Docker

Building the container

In the base PrairieLearn directory run:

docker build -t prairielearn .

Running the container

See the installation page.

docker run primer

Here's what the various parts of the docker run commands mean.

The basic format is docker run [OPTIONS] IMAGE [COMMAND], with the parts in brackets being optional.

Options

  • -it means "run this container interactively."
  • --rm means "delete this container when I'm done with it." Unless you have a reason to keep a container, you should always use this flag.
  • -p 3000:3000 means "forward port 3000 on the host to port 3000 in the container."
  • -v /path/to/course:/course means "mount /path/to/course on the host as /course in the container."
  • --name pl gives the container a human-friendly name.

Useful commands

In all of these commands, IMAGE refers to a docker image; if you built the image manually (with docker build), then you should use prairielearn. If you downloaded it (following the installation guide), use prairielearn/prairielearn.

Most of these should be run from the root of your course directory.

  • List running containers:
docker ps
  • Run a specific command in the container:
docker run -it --rm -p 3000:3000 -v /path/to/course:/course IMAGE COMMAND

E.g.,

docker run -it --rm -p 3000:3000 -v /path/to/course:/course IMAGE ls -lah /course
  • Start an interactive shell session:
docker run -it --rm -p 3000:3000 -v /path/to/course:/course IMAGE /bin/bash
  • Run a command in an existing container:
docker exec -it CONTAINER_NAME COMMAND

E.g., to start a shell in a container started with --name pl:

docker exec -it pl /bin/bash

Docker-Compose

This section describes common applications for Docker Compose with PrairieLearn. See the official Docker Compose documentation for more.

Basics

A docker-compose file describes the services an application needs to run. In our case, we use docker-compose to configure and run the PrairieLearn docker container locally.

To run PrairieLearn with docker-compose, run docker-compose up pl. This will, in order:

  • Build the PL docker image, and tag it as prairielearn/prairielearn:local
  • Mount ./testCourse as a volume for a test course
  • Set up the container to run external grading jobs
  • Mount the current directory as /PrairieLearn and enable nodemon, so the container live reloads

The server will be available on port 3000.

The equivalent docker run command to perform all these actions would be:

docker build -t prairielearn/prairielearn:local .
docker run -it --rm \
      -p 3000:3000 \
      - ./testCourse:/course \
      -v ${HOME}/pl_ag_jobs:/jobs -e HOST_JOBS_DIR=${HOME}/pl_ag_jobs \
      -v .:/PrairieLearn -e NODEMON=true \
      -v /var/run/docker.sock:/var/run/docker.sock
      prairielearn/prairielearn

Useful Commands

Usually, you will not have to rebuild the base image. If you do, then you can either run docker-compose build pl or docker-compose up --build pl (the later will rebuild the image, and then start the container).

To remove all containers and clean up compose artifacts, run docker-compose down.

Most docker commands map directly to docker-compose commands. You can use docker-compose run pl ... to run the container as if you were typing docker run ..., or docker-compose exec pl ... to execute a command on the running container.

Multiple Compose Files

If you're developing locally, and want to override parts of the config, you can create your own compose file (perhaps docker-compose.local.yml). Then, if you type:

docker-compose -f docker-compose.yml -f docker-compose.local.yml ...

compose will use values from docker-compose.local.yml to override those from docker-compose.yml.

If a file docker-compose.override.yml exists, Docker Compose will override all configurations with that file, even if it isn't specified in the invoking command.

Docker Hub

Docker Hub automatically (re)builds the prairielearn/prairielearn image whenever a commit is pushed to master.

If you need to publish a local build, here's how:

Pushing to Docker Hub

List images:

docker images

Tag the correct one by ID:

docker tag 7d9495d03763 prairielearn/prairielearn:latest

Login to Docker Hub:

docker login

Push the image:

docker push prairielearn/prairielearn

Checking a push was successful

Delete all local versions:

docker rmi -f 7d9495d03763

Pull and run the new version:

docker run -it -p 3000:3000 -v ~/git/pl-tam212:/course prairielearn/prairielearn