[TOOLS] Support remote debugging in helloworld framework (#2660)

Add debug cmd to helloworld

Author: takirala

TESTING.md

@@ -130,3 +130,10 @@ Running
 ./test.sh --help
 ```
 Will show all the options that are available for the `test.sh` script.
+
+#### Experimental Commands
+
+Remote debugging is supported in `helloworld` framework. This is ONLY for developing purposes. You can launch the `helloworld` framework with debugging as using the `debug` section of config.json. Once the marathon app for scheduler is ready, bind to the remote port using
+`ssh -L ${DEBUG_PORT:-6242}:${CUSTOM_SERVICE_NAME:-"hello-world"}.marathon.mesos:${DEBUG_PORT:-6242} -N core@${MASTER_IP}`
+
+SDK prints GIT SHA of its build at bootstrap and that can be used to checkout the current codebase. Connect to the above debug server and you should be able to remotely debug the scheduler.

frameworks/helloworld/universe/config.json

@@ -144,6 +144,28 @@
         }
       }
     },
+    "debug" : {
+      "description": "Config to start the scheduler with remote debug options enabled. THIS SHOULD NOT HAVE ANY DEFAULTS",
+      "type": "object",
+      "properties" : {
+        "suspend": {
+          "description": "Suspend the JVM until a debugger is attached",
+          "type": "string",
+          "enum":[
+            "y",
+            "n"
+          ]
+        },
+        "address": {
+          "description": "Interface to listen. This is a string to support *:6242 style to bind to all interfaces",
+          "type": "string"
+        }
+      },
+      "required": [
+        "suspend",
+        "address"
+      ]
+    },
     "hello": {
       "description": "Hello pod configuration properties",
       "type": "object",

frameworks/helloworld/universe/marathon.json.mustache

@@ -4,7 +4,7 @@
   "mem": 1024,
   "instances": 1,
   "user": "{{service.user}}",
-  "cmd": "export LD_LIBRARY_PATH=$MESOS_SANDBOX/libmesos-bundle/lib:$LD_LIBRARY_PATH; export MESOS_NATIVE_JAVA_LIBRARY=$(ls $MESOS_SANDBOX/libmesos-bundle/lib/libmesos-*.so); export JAVA_HOME=$(ls -d $MESOS_SANDBOX/jdk*/jre/); export JAVA_HOME=${JAVA_HOME%/}; export PATH=$(ls -d $JAVA_HOME/bin):$PATH && export JAVA_OPTS=\"-Xms256M -Xmx512M -XX:-HeapDumpOnOutOfMemoryError\" && ./bootstrap -resolve=false -template=false && ./hello-world-scheduler/bin/helloworld {{service.yaml}} {{service.yamls}}",
+  "cmd": "export LD_LIBRARY_PATH=$MESOS_SANDBOX/libmesos-bundle/lib:$LD_LIBRARY_PATH; export MESOS_NATIVE_JAVA_LIBRARY=$(ls $MESOS_SANDBOX/libmesos-bundle/lib/libmesos-*.so); export JAVA_HOME=$(ls -d $MESOS_SANDBOX/jdk*/jre/); export JAVA_HOME=${JAVA_HOME%/}; export PATH=$(ls -d $JAVA_HOME/bin):$PATH && export JAVA_OPTS=\"-Xms256M -Xmx512M -XX:-HeapDumpOnOutOfMemoryError {{#debug}}-agentlib:jdwp=transport=dt_socket,server=y,suspend={{debug.suspend}},address={{debug.address}}{{/debug}}\" && ./bootstrap -resolve=false -template=false && ./hello-world-scheduler/bin/helloworld {{service.yaml}} {{service.yamls}}",
   "constraints": {{service.constraints}},
   "labels": {
     "DCOS_COMMONS_API_VERSION": "v1",