Monday, October 15, 2018

Printing documents from Ubuntu Touch

Early previews of Ubuntu Touch 16.04 OTA-4 came with a settings panel for configuring printers. But the dual concerns of a root image that was growing too large, and the unfinished feature being deemed expendable conspired to make it so that the feature was dropped in subsequent previews. It has not made a reappearance in the recently released OTA-5 either. I expect it will be revisited when space is made available in the root image by removing some deprecated libraries.

Need To Print

But what if I want to be able to print the attachment of an email from the convenience of my mobile device? Going up the stairs, turning on the desktop, waiting for it to boot, logging in, opening my email, then printing the attachment, takes up so much time! Accessing the correct email is so much faster on my phone. So I would want to be able to print from it too.

I got to thinking that it should be possible to set up printing in a Libertine container. And turns out it is! Let's walk through the steps. I will assume that you already have a running Libertine container. Lets call ours xenial. I will also assume that you have a network printer that is accessible in a browser under http://<address of printer server>:631. In other words, that you have a CUPS server running somewhere on your local network. For the purposes of this walk-through let us assume the IP address of the server is 192.168.0.4

The Setup

Fire up the Terminal app in Ubuntu Touch and install the CUPS client package in the xenial container:
$ libertine-container-manager install-package -i xenial -p cups-client
We only want the client package since we will not be running a CUPS server locally in the container. This would not have been possible even if we wanted to, because daemons cannot be started inside Libertine containers.
The next enter the container shell:
$ libertine-container-manager exec -i xenial -c /bin/bash
You will now be in a root shell inside the xenial container. What we need to do here is tell the CUPS client where to look for a CUPS server. The default location is localhost. But we wouldn't be running a CUPS server on the device itself. So we need to point it to our server. Remember that ours is running at address 192.168.0.4:
# mkdir -p /etc/cups
# touch /etc/cups/client.conf
# echo "ServerName 192.168.0.4" >> /etc/cups/client.conf
Now you should be able to print from any other application installed in the container. Just install your favorite editor and viewers alongside. In my setup I have installed firefox, libreoffice and evince.

Notice that if you have more than one container on your device and you want to be able to print from within that container also, you would have to repeat the above steps for that container also. So it might be worth it to take a moment to consider how you want to distribute your applications among the different containers.

Saturday, October 13, 2018

Migrating from ElementaryOS 0.4 to Ubuntu 16.04 without reinstalling

The Good

ElementaryOS is one handsome Linux distribution. It is elegant in the execution and I would recommend it to any Apple refugees who're not tied to any exclusively MacOS applications, along with any newcomer to Linux in general.

It had been my distribution of choice on a netbook at home for a while to my great satisfaction. So when it came time to replace my development workstation I thought, "Why not give Elementary a go in the work environment?"

The Bad

The Elementary team deservedly pride themselves in delivering a coherent experience. The project has its own UI and UX guidelines, its own toolkit, its own libraries, its own utilities and applications like the desktop and terminal app to name just two. This is understandable, because it helps give the user a consistent interface and experience.

But the applications I use in my work environment make assumptions about the environment they are running on, and try to integrate with that environment. For example: at my job we use Subversion as our revision control solution. We also use C# as the main development language. So RabbitVCS and MonoDevelop are an important part of my everyday workflow. But RabbitVCS integrates with Gnome's Files (nautilus) but not with Elementary's Files (pantheon-files). Similarly MonoDevelop fails to launch a console application for debugging if Gnome's Terminal application (gnome-terminal) is not installed, thereby completely ignoring the availability of Elementary's Terminal application (pantheon-terminal).

I also needed to run DBeaver, Thunderbird and Virtual Machine Manager, to name a few of the other applications that are outside of the Elementary ecosystem. Granted, it is easy enough to install these applications. But having them living on my desktop destroyed the aesthetic harmony that was the main reason to run this distribution in the first place.

So after some internal deliberation I decided that I might just as well migrate my machine to Ubuntu, as that would be more in line to what the applications I use expect to be running on.

And The Ugly

Being that Elementary is based on Ubuntu I wanted to perform the migration without requiring a reinstall. But what packages would I need to install and uninstall to leave my machine running as if I had installed Ubuntu on it in the first place?

I decided to fire up a VM on my laptop to investigate. I first installed ElementaryOS 0.4.1 Loki (the current stable, and the one I run on my workstation) on it. Then I went about installing the ubuntu-desktop meta packages, which pulled in and installed all the dependencies:
$ sudo apt install sudo apt install ubuntu-desktop
Next I removed every package that I could find that was obviously related to ElementaryOS and the pantheon distribution:
$ sudo apt --purge autoremove elementary-desktop elementary-standard \
  elementary-minimal plymouth-theme-elementary* \
  elementary-icon-theme elementary-theme libgranite-common \
  pantheon-terminal libwingpanel-2.0-0 elementary-dpms-helper \
  libreoffice-style-elementary libswitchboard-2.0-0 
Lastly I disabled the ElementaryOS specific repositories under Software-Updates:
After a reboot, I had me an Ubuntu 16.04 with Unity 7 that looked like it was what I had installed in the first place.

Now it probably is not completely like a fresh Ubuntu 16.04 install, as I suspect a few of the Ubuntu packages that were patched by the Elementary project still linger on. At some time in the future I might dive in and weed these out. The responsible thing would be to do this sooner rather than later, since by disabling the repositories these packages came from I also blocked off the route to security updates on them. But that might be the subject of a future blogpost.

Running Firefox in a 16.04 Libertine Container

The latest Ubuntu Touch image comes with the possibility of creating a Libertine container in which to install and run 'legacy' X11 apps. This feature is not new, since the last image of the mobile OS released by Canonical also had this functionality. What is new however is that with the upgrade to 16.04 the containers that are created are also based on an Ubuntu 16.04 chroot.

In the previous post I detailed how to install command-line utilities in such a container. In this post I will focus on installing a graphical application, namely Firefox.

Update:

@TartanSpartan on Telegram has brought to my attention a github repo that contains recent builds of Firefox (65 at the time of this writing) for armhf achitecture that have the mentioned bugs patched. The releases can be found at https://github.com/jdonald/firefox-armhf/releases. Scroll down for the installation instructions.

Installation

One of the first graphical applications many (including me) want to install in a container is the Firefox browser. I mean, imagine having the power of a fully featured browser, including any extensions or plugins that would run on ARM, on your mobile device. Do I hear echos of convergence?
Once the container is created, (for instructions on how to do that, see the previous post) it should be trivial to install firefox:
$ libertine-container-manager install-package -i xenial -p firefox
Let it finish installing, head over to the Libertine scope and tap on the Firefox icon... And it crashes...  😞

It turns out that there is an unspecified bug that causes all versions of Firefox newer than at least 45 to crash on certain architectures. To date, crashes on i386 and armhf have been reborted. Luckily there is a version 45 of Firefox still available in de Ubuntu repositories for 16.04. So we can try that one. First we remove the current firefox:
$ libertine-container-manager remove-package -i xenial -p firefox
then we install the version we want:
$ libertine-container-manager install-package -i xenial \
 -p firefox=45.0.2+build1-0ubuntu1
Once the installation finishes we can try again, and this time Firefox does launch. There are still a few issues to tackle to enhance the user experience though.

Configuration

Because the dpi of the devices is high and the screens are small, the text and icons are minuscule. This is an issue with most X11 applications running in a libertine container, and there are  workarounds, for the text at least, but none of them are ideal, and I will not reproduce them here.

However, in the specific case of Firefox, there is an in app setting that will increase the rendering size of the UI. In the address bar enter: about:config. You might get a warning page about voiding your warranty. Click on "I accept the risk!" and proceed. In the search bar at the top of the resulting page type: devPix. You should now see the configuration setting: layout.css.devPixelsPerPx. Edit the value to something between 1.5 and 2. I have it set to 1.75 on my tablet. This give a nice increase in size, without taking up too much extra  space and causing items inside pages to overlap.

Now that the controls are big enough for us to be able to tap on them, we need to tackle the annoying behavior that causes every menu or popup screen to open in its own window. Actually, it is more than just annoying, it makes the applications unusable. Good thing this is Linux, so all that is needed is to tweak a config text file somewhere.

The information to do this came from this post on the UBports forum. But I will recapitulate the instructions below.
First off, make the root filesystem writeable:
$ sudo mount -o remount,rw /
then edit the file at /usr/bin/libertine-xmir using sudo by changing the line
Xmir -rootless $@
to
Xmir -rootless -flatten $@
exit and save the file. Remember to remount the filesystem read-only returning things to the way we found them:
$ sudo mount -o remount,ro /

Lastly, since we installed an older version of the Firefox package, if and when we update all the packages from the container, Firefox will also be updated to the latest version. To stop this from happening we need to tell the package manager that we want to pin Firefox to the version we have installed. First we need to gain root access to our container. This is achieved with:
$ libertine-container-manager exec -i xenial -c /bin/bash
Some errors will be printed, but these can safely be ignored, and we will be landed in a root shell in the container. Once there type:
# apt-mark hold firefox
and our Firefox package will not be updated. It will not even be able to be removed!

If we should tire of Firefox, or we wnat to delete it to reclaim storage space on the device we can do:
# apt-mark unhold firefox
then exit the container shell. The package can now be removed.

Caveat emptor

Running Firefox on a touch device does not automagically convert it into a touch aware application. Especially scrolling provides a very poor user experience. It should also not be forgotten that we are running a very old version of Firefox in our Libertine container. This could be a security risk, but it is a risk I am willing to accept. I intend to use Firefox for the few websites that refuse to play well with the native browser on the device. Also if the container should be compromised in any way, I could easily delete it and start again with a fresh one, sans any loss of data on the device.

Installing newer versions of Firefox

@TartanSpartan on Telegram brought to my attention a repo containing recent builds of Firefox that do run on armhf. I have had inconsistent results with these builds, so YMMV.

To install any of these deb files do the following:
  • Navigate to https://github.com/jdonald/firefox-armhf/releases on your UTouch device.
  • Download the version of your choice. Just make sure it is compiled to run on 16.04. I clicked on firefox_65.0+build2-0ubuntu0.16.04.1_armhf.deb as that was the lastest build at the time of this writing.
  • Navigate to the Downloads folder in the File Manager app and copy the name of the downloaded file to the clipboard. You really don't want to be typing it out in the next step.
  • Next go to the Libertine Manager in the Systems Settings app.
    Click on the container you would like to install Firefox in and then click on the + icon in the upper right corner.
    Select Enter package name of Debian file. In the edit box type the complete path to the downloaded deb file. In my case that was /home/phablet/Downloads/firefox_65.0+build2-0ubuntu0.16.04.1_armhf.deb. Hit enter or click on OK and the package, including any dependencies, will be installed.