feat: add autoware_node_death_monitor package for monitoring node crashes

system/autoware_node_death_monitor/CMakeLists.txt

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+cmake_minimum_required(VERSION 3.14)
+project(autoware_node_death_monitor)
+
+find_package(autoware_cmake REQUIRED)
+autoware_package()
+
+ament_auto_add_library(${PROJECT_NAME} SHARED
+  src/autoware_node_death_monitor.cpp
+)
+
+rclcpp_components_register_node(${PROJECT_NAME}
+  PLUGIN "autoware::node_death_monitor::NodeDeathMonitor"
+  EXECUTABLE ${PROJECT_NAME}_node)
+
+ament_auto_package(INSTALL_TO_SHARE
+  config
+  launch
+)

system/autoware_node_death_monitor/README.md

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+# autoware_node_death_monitor
+
+This package provides a monitoring node that detects ROS 2 node crashes by analyzing `launch.log` files, rather than subscribing to `/rosout` logs.
+
+---
+
+## Overview
+
+- **Node name**: `autoware_node_death_monitor`
+- **Monitored file**: `launch.log`
+- **Detected event**: Looks for lines containing the substring `"process has died"` and extracts the node name and exit code.
+
+When a crash or unexpected shutdown occurs, `ros2 launch` typically outputs a line in `launch.log` such as:
+
+```bash
+[ERROR] [node_name-1]: process has died [pid 12345, exit code 139, cmd '...']
+```
+
+The `autoware_node_death_monitor` node continuously reads the latest `launch.log` file, detects these messages, and logs a warning or marks the node as "dead."
+
+---
+
+## How it Works
+
+1. **Find `launch.log`**:
+   - First, checks the `ROS_LOG_DIR` environment variable.
+   - If not set, falls back to `~/.ros/log`.
+   - Identifies the latest log directory based on modification time.
+2. **Monitor `launch.log`**:
+   - Reads the file from the last known position to detect new log entries.
+   - Looks for lines containing `"process has died"`.
+   - Extracts the node name and exit code.
+3. **Filtering**:
+   - **Ignored node names**: Nodes matching patterns in `ignore_node_names` are skipped.
+   - **Ignored exit codes**: Logs with ignored exit codes are not flagged as errors.
+4. **Regular Updates**:
+   - A timer periodically reads new entries from `launch.log`.
+   - Dead nodes are reported in the logs. (will be changed to publish diagnostics)
+
+---
+
+## Parameters
+
+| Parameter Name      | Type       | Default           | Description                                                |
+| ------------------- | ---------- | ----------------- | ---------------------------------------------------------- |
+| `ignore_node_names` | `string[]` | `[]` (empty list) | Node name patterns to ignore. E.g., `['rviz2']`.           |
+| `ignore_exit_codes` | `int[]`    | `[]` (empty list) | Exit codes to ignore (e.g., `0` or `130` for normal exit). |
+| `check_interval`    | `double`   | `1.0`             | Timer interval (seconds) for scanning the log file.        |
+| `enable_debug`      | `bool`     | `false`           | Enables debug logging for detailed output.                 |
+
+Example **`autoware_node_death_monitor.param.yaml`**:
+
+```yaml
+autoware_node_death_monitor:
+  ros__parameters:
+    ignore_node_names:
+      - rviz2
+      - teleop_twist_joy
+    ignore_exit_codes:
+      - 0
+      - 130
+    check_interval: 1.0
+    enable_debug: false
+```
+
+---
+
+## Limitations
+
+- **後で書く**: TBD.
+- **Robust Monitoring**: Works alongside systemd, supervisord, or other process supervisors for enhanced fault detection.
+
+---

system/autoware_node_death_monitor/config/autoware_node_death_monitor.param.yaml

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+/**:
+  ros__parameters:
+    # Node names to exclude from monitoring (Note: be careful with the "[node_name-#]" format)
+    # Example: Do not issue a warning if rviz2 crashes.
+    ignore_node_names:
+      - rviz2
+
+    # Exit codes to exclude from monitoring (e.g., Ctrl+C)
+    # Example: 0, 130 are considered normal exits and not treated as errors.
+    ignore_exit_codes:
+      - 0
+      - 130
+
+    # Check interval (seconds)
+    check_interval: 1.0
+
+    # Enable/disable debug output
+    enable_debug: false

system/autoware_node_death_monitor/include/autoware_node_death_monitor/autoware_node_death_monitor.hpp

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+// Copyright 2025 Tier IV, Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#ifndef AUTOWARE_NODE_DEATH_MONITOR__AUTOWARE_NODE_DEATH_MONITOR_HPP_
+#define AUTOWARE_NODE_DEATH_MONITOR__AUTOWARE_NODE_DEATH_MONITOR_HPP_
+
+#include "rclcpp/rclcpp.hpp"
+
+#include <filesystem>
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+namespace autoware::node_death_monitor
+{
+
+class NodeDeathMonitor : public rclcpp::Node
+{
+public:
+  /**
+   * @brief Constructor for NodeDeathMonitor
+   * @param options Node options for configuration
+   */
+  explicit NodeDeathMonitor(const rclcpp::NodeOptions & options);
+
+private:
+  /**
+   * @brief Read and process new content appended to launch.log
+   */
+  void read_launch_log_diff();
+
+  /**
+   * @brief Parse a single line from the log for process death information
+   * @param line The log line to parse
+   */
+  void parse_log_line(const std::string & line);
+
+  /**
+   * @brief Timer callback to report and manage dead node list
+   */
+  void on_timer();
+
+  // Map to track dead nodes: [node_name-#] -> true
+  std::unordered_map<std::string, bool> dead_nodes_;
+
+  rclcpp::TimerBase::SharedPtr timer_;
+
+  // Launch log file path and read position
+  std::filesystem::path launch_log_path_;
+  size_t last_file_pos_{static_cast<size_t>(-1)};
+
+  // Parameters
+  std::vector<std::string> ignore_node_names_;  // Node names to exclude from monitoring
+  std::vector<int64_t> ignore_exit_codes_;      // Exit codes to ignore (e.g., normal termination)
+  double check_interval_{1.0};                  // Check interval in seconds
+  bool enable_debug_{false};                    // Enable debug output
+};
+
+}  // namespace autoware::node_death_monitor
+
+#endif  // AUTOWARE_NODE_DEATH_MONITOR__AUTOWARE_NODE_DEATH_MONITOR_HPP_

system/autoware_node_death_monitor/launch/autoware_node_death_monitor.launch.xml

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+<launch>
+  <!-- Parameter -->
+  <arg name="config_file" default="$(find-pkg-share autoware_node_death_monitor)/config/autoware_node_death_monitor.param.yaml"/>
+
+  <!-- Set log level -->
+  <arg name="log_level" default="info"/>
+
+  <node pkg="autoware_node_death_monitor" exec="autoware_node_death_monitor_node" name="node_death_monitor" output="screen" args="--ros-args --log-level $(var log_level)">
+    <!-- Parameter -->
+    <param from="$(var config_file)"/>
+  </node>
+</launch>

system/autoware_node_death_monitor/package.xml

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+<?xml version="1.0"?>
+<package format="3">
+  <name>autoware_node_death_monitor</name>
+  <version>0.0.1</version>
+  <description>The node_death_monitor package</description>
+
+  <maintainer email="kyoichi.sugahara@tier4.jp">Kyoichi Sugahara</maintainer>
+  <license>Apache License 2.0</license>
+
+  <buildtool_depend>ament_cmake_auto</buildtool_depend>
+  <buildtool_depend>autoware_cmake</buildtool_depend>
+
+  <depend>rcl_interfaces</depend>
+  <depend>rclcpp</depend>
+  <depend>rclcpp_components</depend>
+
+  <test_depend>ament_cmake_gtest</test_depend>
+  <test_depend>ament_lint_auto</test_depend>
+
+  <export>
+    <build_type>ament_cmake</build_type>
+  </export>
+</package>