Fixing rotateExisting feature

Adding tests so that it doesn't rot again.

README.md

@@ -21,6 +21,11 @@ Bunyan Rotating File Stream is a stream component for the logging system "node b
 
 # Recent changes
 
+## 1.6.1 Fixed support for the "rotateExisting" flag
+
+Tests have been added to ensure that this feature keeps working in the future.
+Note that this feature may not work as expected with linux on EXT4.
+
 ## 1.6 Support for non-JSON logs
 
 Minor release but now that logs which are written in a non-json format are supported.
@@ -40,6 +45,7 @@ Implemented tests and strategies to support specific node versions:
 * 0.12.*latest*
 * 4.*latest*
 * 6.*latest*
+* 7.*latest*
 
 *0.10 and earlier*
 
@@ -172,7 +178,10 @@ the scope: top of the hour (h), midnight (d), start of Sunday (w), start of the
 <td>If period is also set, will rotate an existing log file when the process
 starts up if that file needs rotating due to its age. This means that
 if you want a new file every day, and the process isn't running over midnight,
-this option will give you that new file when you next startup.</td>
+this option will give you that new file when you next startup.
+
+See note on EXT4.
+</td>
 </tr>
 <tr>
 <td>threshold</td>
@@ -233,6 +242,20 @@ force the stream to create a new file instead.</p>
 </tr>
 </table>
 
+## rotateExisting and Linux filesystems (EXT4) support
+
+Some filesystems on Linux (in particular EXT4) do not record the file creation date.
+
+Since the rotateExisting requires us to look at this date to see if the file would have been rotated had the
+system been running for all that time, this feature cannot work as required.
+
+You can check if this feature will work on your filesystem by executing `stat [mylogfile]`. If the "Birth" field
+has a value in it, rfs will be able to see the creation time correctly.
+
+Otherwise behaviour of this flag will be based on what birthtime is filled with. If it returns 0, then the file
+will always be rotated. If it returns ctime, it will only be rotated if the rotation period has expired since the
+last write.
+
 # Templating
 
 ## Behaviour without templating

lib/initialperiodtrigger.js

@@ -23,22 +23,22 @@ function InitialPeriodRotateTrigger(options) {
     function shutdown() {
     }
 
-    function checkIfRotationNeeded(ctime, now) {
-        var nextRot = ctime;
-        var lastRot = nextRot;
+    function checkIfRotationNeeded(birthtime, now) {
+        var nextRot = birthtime;
+        var lastRot = birthtime;
         while (nextRot < now) {
             lastRot = nextRot;
             nextRot = nextRotTime(lastRot, periodScope, periodNum);
         }
 
-        return { needsRotation: lastRot != ctime, rotateTo: lastRot };
+        return { needsRotation: lastRot != birthtime, rotateTo: lastRot };
     }
 
     function newFile(data) {
         if (rotatingoldfiles) {
             // First setup, see if the file is old and needs rotating
             rotatingoldfiles = false;
-            var rotation = checkIfRotationNeeded(data.path, Date.now());
+            var rotation = checkIfRotationNeeded(data.stats.birthtime.getTime(), new Date().getTime());
             if (rotation.needsRotation) {
                 // The current file is old enough to need a rotation.
                 base.emit('rotate', {date: rotation.rotateTo});

test/functionality.js

@@ -52,14 +52,15 @@ function runTest(name, options, next) {
     });
 
     var i = 1;
+    var offset = (options.batch.startAt || 1) - 1;
     var batch = _.extend({}, { size: 10 }, options.batch);
 
     // Prior to node v4, high load scenarios (like these tests) can starve timer events
     var logdelay = batch.delay || (semver.lt(process.version, '4.0.0') ? 20 : 0);
 
     var ia = setInterval(function () {
         for (var j = 0; j < batch.size; j += 1) {
-            log.info({node: 'a', i: i});
+            log.info({node: 'a', i: i + offset});
             i += 1;
 
             if (typeof (batch.iterations) !== 'undefined' && i >= batch.iterations) {
@@ -393,6 +394,45 @@ function totalfiles(template) {
     }
 }
 
+function rotateExisting(template) {
+    return function (next) {
+        var name = 'testlogs/' + 'rotateExisting-' + template;
+
+        async.series([
+            function (next) { rmdir(name, ignoreMissing(next)); },
+            function (next) { mkdirp(name, next); },
+            function createBaseFile(next) { runTest (name, {
+                stream: { path: name + '/' + template + '.log', period: '1000ms', rotateExisting: true },
+                batch: { startAt: 1, iterations: 100 }
+            }, next); },
+            function waitLongTime(next) { 
+                setTimeout(next, 2000);
+            },
+            function writeToNewFile(next) { runTest (name, {
+                stream: { path: name + '/' + template + '.log', period: '1000ms', rotateExisting: true },
+                batch: { startAt: 100, iterations: 101 }
+            }, next); },
+            function waitShortTime(next) { 
+                setTimeout(next, 100);
+            },
+            function writeToExistingFile(next) { runTest (name, {
+                stream: { path: name + '/' + template + '.log', period: '1000ms', rotateExisting: true },
+                batch: { startAt: 200, iterations: 101 }
+            }, next); },
+            function (next) {
+                checkFileConsistency(name, {first: 1, last: 300}, next);
+            },
+            function (next) {
+                var files = fs.readdirSync(name);
+                assert.equal(2, files.length);
+                console.log(name.replace('%d', '%%d'), 'passed');
+                next();
+            },
+            function (next) { rmdir(name, ignoreMissing(next)); }
+        ], next);
+    }
+}
+
 function shorthandperiod(template) {
     return function (next) {
         var name = 'testlogs/' + 'shorthandperiod-' + template;
@@ -623,6 +663,11 @@ mkdirp('testlogs', function () {
         toosmallthresholdstillgetswrites('test-%Y-%m-%d'),
         toosmallthresholdstillgetswrites('test-%Y-%m-%d-%H-%M-%S'),
         toosmallthresholdstillgetswrites('test-%N-%Y-%m-%d'),
+        rotateExisting('test'),
+        rotateExisting('test-%N'),
+        rotateExisting('test-%Y-%m-%d'),
+        rotateExisting('test-%Y-%m-%d-%H-%M-%S'),
+        rotateExisting('test-%N-%Y-%m-%d'),
 
         checkrotationofoldfile,
         checkrotationofnewfile,