DeviceConfigMonitorService

DeviceConfigMonitorService is a C++17 Windows service that monitors device configurations and writes periodic heartbeat logs to a daily-rotated log file.

It supports two operating modes:

• Console mode (--console): foreground process for development and debugging. Loads configuration, prints a summary, then runs the heartbeat loop until Ctrl+C.
• Windows Service mode (no flag): registered as a Windows service via the scripts/*.bat control scripts, managed by the Windows Service Control Manager (SCM).

This project was implemented as the Week 1 deliverable of the NanningTraining / DeviceConfigMonitorService plan.

• Visual Studio 2022 (Community or higher)
• Windows SDK 10.0+
• C++17 compiler (MSVC v143 toolset)
• Windows 10/11 or Windows Server 2016+

1. Open DeviceConfigMonitorService.sln in Visual Studio 2022.
2. Select configuration Debug | x64 (or Release | x64).
3. Build the solution (Build > Build Solution or Ctrl+Shift+B).

The output binary is produced at:

x64\Debug\DeviceConfigMonitorService.exe

The project is compiled with /std:c++17 /utf-8 on all four configurations. The /utf-8 flag is required to correctly handle non-ASCII characters on Chinese Windows (code page 936).

DeviceConfigMonitorService/
+- DeviceConfigMonitorService.sln
+- README.md
+- README_CN.md
+- .gitignore
+- .gitattributes
+- x64/                          # 构建输出（已 gitignore）
+- DeviceConfigMonitorService/
   +- src/                       # 源码（C++ 实现文件）
   |  +- main.cpp                # 入口：--console 或 SCM 分发
   |  +- config.cpp              # AppConfig + JSON 加载/保存
   |  +- logger.cpp              # Logger
   |  +- heartbeat_worker.cpp    # HeartbeatWorker
   |  +- service_main.cpp        # ServiceMain + ServiceCtrlHandler
   +- config.h                   # AppConfig 头文件（与 src/config.cpp 配对）
   +- logger.h                   # 与 src/logger.cpp 配对
   +- heartbeat_worker.h         # 与 src/heartbeat_worker.cpp 配对
   +- service_main.h             # 与 src/service_main.cpp 配对
   +- config.example.json        # 配置样例
   +- DeviceConfigMonitorService.vcxproj
   +- DeviceConfigMonitorService.vcxproj.filters
   +- scripts/                   # 服务控制 .bat 文件
   |  +- install.bat
   |  +- uninstall.bat
   |  +- start.bat
   |  +- stop.bat
   |  +- query.bat
   +- docs/                      # 文档
   |  +- test_report.md
   |  +- week1_summary.md
   +- third_party/               # 第三方依赖库
      +- nlohmann/
         +- json.hpp             # nlohmann/json v3.12.0（仅头文件）

The configuration file is read from and written to:

C:\ProgramData\NanningTraining\DeviceConfigMonitorService\config.json

If the file does not exist on startup, a default configuration is generated and saved automatically.

{
  "DeviceId": "DEVICE-0001",
  "ServiceName": "DeviceConfigMonitorService",
  "EnableHeartbeat": true,
  "HeartbeatIntervalSeconds": 30,
  "LogLevel": "INFO",
  "LogPath": "C:\\ProgramData\\NanningTraining\\DeviceConfigMonitorService\\logs"
}

If the JSON cannot be parsed, the program:

1. Prints an error to stderr (e.g. [ERROR] Failed to parse config file (JSON error): ...).
2. Falls back to the default configuration.
3. Continues running without crashing.

Log files are written to the directory specified by LogPath (default C:\ProgramData\NanningTraining\DeviceConfigMonitorService\logs).

service-YYYY-MM-DD.log

One file per day. Cross-day rollover is detected on every write.

[YYYY-MM-DD HH:MM:SS.mmm] [LEVEL] message

Example:

[2026-07-08 14:00:00.123] [INFO] Service starting up...
[2026-07-08 14:00:00.124] [INFO] Heartbeat worker starting. DeviceId=DEVICE-0001, interval=10s
[2026-07-08 14:00:10.118] [INFO] [Heartbeat] DeviceId=DEVICE-0001, ServiceName=DeviceConfigMonitorService

Errors are written to stderr; Info/Warn are written to stdout.

cd x64\Debug
DeviceConfigMonitorService.exe --console

• Loads configuration and prints a summary.
• Initializes the Logger and starts the heartbeat worker.
• Press Ctrl+C for graceful shutdown (heartbeat thread is joined first, then logs are flushed).

All control scripts must be run from an Administrator command prompt because sc.exe requires OpenSCManager privileges.

:: Register the service
scripts\install.bat

:: Start the service
scripts\start.bat

:: Query status (STATE, PID, controls accepted)
scripts\query.bat

:: Stop the service (graceful)
scripts\stop.bat

:: Remove from SCM (stops first if running)
scripts\uninstall.bat

Service status transitions:

START_PENDING -> RUNNING -> STOP_PENDING -> STOPPED

The service responds to SERVICE_CONTROL_STOP and SERVICE_CONTROL_SHUTDOWN. On stop, the heartbeat thread is joined and logs are flushed before the process exits.

DeviceConfigMonitorService.exe --help

*Q: Git status shows .vs/, x64/ or .user files even though .gitignore is in place. A: They may have been committed before .gitignore was added. Run git rm -r --cached .vs x64 and any tracked *.user file. Future builds will not add them.

Q: The build fails with "code page 936" / "cannot represent character" errors. A: This is the Chinese Windows GBK code page. The project compiles with /utf-8; ensure your Visual Studio installation is 16.10+ and rebuild. Do not edit source files in editors that do not save as UTF-8.

Q: install.bat says "sc create failed" / "OpenSCManager failed 5". A: The script must be run from a command prompt launched as Administrator. The script also checks for write access to %SystemRoot%\System32 to confirm privileges.

Q: start.bat succeeds but the service exits immediately. A: Check scripts\query.bat for the exit reason. The most common cause is a missing Visual C++ runtime on the target machine, or the executable was moved/renamed after install. Re-run install.bat.

Q: Logs are not being written. A: Verify the value of LogPath in config.json. Ensure the process has write permission to that directory. In service mode, the LocalSystem account is used, which can write to C:\ProgramData\... by default.

Q: After changing HeartbeatIntervalSeconds, the heartbeat interval does not update. A: The config is read only at startup. Stop and restart the service (or the console process) to pick up changes.

Q: How do I uninstall the service completely? A: Run scripts\uninstall.bat (it stops the service first if running). This removes the service entry from the Windows registry.

Q: How do I test the console mode after uninstalling? A: Just run DeviceConfigMonitorService.exe --console directly from x64\Debug\. The Windows Service is not involved.

• This is a Week 1 training project. The current implementation is deliberately minimal: it focuses on clean architecture, thread safety, and a working SCM integration, not on production hardening (e.g. ACLs, event log integration, retry policy, etc.).
• All commit messages follow the department template: TYPE: app: SUBJECT where TYPE is one of func / fix / conf / docs / build / style / refactor.