Docker container for Calibre

Warning! This is my first try with docker containers. There might be some serious bugs.
Use at your own risk!

This is a test container with Calibre E-book management software, that is based on jlasege's great docker-baseimage-gui. See Sources

The GUI of the application is accessed through a modern web browser (no installation or configuration needed on client side) or via any VNC client.

Calibre is a powerful and easy to use e-book manager.

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Table of Content

• Docker container for Calibre
  • Table of Content
  • Quick Start
  • Usage
    • Environment Variables
    • Data Volumes
    • Ports
    • Changing Parameters of a Running Container
  • Docker Image Update
    • unRAID
  • User/Group IDs
  • Accessing the GUI
  • Security
    • SSVNC
    • VNC Password
  • Shell Access
  • Sources

Quick Start

If you want to run this container on unRAID, please follow instructions for installation using template here.

NOTE: The Docker command provided in this quick start is given as an example and parameters should be adjusted to your need.

Launch the Calibre-gui container with the following command:

docker run -d \
    --name=calibre-gui \
    -p 5800:5800 \
    -p 8081:8081\
    -v /mnt/cache/appdata/calibre-gui:/config:rw \
    -v $HOME/Library:/storage:rw \
    -v $HOME/Downloads:/import:r \
    jiris97/calibre-gui

Where:

• /mnt/cache/appdata/calibre-gui: This is where the application stores its configuration, log and any files needing persistency.
• $HOME: This location contains your e-books library.

Browse to http://your-host-ip:5800 to access the Calibre GUI. Files from the host appear under the /storage folder in the container.

Usage

docker run [-d] \
    --name=calibre-gui \
    [-e <VARIABLE_NAME>=<VALUE>]... \
    [-v <HOST_DIR>:<CONTAINER_DIR>[:PERMISSIONS]]... \
    [-p <HOST_PORT>:<CONTAINER_PORT>]... \
    jiris97/calibre-gui

Parameter	Description
-d	Run the container in background. If not set, the container runs in foreground.
-e	Pass an environment variable to the container. See the Environment Variables section for more details.
-v	Set a volume mapping (allows to share a folder/file between the host and the container). See the Data Volumes section for more details.
-p	Set a network port mapping (exposes an internal container port to the host). See the Ports section for more details.

Environment Variables

To customize some properties of the container, the following environment variables can be passed via the -e parameter (one for each variable). Value of this parameter has the format <VARIABLE_NAME>=<VALUE>.

Variable	Description	Default
USER_ID	ID of the user the application runs as. See User/Group IDs to better understand when this should be set.	1000
GROUP_ID	ID of the group the application runs as. See User/Group IDs to better understand when this should be set.	1000
SUP_GROUP_IDS	Comma-separated list of supplementary group IDs of the application.	(unset)
UMASK	Mask that controls how file permissions are set for newly created files. The value of the mask is in octal notation. By default, this variable is not set and the default umask of 022 is used, meaning that newly created files are readable by everyone, but only writable by the owner. See the following online umask calculator: http://wintelguy.com/umask-calc.pl	(unset)
TZ	[TimeZone] of the container. Timezone can also be set by mapping /etc/localtime between the host and the container.	Etc/UTC
KEEP_APP_RUNNING	When set to 1, the application will be automatically restarted if it crashes or if user quits it.	0
APP_NICENESS	Priority at which the application should run. A niceness value of -20 is the highest priority and 19 is the lowest priority. By default, niceness is not set, meaning that the default niceness of 0 is used. NOTE: A negative niceness (priority increase) requires additional permissions. In this case, the container should be run with the docker option --cap-add=SYS_NICE.	(unset)
CLEAN_TMP_DIR	When set to 1, all files in the /tmp directory are delete during the container startup.	1
DISPLAY_WIDTH	Width (in pixels) of the application's window.	1280
DISPLAY_HEIGHT	Height (in pixels) of the application's window.	768
SECURE_CONNECTION	When set to 1, an encrypted connection is used to access the application's GUI (either via web browser or VNC client). See the Security section for more details.	0
VNC_PASSWORD	Password needed to connect to the application's GUI. See the VNC Password section for more details.	(unset)
X11VNC_EXTRA_OPTS	Extra options to pass to the x11vnc server running in the Docker container. WARNING: For advanced users. Do not use unless you know what you are doing.	(unset)
UPDATE	When set to 1, it forces Calibre to update itself.	0

Data Volumes

The following table describes data volumes used by the container. The mappings are set via the -v parameter. Each mapping is specified with the following format: <HOST_DIR>:<CONTAINER_DIR>[:PERMISSIONS].

Container path	Permissions	Description
/config	rw	This is where the application stores its configuration, log and any files needing persistency.
/storage	rw	This location contains your e-books library.
/import	r	This location is for importing e-book into the library.

Ports

Here is the list of ports used by the container. They can be mapped to the host via the -p parameter (one per port mapping). Each mapping is defined in the following format: <HOST_PORT>:<CONTAINER_PORT>. The port number inside the container cannot be changed, but you are free to use any port on the host side.

Port	Mapping to host	Description
5800	Mandatory	Port used to access the application's GUI via the web interface.
8081	Optional	Port used to access the application's Content server
5900	Optional	Port used to access the application's GUI via the VNC protocol. Optional if no VNC client is used.

Changing Parameters of a Running Container

As seen, environment variables, volume mappings and port mappings are specified while creating the container.

The following steps describe the method used to add, remove or update parameter(s) of an existing container. The generic idea is to destroy and re-create the container:

1. Stop the container (if it is running):

docker stop calibre-gui

2. Remove the container:

docker rm calibre-gui

3. Create/start the container using the docker run command, by adjusting parameters as needed.

Docker Image Update

If the system on which the container runs doesn't provide a way to easily update the Docker image, the following steps can be followed:

1. Fetch the latest image:

docker pull jiris97/calibre-gui

2. Stop the container:

docker stop jiris97/calibre-gui

3. Remove the container:

docker rm jiris97/calibre-gui

4. Start the container using the docker run command.

unRAID

For unRAID, a container image can be updated by following these steps:

1. Select the Docker tab.
2. Click the Check for Updates button at the bottom of the page.
3. Click the update ready link of the container to be updated.

User/Group IDs

When using data volumes (-v flags), permissions issues can occur between the host and the container. For example, the user within the container may not exists on the host. This could prevent the host from properly accessing files and folders on the shared volume.

To avoid any problem, you can specify the user the application should run as.

This is done by passing the user ID and group ID to the container via the USER_ID and GROUP_ID environment variables.

To find the right IDs to use, issue the following command on the host, with the user owning the data volume on the host:

id <username>

Which gives an output like this one:

uid=1000(myuser) gid=1000(myuser) groups=1000(myuser),4(adm),24(cdrom),27(sudo),46(plugdev),113(lpadmin)

The value of uid (user ID) and gid (group ID) are the ones that you should be given the container.

Accessing the GUI

Assuming that container's ports are mapped to the same host's ports, the graphical interface of the application can be accessed via:

• A web browser:

http://<HOST IP ADDR>:5800

• Any VNC client:

<HOST IP ADDR>:5900

Security

By default, access to the application's GUI is done over an unencrypted connection (HTTP or VNC).

Secure connection can be enabled via the SECURE_CONNECTION environment variable. See the Environment Variables section for more details on how to set an environment variable.

When enabled, application's GUI is performed over an HTTPs connection when accessed with a browser. All HTTP accesses are automatically redirected to HTTPs.

When using a VNC client, the VNC connection is performed over SSL. Note that few VNC clients support this method. SSVNC is one of them.

SSVNC

SSVNC is a VNC viewer that adds encryption security to VNC connections.

While the Linux version of SSVNC works well, the Windows version has some issues. At the time of writing, the latest version 1.0.30 is not functional, as a connection fails with the following error:

ReadExact: Socket error while reading

However, for your convienence, an unoffical and working version is provided here:

https://github.com/jlesage/docker-baseimage-gui/raw/master/tools/ssvnc_windows_only-1.0.30-r1.zip

The only difference with the offical package is that the bundled version of stunnel has been upgraded to version 5.49, which fixes the connection problems.

VNC Password

To restrict access to your application, a password can be specified. This can be done via two methods:

• By using the VNC_PASSWORD environment variable.
• By creating a .vncpass_clear file at the root of the /config volume. This file should contains the password in clear-text. During the container startup, content of the file is obfuscated and moved to .vncpass.

The level of security provided by the VNC password depends on two things:

• The type of communication channel (encrypted/unencrypted).
• How secure access to the host is.

When using a VNC password, it is highly desirable to enable the secure connection to prevent sending the password in clear over an unencrypted channel.

ATTENTION: Password is limited to 8 characters. This limitation comes from the Remote Framebuffer Protocol RFC (see section 7.2.2). Any characters beyhond the limit are ignored.

Shell Access

To get shell access to a the running container, execute the following command:

docker exec -ti CONTAINER sh

Where CONTAINER is the ID or the name of the container used during its creation (e.g. crashplan-pro).

Sources

The base of this image is jlesage's repository docker-baseimage-gui. Most of the content in this readme is also inspired by his work. Thanks for sharing a template to dockerize GUI apps!