added tailhead age check for tailreadstream

removed getfilesize for tailreadstream
logdna · Mar 31, 2017 · 61c176f · 61c176f
1 parent 2bd7d33
commit 61c176f
Showing 1 changed file with 14 additions and 22 deletions.
diff --git a/lib/tailreadstream/tailreadstream.js b/lib/tailreadstream/tailreadstream.js
@@ -12,6 +12,7 @@ const DEFAULT_WATCH_INTERVAL = 1000;
 const DEFAULT_READ_INTERVAL = 250;
 const DEFAULT_READ_TIMEOUT = 3600000; // 1hr timeout
 const DEFAULT_TAILHEAD_SIZE = 32768; // 32kb
+const DEFAULT_TAILHEAD_AGE = 60000; // 1min
 
 
 class TailReadStream extends Readable {
@@ -30,6 +31,7 @@ class TailReadStream extends Readable {
         this._timeout = options.timeout || DEFAULT_READ_TIMEOUT;
         this._watchinterval = options.watchinterval || DEFAULT_WATCH_INTERVAL;
         this._tailheadsize = options.tailheadsize || DEFAULT_TAILHEAD_SIZE;
+        this._tailheadage = options.tailheadage || DEFAULT_TAILHEAD_AGE;
         this._idle = 0;
 
         this._reading = false;
@@ -58,7 +60,6 @@ class TailReadStream extends Readable {
             }
         } else {
             // tail from end
-            debug(filepath + ': tailing from end');
             file._getFileSizeAndReadUntilEof();
         }
         return file;
@@ -105,19 +106,10 @@ class TailReadStream extends Readable {
         this._stream.on('end', this._handleEnd.bind(this));
     }
 
-    _getFileSize(callback) {
-        fs.stat(this._filepath, (err, stats) => {
-            if (err) {
-                return callback(err);
-            }
-            callback(null, stats.size);
-        });
-    }
-
     _getFileSizeAndReadUntilEof() {
         var that = this;
 
-        this._getFileSize((err, size) => {
+        fs.stat(this._filepath, (err, stats) => {
             if (err) {
                 that.readable = false;
 
@@ -138,12 +130,12 @@ class TailReadStream extends Readable {
                 return;
             }
 
-            if (size < that._tailheadsize) {
-                debug(that._filepath + ': file is smaller than ' + that._tailheadsize + ' bytes, reading from beginning');
-                size = 0; // tail from beginning of file if small enough (e.g. newly created files)
+            if (stats.size < that._tailheadsize && Date.now() - stats.birthtime.getTime() < that._tailheadage) {
+                debug(that._filepath + ': file is smaller than ' + that._tailheadsize + ' bytes and is ' + (Date.now() - stats.birthtime.getTime()) + 'ms old, reading from beginning');
+                that._readFromOffsetUntilEof(0); // tail from beginning of file if small enough (e.g. newly created files)
+            } else {
+                that._readFromOffsetUntilEof(stats.size);
             }
-
-            that._readFromOffsetUntilEof(size);
         });
     }
 
@@ -216,19 +208,19 @@ class TailReadStream extends Readable {
             return;
         }
 
-        this._getFileSize((err, size) => {
+        fs.stat(this._filepath, (err, stats) => {
             if (err) {
                 return setTimeout(that._watchFile.bind(that), that._watchinterval);
             }
 
-            if (size < that._offset) {
-                that.emit('truncate', size);
-                if (size < that._tailheadsize) {
+            if (stats.size < that._offset) {
+                that.emit('truncate', stats.size);
+                if (stats.size < that._tailheadsize) {
                     debug(that._filepath + ': file truncated but smaller than ' + that._tailheadsize + ' bytes, reading from beginning');
                     that._offset = 0;
                 } else {
-                    debug(that._filepath + ': file truncated but larger than ' + that._tailheadsize + ' bytes, reading from ' + size);
-                    that._offset = size;
+                    debug(that._filepath + ': file truncated but larger than ' + that._tailheadsize + ' bytes, reading from ' + stats.size);
+                    that._offset = stats.size;
                 }
             }