Passing object to REEF Task

[changyeon]

I want to pass an object to REEF Task and I found "bindNameParameter" method in Tang configuration builder. It seems the "bindNameParameter" support only String type for parameter passing, but I want to pass complex type such as object to REEF Task. So, my question is can I pass an object to REEF Task as parameter?

[bchocho]

bindNamedParameter takes a type of Name<T> where T can be any type.

[changyeon]

Thank you for answering so quickly

[ks881115]

Thanks for your reply, but could we ask one more question to catch-up?

I found out that bindNamedParameter takes value in the form of Java String. For example, given I have the class below:

@NamedParameter(doc = "A description of a query that QueryMaster will execute", short_name = "queryRequest") public static final class QueryRequestProto implements Name { }

The method still requires the value to be given in the form of String bindNamedParameter(QueryRequestProto.class, <>)

In this case, what String value should I give?

• The type we are trying to send does not implement toString() method
• Since the object we are trying to send is not a Java basic type, I cannot expect REEF will deserialize any format we give.

[bchocho]

Your named parameter should look something like this:

@NamedParameter(doc = "A description of a query that QueryMaster will execute",
short_name = "queryRequest")
public static final class QueryRequestProtoParam implements Name<QueryRequestProto> {
}

Then your call to would look something like this (assuming there's an Impl class): bindNamedParameter(QueryRequestProto.class, QueryRequestProtoImpl.class)

Here, you're binding an implementation to an interface. Tang will then create a singleton object at the Task, given that the Impl class is injectable (has a valid constructor with @Inject). Is this what you want to do?

[ks881115]

Thanks for the quick reply And sorry, the editor hided some of my writing regarding it as a tag

Following is the parameter that I'm trying to send:

@NamedParameter(doc = "A description of a query that QueryMaster will execute",
      short_name = "queryRequest")
  public static final class QueryRequestProto implements Name<TajoWorkerProtocol.QueryExecutionRequestProto> {
  }

TajoWorkerProtocol.QueryExecutionRequestProto is the actual parameter we want to send.

So, my question is: to use the following method, bindNamedParameter(QueryRequestProto.class, <<String value the method expects to have>>) What value should I give for the second parameter? (String value)

[bchocho]

Are you referring to JavaConfigurationBuilder? It has two overloaded methods named bindNamedParameter:

  public JavaConfigurationBuilder bindNamedParameter(Class<? extends Name<?>> name, String value)
      throws BindException;

  public <T> JavaConfigurationBuilder bindNamedParameter(Class<? extends Name<T>> iface,
                                                         Class<? extends T> impl) throws BindException;

The second, you can give an Implementation. If this is not what you're looking for, please give a high-level explanation of what you need the code to do.

[ks881115]

What we want to send is the request of the following code fragment:

TajoWorkerProtocol.QueryExecutionRequestProto request = builder.setQueryId(queryId.getProto())
          .setSession(session.getProto())
          .setQueryContext(queryContext.getProto())
          .setExprInJson(PrimitiveProtos.StringProto.newBuilder().setValue(queryInfo.getJsonExpr()))
          .setLogicalPlanJson(PrimitiveProtos.StringProto.newBuilder().setValue(plan.toJson()).build())
          .build();

request contains the description of the query we want to execute. We want this instance to be sent to the QueryMaster(=REEFDriver)

What would be the best way to give request instance above as a parameter?

[ks881115]

I deleted Cho's comment by mistake (I didn't know I have such a power). So I'm restoring it. I apologize this.... and thank for the reply!

Have you thought of sending the protobuf as a byte[] message from the Client to the Driver?

See RunningJob#send(byte[]). You can get an instance of RunningJob through the JobRunningHandler on the client. When the message is received on the Driver side, the ClientMessageHandlers handler will be triggered.

Using bindNamedParameter, you would need to construct the object on the Driver side, which doesn't seem to be the right thing to do, given you want to send a request that is already constructed.

Hope this helps.