RPC response not correct

user_4726258 0
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I am trying to use a remote procedure which will set a reply in a struct, with a boolean status and a string as next input. In the procedure, I am setting the boolean status as true and putting a value into input. But in the client, it gets a false status and empty string. In Procedure:

func(c *Coordinator)MapJob(req mr.MapRequest, reply *mr.MapResponse) error {
    //logic to set up response...
    reply = &mr.MapResponse{
        Status: newStatus,
        Input:  newIn,
    }
    fmt.Printf("[REPLY] %+v\n", reply)

    return nil
}

prints [REPLY] &{Status:true Input:1.txt}

while in client:

err := client.Call("Coordinator.MapJob", req, &reply)
        fmt.Printf("reply from procedure %+v\n", reply)

prints:reply from procedure {Status:false Input:}

What am I missing here? I have put the whole code in https://github.com/Brotchu/ProjectMR The procedure is defined in coordinator, and client in worker. It may be too much to paste it all in here.

go rpc
2 Answers

The client structure look like it is only made of zero values (false and the empty string).

I think the client.Call call do not mutate the reply. And i think this is because MapJob doesn't mutate the reply either.

reply = &mr.MapResponse{
        Status: newStatus,
        Input:  newIn,
    }

Should be

reply.Status = newStatus
reply.Input =  newIn
user_146369320

You have to change the reply value that passed during the call, so replace

reply = &mr.MapResponse{
    Status: newStatus,
    Input:  newIn,
}

With

*reply = mr.MapResponse{
    Status: newStatus,
    Input:  newIn,
}
user_11851480
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