Merge pull request #113 from bitcloud/patternLayout_tokens

add your own tokens to the patternLayout

examples/patternLayout-tokens.js

@@ -0,0 +1,21 @@
+var log4js = require('./lib/log4js');
+
+var config = {
+    "appenders": [
+      {
+        "type": "console",
+        "layout": {
+          "type": "pattern",
+          "pattern": "%[%r (%x{pid}) %p %c -%] %m%n",
+          "tokens": {
+            "pid" : function() { return process.pid; }
+          }
+        }
+      }
+    ]
+  };
+
+log4js.configure(config, {});
+
+var logger = log4js.getLogger("app");
+logger.info("Test log message");

lib/layouts.js

@@ -10,8 +10,9 @@ var dateFormat = require('./date_format')
     , "coloured": function() { return colouredLayout; }
     , "pattern": function (config) {
 	  var pattern = config.pattern || undefined;
-	  return patternLayout(pattern);
-      }
+	  var tokens = config.tokens || undefined;
+	  return patternLayout(pattern, tokens);
+	}
   }
   , colours = {
       ALL: "grey"
@@ -139,13 +140,26 @@ function messagePassThroughLayout (loggingEvent) {
  *  - %d date in various formats
  *  - %% %
  *  - %n newline
+ *  - %x{<tokenname>} add dynamic tokens to your log. Tokens are specified in the tokens parameter
  * You can use %[ and %] to define a colored block.
- * Takes a pattern string and returns a layout function.
+ *
+ * Tokens are specified as simple key:value objects. 
+ * The key represents the token name whereas the value can be a string or function
+ * which is called to extract the value to put in the log message. If token is not
+ * found, it doesn't replace the field.
+ *
+ * A sample token would be: { "pid" : function() { return process.pid; } }
+ *
+ * Takes a pattern string, array of tokens and returns a layout function.
+ * @param {String} Log format pattern String
+ * @param {object} map object of different tokens
+ * @return {Function}
  * @author Stephan Strittmatter
+ * @author Jan Schmidle
  */
-function patternLayout (pattern) {
+function patternLayout (pattern, tokens) {
     var TTCC_CONVERSION_PATTERN  = "%r %p %c - %m%n";
-    var regex = /%(-?[0-9]+)?(\.?[0-9]+)?([\[\]cdmnpr%])(\{([^\}]+)\})?|([^%]+)/;
+    var regex = /%(-?[0-9]+)?(\.?[0-9]+)?([\[\]cdmnprx%])(\{([^\}]+)\})?|([^%]+)/;
 
     pattern = pattern || TTCC_CONVERSION_PATTERN;
 
@@ -221,6 +235,17 @@ function patternLayout (pattern) {
 		case "%":
 		    replacement = "%";
 		    break;
+		case "x":
+			if(typeof(tokens[specifier]) !== 'undefined') {
+				if(typeof(tokens[specifier]) === 'function') {
+					replacement = tokens[specifier]();
+				} else {
+					replacement = tokens[specifier];
+				}
+			} else {
+				replacement = matchedString;
+			}
+			break;
 		default:
 		    replacement = matchedString;
 		    break;

test/layouts-test.js

@@ -4,9 +4,10 @@ assert = require('assert');
 //used for patternLayout tests.
 function test(args, pattern, value) {
     var layout = args[0]
-    , event = args[1];
+    , event = args[1]
+    , tokens = args[2];
 
-    assert.equal(layout(pattern)(event), value);
+    assert.equal(layout(pattern, tokens)(event), value);
 }
 
 vows.describe('log4js layouts').addBatch({
@@ -175,8 +176,12 @@ vows.describe('log4js layouts').addBatch({
                 level: {
                     toString: function() { return "DEBUG"; }
                 }
-            }, layout = require('../lib/layouts').patternLayout;
-            return [layout, event];
+            }, layout = require('../lib/layouts').patternLayout
+            , tokens = {
+                testString: 'testStringToken',
+                testFunction: function() { return 'testFunctionToken'; }
+            };
+            return [layout, event, tokens];
         },
 
         'should default to "time logLevel loggerName - message"': function(args) {
@@ -246,6 +251,18 @@ vows.describe('log4js layouts').addBatch({
         },
         '%[%r%] should output colored time': function(args) {
             test(args, '%[%r%]', '\033[36m14:18:30\033[39m');
-        }
+        },
+        '%x{testString} should output the string stored in tokens': function(args) {
+            test(args, '%x{testString}', 'testStringToken');
+        },
+        '%x{testFunction} should output the result of the function stored in tokens': function(args) {
+            test(args, '%x{testFunction}', 'testFunctionToken');
+        },
+        '%x{doesNotExist} should output the string stored in tokens': function(args) {
+            test(args, '%x{doesNotExist}', '%x{doesNotExist}');
+        },
+        '%x should output the string stored in tokens': function(args) {
+            test(args, '%x', '%x');
+        },
     }
 }).export(module);