Gracefully closes connection.

.github/workflows/ci.yml

@@ -92,6 +92,9 @@ jobs:
           restore-keys: |
             xogmios-versions-${{ hashFiles('.tool-versions') }}-${{ hashFiles('mix.lock') }}-YYYY-MM-DD
 
+      - name: Credo
+        run: mix credo
+
       - name: Mix Audit
         run: mix deps.audit
 

README.md

@@ -55,22 +55,26 @@ Clone this repo, populate `OGMIOS_URL` and run the following to start following
 
 ```shell
 OGMIOS_URL="ws://..." mix run --no-halt
-connected!
-Finding intersection...
+Compiling 4 files (.ex)
 
-Intersection found.
-Waiting for next block...
+21:29:25.609 [info] Finding intersection...
 
-New Block!
-Height: 9739937 ID: 1a13643c99270355251808eec434f99f2ac439971b88b9afda5b055752b546b2
+21:29:25.619 [info] Intersection found.
 
-New Block!
-Height: 9739938 ID: eba6cfb41f2e1c777ec282b24ea27cf23d118d4522fd26397d8f4b179ea70340
+21:29:25.619 [info] Waiting for next block...
+
+21:29:36.330 [info] Elixir.Xogmios.ClientExampleA handle_block 9751015
+
+21:29:53.522 [info] Elixir.Xogmios.ClientExampleA handle_block 9751016
+
+21:30:08.763 [info] Elixir.Xogmios.ClientExampleA handle_block 9751017
+
+21:30:12.240 [info] Elixir.Xogmios.ClientExampleA handle_block 9751018
 
 ...
 ```
 
-## Text
+## Test
 
 Run `mix test`
 

config/runtime.exs

@@ -0,0 +1,14 @@
+import Config
+
+# Set LOGGER_LEVEL env to one of the valid
+# values for level https://hexdocs.pm/logger/1.12.3/Logger.html#module-levels
+# In order to help with debugging, set LOGGER_LEVEL="debug"
+case config_env() do
+  :test ->
+    config :logger,
+      level: System.get_env("LOGGER_LEVEL", "warning") |> String.to_existing_atom()
+
+  _ ->
+    config :logger,
+      level: System.get_env("LOGGER_LEVEL", "info") |> String.to_existing_atom()
+end

lib/xogmios.ex

@@ -1,2 +1,3 @@
 defmodule Xogmios do
+  @moduledoc false
 end

lib/xogmios/application.ex

@@ -1,4 +1,6 @@
 defmodule Xogmios.Application do
+  @moduledoc false
+
   use Application
 
   @impl true

lib/xogmios/chain_sync.ex

@@ -4,17 +4,35 @@ defmodule Xogmios.ChainSync do
   implements the connection with the Websocket server
   """
 
+  alias Xogmios.ChainSync.Messages
+
   @callback init(keyword()) :: {:ok, map()}
   @callback handle_block(map(), any()) ::
-              {:ok, :next_block, map()} | {:ok, map()}
+              {:ok, :next_block, map()} | {:ok, map()} | {:ok, :close, map()}
 
   defmacro __using__(_opts) do
     quote do
-      use WebSockex
       @behaviour Xogmios.ChainSync
 
+      use WebSockex
+
+      require Logger
+
       @name __MODULE__
 
+      def init(_opts), do: {:ok, %{}}
+      defoverridable init: 1
+
+      def child_spec(opts) do
+        %{
+          id: __MODULE__,
+          start: {__MODULE__, :start_link, [opts]},
+          shutdown: 5_000,
+          restart: Keyword.get(opts, :restart, :transient),
+          type: :worker
+        }
+      end
+
       def start_connection(opts),
         do: do_start_link(opts)
 
@@ -29,15 +47,8 @@ defmodule Xogmios.ChainSync do
           {:ok, ws} ->
             receive do
               {:connected, _connection} ->
-                start = ~S"""
-                {
-                  "jsonrpc": "2.0",
-                  "method": "nextBlock",
-                  "id": "start"
-                }
-                """
-
-                send_frame(ws, start)
+                message = Messages.next_block_start()
+                send_frame(ws, message)
 
                 {:ok, ws}
             after
@@ -51,12 +62,6 @@ defmodule Xogmios.ChainSync do
         end
       end
 
-      def init(_opts) do
-        {:ok, %{}}
-      end
-
-      defoverridable init: 1
-
       def send_frame(connection, frame) do
         try do
           case WebSockex.send_frame(connection, {:text, frame}) do
@@ -74,7 +79,7 @@ defmodule Xogmios.ChainSync do
             handle_message(message, state)
 
           {:error, error} ->
-            IO.puts("Error decoding response #{inspect(error)}")
+            Logger.warning("Error decoding response #{inspect(error)}")
             {:close, state}
         end
       end
@@ -87,38 +92,20 @@ defmodule Xogmios.ChainSync do
              } = _message,
              state
            ) do
-        IO.puts("Finding intersection...\n")
-
-        reply = ~s"""
-        {
-          "jsonrpc": "2.0",
-          "method": "findIntersection",
-          "params": {
-              "points": [
-                {
-                  "slot": #{tip["slot"]},
-                  "id": "#{tip["id"]}"
-                }
-            ]
-          }
-        }
-        """
+        Logger.info("Finding intersection...")
 
-        {:reply, {:text, reply}, state}
+        message = Messages.find_intersection(tip["slot"], tip["id"])
+
+        {:reply, {:text, message}, state}
       end
 
       defp handle_message(
              %{"method" => "nextBlock", "result" => %{"direction" => "backward"}} = _message,
              state
            ) do
-        reply = ~S"""
-        {
-          "jsonrpc": "2.0",
-          "method": "nextBlock"
-        }
-        """
+        message = Messages.next_block()
 
-        {:reply, {:text, reply}, state}
+        {:reply, {:text, message}, state}
       end
 
       defp handle_message(
@@ -130,38 +117,31 @@ defmodule Xogmios.ChainSync do
 
         case apply(__MODULE__, :handle_block, [block, state]) do
           {:ok, :next_block, new_state} ->
-            reply = ~S"""
-            {
-              "jsonrpc": "2.0",
-              "method": "nextBlock"
-            }
-            """
-
-            {:reply, {:text, reply}, new_state}
+            message = Messages.next_block()
+            {:reply, {:text, message}, new_state}
 
           {:ok, new_state} ->
             {:ok, new_state}
 
+          {:ok, :close, new_state} ->
+            {:close, new_state}
+
           _ ->
             raise "Invalid return type"
         end
       end
 
       defp handle_message(%{"method" => "findIntersection"}, state) do
-        IO.puts("Intersection found.\nWaiting for next block...\n")
+        Logger.info("Intersection found.")
+        Logger.info("Waiting for next block...")
 
-        reply = ~S"""
-        {
-          "jsonrpc": "2.0",
-          "method": "nextBlock"
-        }
-        """
+        message = Messages.next_block()
 
-        {:reply, {:text, reply}, state}
+        {:reply, {:text, message}, state}
       end
 
       defp handle_message(message, state) do
-        IO.puts("handle message: #{message}")
+        Logger.info("handle message: #{message}")
         {:ok, state}
       end
 
@@ -171,7 +151,7 @@ defmodule Xogmios.ChainSync do
       end
 
       def handle_disconnect(%{reason: {:local, reason}}, state) do
-        IO.puts("Local close with reason: #{inspect(reason)}")
+        Logger.info("#{__MODULE__} local close with reason: #{inspect(reason)}")
         {:ok, state}
       end
     end

lib/xogmios/chain_sync/messages.ex

@@ -0,0 +1,41 @@
+defmodule Xogmios.ChainSync.Messages do
+  @moduledoc """
+  This module returns messages according to the Ogmios API
+  """
+
+  def next_block_start() do
+    ~S"""
+    {
+      "jsonrpc": "2.0",
+      "method": "nextBlock",
+      "id": "start"
+    }
+    """
+  end
+
+  def next_block() do
+    ~S"""
+    {
+      "jsonrpc": "2.0",
+      "method": "nextBlock"
+    }
+    """
+  end
+
+  def find_intersection(slot, id) do
+    ~s"""
+    {
+      "jsonrpc": "2.0",
+      "method": "findIntersection",
+      "params": {
+          "points": [
+            {
+              "slot": #{slot},
+              "id": "#{id}"
+            }
+        ]
+      }
+    }
+    """
+  end
+end

lib/xogmios/client_example_a.ex

@@ -5,12 +5,14 @@ defmodule Xogmios.ClientExampleA do
 
   use Xogmios.ChainSync
 
+  require Logger
+
   def start_link(opts),
     do: start_connection(opts)
 
   @impl true
   def handle_block(block, state) do
-    IO.puts("#{__MODULE__} handle_block #{block["height"]}")
+    Logger.info("#{__MODULE__} handle_block #{block["height"]}")
     {:ok, :next_block, state}
   end
 end

lib/xogmios/client_example_b.ex

@@ -5,24 +5,26 @@ defmodule Xogmios.ClientExampleB do
 
   use Xogmios.ChainSync
 
+  require Logger
+
   def start_link(opts),
     do: start_connection(opts)
 
   @impl true
   def init(_args) do
-    {:ok, %{counter: 3}}
+    {:ok, %{counter: 2}}
   end
 
   @impl true
   def handle_block(block, %{counter: counter} = state) when counter > 1 do
-    IO.puts("#{__MODULE__} handle_block #{block["height"]}")
+    Logger.info("#{__MODULE__} handle_block #{block["height"]}")
     new_state = Map.merge(state, %{counter: counter - 1})
     {:ok, :next_block, new_state}
   end
 
   @impl true
   def handle_block(block, state) do
-    IO.puts("#{__MODULE__} final handle_block #{block["height"]}")
-    {:ok, state}
+    Logger.info("#{__MODULE__} final handle_block #{block["height"]}")
+    {:ok, :close, state}
   end
 end

mix.exs

@@ -38,6 +38,7 @@ defmodule Xogmios.MixProject do
   defp deps do
     [
       {:cowboy, "~> 2.10", only: :test},
+      {:credo, "~> 1.7", only: [:dev, :test], runtime: false},
       {:dialyxir, "~> 1.4.1", only: [:dev, :test], runtime: false},
       {:jason, "~> 1.4"},
       {:mix_audit, "~> 2.1", only: [:dev, :test], runtime: false},

mix.lock

@@ -15,7 +15,6 @@
   "plug_crypto": {:hex, :plug_crypto, "2.0.0", "77515cc10af06645abbfb5e6ad7a3e9714f805ae118fa1a70205f80d2d70fe73", [:mix], [], "hexpm", "53695bae57cc4e54566d993eb01074e4d894b65a3766f1c43e2c61a1b0f45ea9"},
   "ranch": {:hex, :ranch, "1.8.0", "8c7a100a139fd57f17327b6413e4167ac559fbc04ca7448e9be9057311597a1d", [:make, :rebar3], [], "hexpm", "49fbcfd3682fab1f5d109351b61257676da1a2fdbe295904176d5e521a2ddfe5"},
   "telemetry": {:hex, :telemetry, "1.2.1", "68fdfe8d8f05a8428483a97d7aab2f268aaff24b49e0f599faa091f1d4e7f61c", [:rebar3], [], "hexpm", "dad9ce9d8effc621708f99eac538ef1cbe05d6a874dd741de2e689c47feafed5"},
-  "websocket_client": {:hex, :websocket_client, "1.5.0", "e825f23c51a867681a222148ed5200cc4a12e4fb5ff0b0b35963e916e2b5766b", [:rebar3], [], "hexpm", "2b9b201cc5c82b9d4e6966ad8e605832eab8f4ddb39f57ac62f34cb208b68de9"},
   "websockex": {:hex, :websockex, "0.4.3", "92b7905769c79c6480c02daacaca2ddd49de936d912976a4d3c923723b647bf0", [:mix], [], "hexpm", "95f2e7072b85a3a4cc385602d42115b73ce0b74a9121d0d6dbbf557645ac53e4"},
   "yamerl": {:hex, :yamerl, "0.10.0", "4ff81fee2f1f6a46f1700c0d880b24d193ddb74bd14ef42cb0bcf46e81ef2f8e", [:rebar3], [], "hexpm", "346adb2963f1051dc837a2364e4acf6eb7d80097c0f53cbdc3046ec8ec4b4e6e"},
   "yaml_elixir": {:hex, :yaml_elixir, "2.9.0", "9a256da867b37b8d2c1ffd5d9de373a4fda77a32a45b452f1708508ba7bbcb53", [:mix], [{:yamerl, "~> 0.10", [hex: :yamerl, repo: "hexpm", optional: false]}], "hexpm", "0cb0e7d4c56f5e99a6253ed1a670ed0e39c13fc45a6da054033928607ac08dfc"},

test/support/chain_sync/test_handler.ex

@@ -1,4 +1,6 @@
 defmodule ChainSync.TestHandler do
+  @moduledoc false
+
   @behaviour :cowboy_websocket
 
   @impl true
@@ -28,6 +30,11 @@ defmodule ChainSync.TestHandler do
     end
   end
 
+  @impl true
+  def terminate(_arg1, _arg2, _arg3) do
+    :ok
+  end
+
   def websocket_info(:stop, state) do
     {:stop, state}
   end

test/support/chain_sync/test_router.ex

@@ -1,4 +1,6 @@
 defmodule ChainSync.TestRouter do
+  @moduledoc false
+
   use Plug.Router
 
   plug(:match)

test/support/chain_sync/test_server.ex

@@ -1,4 +1,6 @@
 defmodule ChainSync.TestServer do
+  @moduledoc false
+
   @default_port 8989
 
   def get_url(port \\ @default_port) do