Difference between revisions of "Raspberry Pi 3 - Browser Client"

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(Digital Signage)
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     Once the installation is complete, commit the changes by typing lbu commit -d
 
     Once the installation is complete, commit the changes by typing lbu commit -d
  
 +
Things to keep in mind here:
 +
* There is no need to make multiple partitions (e.g. on an sdcard). One partition that takes up the whole of the storage will suffice in diskless / sys mode.
 +
* For the setup-alpine install, most of the choices will be at the defaults. Particularly when prompted with "No disks available, try boot media /mmcblk0p1". Here you will click the default [n]. If you make a mistake during the install, you can always reimage and start over.
  
saving space: busybox instead of chronyd, dropbear instead of openssh
+
Saving space: busybox instead of chronyd, dropbear instead of openssh
  
 
After setup, make sure dropbear is installed
 
After setup, make sure dropbear is installed
Line 162: Line 165:
  
 
==Digital Signage==
 
==Digital Signage==
It's common to use GNULinux and x86/RPIs for digital signage projects. A quick glance at https://elinux.org/RPi_Projects/Digital_Signage will show a number of projects. Why would you use this guide for digital signage vs. those projects? 1) Alpine runs from RAM, which has less wear on the SD card 2) There is no requirement to use 'cloud' services, or depend upon an internet connection. 3) Full control over the build and design (all build steps are documented & small learning curve) 4) Zero cost & Free software
+
It's common to use GNULinux and x86/RPIs for digital signage. A quick glance at https://elinux.org/RPi_Projects/Digital_Signage will show a number of options. Why would you use this guide for digital signage vs. those pre-built projects?  
 +
# Alpine runs from RAM, which increases the lifetime of the storage (flash / hdd).
 +
# There is no requirement to use 'cloud' services, or depend upon an internet connection.  
 +
# You have full control over the build and design (all kiosk build steps are documented & have a small learning curve, compared to some of the more complex projects mentioned above).
 +
# Free software. No recurring costs (outside of optional maintenance).
 +
# No ties to external infrastructure / frameworks. Full freedom.
  
In this addition to the guide, I will build off the above steps but install Chromium, which seems to be the defacto standard. However, you could use any application that runs in X. Here we will also run a web server with PHP, which hosts the resources we want to display on the sign.
+
In this addition to the guide above, I will install Chromium, which seems to be the defacto standard. However, you could use any application that runs in X. Here we will also run a web server with PHP, which hosts the resources we want to display on the sign.
 
Make sure community apk is enabled in /etc/apk/repositories
 
Make sure community apk is enabled in /etc/apk/repositories
 
  apk add chromium
 
  apk add chromium
 
In /etc/startup.sh add the browser instead of firefox:
 
In /etc/startup.sh add the browser instead of firefox:
 
   chromium-browser --home-page http://127.0.0.1/resource --no-sandbox --window-size=1920,1280 --start-fullscreen --test-type
 
   chromium-browser --home-page http://127.0.0.1/resource --no-sandbox --window-size=1920,1280 --start-fullscreen --test-type
Note that this is a potentially insecure setup, and users are advised to add a user, and remove the --no-sandbox tag. The tags used are the following: --home-page will start us on a given URL. --no-sandbox will allow root to run chromium. --window-size will give us the resolution we want, and start-fullscreen will ensure the browser takes up all screen real estate.
+
Note that this is a potentially insecure setup, and users are advised to add a user, and remove the --no-sandbox tag. The tags used are the following: --home-page will start us on a given URL. --no-sandbox will allow root to run chromium. --window-size will give us the resolution we want, and start-fullscreen will ensure the browser takes up all of the screen.
  
If you deploy the device on a TV, and you are unsure what resolution it is, you can access this value from a different tty (not X), by using  
+
If you deploy the device on a TV, and you are unsure what resolution it is, you can access the resolution from the terminal (not in X), by using  
 
  xrandr -d :0
 
  xrandr -d :0
For example, I built my device on a computer monitor that was 1920x1280, but when I deployed, the TV was 1920x1080. Since we run chromium straight on X, without any WM, it's necessary to query xrandr from the console. If desired, you could install DWM and hide the bar, obtaining access to an X terminal accessible via keyboard shortcut configured in dwm's config.h. This might work identical but is not tested.
+
For example, I built my device on a computer monitor that was 1920x1280, but when I deployed, the TV was 1920x1080. Since we run chromium straight on X, without any WM, it's necessary to query xrandr from the console. If desired, you could install DWM and hide the bar, obtaining access to a terminal accessible via keyboard shortcut configured in dwm's config.h, But a WM is not required.
  
 
Make sure to lbu_commit -d, in order to save any changes as needed in the apkvol on the SD or HDD storage.
 
Make sure to lbu_commit -d, in order to save any changes as needed in the apkvol on the SD or HDD storage.

Revision as of 06:37, 1 July 2021

This is a guide for setting up a RAM based Alpine which is able to run X, and firefox. This tutorial will go through setting up auto login, and starting X on boot without user interaction. It is a type of kiosk or possibly digital signage.

Tested as of 05/2020 - RPI 3

12/2020 - x86

04/2021 - RPI 4

Overview

This guide uses the following:

  • aarch64 img (though this guide is also x86-compatible)
  • RPI3
  • community repo is used.

It is based off of this guide: Raspberry_Pi. Due to the dependencies required to run X and FF, there is very little RAM disk space for the user to operate in, after this tutorial is complete (about 30MB is v3.11). The 2GB RPI 4 has 1GB of ram, without adjusting /boot/config.txt. 1GB may be enough for most needs.

aarch64 is used, because firefox-esr is in the community repo. armhf (as of v3.11) does not have firefox prepackaged in the base or community repo.

See https://pkgs.alpinelinux.org/packages?name=*firefox*&branch=v3.11&arch=aarch64

Note that the aarch64 build is not compatible with all RPI. See Raspberry Pi.

Steps

Base Install

These steps are duplicated from Raspberry_Pi page.

Use fdisk or gdisk to format the SD card. You must have the first partition be a bootable, FAT filesystem. e.g.:

Command (m for help): p
Disk /dev/sdb: 59.5 GiB, 63864569856 bytes, 124735488 sectors
Units: sectors of 1 * 512 = 512 bytes
Sector size (logical/physical): 512 bytes / 512 bytes
I/O size (minimum/optimal): 512 bytes / 512 bytes
Disklabel type: dos
Disk identifier: 0x00000000

Device     Boot Start      End  Sectors Size Id Type
/dev/sdb1  *     2048 62916607 62914560  30G  b W95 FAT32
mkdosfs -F 32 /dev/sdX1

untar onto mounted disk

mount /dev/sdX1 /mnt/folder
tar xvf archive.tar -C /mnt/folder/.

If you plan to enable increased RAM (e.g. for RPI4 with 2 or 4GB) or other config settings, do so in a usercfg.txt now.

Again, duplicating the Raspberry Pi page

   Insert the SD card into the Raspberry Pi and turn it on
   Login into the Alpine system as root. Leave the password empty.
   Type setup-alpine
   Once the installation is complete, commit the changes by typing lbu commit -d

Things to keep in mind here:

  • There is no need to make multiple partitions (e.g. on an sdcard). One partition that takes up the whole of the storage will suffice in diskless / sys mode.
  • For the setup-alpine install, most of the choices will be at the defaults. Particularly when prompted with "No disks available, try boot media /mmcblk0p1". Here you will click the default [n]. If you make a mistake during the install, you can always reimage and start over.

Saving space: busybox instead of chronyd, dropbear instead of openssh

After setup, make sure dropbear is installed

apk add dropbear

Start it:

rc-service dropbear start

Add it to the default runlevel:

rc-update add dropbear

If you need an accurate clock, enable software/ntp here (optional, i don't need a clock for the website I view).

rc-update add swclock boot # enable the software clock 
rc-update del hwclock boot # disable the hardware clock
setup-ntp

Browser Client Install

Enable community repo (/etc/apk/repositories) (uncomment community)

nano /etc/apk/repositories
apk update

install firefox and X dependencies:

apk add libx11-dev libxft-dev libxinerama-dev adwaita-gtk2-theme adwaita-icon-theme ttf-dejavu

Note that the fonts/icon theme are required for FF to display correctly. Without these, firefox will load, but text will not render on the browser menus.

the RAM tmp fs remaining can be viewed while installing, with watch df -h

install firefox

apk add firefox-esr

install X

setup-xorg-base

The RPI also requires for X:

apk add xf86-video-fbdev

note: this command can vary if you are using x86. For example, I installed no xf86-video... drivers, and had a libEGL.so missing library error on Xorg, and that was resolved via "apk search libEGL.so" which pointed to mesa-egl. Note that apk search is case sensitive.

At this point, we have about 421MB used up (if NTP was not setup).

Filesystem                Size      Used Available Use% Mounted on
devtmpfs                 10.0M         0     10.0M   0% /dev
shm                     457.9M         0    457.9M   0% /dev/shm
/dev/mmcblk0p1           30.0G    259.4M     29.7G   1% /media/mmcblk0p1
tmpfs                   457.9M    420.0M     37.9M  92% /
tmpfs                    91.6M    188.0K     91.4M   0% /run
/dev/loop0               24.9M     24.9M         0 100% /.modloop
lbu_commit -d

AutoLogin, Startx automatically on Boot

At this point, you should be able to login as root, and run startx manually. Now, we will add a number of configuration files that allow this to happen without user interaction.

/root/ doesn't save any files, so it's necessary to edit files in /etc/ and lbu_commit -d after all changes. First let's add a file that will call firefox. lbu_commit is alpine local backup. If you want to save folders other than /etc see:https://wiki.alpinelinux.org/wiki/Alpine_local_backup#Include_special_files.2Ffolders_to_the_apkovl also see: /etc/apk/protected_paths.d/lbu.list

create a file named /etc/startup.sh:

#!/bin/ash
firefox http://somewebsite.com

!!!NOTE: This is ash, not bash. By default, alpine ships with the ashbourne shell. Although bash is available in the repositories.

We have to edit xinitrc, and the profile configs. Normally, this would be done in the user's directory, but here we will use the globals for simplicity.

mv /etc/X11/xinit/xinitrc /etc/X11/xinit/xinitrc_BAK
nano /etc/X11/xinit/xinitrc

In this file put:

/etc/startup.sh

At the end of /etc/profile (leave the existing file) append

startx

And remember to: lbu_commit -d For autologin, alpine uses busybox, which has an alias to /sbin/getty as well as /bin/login. It's possible to navigate to /sbin/ or /bin/ and run /sbin/getty -h to see what settings are available. To have root auto login upon boot, review the existing inittab and edit as needed, according to the config below.

# Set up a couple of getty's
#tty1::respawn:/sbin/getty 38400 tty1
tty2::respawn:/sbin/getty 38400 tty2
tty3::respawn:/sbin/getty 38400 tty3
tty4::respawn:/sbin/getty 38400 tty4
tty5::respawn:/sbin/getty 38400 tty5
tty6::respawn:/sbin/getty 38400 tty6

tty1::respawn:/bin/login -f root

Disable Screensaver, and refresh webpage (optional)

As a kiosk, the RPI will need to have the screensaver (DPMS) disabled. Also, my particular application (video streams) required a refresh occasionally. These were managed with xorg.conf, xdotool, and crontab respectively.

Contents of /etc/X11/xorg.conf

Section "Extensions" Option "DPMS" "Disable" EndSection

# apk add xdotool

# crontab -u root -e 
* * * * * DISPLAY=:0 /usr/bin/xdotool key F5

Note that xset is not an option here, as it's not included by default. It can be installed from repositories, if needed. That's it. Now reboot, and watch the RPI boot into firefox without user intervention. At this point, you have a functioning minimal OS booting from RAM, with firefox, and ~30MB of available space for further configuration.

Digital Signage

It's common to use GNULinux and x86/RPIs for digital signage. A quick glance at https://elinux.org/RPi_Projects/Digital_Signage will show a number of options. Why would you use this guide for digital signage vs. those pre-built projects?

  1. Alpine runs from RAM, which increases the lifetime of the storage (flash / hdd).
  2. There is no requirement to use 'cloud' services, or depend upon an internet connection.
  3. You have full control over the build and design (all kiosk build steps are documented & have a small learning curve, compared to some of the more complex projects mentioned above).
  4. Free software. No recurring costs (outside of optional maintenance).
  5. No ties to external infrastructure / frameworks. Full freedom.

In this addition to the guide above, I will install Chromium, which seems to be the defacto standard. However, you could use any application that runs in X. Here we will also run a web server with PHP, which hosts the resources we want to display on the sign. Make sure community apk is enabled in /etc/apk/repositories

apk add chromium

In /etc/startup.sh add the browser instead of firefox:

 chromium-browser --home-page http://127.0.0.1/resource --no-sandbox --window-size=1920,1280 --start-fullscreen --test-type

Note that this is a potentially insecure setup, and users are advised to add a user, and remove the --no-sandbox tag. The tags used are the following: --home-page will start us on a given URL. --no-sandbox will allow root to run chromium. --window-size will give us the resolution we want, and start-fullscreen will ensure the browser takes up all of the screen.

If you deploy the device on a TV, and you are unsure what resolution it is, you can access the resolution from the terminal (not in X), by using

xrandr -d :0

For example, I built my device on a computer monitor that was 1920x1280, but when I deployed, the TV was 1920x1080. Since we run chromium straight on X, without any WM, it's necessary to query xrandr from the console. If desired, you could install DWM and hide the bar, obtaining access to a terminal accessible via keyboard shortcut configured in dwm's config.h, But a WM is not required.

Make sure to lbu_commit -d, in order to save any changes as needed in the apkvol on the SD or HDD storage.

Install Apache/PHP

See Apache.

Install xset to disable screensaver

apk add xset
xset q
xset s off

Hide Scrollbars of Browser

This can be done in CSS.

body {
  overflow: hidden; /* Hide scrollbars */
}

Tips/Troubleshooting

Why was this setup used? Why not Awesome, or dwm?

I ran through a few different setups of alpine on the rpi, and found that (dwm | awesome) & firefox required too many dependencies to run on an RPI3 with 512MB in /tmp (running in RAM), or other browsers which used less dependencies were unstable (the application was viewing video streams). Therefore, running firefox direct off X was just barely able to fit into the available space, and was stable. This is one of the reasons aarch64 was used, instead of armhf. The 2GB RPI4 by default has 1GB of ram in alpine available (for storage), and doesn't have this limitation. It should be possible to get more RAM via /boot/config.txt

If your application doesn't require media (i.e. a static webpage) you may be able to run other browsers, such as midori, falkon, or surf, without stability issues on the RPI.

It is possible that VLC or a GTK/QT app would also fit into the limited space on the RPI 3. This was not tested.

Width & height of firefox doesn't fit the monitor

Firefox can be called with -height and -width flags, e.g.

firefox -width 480 -height 640 somewebsite.com

Periodic Firefox Crashes on RPI3 due to Low Memory

With the RPI3, I found firefox crashing reliably after a couple days uptime of watching video. On the server I saw notices of memory running out. This may have been a memory leak, and with the small amount of RAM available, it would crash firefox, leaving the screen blank.

The solution was to setup a nightly reboot of the system via cron, and this has kept the system stable since. However, if I was to do this again, I would try an RPI4 with >1GB ram which may obviate the need for a nightly reboot.


Related Links