DMOJ Online Judge - Docker Setup

Docker Compose setup for running the DMOJ competitive programming platform on a local area network.

Services

Service	Description
db	MariaDB 10.5 database
redis	Redis 7 cache and session store
site	Django web application (port 8080)
worker	Celery background task worker
bridged	Judge bridge (ports 9999/9998) -- relays between site and judges
judge	Code execution engine (privileged, sandboxed)
nginx	Reverse proxy (port 80), serves static/media files

Quick Start

# 1. First-time setup (generates secrets, builds, starts everything)
./manage.sh init

# 2. Access the site
# http://<HOST_IP>      (via nginx)
# http://<HOST_IP>:8080 (direct to Django)

Or manually:

# 1. Configure environment
cp .env.example .env
# Edit .env -- set HOST_IP to your server's LAN IP and update passwords/keys

# 2. Build and start
./manage.sh start

# 3. Create admin account
./manage.sh create-admin

Configuration

All configuration lives in .env. Key variables:

Variable	Description
HOST_IP	Your server's LAN IP (e.g. 192.168.0.3). Drives ALLOWED_HOSTS and SITE_URL
MYSQL_ROOT_PASSWORD	MariaDB root password
MYSQL_PASSWORD	MariaDB application password
SECRET_KEY	Django signing key (generate with openssl rand -hex 32)
JUDGE_NAME	Judge identifier (auto-registered at startup)
JUDGE_KEY	Judge authentication key
BRIDGE_API_KEY	Bridge communication key
TIME_ZONE	Server timezone (e.g. America/Argentina/Buenos_Aires)

Judge Setup

The judge is automatically registered at startup using JUDGE_NAME and JUDGE_KEY from .env. No manual registration is needed.

Verify the Judge

# Check judge logs
./manage.sh logs -n 50 judge

# Check bridge logs
./manage.sh logs -n 50 bridged

You should see Judge "juez_paradigmas" online in the judge logs and judge successfully authenticated in the bridge logs. The judge will also appear as online in the admin panel under Judges, with its detected language executors.

Adding a Teacher

./manage.sh add-teacher \
  --username functional_robot \
  --password "myLongAndinoperantPassword123" \
  --email "functional_robot@ibm.com" \
  --first-name "Functional" \
  --last-name "Robot" \
  --organization "Paradigmas"

All options:

Option	Required	Default	Description
--username	yes		Login username
--password	no	auto-generated	Password (printed on creation)
--email	no		Email address
--first-name	no		First name
--last-name	no		Last name
--organization	no		Organization slug to join as admin

Teachers are created as staff users. If --organization is provided, the teacher is added as a member and admin of that organization.

Bulk Import (CSV)

To add many teachers at once, prepare a CSV file:

username,password,email,first_name,last_name,organization
prof_garcia,,garcia@school.edu,Maria,Garcia,Paradigmas
prof_chen,,chen@school.edu,Wei,Chen,Paradigmas

Then run:

./manage.sh load-teachers teachers.csv

Loading Students

Prepare a CSV file with the format:

username,password,email,first_name,last_name,organization
jdoe,,jdoe@school.edu,John,Doe,Paradigmas
asmith,custompass123,asmith@school.edu,Alice,Smith,Paradigmas

Then run:

# Validate first
./manage.sh load-students students.csv --dry-run

# Import for real
./manage.sh load-students students.csv

Loading Problems

Prepare a CSV file with the format:

code,name,description,time_limit,memory_limit,points,group
hello,Hello World,Write a program that prints "Hello World!",1.0,262144,1.0,Basics
sum2,Sum of Two Numbers,Read two integers and print their sum.,2.0,262144,2.0,Basics

Then run:

./manage.sh load-problems problems.csv --dry-run
./manage.sh load-problems problems.csv

After importing problem metadata, upload test cases via Admin > Problems > Edit > Test Data, or copy test data files directly into data/problems/<problem_code>/.

See data/imports/*.example.csv for template files.

manage.sh Reference

Lifecycle:
  start             Build (if needed) and start all services
  stop              Stop all services (data preserved)
  restart [svc]     Restart all services, or a specific one
  rebuild [svc]     Rebuild and restart all or specific service
  status            Show service status and health
  destroy           Stop and remove all volumes (CAUTION: deletes data)

Logs:
  logs [svc]        Follow logs (all services or specific one)
  logs -n N [svc]   Show last N lines

Django:
  create-admin      Create a superuser account interactively
  migrate           Run database migrations
  collectstatic     Collect static files and restart nginx
  shell             Open Django interactive shell
  djcommand <cmd>   Run arbitrary manage.py command

Database:
  backup [file]     Dump database to SQL file (default: backup_YYYYMMDD_HHMMSS.sql)
  restore <file>    Restore database from SQL dump
  dbshell           Open MySQL shell

Setup:
  init              First-time setup: copy .env, generate secrets, build, start
  check             Run Django system checks

Users:
  add-teacher            Create a single teacher account (see options with --help)

Problems:
  create-problem         Create a single problem (see options with --help)

Data Import (REST API):
  load-students <csv>    Import students from CSV via API
  load-teachers <csv>    Import teachers from CSV via API (staff + org admin)
  load-problems <csv>    Import problems from CSV via API
  Append --dry-run to validate without saving

Debug:
  exec <svc> <cmd>  Run a command inside a service container
  health            Show health status of all services

Volumes

• dmoj_database -- MariaDB data (named volume)
• dmoj_redis_data -- Redis persistence (named volume)
• ./data/static/ -- Collected static files
• ./data/media/ -- User uploads
• ./data/problems/ -- Problem test data (shared with judge)
• ./data/log/ -- Application logs

Ports

Port	Service	Purpose
80	nginx	Main entry point (LAN access)
8080	site	Direct Django access (debugging)
9999	bridged	Judge connection port
9998	bridged	Site-to-bridge push updates

Troubleshooting

Port 80 in use: Change nginx port in docker-compose.yml to e.g. "8000:80"

Judge not connecting: Verify JUDGE_KEY in .env matches the key registered in the admin panel. Check logs with ./manage.sh logs judge and ./manage.sh logs bridged.

Static files missing: Run ./manage.sh collectstatic

Changing server IP: Update HOST_IP in .env and restart: ./manage.sh rebuild

References

• DMOJ Documentation
• DMOJ Site Source
• DMOJ Judge Source