How do i connect to the remote node using Golang ?

[khanakia]

Hi,

How do i connect to the remote node using Golang? I do not see any examples of that.

For e.g. i can do in elixir like this

iex --sname bar
GenServer.call({B, :'foo@Amans-MacBook-Pro'}, :get_balance)

So I want to do the same from golang to connect to the remote node and run a function

[halturin]

Hi, thanks for the question.

You may want to try this example https://github.com/ergo-services/ergo/tree/master/examples/genserver

gen.ServerProcess has methods Cast and Call

[khanakia]

Yes, i checked that but that requires me to create a node. But on the client-side, why do I need to create a node.
Basically, I have 2 going apps. So I want one to be a SERVER and the other to be a CLIENT so I can connect by node name from client to server.

As you can see this repo for reference they have a very simple example https://github.com/grpc/grpc-go/tree/master/examples/helloworld

Can we have something like this so it will help the users to understand easily how to create separate server and client app ?

[halturin]

in Erlang/Elixir and in Ergo as well, making any requests (sending a message, to be specific) can be done by the process only, which can exist only within a node. There is no other way (like "client-library").

[khanakia]

So i am using genserver as SERVER https://github.com/ergo-services/ergo/tree/master/examples/genserver

and then I created a CLIENT app here https://github.com/khanakia/ergo_examples/blob/main/client_server/client/main.go

func main() {
	node, _ := ergo.StartNode("node@localhost", "cookies", node.Options{})
	process, _ := node.Spawn("gs1", gen.ProcessOptions{}, &simple{})

	to := gen.ProcessID{Name: "example", Node: "demo@127.0.0.1"}
	err := process.Send(to, "hello")
	fmt.Println(err)
	// out: no route to node
}

But it returns an error no route to node

[halturin]

you used the wrong cookie value. Example uses "123" as a cookie
https://github.com/ergo-services/ergo/blob/master/examples/genserver/server.go#L66

your client has also wrong process ID value
https://github.com/khanakia/ergo_examples/blob/main/client_server/client/main.go#L37

to := gen.ProcessID{Name: "demo@127.0.0.1", Node: "example"}

must be

to := gen.ProcessID{Node: "demo@127.0.0.1", Name: "example"}

[khanakia]

Thanks :) It worked.

Last thing how do I send a CALL method and get the Response back because process.Send does not returns any response

[halturin]

The Cast and Call are gen.ServerProcess methods and are available within an actor only (to be specific - within the actor's callbacks). To operate with an actor from outside, you should use gen.Process methods: Send method for async messaging (will be invoked HandleInfo callback) or Direct to make sync calls to the actor (will be invoked HandleDirect).

• gen.ServerProcess is available as a first argument in the callbacks like Init, HandleCast, HandleCall etc. (see gen.ServerBehavior interface)
• gen.Process is an interface returned by Spawn method.

[khanakia]

Ok