JOTA: JBNU Online Teaching Assistant (Judge)

JOTA는 전북대 컴퓨터공학부에서 프로그래밍 과제 제출 및 자동 채점을 위해 만들어진 서비스입니다. 오픈소스인 아래 DMOJ 프로젝트를 기반으로 구축하였고 필요한 기능, 오류 수정 등을 학부 학생들이 직접 진행하고 있습니다. 특히 3학년 2학기 오픈소스SW개발 수업에서 프로젝트로 진행합니다.

Contact: [email protected] (박현찬 교수님)

Repositories

JOTA는 DMOJ와 마찬가지로 Site, Judge Server 두 개의 파트로 분리되어 각각 다른 프로젝트로 관리합니다.

• Site: https://github.com/hyunchan-park/JOTA-dmoj-online-judge
• Judge: https://github.com/hyunchan-park/JOTA-dmoj-judge-server

Documents

General

1. JCloud 인스턴스 생성 및 설정하기
2. JOTA Site 설정하기
3. JOTA Judge 설정하기
4. 문제 등록하기

Appendix

• dmoj release 버전으로 JOTA 구축하기 (Not Forked Version, Cannot PR)

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DMOJ Judge

Python AGPLv3 contest judge backend for the DMOJ site interface. See it in action at dmoj.ca!

A modern online judge and contest platform system, supporting IO-based, interactive, and signature-graded tasks, with runtime data generators and custom output validators.

Supported Platforms and Runtimes

The judge implements secure grading on Linux and FreeBSD machines.

	Linux	FreeBSD
x64	✔	✔
x86	✔	¯\_(ツ)_/¯
x32	✔	—
ARM	✔	❌

Versions up to and including v1.4.0 also supported grading on Windows machines.

The DMOJ judge does not need a root user to run on Linux machines: it will run just fine under a normal user.

Supported languages include:

• C++ 11/14/17/20 (GCC and Clang)
• C 99/11
• Java 8/9/10/11/15
• Python 2/3
• PyPy 2/3
• Pascal
• Perl
• Mono C#/F#/VB

The judge can also grade in the languages listed below. These languages are less tested and more likely to be buggy.

• Ada
• AWK
• COBOL
• D
• Dart
• Fortran
• Forth
• Go
• Groovy
• Haskell
• INTERCAL
• Kotlin
• Lua
• NASM
• Objective-C
• OCaml
• PHP
• Pike
• Prolog
• Racket
• Ruby
• Rust
• Scala
• Chicken Scheme
• sed
• Steel Bank Common Lisp
• Swift
• Tcl
• Turing
• V8 JavaScript
• Brain****
• Zig

Installation

Installing the DMOJ judge creates two executables in your Python's script directory: dmoj and dmoj-cli. dmoj is used to connect a judge to a DMOJ site instance, while dmoj-cli provides a command-line interface to a local judge, useful for testing problems.

For more detailed steps, read the installation instructions.

Note that the only officially-supported Linux distribution is the latest Debian, with the default apt versions of all runtimes. This is what we run on dmoj.ca, and it should "just work". While the judge will likely still work with other distributions and runtime versions, some runtimes might fail to initialize. In these cases, please file an issue.

Stable Build

We periodically publish builds on PyPI. This is the easiest way to get started, but may not contain all the latest features and improvements.

$ pip install dmoj

Bleeding-Edge Build

This is the version of the codebase we run live on dmoj.ca.

$ git clone --recursive https://github.com/DMOJ/judge-server.git
$ cd judge-server
$ pip install -e .

Several environment variables can be specified to control the compilation of the sandbox:

• DMOJ_USE_SECCOMP; set it to no if you're building on a pre-Linux 3.5 kernel to disable seccomp filtering in favour of pure ptrace (slower). This flag has no effect when building outside of Linux.
• DMOJ_TARGET_ARCH; use it to override the default architecture specified for compiling the sandbox (via -march). Usually this is native, but will not be specified on ARM unless DMOJ_TARGET_ARCH is set (a generic, slow build will be compiled instead).

With Docker

We maintain Docker images with all runtimes we support in the runtimes-docker project.

Runtimes are split into three tiers of decreasing support. Tier 1 includes Python 2/3, C/C++ (GCC only), Java 8, and Pascal. Tier 3 contains all the runtimes we run on dmoj.ca. Tier 2 contains some in-between mix; read the Dockerfile for each tier for details. These images are rebuilt and tested every week to contain the latest runtime versions.

The script below spawns a tier 1 judge image. It expects the relevant environment variables to be set, the network device to be enp1s0, problems to be placed under /mnt/problems, and judge-specific configuration to be in /mnt/problems/judge.yml. Note that runtime configuration is already done for you, and will be merged automatically into the judge.yml provided.

$ git clone --recursive https://github.com/DMOJ/judge-server.git
$ cd judge-server/.docker
$ make judge-tier1
$ exec docker run \
    --name judge \
    -p "$(ip addr show dev enp1s0 | perl -ne 'm@inet (.*)/.*@ and print$1 and exit')":9998:9998 \
    -v /mnt/problems:/problems \
    --cap-add=SYS_PTRACE \
    -d \
    --restart=always \
    dmoj/judge-tier1:latest \
    run -p15001 -s -c /problems/judge.yml \
    "$BRIDGE_ADDRESS" "$JUDGE_NAME" "$JUDGE_KEY"

Usage

Running a Judge Server

$ dmoj --help
usage: dmoj [-h] [-p SERVER_PORT] -c CONFIG [-l LOG_FILE] [--no-watchdog]
            [-a API_PORT] [-A API_HOST] [-s] [-k] [-T TRUSTED_CERTIFICATES]
            [-e ONLY_EXECUTORS | -x EXCLUDE_EXECUTORS] [--no-ansi]
            server_host [judge_name] [judge_key]

Spawns a judge for a submission server.

positional arguments:
  server_host           host to connect for the server
  judge_name            judge name (overrides configuration)
  judge_key             judge key (overrides configuration)

optional arguments:
  -h, --help            show this help message and exit
  -p SERVER_PORT, --server-port SERVER_PORT
                        port to connect for the server
  -c CONFIG, --config CONFIG
                        file to load judge configurations from
  -l LOG_FILE, --log-file LOG_FILE
                        log file to use
  --no-watchdog         disable use of watchdog on problem directories
  -a API_PORT, --api-port API_PORT
                        port to listen for the judge API (do not expose to
                        public, security is left as an exercise for the
                        reverse proxy)
  -A API_HOST, --api-host API_HOST
                        IPv4 address to listen for judge API
  -s, --secure          connect to server via TLS
  -k, --no-certificate-check
                        do not check TLS certificate
  -T TRUSTED_CERTIFICATES, --trusted-certificates TRUSTED_CERTIFICATES
                        use trusted certificate file instead of system
  -e ONLY_EXECUTORS, --only-executors ONLY_EXECUTORS
                        only listed executors will be loaded (comma-separated)
  -x EXCLUDE_EXECUTORS, --exclude-executors EXCLUDE_EXECUTORS
                        prevent listed executors from loading (comma-
                        separated)
  --no-ansi             disable ANSI output
  --skip-self-test      skip executor self-tests

Running a CLI Judge

$ dmoj-cli --help
usage: dmoj-cli [-h] -c CONFIG
                [-e ONLY_EXECUTORS | -x EXCLUDE_EXECUTORS]
                [--no-ansi]

Spawns a judge for a submission server.

optional arguments:
  -h, --help            show this help message and exit
  -c CONFIG, --config CONFIG
                        file to load judge configurations from
  -e ONLY_EXECUTORS, --only-executors ONLY_EXECUTORS
                        only listed executors will be loaded (comma-separated)
  -x EXCLUDE_EXECUTORS, --exclude-executors EXCLUDE_EXECUTORS
                        prevent listed executors from loading (comma-
                        separated)
  --no-ansi             disable ANSI output
  --skip-self-test      skip executor self-tests

Documentation

For info on the problem file format and more, read the documentation.