CODEWITHSUNDEEP
gorpc
Peniblec
Peniblec

Reputation: 457

Simple RPC Call in Go

I am trying to get a minimal application working using RPC calls in Go. I am heavily borrowing from the online example, as you can see from my code:

server.go:

package main

import (
    [...]
)

type InfoDumper int

func (s *InfoDumper) Dump(request string, reply *string) error {

    fmt.Println("Woooh imma deliverin stuff\n")

    current_time := time.Now()

    h:= sha1.New()
    var barray []byte
    copy(barray, request)
    hash_rq := h.Sum(barray)

    *reply = request + "\n" + current_time.Format(time.ANSIC) + "\n"  + string(hash_rq) + "\n"
    return nil
}


func main() {

    server := new(InfoDumper)

    rpc.Register(server)
    rpc.HandleHTTP()

    l, e := net.Listen("tcp", "127.0.0.1:40000")
    if e != nil {
        fmt.Println(e)
    }

    http.Serve(l, nil)

}

client.go:

package main

import (
    [...]
)

func main() {

    client, e := rpc.Dial("tcp", "127.0.0.1:40000")

    if e!=nil {
        fmt.Println(e)
    }   else {
        fmt.Println("wooh server is ok")
    }

    in:= bufio.NewReader(os.Stdin)

    for {

        line, _, _ := in.ReadLine()
        request := string(line)
        var reply string

        e = client.Call("InfoDumper.Dump", request, &reply)

        if (e!=nil) {
            fmt.Println("omg error!", e)
        }

        fmt.Println(reply)
    }

}

The only difference I can see is that I wrote http.Serve(l, nil) instead of go http.Serve(l, nil) ; this is because writing with go makes my server terminate right away. InfoDump is supposed to reply with a copy of whatever was sent, the time and hash of the request.

This is what's happening right now:

In either case, "Woooh imma deliverin stuff" is never displayed on the server's side...

This was done during class as a preliminary step to get acquainted with RPC in Go before going on to more serious exercises ; all the other students managed to get this step working, looked at this code and couldn't see the difference with theirs.

Does anyone see anything wrong with this code?

Upvotes: 3

Views: 3177

Answers (1)

Kyle Lemons
Kyle Lemons

Reputation: 4756

As I noted in my mailing list response, you will need to use DialHTTP if you want to connect to an RPC server that you have served using HandleHTTP.

I've made some other notes about your code (including styling: use gofmt and MixedCaps, per Effective Go, and be sure to bail out on errors) on the mailing list.

Upvotes: 5

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