expose and run GC for nodejs to avoid memory intensive actions to run…

… in memory limit (#1826)

Expose garbage collection so that it is explicitly available for use in actions

core/nodejs6Action/Dockerfile

@@ -75,4 +75,4 @@ xmlhttprequest@1.8.0 \
 yauzl@2.7.0
 
 # See app.js
-CMD node app.js
+CMD node --expose-gc app.js

tests/dat/actions/memoryWithGC.js

@@ -0,0 +1,13 @@
+function eat(memoryMB) {
+    var bytes = 1*1024*1024*memoryMB;
+    var buffer = new Buffer.alloc(bytes, 'a');
+    buffer = null;
+    console.log('done.');
+}
+
+function main(msg) {
+    console.log('helloEatMemory', 'memory ' + msg.payload + 'MB');
+    global.gc();
+    eat(msg.payload);
+    return {msg: 'OK, buffer of size ' + msg.payload + ' MB has been filled.'};
+}

tests/src/test/scala/whisk/core/limits/ActionLimitsTests.scala

@@ -234,4 +234,24 @@ class ActionLimitsTests extends TestHelpers with WskTestHelpers {
                     }.length shouldBe 1
             }
     }
+
+    it should "be able to run memory intensive actions multiple times by running the GC in the action" in withAssetCleaner(wskprops) {
+        (wp, assetHelper) =>
+            val name = "TestNodeJsMemoryActionAbleToRunOften"
+            assetHelper.withCleaner(wsk.action, name, confirmDelete = true) {
+                val allowedMemory = 512 megabytes
+                val actionName = TestUtils.getTestActionFilename("memoryWithGC.js")
+                (action, _) => action.create(name, Some(actionName), memory = Some(allowedMemory))
+            }
+
+            for( a <- 1 to 10){
+                val run = wsk.action.invoke(name, Map("payload" -> "128".toJson))
+                withActivation(wsk.activation, run) { response =>
+                    response.response.status shouldBe "success"
+                    response.response.result shouldBe Some(JsObject(
+                        "msg" -> "OK, buffer of size 128 MB has been filled.".toJson))
+                }
+            }
+    }
+
 }