Docker image for FACT_core

The docker image provides an installation of all fact components (db, frontend, backend). Currently, you have to build it yourself, but we plan to provide a prebuilt image via Dockerhub. For instructions see Usage.

Because FACT uses docker itself, the docker socket from the host will be passed to the container. Please make sure that your user is a member of the docker group.

Usage

For more advanced usage we provide a Python script to cover most usecases. If your usecase is not supported feel free to open a PR or hack it up privately.

Probably the most important command is ./start.py build. After that you might run:

$ mkdir ~/fact_mongo && mkdir ~/fact_data
$ ./start.py run --wt-mongodb-path ~/fact_mongo --fw-data-path ~/fact_data

Use ./start.py --help to get help about the usage of the script.

If you use --config and change anything related to the mongodb database run touch <your fact_wt_mongodb path>/REINITIALIZE_DB (i.e. touch /media/data/fact_wt_mongodb/REINITIALIZE_DB). This will tell the container to (re)initialize the database. If you use the container the first time the script does this automatically for you. Also be aware that the temp_dir_path in main.cfg has to match the path specified by --docker-dir.

Entrypoint

The docker entrypoint accepts three arguments. start to start the container.

pull-containers to pull docker containers needed on the host.

start-branch to checkout a different branch before running FACT.

Distributed setup

If you want to have a distributed setup you have to build the three images. For this you can simply adapt the Dockerfile to install the respective components and change the entrypoint. Then follow the instructions in INSTALL.md for a distributed setup. You should also have a look at start.py to see what arguments docker should be started with.

Workarounds used

If you tinker around with the docker image you might encounter some strange behavior caused by the following workarounds.

Docker in docker

As FACT uses docker heavily, we pass the docker socket to the container.

One use of docker is the unpacker. Docker is started with something along the lines of docker run -v PATH_ON_DOCKER_HOST:HARDCODED_PATH_USED_IN_THE_CONTAINER unpacker.

This means that when FACT runs inside a container it must have access to PATH_ON_DOCKER_HOST. Currently PATH_ON_DOCKER_HOST is always a subdirectory of temp_dir_path and created dynamically (similar to mktemp) or it is a subdirectory of the fw-data-path. Can't know in advance what directories on the host will be needed in the container because of the dynamically created directories. To work around this we simply mount temp_dir_path in the container.