled path already exist, rename it to cloudflared-2.log, then do this one.
+	// recursive call since the oldest one needs to be renamed, before the newer ones can be moved
+	if exists(destinationPath) {
+		w.rename(destinationPath, index+1)
+	}
+
+	os.Rename(sourcePath, destinationPath)
+}
+
+func buildPath(directory, fileName string) string {
+	return filepath.Join(directory, fileName+".log")
+}
+
+func exists(filePath string) bool {
+	if _, err := os.Stat(filePath); os.IsNotExist(err) {
+		return false
+	}
+	return true
+}