Multi-arch software building and distribution is a complex and time-consuming maintenance task in which maintainer/developer need to compile somehow their software for all supported architectures, often, on a single machine. Automation solution such as Jenkins allows to automatize this task and facilitating continuous integration and continuous delivery. Multi-arch software building on a single machine involves the use of different techniques:
This post introduces the basic steps of setting up an automation server that allows to build and distribute multi-arch software using Jenkins and docker.
Application log is the traditional way to monitor an application/service. On *nix-based system, Syslog is a common but powerful tool for centrally monitoring applications logs. The primary use of syslog is for system management as capturing log data is critical for sysadmin, devOp team, or system analysts, etc. This log data is helpful in case of investigating/troubleshooting problems and maintaining healthy functioning of systems.
Syslog offers a standard log format and a standard alert system with different severity levels to applications in form of a log API. Log daemons such as rsyslog are versatile and flexible with various configuration options that enable different way to interact with the logs: log to file, log to a remote server via network (TCP, UDP sockets), log to local Unix domain socket. Log clients or log analytic applications can collect log data from the log daemon via these interfaces.
Although it is feasible to directly read log messages from the regular syslog output files, it is more preferable to collect log data from the daemon using the socket interface since socket is more suitable for data streaming. TCP/UDP sockets can be used to access log data from the network (TCP/IP). But if the application runs locally on the same machine as the log daemon, Unix domain socket (UDS) may be the best option.
Unix Domain Socket is an inter-process communication mechanism that allows bidirectional data exchange between processes running on the same machine. Thus, UDSs can avoid some checks and operations (like routing); which makes them faster and lighter than IP sockets.
In this post, we will learn how to collect log data from syslog via UDS in C. We will use rsyslog as log daemon in this post.
A use case will be presented at the end of the post.
After a long testing period, AntOS v1.2.0-beta is now released!!!
A demo of the VDE is available at https://app.iohub.dev/antos/ using username: demo and password: demo.
If one want to run AntOS VDE locally in their system, a docker image is available at:
As stated on a post where i talked about using tf-idf to detect similarity between two blog posts, my blog is just a bunch of posts sorted by date, no category, no fancy features like user interest tracking, post ranking, etc. I usually work on many different domains (robotic, IoT, backend, frontend platform design, etc.), so my posts are mixed up between these domains. This may be difficult for readers who want to follow up their interesting topic on my blog.
So what is a good strategy for navigating between posts on a blog ?
Working on my DIY robot software (Jarvis) in headless mode, i came across a situation where i needed to monitor the system resource such as CPU, battery, memory, network and temperature to measure the "greedy" of my robotic application. Furthermore, as the robot was battery powered, battery safety was a real concern, so i needed something to monitor the battery and shutdown the system when the battery was low to protect it from falling bellow the usable voltage range.
So i've searched for an application/service that allows me to:
None of existing applications/services satisfy all of these requirements, especially, the battery monitoring feature. So i've decided to write a small service that i called
sysmond is a simple service that monitors and collects system information such as battery, temperature, memory, CPU, and network usage. The service can be used as backend for applications that need to consult system status. Although it is a part of Jarvis ecosystem,
sysmond is a generic service and can be easily adapted to other use cases.
Sysmond monitors resource available on the system via the user space sysfs interface provided by the linux kernel.
This post is the follow up post of the previous JETTY: Jarvis Serial to ROS-2 Transport Layer post.
The arduino firmware on the one hand implements the JETTY protocol for communicating with ROS and on the other hand takes care of all low-level hardware communication including:
The Jarvis booklet section Arduino Firmware presents the insight detail on the firmware implementation. It covers the following topics:
Follow up reading at: https://doc.iohub.dev/jarvis/Ym9vazovLy9jXzIvc18yL0lOVFJPLm1k/Arduino_Firmware.md
My ROS based DIY robot( presented in the previous post) uses the NVIDIA Jetson Nano for high level robotic algorithms with the ROS 2 middle-ware. The Jetson is connected to an Arduino via a serial link for low-level hardware interaction and control.
As the Arduino is used for low-level communication with actuators/sensors. We need a software transport layer on top of the physical serial link (Jetson - Arduino) to stream (sensor) data/command from Arduino to ROS 2 and vice versa. On Dolly (my previous robot version), which used ROS 1, this was handled by Rosserial, a protocol for wrapping standard ROS serialized messages and multiplexing multiple topics and services over a serial link. On ROS 2, however, Rosserial is not available. Other alternative solutions exist but are not mature enough, some implementations require more computational resource which exceeds the capability of the Arduino Mega 2560.
So i decided to implement a dedicated transport layer for Jarvis called JETTY (Jarvis SErial to ROS-2 TransporT LaYer). I do not aim at a generic protocol for ROS to serial communication like ROS serial. Instead, the implementation of the transport layer should be specific only to the robot. However, the protocol must be easy to extend to adapt to any future upgrade of the robot such as adding more sensor/actuators.
Requirements on the transport layer:
Brief, we need an efficient and reliable delimiting/synchronization scheme to detect the frame with short recovery time.
The detail on the choice of protocol and algorithm as well as insight implementation is presented on a section of my Jarvis booklet accessible via the following link:
It has been a while since i started to build an upgraded version of Dolly, my first DIY ROS based robot. This upgraded version is named Jarvis.
Changes from the previous version:
As a work in progress, I'm now writing a booklet that detail the building process of the robot both on hardware and soft software (Arduino, ROS 2), as well as some application use cases. The initial plan is:
All further updates on the booklet can be found here: https://doc.iohub.dev/jarvis/.
From the version 4.8, the Linux kernel introduces a new user space API based on character devices for managing and controlling GPIOs ( General-Purpose Input/Output). This post presents the basic of the new interface as well as a simple tutorial/example to demonstrate how to use the new API to control GPIOs.
The hardware used in the tutorial is the Raspberry Pi 3B but the code is generic and can be used on any embedded hardware.
[Update 27/03/2021]: The image is now available on docker hub at: https://hub.docker.com/r/xsangle/antosaio (image:
xsangle/antosaio:latest). This post has been updated with latest instruction on how to host a local instance of Antos VDE using docker.
More information on AntOS https://doc.iohub.dev/antos
The docker image provide out-of-the-box working AntOS system which consist of:
AntOS user can be created at creation of of the container, each user is attached to a separated container.
In a multi-users scenario, This mean that user working instance is completely isolated to other. Resource consumption such as CPU, storage and RAM of each instance is configurable.