Awesome

LanguageTool

LanguageTool is an Open Source proofreading software for English, French, German, Polish, Russian, and more than 20 other languages. It finds many errors that a simple spell checker cannot detect.

The source repository can be found here.

About this image:

• Uses official release zip
• Uses the latest Alpine 3.20 base image
• Uses custom Eclipse Temurin 21 JRE limited to modules required by the current LanguageTool release
• includes fasttext
• includes su-exec
  • container starts as root and executes languagetool as restricted user using exec su-exec
  • container fixes folder ownership for ngrams and fasttext folders
• Entrypoint uses tini to suppress the container exiting with status code 143 (LanguageTool does not handle SIGTERM as it should)
• optional: downloads ngram language modules if configured (if they don't already exist)
• optional: downloads fasttext module (if it doesn't already exist)
• optional: support user mapping (make sure to check MAP_UID and MAP_GID below) is started as root user (default).
• optional: can be started as unprivileged user instead of root user
• optional: set log level
• optional: works with read-only filesystem

Setup

Docker CLI Usage

Start container as root user with read-only filesystem, start LanguageTool as MAP_UID:MAP_GID

docker run -d \
  --name languagetool \
  --restart unless-stopped \
  --cap-drop ALL \
  --cap-add CAP_SETUID \
  --cap-add CAP_SETGID \
  --cap-add CAP_CHOWN \
  --security-opt no-new-privileges \
  --publish 8010:8010 \
  --env download_ngrams_for_langs=en \
  --read-only \
  --tmpfs /tmp \
  --volume $PWD/ngrams:/ngrams \
  --volume $PWD/fasttext:/fasttext \
  meyay/languagetool:latest

Start container as unpriveleged user with read-only filesystem

docker run -d \
  --name languagetool \
  --restart unless-stopped \
  --cap-drop ALL \
  --security-opt no-new-privileges \
  --publish 8010:8010 \
  --env download_ngrams_for_langs=en \
  --user 1000:1000 \
  --read-only \
  --tmpfs /tmp \
  --volume $PWD/ngrams:/ngrams \
  --volume $PWD/fasttext:/fasttext \
  meyay/languagetool:latest

Note: the container will not fix ownership and permissions, so make sure the directories bound as volume exist and are owned by the user!

Docker Compose Usage

Start container as root user with read-only filesystem, start LanguageTool as MAP_UID:MAP_GID

---
services:
  languagetool:
    image: meyay/languagetool:latest
    container_name: languagetool
    restart: always
    read_only: true
    tmpfs:
      - /tmp
    cap_drop:
      - ALL
    cap_add:
      - CAP_SETUID
      - CAP_SETGID
      - CAP_CHOWN
    security_opt:
      - no-new-privileges
    ports:
      - 8010:8010
    environment:
      download_ngrams_for_langs: en
    volumes:
      - ./ngrams:/ngrams
      - ./fasttext:/fasttext

An example compose file can be downloaded from here.

Start container as unpriveleged user with read-only filesystem

---
services:
  languagetool:
    image: meyay/languagetool:latest
    container_name: languagetool
    restart: unless-stopped
    user: "783:783"
    read_only: true
    tmpfs:
      - /tmp
    cap_drop:
      - ALL
    security_opt:
      - no-new-privileges
    ports:
      - 8010:8010
    environment:
      download_ngrams_for_langs: en
    volumes:
      - ./ngrams:/ngrams
      - ./fasttext:/fasttext

Usage

You need to install and use one of the add-ons from https://languagetool.org/services and configure it to use the self-hosted LanguageTool server http://{ip-of-your-docker-host}:{published host port}/v2. The self-hosted LanguageTool server does not come with its own UI!

Note: some add-ons require https connections, which is not (and will not be) supported by this image. You will need to put a reverse proxy in front of it to take care of the TLS termination.

Capabilities

If the container is started as unpriviliged user, the capabilites CAP_SETUID, CAP_SETGID, and CAP_CHOWN are not required, and can be omitted. If the container is started as privliged user (default), and the environment variable DISABLE_PERMISSION_FIX is set to true, the capability CAP_CHOWN is not required and can be omitted

Volumes

Parameters

The environment parameters are split into two halves, separated by an equal, the left-hand side represents the variable names (use them as is) the right-hand side the value (change if necessary).

Fasttext support

Now that fasttext is available since Alpine 3.19, the image switched to using the Alpine package, instead of compiling the binaries from the sources. This hopefully fixes the compatibility issue users with older cpus experienced with my previous images, that were build on a amd64v3 architecture cpu, which compiled the fasttext binary with cpu optimizations older cpus do not support.

If the Alpine fasttext package does not work for you, you can build a custom image to compile the fasttext binary using cpu optimizations your cpu (as long as it's x86_64 based) actually understands:

git clone  https://github.com/meyayl/docker-languagetool.git
cd docker-languagetool
sudo docker build -t meyay/languagetool:latest -f Dockerfile.fasttext .

Once the image is build, you can docker compose up -d like you would do with the images hosted on Docker Hub.

NOTE1: Alpine version 3.19+ comes with gcc13, and does not provide older versions which are required to compile the fasttext sources. As a result Alpine 3.18.8 is used to compile fasttext with gcc12.

NOTE2: Synology users can find a git package in the SynoCommunity repository.

Changelog