From 2c2459df2f871d9d3dc0696b024e86107328f586 Mon Sep 17 00:00:00 2001
From: Trent Mick <trentm@gmail.com>
Date: Sun, 1 Jun 2014 23:34:50 -0700
Subject: [PATCH] #117 add warning about using rotating-file and cluster
 together

---
 README.md     | 13 +++++++++++--
 lib/bunyan.js | 12 +++++++++---
 2 files changed, 20 insertions(+), 5 deletions(-)

diff --git a/README.md b/README.md
index ed261f3..31dca52 100644
--- a/README.md
+++ b/README.md
@@ -643,13 +643,22 @@ used for anything else.</td>
 
 ## stream type: `rotating-file`
 
-**WARNING:** Users of Bunyan's `rotating-file` should (a) be using at least
-bunyan 0.23.1 (with the fix for [this
+**WARNING on node 0.8 usage:** Users of Bunyan's `rotating-file` should (a) be
+using at least bunyan 0.23.1 (with the fix for [this
 issue](https://github.com/trentm/node-bunyan/pull/97)), and (b) should use at
 least node 0.10 (node 0.8 does not support the `unref()` method on
 `setTimeout(...)` needed for the mentioned fix). The symptom is that process
 termination will hang for up to a full rotation period.
 
+**WARNING on [cluster](http://nodejs.org/docs/latest/api/all.html#all_cluster)
+usage:** Using Bunyan's `rotating-file` stream with node.js's "cluster" module
+can result in unexpected file rotation. You must not have multiple processes
+in the cluster logging to the same file path. In other words, you must have
+a separate log file path for the master and each worker in the cluster.
+Alternatively, consider using a system file rotation facility such as
+`logrotate` on Linux or `logadm` on SmartOS/Illumos. See
+[this comment on issue #117](https://github.com/trentm/node-bunyan/issues/117#issuecomment-44804938)
+for details.
 
 A `type === 'rotating-file'` is a file stream that handles file automatic
 rotation.
diff --git a/lib/bunyan.js b/lib/bunyan.js
index 1ea6ea4..f4b84ce 100644
--- a/lib/bunyan.js
+++ b/lib/bunyan.js
@@ -1107,7 +1107,10 @@ RotatingFileStream.prototype.rotate = function rotate() {
     var self = this;
     var _DEBUG = false;
 
-    if (_DEBUG) console.log('-- [%s] rotating %s', new Date(), self.path);
+    if (_DEBUG) {
+        console.log('-- [%s, pid=%s] rotating %s',
+            new Date(), process.pid, self.path);
+    }
     if (self.rotating) {
         throw new TypeError('cannot start a rotation when already rotating');
     }
@@ -1142,7 +1145,10 @@ RotatingFileStream.prototype.rotate = function rotate() {
             if (!exists) {
                 moves();
             } else {
-                if (_DEBUG) console.log('mv %s %s', before, after);
+                if (_DEBUG) {
+                    console.log('[pid %s] mv %s %s',
+                        process.pid, before, after);
+                }
                 mv(before, after, function (mvErr) {
                     if (mvErr) {
                         self.emit('error', mvErr);
@@ -1156,7 +1162,7 @@ RotatingFileStream.prototype.rotate = function rotate() {
     }
 
     function finish() {
-        if (_DEBUG) console.log('open %s', self.path);
+        if (_DEBUG) console.log('[pid %s] open %s', process.pid, self.path);
         self.stream = fs.createWriteStream(self.path,
             {flags: 'a', encoding: 'utf8'});
         var q = self.rotQueue, len = q.length;