Added MDC support for logger indirect logger creation

README.md

@@ -167,6 +167,10 @@ var settings = {
     logger: {
       level: SDK.Logger.Level.Info,
       name: 'custom-name',
+      // mapping diagnostic context as described above
+      mdc: {
+        entity: 'call#123'
+      },
       instance: new MyCustomLogger()
     }
 };

lib/logger/_definitions.js

@@ -210,4 +210,5 @@
  * @property {(ILoggerContext|null)} context
  * @property {(String|null)} name
  * @property {(Level|null)} level
+ * @property {(Object|null)} mdc
  */

lib/logger/slf4j.js

@@ -113,7 +113,11 @@ function Slf4j (name, context) {
 
   this.attachAll = function (values) { mdc = values }
 
-  this.detachAll = function () { mdc = {} }
+  this.detachAll = function () {
+    var b = mdc
+    mdc = {}
+    return b
+  }
 
   /**
    * @function Slf4j#trace
@@ -245,7 +249,9 @@ Slf4j.factory = function (options, name, context, level) {
     return options.instance
   }
   context = options.context || context || Slf4j
-  return context.create(options.name || name, level || options.level)
+  var logger = context.create(options.name || name, level || options.level)
+  logger.attachAll(options.mdc || {})
+  return logger
 }
 
 module.exports = {

test/suites/integration/logger/slf4j.spec.js

@@ -328,6 +328,12 @@ describe('Integration', function () {
             var mockingbird = {}
             expect(Slf4j.factory({instance: mockingbird})).to.eq(mockingbird)
           })
+
+          it('allows setting mapping diagnostic context', function () {
+            var mdc = {alpha: 'beta'}
+            var logger = Slf4j.factory({mdc: mdc})
+            expect(logger.detachAll()).to.deep.eq(mdc)
+          })
         })
       })
     })