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

Container Path	DESCRIPTION
/ngrams	Location to store the ngram language models. If container is started as unprivileged user, make sure the host path is owned by the user that starts the container.
/fasttext	Location to store the fasttext model. If container is started as unprivileged user, make sure the host path is owned by the user that starts the container.
/tmp	Location to store the created logback.xml and config.property. Preferably a tmpfs mount.

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).

ENV	DEFAULT	DESCRIPTION
download_ngrams_for_langs	none	Optional: Comma separated list of languages to download ngrams for. Skips download if the ngrams for that language already exist. Valid languages: en, de, es, fr and nl. Example value: en,de
langtool_languageModel	/ngrams	Optional: The base path to the ngrams models.
langtool_fasttextBinary	/usr/local/bin/fasttext	Optional: Path to the fasttext binary. Change only if you want to test your own compiled binary. Don't forget to map it into the container as volume.
langtool_fasttextModel	/fasttext/lid.176.bin	Optional: The container path to the fasttext model binary. If the variable is set, the fasttext model will be downloaded if doesn't exist yet.
langtool_*		Optional: An arbitrary languagetool configuration, consisting of the prefix langtool_ and the key name as written in the config file. Execute docker run -ti --rm meyay/languagetool help to see the list of config options
JAVA_XMS	256m	Optional: Minimum size of the Java heap space. Valid suffixes are m for megabytes and g for gigabytes.
JAVA_XMX	1536m	Optional: Maximum size of the Java heap space. Valid suffixes are m for megabytes and g for gigabytes. Set a higher value if you experience OOM kills, but do not use more than 1/4 of the host memory!
JAVA_GC	SerialGC	Optional: Configure the garbage collector the JVM will use. Valid options are: SerialGC, ParallelGC, ParNewGC, G1GC, ZGC
JAVA_OPTS		Optional: Set you own custom Java options for the JVM. This will render the other JAVA_* options useless.
MAP_UID	783	Optional: UID of the user inside the container that runs LanguageTool. If you encounter permission problems with your volumes, make sure to set the parameter to the UID of the host folder owner.
MAP_GID	783	Optional: GID of the user inside the container that runs LanguageTool. If you encounter permission problems with your volumes, make sure to set the parameter to the GID of the host folder owner.
LOG_LEVEL	INFO	Optional: set log level for LanguageTool. Valid options are: TRACE, DEBUG, INFO, WARN, ERROR.
DISABLE_PERMISSION_FIX	false	Optional: Disables the permission fix, if set to true. Will be used implicitly, if the container is started with an upriviliged user. The Valid options are: true, anything else is treated as false.
DISABLE_FASTTEXT	false	Optional: Disables fasttext, if set to true, neither the model is downloaded, nor fasttext enabled in LanguageTool. The Valid options are: true, anything else is treated as false.
DEBUG_ENTRYPOINT		Optional: Enables debug logs, if set to true. The Valid options are: true, anything else is treated as false.

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

Date	Tag	Change
2024-10-30	6.5-1	- Massive refactoring of Entrypoint script - Update Java to 21.0.5+11
2024-09-29	6.5-0	- Update to LaguageTool 6.5
2024-09-14	6.4-4	- Update base image to Alpine 3.20.3
2024-07-31	6.4-3	- Update base image to Alpine 3.20.2 - Update Java to 21.0.4+7
2024-07-05	6.4-2	- Update base image to Alpine 3.20.1 - Update Java to 21.0.3+9
2024-05-27	6.4-1	- Update base image to Alpine 3.20.0
2024-04-02	6.4-0	- Update to LanguageTool 6.4 - Modified entrypoint script, to require 7x5 permissions instead of 7x7 for ngrams and fasttext volumes anymore.
2024-03-26	6.3a-5	- Update Java to 21.0.2+13 - Add capability CAP_CHOWN to README.md and compose file.
2024-02-26	6.3a-4	- Fix entrypoint script bug that affected new users when downloading the ngram models.
2024-02-17	6.3a-3	- Update base image to Alpine 3.19.1 - Migrate from compiling fasttext to using the Alpine fasttext package.
2024-02-17	6.3a-2	- Modify Dockerfile to create the languagetool user without home directory - Modify entrypoint script to modify uid:gid of languagetool user and group if actually changed.
2024-02-12	6.3a-1	- Update base image to Alpine 3.18.6 - Update Java to 17.0.10+7
2023-12-20	6.3a-0	- Update to LanguageTool 6.3a
2023-12-03	6.3-1	- Update base image to Alpine 3.18.5 - Update Java to 17.0.9+9
2023-10-10	6.3-0	- Update to LanguageTool 6.3 - Update base image to Alpine 3.18.4 - Update Java to 17.0.8.1+1
2023-08-10	6.2-1	- Update base image to Alpine 3.18.3 - Update Java to 17.0.8+7
2023-07-09	6.2-0	- Update to languagetool 6.2
2023-06-30	6.1-4	- Update base image to Alpine 3.18.2
2023-05-19	6.1-3	- Update base image to Alpine 3.18.0 - Update Java to 17.0.7+7
2023-04-01	6.1-2	- Update base image to Alpine 3.17.3.
2023-03-28	6.1-1	- Add logic to set log level
2023-03-28	6.1-0	- Upgrade to languagetool 6.1
2023-02-23	6.0-5	- Update base image to Alpine 3.17.2.
2023-01-23	6.0-4	- Update Java to Eclipse Temurin 17.0.6+10.
2023-01-15	6.0-3	- Update base image to Alpine 3.17.1.
2023-01-01	6.0-2	- Add alpine package gcompat to satisfy ld-linux-x86-64.so.2 dependency. (this fixes the issue of the 6.0-1 image)
2022-12-29 2023-01-01	6.0-1	- Upgrade to languagetool 6.0 - Removed tag due to ClassPath exception.
2022-12-07	5.9-7	- Fix health check command
2022-12-04	5.9-6	- Add help command to display languagetool configuration items to be used with languagetool_*
2022-12-04	5.9-5	- Switch to stripped down Eclipse Temurin 17 JRE - Remove JVM argument -XX:+UseStringDeduplication except for G1GC - Add tini to suppress exit code 143 - Removed curl and switch to wget - Print version info about Alpine and Eclipse Temurin during start
2022-11-29	5.9-4	- Update base image to Alpine 3.17.0
2022-11-24	5.9-3	- Add support to configure garbage collector - Add JVM argument -XX:+UseStringDeduplication - Add support to pass custom JAVA_OPTS - Change Java_Xm? variables to JAVA_XM?
2022-11-12	5.9-2	- Update base image to Alpine 3.16.3
2022-09-28	5.9-1	- Update LanguageTool to 5.9
2022-09-10	5.8-2	- Add user mapping support
2022-09-10	5.8-1	- Initial release with Alpine 3.16.2, LanguageTool 5.8