beef up RotatingFileStream internal debugging

lib/bunyan.js

@@ -1243,6 +1243,7 @@ RotatingFileStream = function RotatingFileStream(options) {
     this.rotQueue = [];
     this.rotating = false;
     if (rotateAfterOpen) {
+        this._debug('rotateAfterOpen -> call rotate()');
         this.rotate();
     } else {
         this._setupNextRot();
@@ -1251,6 +1252,21 @@ RotatingFileStream = function RotatingFileStream(options) {
 
 util.inherits(RotatingFileStream, EventEmitter);
 
+RotatingFileStream.prototype._debug = function () {
+    // Set this to `true` to add debug logging.
+    if (false) {
+        if (arguments.length === 0) {
+            return true;
+        }
+        var args = Array.prototype.slice.call(arguments);
+        args[0] = '[' + (new Date().toISOString()) + ', '
+            + this.path + '] ' + args[0];
+        console.log.apply(this, args);
+    } else {
+        return false;
+    }
+};
+
 RotatingFileStream.prototype._setupNextRot = function () {
     this.rotAt = this._calcRotTime(1);
     this._setRotationTimer();
@@ -1266,7 +1282,10 @@ RotatingFileStream.prototype._setRotationTimer = function () {
         delay = TIMEOUT_MAX;
     }
     this.timeout = setTimeout(
-        function () { self.rotate(); },
+        function () {
+            self._debug('_setRotationTimer timeout -> call rotate()');
+            self.rotate();
+        },
         delay);
     if (typeof (this.timeout.unref) === 'function') {
         this.timeout.unref();
@@ -1275,13 +1294,11 @@ RotatingFileStream.prototype._setRotationTimer = function () {
 
 RotatingFileStream.prototype._calcRotTime =
 function _calcRotTime(periodOffset) {
-    var _DEBUG = false;
-    if (_DEBUG)
-        console.log('-- _calcRotTime: %s%s', this.periodNum, this.periodScope);
+    this._debug('_calcRotTime: %s%s', this.periodNum, this.periodScope);
     var d = new Date();
 
-    if (_DEBUG) console.log('  now local: %s', d);
-    if (_DEBUG) console.log('    now utc: %s', d.toISOString());
+    this._debug('  now local: %s', d);
+    this._debug('    now utc: %s', d.toISOString());
     var rotAt;
     switch (this.periodScope) {
     case 'ms':
@@ -1352,11 +1369,11 @@ function _calcRotTime(periodOffset) {
         assert.fail(format('invalid period scope: "%s"', this.periodScope));
     }
 
-    if (_DEBUG) {
-        console.log('  **rotAt**: %s (utc: %s)', rotAt,
+    if (this._debug()) {
+        this._debug('  **rotAt**: %s (utc: %s)', rotAt,
             new Date(rotAt).toUTCString());
         var now = Date.now();
-        console.log('        now: %s (%sms == %smin == %sh to go)',
+        this._debug('        now: %s (%sms == %smin == %sh to go)',
             now,
             rotAt - now,
             (rotAt-now)/1000/60,
@@ -1368,7 +1385,6 @@ function _calcRotTime(periodOffset) {
 RotatingFileStream.prototype.rotate = function rotate() {
     // XXX What about shutdown?
     var self = this;
-    var _DEBUG = false;
 
     // If rotation period is > ~25 days, we have to break into multiple
     // setTimeout's. See <https://github.com/joyent/node/issues/8656>.
@@ -1376,10 +1392,7 @@ RotatingFileStream.prototype.rotate = function rotate() {
         return self._setRotationTimer();
     }
 
-    if (_DEBUG) {
-        console.log('-- [%s, pid=%s] rotating %s',
-            new Date(), process.pid, self.path);
-    }
+    this._debug('rotate');
     if (self.rotating) {
         throw new TypeError('cannot start a rotation when already rotating');
     }
@@ -1393,7 +1406,7 @@ RotatingFileStream.prototype.rotate = function rotate() {
             toDel = self.path;
         }
         n -= 1;
-        if (_DEBUG) console.log('rm %s', toDel);
+        self._debug('  rm %s', toDel);
         fs.unlink(toDel, function (delErr) {
             //XXX handle err other than not exists
             moves();
@@ -1414,10 +1427,7 @@ RotatingFileStream.prototype.rotate = function rotate() {
             if (!exists) {
                 moves();
             } else {
-                if (_DEBUG) {
-                    console.log('[pid %s] mv %s %s',
-                        process.pid, before, after);
-                }
+                self._debug('  mv %s %s', before, after);
                 mv(before, after, function (mvErr) {
                     if (mvErr) {
                         self.emit('error', mvErr);
@@ -1431,7 +1441,7 @@ RotatingFileStream.prototype.rotate = function rotate() {
     }
 
     function finish() {
-        if (_DEBUG) console.log('[pid %s] open %s', process.pid, self.path);
+        self._debug('  open %s', self.path);
         self.stream = fs.createWriteStream(self.path,
             {flags: 'a', encoding: 'utf8'});
         var q = self.rotQueue, len = q.length;