system-monitor

This application aims to expose the machine's CPU usage stats to the user, both via an endpoint, and visaully with a custom Grafana dashboard. The stats are scraped from the /proc fs of the system.

As of now, only supported for *NIX systems with a /proc fs.

Requirements:

• CMake (min v3.14.2)
• GCC
• Make
• X11
• Docker (for the grafana dashboard)
• Docker Compose

Launching system-monitor

• Grab the latest binary from the "Releases" section of this repo(unzip the downloaded file to get the binary).
• Provide execute permission for the file, by running the following command in the terminal, in the directory where the binary is downloaded:

chmod +x ./system-monitor

• Launch the application by executing the binary:

./system-monitor

This opens up port 8080 on the host machine, and emits the scraped metrics, updated every 5s, in the OpenMetrics Standard. The scraped metrics are also written into a file named accumulated_metrics.txt in the same directory where the binary is downloaded.

• For getting the metrics on a grafana dashboard, execute the following commands in the main project directory:

docker compose up -d

This launches the prometheus db application on port 9090 of the host machine, and grafana on port 3000. The default username and password for the grafana dashboard is admin and admin respectively.

Memory Leak Tests

To run tests to find potential memory leaks that may be caused by the binary, execute the following command:

valgrind --leak-check=full --show-leak-kinds=all ./system-monitor

Directory Structure

.
|-- CMakeLists.txt
|-- Dockerfile
|-- LICENSE
|-- README.md
|-- configs
|   |-- grafana_dashboard_config.json
|   |-- grafana_dashboard_provider.yml
|   |-- grafana_datasource.yml
|   `-- prometheus_config.yml
|-- docker-compose.yml
|-- include
|   |-- accumulator_queue.h
|   |-- app_timer.h
|   |-- metrics_exporter.h
|   |-- monitor_metrics.h
|   |-- signal_handler.h
|   |-- socket_manager.h
|   |-- stat_parser.h
|   |-- thread_manager.h
|   |-- usage_calculator.h
|   `-- watchdog_timer.h
|-- main.c
|-- source
|   |-- accumulator_queue.c
|   |-- app_timer.c
|   |-- metrics_exporter.c
|   |-- monitor_metrics.c
|   |-- signal_handler.c
|   |-- socket_manager.c
|   |-- stat_parser.c
|   |-- threads
|   |   |-- accumulator_thread.c
|   |   |-- export_thread.c
|   |   |-- file_write_thread.c
|   |   `-- watchdog_thread.c
|   |-- usage_calculator.c
|   `-- watchdog_timer.c
|-- start.sh
`-- valgrind_test_results.txt

5 directories, 35 files

Manually build from source

To manually build the binary from the source code, execute the following commands in the terminal, from the project root directory:

chmod +x ./start.sh
./start.sh

The start.sh script executes the binary by itself. The built binary is present in $PROJECT_ROOT/build. In this case, the accumulated_metrics.txt file is also created in the build directory, and the valgrind test can also be run from inside the build directory with the same command as above.

To change the type of build, change the DCMAKE_BUILD_TYPE switch in ./start.sh. Some of the supported enums for the switch are Release, Debug, RelWithDebugInfo.

Sample Valgrind Result after building from source

akshayrevankar@cuttlefish:~/system-monitor/build$ valgrind --leak-check=full --show-leak-kinds=all ./system-monitor
==22658== Memcheck, a memory error detector
==22658== Copyright (C) 2002-2017, and GNU GPL'd, by Julian Seward et al.
==22658== Using Valgrind-3.18.1 and LibVEX; rerun with -h for copyright info
==22658== Command: ./system-monitor
==22658==
Threads created!
==22658== Thread 2:
==22658== Conditional jump or move depends on uninitialised value(s)
==22658==    at 0x10A91C: calculate_all_cpus (in /home/akshayrevankar/system-monitor/build/system-monitor)
==22658==    by 0x109D58: monitor_metrics (in /home/akshayrevankar/system-monitor/build/system-monitor)
==22658==    by 0x10A450: accumulator_function (in /home/akshayrevankar/system-monitor/build/system-monitor)
==22658==    by 0x48F6AC2: start_thread (pthread_create.c:442)
==22658==    by 0x4987A03: clone (clone.S:100)
==22658==
^CGracefully exiting...
Threads joined, program ends!
==22658==
==22658== HEAP SUMMARY:
==22658==     in use at exit: 383 bytes in 1 blocks
==22658==   total heap usage: 48 allocs, 47 frees, 72,501 bytes allocated
==22658==
==22658== Thread 1:
==22658== 383 bytes in 1 blocks are still reachable in loss record 1 of 1
==22658==    at 0x4848899: malloc (in /usr/libexec/valgrind/vgpreload_memcheck-amd64-linux.so)
==22658==    by 0x490A58E: strdup (strdup.c:42)
==22658==    by 0x109804: enqueue (in /home/akshayrevankar/system-monitor/build/system-monitor)
==22658==    by 0x109B51: record_metrics (in /home/akshayrevankar/system-monitor/build/system-monitor)
==22658==    by 0x10A460: accumulator_function (in /home/akshayrevankar/system-monitor/build/system-monitor)
==22658==    by 0x48F6AC2: start_thread (pthread_create.c:442)
==22658==    by 0x4987A03: clone (clone.S:100)
==22658==
==22658== LEAK SUMMARY:
==22658==    definitely lost: 0 bytes in 0 blocks
==22658==    indirectly lost: 0 bytes in 0 blocks
==22658==      possibly lost: 0 bytes in 0 blocks
==22658==    still reachable: 383 bytes in 1 blocks
==22658==         suppressed: 0 bytes in 0 blocks
==22658==
==22658== Use --track-origins=yes to see where uninitialised values come from
==22658== For lists of detected and suppressed errors, rerun with: -s
==22658== ERROR SUMMARY: 4 errors from 1 contexts (suppressed: 0 from 0)