web-gui-base

A docker base image for running desktop (graphical) applications as a website.

Quick try

Using this image as a standalone image would serve no purpose but gives you some eyes :-) You can try it out:

docker run -d --name eyes -p 8080:32000 ivonet/web-gui-base

and goto http://localhost:8080 to test it out.

USERNAME: guest
PASSWORD: secret

Usage

So for serious usage of this image you should create your own image based on this one to add the desktop application of your choice.

• Create a directory structure like this:

root
├── etc
│   ├── cont-init.d
│   │   ├── 100-init.sh
│   │   ├── 110-user-config.sh
│   │   └── 199-cleanup.sh
│   └── services.d
│       ├── your_service_here
│       │   └── run
│       └── another_service_here
│           └── run
└── startapp.sh

In the cont-init.d folder you can create scripts that will be executed during startup before the service.d services are started. start numbering from 100 onwards to 999 to make sure of the ordering as they will be executed in order. the numbers below 100 are for the base image.

Every service you want to start after the cont-init.d gets its own folder in the services.d folder and a run bash script

the shebang should be #!/usr/bin/with-contenv bash for all bash scripts if you want to enable variables between scripts (cont-init.d and services.d)

If you want to know more about this read this s6-overlay

• Create your own Dockerfile

FROM ivonet/web-gui-base:latest

COPY root/ /
# do your stuff here to add and configure your desktop application

create a startapp.sh script in your project/root looking something like this:

#!/usr/bin/env bash
# to make sure the application restarts when closed in the browser
while true;
do
  # Your startup command(s) should come here
  /usr/bin/xeyes
done

build your image and you should be gearing to go...

Configurable environment variables

Default variables

These variables should be defined by yourself at startup or in your Dockerfile during the build to make the application look good and give yourself some control over the working.

Variable name	Description	Default
APPNAME	the name of the guacamole connection	DESKTOP_APPLICATION of you have your own image but did not define a name and eyes if you are just testing the base image
GUACAMOLE_ADMIN_USERNAME	the guacamole admin username if you log in with this user you can configure everything	guacadmin
GUACAMOLE_ADMIN_PASSWORD	the guacamole admin passoword	guacadmin
GUACAMOLE_USER_NAME	a guacamole limited user with only access to the defined application	guest
GUACAMOLE_USER_PASSWORD	the password for the limited user	secret
PULSE_SERVER	the server to connect to if you want sound	see section below about Using audio

Advanced variables

Most of the time these variables do not need to be changed often unless you want to :-)

Variable name	Description	Default
WIDTH	the width of the screen displayed in the browser	1920
HEIGHT	the height of the screen displayed in the browser	1080
VNC_DEPTH	specify the pixel depth in bits of the vnc desktop to be created. Options are 8, 15, 16 and 24. doc	24
VNC_DPI	the dots per inc for the vnc desktop	96
USER_ID	the userid for the nobody user	99
GROUP_ID	the groupid for the nobody user	100
DISPLAY	the display number used by openbox. This value probably does not need to be changed ever unless you get the following error message during startup Openbox-Message: Failed to open the display from the DISPLAY environment variable. then you might want to change it to :0 or some such	:1
SERVER_PORT	the port on which tomcat (guacamole-client) will run. Note that if you overrule this you also overrule the exposed internal port.	32000

Using audio

If you have a desktop app with sound and you want to be able to hear it outside of your docker container you need something special like pulseaudio. The base image already has this available but you need to make it available to the host machine by adding the following to your startup command:

-e PULSE_SERVER=docker.for.mac.localhost  -v ~/.config/pulse:/nobody/.config/pulse

Note: only tested on macOs Oh and on the mac you need to install a Pulseaudio server and start it.

Install pulseaudio:

brew install pulseaudio

Start pulseaudio server:

pulseaudio --load=module-native-protocol-tcp --exit-idle-time=-1 --daemon 2>/dev/null

After these steps you should be able to hear sound created inside the docker image on your host machine.

Stop pulseaudio server on host:

pulseaudio --kill 2>/dev/null
killall pulseaudio 2>/dev/null

Sample commands

The following commands are only here to give you an idea on how it all might work but all of these will only show you the eyes as you should use this image as a base not as the main thing

Start in deamon mode with minimal options:

docker run -d                         \
  --name gui                          \
  -p 32000:32000                      \
  ivonet/web-gui-base

Start in interactive mode with lots of options:

docker run                            \
  -it                                 \
  --rm                                \
  --name gui                          \
  -p 32000:32000                      \
  -e WIDTH=3440                       \
  -e HEIGHT=1440                      \
  -e APPNAME=eyes                     \
  -e GUACAMOLE_ADMIN_USERNAME=admin   \
  -e GUACAMOLE_ADMIN_PASSWORD=secret  \
  -e GUACAMOLE_USER_NAME=user         \
  -e GUACAMOLE_USER_PASSWORD=secret   \
  -e VNC_DEPTH=24                     \
  ivonet/web-gui-base

Release Notes

v1.4

• removed audio config as many desktop applications don't need it and it is easy to add later

v1.3

• leaving gnupg and dirmng as dependencies as I need them often (removed from cleanup)
• Fix a security warning for VNC
• added dbus-x11
• Clean and reinstall alsa-base / pulseaudio (workaround - test in prod...)
• make nobody files owned by nobody :-)

v1.2

• made the tomcat server port configurable as it ran by default on a wel known port
• changed default server port to 32000
• small documentation changes
• added these release notes

v1.1

• made the default colour depth 24
• pulse audio fixes
• audio documentation
• added demo dockerfile

v1.0

• First working version