fix #594 memory leaks caused by cls-hooked (#595)

* fix #594 memory leaks caused by cls-hooked

* fix #594 memory leaks caused by cls-hooked

* fix #594 memory leaks caused by cls-hooked

* fix #594 memory leaks caused by cls-hooked

Author: regevbr

packages/core/README.md

@@ -22,9 +22,17 @@ mechanisms, but a few are supplied. See Capturing Function Calls below.
 The AWS X-Ray SDK has two modes: `manual` and `automatic`.
 By default, the SDK is in automatic mode. You can flip the mode of the SDK using the following:
 
-    AWSXRay.enableManualMode();
+```js
+AWSXRay.enableAutomaticMode();
+
+AWSXRay.enableManualMode();
 
-    AWSXRay.enableAutomaticMode();
+/* see https://github.com/aws/aws-xray-sdk-node/pull/595
+ for details on using this environment variable
+ to prevent memory leaks when using manual mode
+ */
+process.env.AWS_XRAY_MANUAL_MODE = 'true';
+```
 
 #### Automatic mode
 
@@ -54,6 +62,7 @@ section for different usages.
 **Environment variables always override values set in code.**
 
     AWS_XRAY_DEBUG_MODE              Enables logging of debug messages to console output. Logging to a file is no longer built in. See 'configure logging' below.
+    AWS_XRAY_MANUAL_MODE             For overriding the default automatic mode. See 'Automatic mode'.
     AWS_XRAY_TRACING_NAME            For overriding the default segment name to use
     with the middleware. See 'dynamic and fixed naming modes'.
     AWS_XRAY_DAEMON_ADDRESS          For setting the daemon address and port.

packages/core/lib/context_utils.js

@@ -205,8 +205,13 @@ var contextUtils = {
   }
 };
 
-cls.createNamespace(NAMESPACE);
-logger.getLogger().debug('Starting the AWS X-Ray SDK in automatic mode (default).');
+if (process.env.AWS_XRAY_MANUAL_MODE) {
+  cls_mode = false;
+  logger.getLogger().debug('Starting the AWS X-Ray SDK in manual mode.');
+} else {
+  cls.createNamespace(NAMESPACE);
+  logger.getLogger().debug('Starting the AWS X-Ray SDK in automatic mode (default).');
+}
 
 if (process.env.AWS_XRAY_CONTEXT_MISSING) {
   contextUtils.setContextMissingStrategy(process.env.AWS_XRAY_CONTEXT_MISSING);

packages/core/test/unit/context_utils.test.js

@@ -11,6 +11,7 @@ var RUNTIME_ERROR = 'RUNTIME_ERROR';
 var RUNTIME_ERROR_FCN_NAME = 'contextMissingRuntimeError';
 var IGNORE_ERROR = 'IGNORE_ERROR';
 var IGNORE_ERROR_FCN_NAME = 'contextMissingIgnoreError';
+var cls = require('cls-hooked/context');
 
 describe('ContextUtils', function() {
   function reloadContextUtils() {
@@ -30,11 +31,20 @@ describe('ContextUtils', function() {
     afterEach(function() {
       sandbox.restore();
       delete process.env.AWS_XRAY_CONTEXT_MISSING;
+      delete process.env.AWS_XRAY_MANUAL_MODE;
+      cls.reset();
       reloadContextUtils();
     });
 
+    it('should start in manual mode when process.env.AWS_XRAY_MANUAL_MODE is present', function() {
+      process.env.AWS_XRAY_MANUAL_MODE = '1';
+      cls.reset();
+      reloadContextUtils();
+      assert.equal(cls.getNamespace('AWSXRay'), undefined);
+    });
+
     it('should start in automatic mode by creating the X-Ray namespace', function() {
-      assert.equal(ContextUtils.getNamespace().name, 'AWSXRay');
+      assert.notEqual(cls.getNamespace('AWSXRay'), undefined);
     });
 
     it('should set the contextMissingStrategy to LOG_ERROR by default', function() {