This is a Taiwanese online judge made into an Docker Image, which would then be able to use with Docker or Podman etc.

Built image is available on GitHub Container Repository and Docker Hub

IMPORTANT: However, setup is REQUIRED before first run, please do follow the instructions below.

中文說明尚未完成 (Chinese Version of this readme is still in the works)

1. Download the lxc container from my Google Drive here. To use the command line to download, use the below commands.

fileid="1UVMDmFYb12o8kzIQDFSzO6etXNUWSsHZ"
filename="lxc-ALL.tar.gz"
curl -c ./cookie -s -L "https://drive.google.com/uc?export=download&id=${fileid}" > /dev/null
curl -Lb ./cookie "https://drive.google.com/uc?export=download&confirm=`awk '/download/ {print $NF}' ./cookie`&id=${fileid}" -o ${filename}

• Optional: If you aren't comfortable downloading it from my drive and prefer to download from the orignal author himself, go to his repository and click on the link 請先下載 ZeroJudge虛擬機 then extract the /var/lib/lxc/lxc-ALL/ folder within the virtual machine.

2. Install lxc and git on your system.
   • Ubuntu/Debian: sudo apt-get update && sudo apt-get install lxc git
   • CentOS: sudo yum -y install epel-release && yum -y install lxc git

• If you don’t have docker yet, follow the offical instructions: Ubuntu, Debian, Fedora, CentOS
• If your LXC version is older than 2.1, likely for CentOS like users, you might need to change some new configuration keys to legacy ones. You could verify this by running lxc-attach --version. If you discover the need of switching, check out this table here to change the keys from the new one to the old ones.

3. Extract the archive from step 1 to /var/lib/lxc/. Then start the lxc service, also set the service to start on boot.

sudo tar -zxf lxc-ALL.tar.gz -C /var/lib/lxc/
sudo systemctl start lxc
sudo systemctl enable lxc

4. Create folders for persistent storage and configuration file. Clone this repository and place the ZeroJudge_CONSOLE folder and configs/ServerConfig.xml file to /container-zerojudge-data/disk/ZeroJudge_CONSOLE and /container-zerojudge-data/configs/ServerConfig.xml respectively. And then remove the git folder if you wish.

sudo mkdir /container-zerojudge-data
sudo mkdir /container-zerojudge-data/configs
sudo mkdir /container-zerojudge-data/disk
sudo mkdir /container-zerojudge-data/ssh
git clone https://github.com/superjeng1/ZeroJudge.git
sudo mv ZeroJudge/ZeroJudge_CONSOLE /container-zerojudge-data/disk/
sudo mv ZeroJudge/configs/ServerConfig.xml /container-zerojudge-data/configs/
rm -fr ZeroJudge

• Note: The directory doesn't have to be this, but make sure to use the same directory for the below steps.
• Note: The ZeroJudge_CONSOLE folder is for storing test-data for the challenges hosted on your site.
• Note: The config file is for the judge itself, not the web interface.

5. Create an user, Generate an SSH keypair, Mark the key authorised, Allow the user to use sudo for lxc-attach in the host for the container to SSH to the host and control the lxc container on the host.

sudo useradd -r -s /bin/bash -m zerojudge
sudo ssh-keygen -f /container-zerojudge-data/ssh/id_rsa -t ecdsa -b 521 -q -N ""
sudo -u zerojudge mkdir /home/zerojudge/.ssh
sudo cat /container-zerojudge-data/ssh/id_rsa.pub | sudo -u zerojudge tee -a /home/zerojudge/.ssh/authorized_keys
echo "zerojudge ALL=(root) NOPASSWD: $(which lxc-attach)" | sudo tee -a /etc/sudoers

6. Make sure the folders have the correct permissions respectively.

sudo chown -R 1000:1000 /container-zerojudge-data
sudo chmod -R 700 /container-zerojudge-data/ssh
sudo chmod -R 770 /container-zerojudge-data/disk
sudo chmod -R 770 /container-zerojudge-data/configs

7. Get the MySQL dumps from the author's repo this and this. And modify the second file:

   • Line 3: Remove DEFAULT '' at near the end of the line
   • Line 4: Remove this line entirely.

8. Create MySQL database and user then import the dumps.

mysql -u root -p
<Enter Password>
CREATE DATABASE zerojudge;
CREATE USER 'zerojudge'@'%' IDENTIFIED WITH mysql_native_password BY '<Your Password of choice>';
FLUSH PRIVILEGES;
exit;
mysql -u root -p zerojudge < Schema_V3.0.sql
<Enter Password>
mysql -u root -p zerojudge < SchemaUpdate_V3.0.sql
<Enter Password>
mysql -u root -p
<Enter Password>
GRANT ALL ON zerojudge.* TO 'zerojudge'@'%';
FLUSH PRIVILEGES;
exit;

• Note: You will likely change the above command. For example, you might want to specify the host of the user, or change the username and database name. Or you might want to use a container for MySQL. It doesn't mean you have to, but it's recommended.

9. Pull the docker image and mount some volumes from the host for persistent storage and the configuration file:

sudo docker network create --subnet=<Subnet> <Network-Name>
sudo docker pull ghcr.io/superjeng1/zerojudge:latest
sudo docker run --name zerojudge \
  -v /container-zerojudge-data:/etc/zerojudge \
  -v /var/lib/lxc/lxc-ALL/:/var/lib/lxc/lxc-ALL/ \
  -e MY_SQL_PASSWORD='<MySql Password>' \
  -e SSH_USER='zerojudge' \
  --net <Network-Name> --ip <IP> \
  -p 80:8080 \
  -d ghcr.io/superjeng1/zerojudge:latest

• Note: Image is also available on Docker Hub, just replace GitHub Container Repository (ghcr.io) with docker.io to use that.
• Note: Look down below to find more image variations and environment variables.
• Note: Make sure to put yourown MySql Settings in the quotes ''. And make sure you don't leave the brackets <> in-place.
• Note: Make sure to put yourown local IP subnet (Ex: 172.18.0.0/16), subnet name (Ex: mynet), and IP within the subnet defined previously (Ex: 172.18.0.2, Don't use 172.18.0.1 in this case, the first IP is for the host) for docker And make sure you don't leave the brackets <> in-place.
• For REVERSE PROXY USERS: Add the environment varible REVERSE_PROXY_IP with -e REVERSE_PROXY_IP='<REVERSE_PROXY_IP>' to make sure tomcat grabs the correct client IP. Also remove the port binding (-p 80:8080) in the docker run command above.

10. Connect to your ZeroJudge with the container's IP. You will need to login with the default credentials listed below and change the server port in 裁判機設定 here http://<Your IP>/EditAppConfig. Change http://127.0.0.1/ZeroJudge_Server/ to http://127.0.0.1:8080/ZeroJudge_Server/. Then go to the Problems tab, navigate to the first and only problem, and click the Solve It! button, then copy and paste the example codes from http://<Your IP>/UserGuide.jsp#Samplecode and see if it's working.

Account: zero
Password: !@#$zerojudge

• Note: If you need to login from external network before setup, run the following command.

mysql -u root -p
<Enter Password>
USE zerojudge;
UPDATE appconfigs set manager_ip = '[0.0.0.0/0]';
UPDATE appconfigs set allowedIP = '[0.0.0.0/0]';

This is an image based on debian slim, and this should be kept stable every version. Just make sure you do docker pull before docker run to ensure docker pulls the newest avalible image.

This is an image based on alpine linux. This should be a way smaller image than latest since the base image size is way smaller (Alpine linux image comes in only 5 MB!). And like zerojudge:latest this should be kept stable every version. Just make sure you do docker pull before docker run to ensure docker pulls the newest avalible image.

This is built directly from the main branch. It should be stable most of the times.

Same as above, but uses Alpine Linux as base image.

Use the tagged releases on GitHub. Should all be reasonably stable.

Same as above, but uses Alpine Linux as base image.

This variable is mandatory and specifies the password that will be used to connect to the MySQL instance.

This variable tells tomcat where the MySQL instance is hosted. If not set, this defaults to the host's IP relative to the container.

This variable tells tomcat which port the MySQL instance is hosted. If not set, this defaults to 3306.

This variable tells tomcat what the MySQL database name is. If not set, this defaults to zerojudge.

This variable specifies the username that will be used to connect to the MySQL instance. If not set, this defaults to zerojudge.

This variable specifies the username that will be used to ssh to the host. If not set, this defaults to root. And you should consider adding a system account and add the user to sudoers. Also only allow it to use the command lxc-attach. (This will be included in the tutorial later.)

This variable specifies the host's IP relative to the container. If not set, the container will detect this for itself.

This variable specifies the IP of reverse proxy relative to the container, and has no defaults.

Logfiles in containers aren't all that useful, and no logfiles can keep the container small, so this defaults to FALSE. With this option FALSE, the logs folder will be symblinked to /dev/null achieving no logfiles.

This variable tells tomcat whether to use SSL. If you use reverse proxy, you might not need this. This defaults to FALSE.

If you have any questions or you encountered any problem when setting this up, feel free to open up an issue and I will make sure I would take a look at it.