Fix ChainSync reconnection

CHANGELOG.md

@@ -5,6 +5,12 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](https://keepachangelog.com/en/1.1.0/),
 and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).
 
+## [Unreleased]
+
+### Fixed
+
+- ChainSync reconnection issue (#33)
+
 ## [v0.4.0](https://github.com/wowica/xogmios/releases/tag/v0.4.0) (2024-05-31)
 
 ### Added

README.md

@@ -161,3 +161,7 @@ For examples of applications using this library, see [Blocks](https://github.com
 ## Test
 
 Run `mix test`. Tests do NOT rely on a running Ogmios instance.
+
+## Help
+
+Join the #elixir channel in the [TxPipe Discord](https://discord.gg/ZTHcHUy5HY)

lib/xogmios/chain_sync.ex

@@ -56,14 +56,20 @@ defmodule Xogmios.ChainSync do
   @doc """
   Invoked upon disconnecting from the server. This callback is optional.
 
-  Returning `{:ok, new_state}` will allow the connection to close.
+  Returning `{:reconnect, interval_in_ms, new_state}` will attempt a reconnection
+  after `interval_in_ms`.
 
-  Returning `{:reconnect, interval_in_ms}` will attempt a reconnection after `interval_in_ms`
+  Returning `{:close, reason, new_state}` will allow the connection to close and
+  shut the process down cleanly.
+
+  Returning `{:ok, new_state}` will allow the connection to close but keeps
+  process alive.
   """
-  @callback handle_disconnect(reason :: String.t(), state) ::
-              {:ok, new_state}
-              | {:reconnect, interval_in_ms :: non_neg_integer(), new_state}
-            when state: term(), new_state: term()
+  @callback handle_disconnect(reason, state) ::
+              {:reconnect, interval_in_ms :: non_neg_integer(), new_state}
+              | {:close, reason, new_state}
+              | {:ok, new_state}
+            when reason: String.t(), state: term(), new_state: term()
 
   # The keepalive option is used to maintain the connection active.
   # This is important because proxies might close idle connections after a few seconds.
@@ -81,20 +87,12 @@ defmodule Xogmios.ChainSync do
   def start_link(client, opts) do
     {url, opts} = Keyword.pop(opts, :url)
     {name, opts} = Keyword.pop(opts, :name, client)
-    initial_state = Keyword.merge(opts, handler: client, notify_on_connect: self())
+
+    initial_state = Keyword.merge(opts, handler: client)
 
     with {:ok, process_name} <- build_process_name(name),
          {:ok, ws_pid} <- start_link(process_name, url, client, initial_state) do
-      # Blocks until the connection with the Ogmios server
-      # is established or until timeout is reached.
-      receive do
-        {:connected, _connection} -> {:ok, ws_pid}
-      after
-        _timeout = 5_000 ->
-          Logger.warning("Timeout connecting to Ogmios server")
-          send(ws_pid, :close)
-          {:error, :connection_timeout}
-      end
+      {:ok, ws_pid}
     else
       {:error, :invalid_process_name} = error ->
         error

lib/xogmios/chain_sync/connection.ex

@@ -20,7 +20,7 @@ defmodule Xogmios.ChainSync.Connection do
           id: Keyword.get(opts, :id, __MODULE__),
           start: {__MODULE__, :start_link, [opts]},
           shutdown: 5_000,
-          restart: Keyword.get(opts, :restart, :transient),
+          restart: Keyword.get(opts, :restart, :temporary),
           type: :worker
         }
       end
@@ -41,7 +41,6 @@ defmodule Xogmios.ChainSync.Connection do
 
         start_message = Messages.initial_sync()
         :websocket_client.cast(self(), {:text, start_message})
-        send(state.notify_on_connect, {:connected, connection})
 
         case state.handler.handle_connect(state) do
           {:ok, new_state} ->
@@ -55,11 +54,17 @@ defmodule Xogmios.ChainSync.Connection do
       @impl true
       def ondisconnect(reason, state) do
         case state.handler.handle_disconnect(reason, state) do
-          {:ok, state} ->
-            {:ok, state}
-
+          # Attempt to reconnect after interval in ms
           {:reconnect, reconnect_interval_in_ms, new_state} ->
             {:reconnect, reconnect_interval_in_ms, new_state}
+
+          # Shut the process down cleanly
+          {:close, reason, state} ->
+            {:close, reason, state}
+
+          # Disconnect but keeps process alive
+          {:ok, state} ->
+            {:ok, state}
         end
       end