added support for global prefix

README.md

@@ -46,6 +46,18 @@ logger.error('This town ain\'t big enough for the two of us!');
 // error [configured] <Fri, 05 Dec 2014 02:10:48 GMT> This town ain't big enough for the two of us!
 ```
 
+It's also possible to set a global prefix:
+- Configure global prefix by specifying a `FASTLOG_GLOBAL_PREFIX` environment variable.
+```javascript
+process.env.FASTLOG_GLOBAL_PREFIX = '[ipAddress]';
+```
+
+```javascript
+var logger = require('fastlog')('configured', 'error', '${level} [${ category }] <${timestamp}>');
+logger.error('You\'ve got a friend in me.');
+// [ipAddress] error [configured] <Fri, 05 Dec 2014 02:10:48 GMT> You've got a friend in me.
+```
+
 ## Usage via shell scripts
 
 You may also use fastlog in shell scripts. First, make sure fastlog is installed globally

index.js

@@ -4,6 +4,10 @@ var util = require('util');
 module.exports = function(category, level, template) {
     category = category || 'default';
     template = template || '[${timestamp}] [${level}] [${category}]';
+    if (process.env.FASTLOG_GLOBAL_PREFIX) {
+        template = process.env.FASTLOG_GLOBAL_PREFIX + ' ' + template;
+    }
+
     var levels = ['debug', 'info', 'warn', 'error', 'fatal'];
     return _(levels).reduce(function(logger, l) {
         logger[l] = function() {

test/fastlog.test.js

@@ -2,7 +2,6 @@ var assert = require('assert');
 var sinon = require('sinon');
 var fastlog = require('../index.js');
 
-var util = require('util');
 var spy = sinon.spy(console, 'log');
 
 describe('string logging', function() {
@@ -87,4 +86,14 @@ describe('string logging', function() {
         assert.ok(spy.calledWith('%s %s', sinon.match(/\[error\] \{configured\} -- .+?:/), 'to infinity and beyond!'));
         assert.equal(spy.callCount, 1);
     });
+
+    it('should include FASTLOG_GLOBAL_PREFIX in prefix', function() {
+        process.env.FASTLOG_GLOBAL_PREFIX = '[global prefix]';
+        var log = fastlog();
+        log.error('reach for the sky!');
+        assert.ok(
+            spy.calledWith('%s %s', sinon.match(/\[global prefix\] \[.+\] \[error\] \[default\]/), 'reach for the sky!')
+        );
+        delete process.env.FASTLOG_GLOBAL_PREFIX;
+    });
 });