EasyRpc

This library help developer easy to wrap a remote procedure call (rpc, library uses Erlang :erpc module) to local function.

EasyRpc supports some basic features for wrapping rpc: retry, timeout, error_handling. Each function can has seperated options or use global options (in a module).

Can use EasyRpc with ClusterHelper for calling a rpc in a dynamic Elixir cluster.

Installation

Adding easy_rpc library to your list of dependencies in mix.exs:

def deps do
  [
    {:easy_rpc, "~> 0.4.0"}
  ]
end

Usage - defrpc way

In this way, you need to add config for node list & its select_mode. The config can add in compile time or runtime or using {module, function arguments} for selecting by function.

For wrapping a remote function to local module you need to use macro defrpc.

Add Configs

config :simple_example, :remote_defrpc,
  nodes: [:"[email protected]"],  # or {ClusterHelper, :get_nodes, [:remote_api]},
  select_mode: :round_robin,
  sticky_node: true

Current version, :round_robin & :sticky_node are worked for process only.

Declare functions

defmodule Remote
  use EasyRpc.DefRpc,
    otp_app: :simple_example,
    config_name: :remote_defrpc,
    # Remote module name
    module: RemoteNode.Interface,
    timeout: 1000

  defrpc :get_data
  defrpc :put_data, args: 1
  defrpc :clear, args: 2, as: :clear_data, private: true
  defrpc :put_data, args: [:name], new_name: :put_with_retry, retry: 3, timeout: 1000
end

Usage - Config way

This is an example for declare by config in config.exs file. All function & node info (excepted nodes: {module, function, arguments}) are generated at compile time. For this way you need to work with config than module.

Follow steps

Add config to config.exs

Put config to config.exs file, and use it in your module by using RpcWrapper. User need separate config for each wrapper, and put it in config.exs

config :app_name, :wrapper_name,
  nodes: [:"[email protected]"], # or using function like nodes: {Module, Fun, Args}
  error_handling: true,
  select_mode: :random,
  module: TargetApp.Interface.Api,
  functions: [
    # {function_name, arity, options}
    {:get_data, 1},
    {:put_data, 1, error_handling: false},
    {:clear, 2, new_name: :clear_data, retry: 3},
    {:clear_all, 0, new_name: :clear_all, private: true}, # wrap to private function.
  ]

Wrap to local module

by using use EasyRpc.RpcWrapper in your module, you can call remote functions as local functions.

defmodule DataHelper do
  use EasyRpc.RpcWrapper,
    otp_app: :app_name,
    config_name: :account_wrapper

  def process_remote() do
    # call rpc like a local function.
    case get_data("key") do
      {:ok, data} ->
        # do something with data

      {:error, reason} ->
        # handle error
    end
  end
end

# Or call from other module like
{:ok, result} = DataHelper.get_data("my_key")

For more details please go to module's docs.

Example

You can go to example folder to see how EasyRpc work, check config & run and see.

Go to lib_examples on Github and follow the README in sub folders.