ZSS ZeroMQ Service Client

Warning: NOT PRODUCTION READY

Purpose

This is an Elixir implementation of a client for the Micro Toolkit ZSS Broker. This is not an official repo.

It allows connecting your Elixir application to an existing NodeJS project using the Broker and its associated clients/workers.

When to use this

This library is intended to use when you need/want to introduce Elixir to your existing stack, which uses the ZSS Suite.

Installation

T.B.D.

Creating a Client and calling a Service Worker

In order to create a client, you start by creating an appropriate configuration. Note that broker and timeout are optional, and will default to the shown values respectively.

config = ZssClient.get_instance %{identity: "EXAMPLE_CLIENT", broker: "tcp://127.0.0.1:7777", timeout: 1000, sid: "PING"}

Based on the config, you can instantiate Clients.

{:ok, client} = ZssClient.get_client(config)

This client can be used to make calls to various specified endpoints.

ZssClient.call(client, request)
with {:ok, payload, status} <- ZssClient.get_response(client) do
  IO.inspect("Received #{inspect payload} with status #{inspect status}")
  {:ok, status}
else
  {:error, payload, code} ->
  IO.inspect("Error! #{inspect payload} with status #{inspect status}")
  {:error, status}
end

Note that receiving messages (get_response) is a blocking action for that client, but calling a service is not. In case you want to perform multiple actions, you can do something akin to

config = ZssClient.get_config %{identity: "EXAMPLE_CLIENT", broker: "tcp://127.0.0.1:7777", timeout: 1000, sid: "PING"}
config2 = ZssClient.get_config %{identity: "EXAMPLE_CLIENT", broker: "tcp://127.0.0.1:7777", timeout: 1000, sid: "PONG"}

{:ok, ping_client} = ZssClient.get_client(config)
{:ok, pong_client} = ZssClient.get_client(config2)

with :ok <- ZssClient.call(ping_client, {"GET", %{}, %{headers: %{request_id: "1"}}}),
     :ok <- ZssClient.call(pong_client, {"LIST", %{}, %{headers: %{request_id: "1"}}}),
     [ping_reply, pong_reply] <- [ZssClient.get_response(ping_client), ZssClient.get_response(pong_client)],
do
  #handle 2 messages
else
  error -> #handle error
end

Client Response contract

Clients will return a 3 value tuple, with the following properties:

Property	Type	Description
indicator	atom	Indicates whether the request can be considered succesfull or an error. Signalled by :ok or :error respectively.
payload	Mixed	The response payload. Keep in mind that data is deserialized and atom based maps get converted to string key maps.
code	Integer	The status code associated with the request. Maps to HTTP codes.

Supervising

This library has a supervisor that each running client will reside under. Currently processes will not be rebooted if they crash.

Running the example

Just execute

mix run ./examples/ping.exs