replace dockerfile (#1410)

* replaces Dockerfile using bazel-based build system

This commit updates the Dockerfile to work with anki's bazel-based build
system.

The anki Dockerfile was originally added in
https://github.com/ankitects/anki/pull/753 back in September 2020. The
file was moved to `docs/Dockerfile` in
0d354da93a, with a note that the file had
to be updated to work with anki's updated build system. The file
`docs/Dockerfile` was removed in
7cd2e9618f.

* install setuptools and wheel + xkb libraries

* install anki virtual env in fresh base image

* move Dockerfile out of root directory

* add readme file for dockerized anki

docs/docker/Dockerfile

@@ -0,0 +1,67 @@
+# This Dockerfile uses three stages.
+#   1. Compile anki (and dependencies) and build python wheels.
+#   2. Create a virtual environment containing anki and its dependencies.
+#   3. Create a final image that only includes anki's virtual environment and required
+#      system packages.
+
+ARG PYTHON_VERSION="3.9"
+ARG DEBIAN_FRONTEND="noninteractive"
+
+# Build anki.
+FROM python:$PYTHON_VERSION AS build
+RUN curl -fsSL https://github.com/bazelbuild/bazelisk/releases/download/v1.7.4/bazelisk-linux-amd64 \
+    > /usr/local/bin/bazel \
+    && chmod +x /usr/local/bin/bazel \
+    # Bazel expects /usr/bin/python
+    && ln -s /usr/local/bin/python /usr/bin/python
+WORKDIR /opt/anki
+COPY . .
+# Build python wheels.
+RUN ./scripts/build
+
+# Install pre-compiled Anki.
+FROM python:${PYTHON_VERSION}-slim as installer
+WORKDIR /opt/anki/
+COPY --from=build /opt/anki/bazel-dist/ wheels/
+# Use virtual environment.
+RUN python -m venv venv \
+    && ./venv/bin/python -m pip install --no-cache-dir setuptools wheel \
+    && ./venv/bin/python -m pip install --no-cache-dir /opt/anki/wheels/*.whl
+
+# We use another build stage here so we don't include the wheels in the final image.
+FROM python:${PYTHON_VERSION}-slim as final
+COPY --from=installer /opt/anki/venv /opt/anki/venv
+ENV PATH=/opt/anki/venv/bin:$PATH
+# Install run-time dependencies.
+RUN apt-get update \
+    && apt-get install --yes --no-install-recommends \
+        libasound2 \
+        libdbus-1-3 \
+        libfontconfig1 \
+        libfreetype6 \
+        libgl1 \
+        libglib2.0-0 \
+        libnss3 \
+        libxcb-icccm4 \
+        libxcb-image0 \
+        libxcb-keysyms1 \
+        libxcb-randr0 \
+        libxcb-render-util0 \
+        libxcb-shape0 \
+        libxcb-xinerama0 \
+        libxcb-xkb1 \
+        libxcomposite1 \
+        libxcursor1 \
+        libxi6 \
+        libxkbcommon0 \
+        libxkbcommon-x11-0 \
+        libxrandr2 \
+        libxrender1 \
+        libxtst6 \
+    && rm -rf /var/lib/apt/lists/*
+# Add non-root user.
+RUN useradd --create-home anki
+USER anki
+WORKDIR /work
+ENTRYPOINT ["/opt/anki/venv/bin/anki"]
+LABEL maintainer="Jakub Kaczmarzyk <jakub.kaczmarzyk@gmail.com>"

docs/docker/README.md

@@ -0,0 +1,112 @@
+# Anki in Docker
+
+This README contains the instructions for building and running the Anki Docker image.
+
+Docker provides a standard for installing software on many systems
+(Windows, macOS, Linux), and it allows one to build software without cluttering a system
+with dependencies. The Dockerfile contains the instructions for building the Docker image,
+and it also serves as instructions for how to build Anki from source on Linux.
+
+# Build the Docker image
+
+For best results, enable BuildKit (`export DOCKER_BUILDKIT=1`).
+
+When in this current directory, one can build the Docker image like this:
+
+```bash
+docker build --tag anki --file Dockerfile ../../
+```
+
+When this is done, run `docker image ls` to see that the image has been created.
+
+If one wants to build from the project's root directory, use this command:
+
+```bash
+docker build --tag anki --file docs/docker/Dockerfile .
+```
+
+# Run the Docker image
+
+Anki starts a graphical user interface, and this requires some extra setup on the user's
+end. These instructions were tested on Linux (Debian 11) and will have to be adapted for
+other operating systems.
+
+To allow the Docker container to pull up a graphical user interface, we need to run the
+following:
+
+```bash
+xhost +local:root
+```
+
+Once done using Anki, undo this with
+
+```bash
+xhost -local:root
+```
+
+Then, we will construct our `docker run` command:
+
+```bash
+docker run --rm -it \
+    --name anki \
+    --volume $HOME/.local/share:$HOME/.local/share:rw \
+    --volume /etc/passwd:/etc/passwd:ro \
+    --user $(id -u):$(id -g) \
+    --volume /tmp/.X11-unix:/tmp/.X11-unix:rw \
+    --env DISPLAY=$DISPLAY \
+    anki
+```
+
+Here is a breakdown of some of the arguments:
+
+- Mount the current user's `~/.local/share` directory onto the container. Anki saves things
+    into this directory, and if we don't mount it, we will lose any changes once the
+    container exits. We mount this as read-write (`rw`) because we want to make changes here.
+
+    ```bash
+    --volume $HOME/.local/share:$HOME/.local/share:rw
+    ```
+
+- Mount `/etc/passwd` so we can enter the container as ourselves. We mount this as
+    read-only because we definitely do not want to modify this.
+
+    ```bash
+    --volume /etc/passwd:/etc/passwd:ro
+    ```
+
+- Enter the container with our user ID and group ID, so we stay as ourselves.
+
+    ```bash
+    --user $(id -u):$(id -g)
+    ```
+
+- Mount the X11 directory that allows us to open displays.
+
+    ```bash
+    --volume /tmp/.X11-unix:/tmp/.X11-unix:rw
+    ```
+
+- Pass the `DISPLAY` variable to the container, so it knows where to display graphics.
+
+    ```bash
+    --env DISPLAY=$DISPLAY
+    ```
+
+# Running Dockerized Anki easily from the command line
+
+One can create a shell function that executes the `docker run` command. Then one can
+simply run `anki` on the command line, and Anki will open in Docker. Make sure to change
+the image name to whatever you used when building Anki.
+
+```bash
+anki() {
+    docker run --rm -it \
+        --name anki \
+        --volume $HOME/.local/share:$HOME/.local/share:rw \
+        --volume /etc/passwd:/etc/passwd:ro \
+        --user $(id -u):$(id -g) \
+        --volume /tmp/.X11-unix:/tmp/.X11-unix:rw \
+        --env DISPLAY=$DISPLAY \
+        anki "$@"
+}
+```