Add basic logging

1 files changed, 35 insertions, 0 deletions

diff --git a/logger.js b/logger.js
new file mode 100644
index 0000000..592342d
--- /dev/null
+++ b/logger.js
@@ -0,0 +1,35 @@
+var fs=require("fs");
+
+var MAX_VOLUME=16*1024*1024;
+
+function Logger(fname){
+	if(!(this instanceof Logger))throw new Error("Logger() called without 'new'");
+	this._fname=fname;
+	this._logstart=new Date();
+	this._currentfname=fname+"."+this._logstart.getTime();
+	this._volume=0;
+	this._stream=fs.createWriteStream(this._currentfname);
+	this._ok=true;
+}
+
+Logger.prototype.log=function log(line){
+	if(!this._ok)return;
+	var now=new Date();
+	var data=now.toISOString()+": "+line+"\n";
+	if(this._volume+data.length>MAX_VOLUME){
+		this._stream.end();
+		this._logstart=now;
+		this._currentfname=this._fname+"."+this._logstart.getTime();
+		this._volume=0;
+		this._stream=fs.createWriteStream(this._currentfname);
+		this._ok=true;
+	}
+	this._volume+=data.length;
+	if(!this._stream.write(data)){
+		console.log("WARNING: LOG STREAM '"+this._currentfname+"' NOT DRAINING!");
+		this._ok=false;
+		this._stream.once("drain",function(){this._ok=true;}.bind(this));
+	}
+};
+
+module.exports=Logger;