Ubuntu Core 18 is out and one of the features that it packs with it is a set of snapd interfaces to access GPIO pins on the Raspberry Pi 2/3 in a fully confined snap. This enables one to just flash Ubuntu Core 18 on a micro sd card, boot, install a snap (which I author), connect a few interfaces and start controlling relays attached to a Raspberry Pi 2/3.
If you don't have Ubuntu Core 18 already installed, you can see the install instructions here
To get started (assuming you have Ubuntu Core 18 installed and have working ssh access to the Pi), you need to install a snap that exposes the said functionality over the network (local)
$ snap install pigpio
The above command installed the pigpio server, which automatically starts in the background. The server could take as much as 30 seconds to start, you have been warned.
We also need to allow the newly installed snap to access a few GPIO pins
Telegram is great, especially because it helps one stay away from the distractions that WhatsApp brings with it. Its unfortunately blocked in Pakistan, due to unknown reason but likely not related to censorship, given WhatsApp, Signal and every other messaging app works just fine.
The good news is Telegram upstream have their own proxy protocol and an implementation (https://github.com/TelegramMessenger/MTProxy), which seems to work well. I published MTProxy as a snap (https://snapcraft.io/mtproxy) yesterday, so thought it would make sense to share how others could setup their own proxy. This guide, will of course help me as a future reference as well.
So lets get started by installing MTProxy
$ snap install mtproxy
Due to security reasons, mtproxy drops privileges (if run as root) by calling setuid(), something a strictly confined snap does not allow due to security reasons, so my workaround was to create a new user on the server, so that mtproxy does not try to drop privileges.
Lately at Crossbar.io, we have been PySide2 for an internal project. Last week it reached a milestone and I am now in the process of code cleanup and refactoring as we had to rush quite a few things for that deadline. We also create a snap package for the project, our previous approach was to ship the whole PySide2 runtime (170mb+) with the Snap, it worked but was a slow process, because each new snap build involved downloading PySide2 from PyPI and installing some deb dependencies.
So I decided to play with the content interface and cooked up a new snap that is now published to snap store. This definitely resulted in overall size reduction of the snap but at the same time opens a lot of different opportunities for app development on the Linux desktop.
I created a 'Hello World' snap that is just 8Kb in size since it doesn't include any dependencies with it as they are provided by the pyside2 snap. I am currently working on a very simple "sound recorder" app using…