Handle Node.js Debug Messages and Improve Port Termination

CHANGELOG.md

@@ -5,6 +5,21 @@ All notable changes to this project will be documented in this file.
 The format is based on [Keep a Changelog](http://keepachangelog.com/en/1.0.0/)
 and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.html).
 
+## [3.1.3]
+
+### Added
+- Added `debug_mode` configuration option to handle Node.js stdout/stderr messages
+- Implemented proper `handle_info/2` callback to handle messages from Node.js processes
+- Added safeguards to reset_terminal to prevent errors during termination with invalid ports
+
+### Fixed
+- Fixed "unexpected message in handle_info/2" errors when Node.js emits debug messages
+- Fixed potential crashes during termination when a port becomes invalid
+
+### Contributors
+- @francois-codes for the initial implementation
+- Revelry team for refinements
+
 ## [3.1.2]
 
 ### Changed

README.md

@@ -36,6 +36,22 @@ directory containing your JavaScript modules.
 supervisor(NodeJS, [[path: "/node_app_root", pool_size: 4]])
 ```
 
+### Debug Mode
+
+When working with Node.js applications, you may encounter debug messages or warnings from the Node.js runtime, especially when using inspector or debugging tools. To properly handle these messages:
+
+```elixir
+# In your config/dev.exs or other appropriate config file
+config :nodejs, debug_mode: true
+```
+
+When `debug_mode` is enabled:
+- Node.js stdout/stderr messages will be logged at the info level
+- Messages like "Debugger listening on..." will not cause errors
+- All Node.js processes will log their output through Elixir's Logger
+
+This is particularly useful during development or when debugging Node.js integration issues.
+
 ### Calling JavaScript module functions with `NodeJS.call(module, args \\ [])`.
 
 If the module exports a function directly, like this:
@@ -111,4 +127,4 @@ module.exports = async function echo(x, delay = 1000) {
 }
 ```
 
-https://github.com/revelrylabs/elixir-nodejs/blob/master/test/js/slow-async-echo.js
+https://github.com/revelrylabs/elixir-nodejs/blob/master/test/js/slow-async-echo.js

lib/nodejs/worker.ex

@@ -124,21 +124,28 @@ defmodule NodeJS.Worker do
     end
   end
 
-  defp env do
-    Mix.env()
-  rescue
-    _ -> :release
+  # Determines if debug mode is enabled via application configuration
+  defp debug_mode? do
+    Application.get_env(:nodejs, :debug_mode, false)
   end
 
-  def handle_info({_pid, data}, state) do
-    with :dev <- env(),
-         {_, {:eol, msg}} <- data do
+  # Handles any messages from the Node.js process
+  # When debug_mode is enabled, these messages (like Node.js debug info)
+  # will be logged at info level
+  @doc false
+  def handle_info({_pid, {:data, {_flag, msg}}}, state) do
+    if debug_mode?() do
       Logger.info("NodeJS: #{msg}")
     end
 
     {:noreply, state}
   end
 
+  # Catch-all handler for other messages
+  def handle_info(_message, state) do
+    {:noreply, state}
+  end
+
   defp decode(data) do
     data
     |> to_string()
@@ -149,9 +156,16 @@ defmodule NodeJS.Worker do
     end
   end
 
+  # Safely resets the terminal, handling potential errors if
+  # the port is already closed or invalid
   defp reset_terminal(port) do
-    Port.command(port, "\x1b[0m\x1b[?7h\x1b[?25h\x1b[H\x1b[2J")
-    Port.command(port, "\x1b[!p\x1b[?47l")
+    try do
+      Port.command(port, "\x1b[0m\x1b[?7h\x1b[?25h\x1b[H\x1b[2J")
+      Port.command(port, "\x1b[!p\x1b[?47l")
+    rescue
+      _ ->
+        Logger.debug("NodeJS: Could not reset terminal - port may be closed")
+    end
   end
 
   @doc false

test/js/debug_test/debug_logger.js

@@ -0,0 +1,10 @@
+// This file outputs debugging information to stdout
+console.log("Debug message: Module loading");
+console.debug("Debug message: Initializing module");
+
+module.exports = function testFunction(input) {
+  console.log(`Debug message: Function called with input: ${input}`);
+  console.debug("Debug message: Processing input");
+
+  return `Processed: ${input}`;
+};

test/nodejs_debug_mode_test.exs

@@ -0,0 +1,105 @@
+defmodule NodeJS.DebugModeTest do
+  use ExUnit.Case
+  import ExUnit.CaptureLog
+
+  describe "debug_mode functionality" do
+    test "logs Node.js stdout messages when debug_mode is enabled" do
+      defmodule TestDebugHandler do
+        use GenServer
+        require Logger
+
+        def start_link do
+          GenServer.start_link(__MODULE__, nil)
+        end
+
+        def init(_) do
+          {:ok, nil}
+        end
+
+        def debug_mode? do
+          Application.get_env(:nodejs, :debug_mode, false)
+        end
+
+        # The implementation from worker.ex
+        def handle_info({_pid, {:data, {_flag, msg}} = _data}, state) do
+          if debug_mode?() do
+            Logger.info("NodeJS: #{msg}")
+          end
+
+          {:noreply, state}
+        end
+      end
+
+      # Start the test process
+      {:ok, pid} = TestDebugHandler.start_link()
+
+      # Test with debug_mode disabled (default)
+      log_without_debug =
+        capture_log(fn ->
+          # Simulate debugger message from Node.js
+          send(pid, {self(), {:data, {:eol, "Debugger listening on ws://127.0.0.1:9229/abc123"}}})
+          # Wait for any potential logging
+          Process.sleep(50)
+        end)
+
+      # Verify no logging occurred
+      refute log_without_debug =~ "NodeJS: Debugger listening"
+
+      # Enable debug_mode
+      Application.put_env(:nodejs, :debug_mode, true)
+
+      # Test with debug_mode enabled
+      log_with_debug =
+        capture_log(fn ->
+          # Simulate debugger message from Node.js
+          send(pid, {self(), {:data, {:eol, "Debugger listening on ws://127.0.0.1:9229/abc123"}}})
+          # Wait for any potential logging
+          Process.sleep(50)
+        end)
+
+      # Clean up
+      Application.delete_env(:nodejs, :debug_mode)
+
+      # Verify logging occurred
+      assert log_with_debug =~ "NodeJS: Debugger listening"
+    end
+  end
+
+  describe "port safety" do
+    test "reset_terminal handles invalid ports gracefully" do
+      defmodule TestPortHandler do
+        use GenServer
+        require Logger
+
+        def start_link do
+          GenServer.start_link(__MODULE__, nil)
+        end
+
+        def init(_) do
+          {:ok, nil}
+        end
+
+        # The implementation from worker.ex
+        def reset_terminal(port) do
+          try do
+            Port.command(port, "\x1b[0m\x1b[?7h\x1b[?25h\x1b[H\x1b[2J")
+            Port.command(port, "\x1b[!p\x1b[?47l")
+          rescue
+            _ ->
+              Logger.debug("NodeJS: Could not reset terminal - port may be closed")
+          end
+        end
+      end
+
+      log =
+        capture_log(fn ->
+          # Try to reset an invalid port
+          TestPortHandler.reset_terminal(:invalid_port)
+          Process.sleep(50)
+        end)
+
+      # Verify proper error handling
+      assert log =~ "NodeJS: Could not reset terminal"
+    end
+  end
+end