PythonのDjangoで管理画面を開発する方法まとめ

$ mkdir django-admin && cd django-admin
$ mkdir -p deploy/docker/local/py && touch deploy/docker/local/py/Dockerfile
$ mkdir -p deploy/docker/local/db && touch deploy/docker/local/db/Dockerfile
$ mkdir -p deploy/docker/local/db/init && touch deploy/docker/local/db/init/init.sql
$ touch .env compose.yml

FROM python:3.14.0-slim-trixie

# タイムゾーン設定
ENV TZ=Asia/Tokyo

# パッケージ管理用のpoetryをインストール
RUN pip3 install --no-cache-dir poetry

# [開発用] 仮想環境を作成
RUN poetry config virtualenvs.in-project true

WORKDIR /py

EXPOSE 8000

FROM postgres:18.1

ENV LANG ja_JP.utf8

# PostgreSQLの日本語化で「ja_JP.utf8」を使うために必要
RUN apt-get update && \
    apt-get install -y locales && \
    rm -rf /var/lib/apt/lists/* && \
    localedef -i ja_JP -c -f UTF-8 -A /usr/share/locale/locale.alias ja_JP.UTF-8

-- usersテーブルの作成
CREATE TABLE "public"."users" ("id" bigint NOT NULL GENERATED BY DEFAULT AS IDENTITY, "uid" character varying NOT NULL, "last_name" character varying NOT NULL, "first_name" character varying NOT NULL, "email" character varying NOT NULL, "created_at" timestamptz NOT NULL, "updated_at" timestamptz NOT NULL, "deleted_at" timestamptz NULL, PRIMARY KEY ("id"));
CREATE INDEX "user_deleted_at" ON "public"."users" ("deleted_at");
CREATE UNIQUE INDEX "users_email_key" ON "public"."users" ("email");
CREATE UNIQUE INDEX "users_uid_key" ON "public"."users" ("uid");

ENV=local
DB_NAME=pg-db
DB_USER=pg-user
DB_PASSWORD=pg-password
DB_HOST=db-django

services:
  django:
    container_name: django-admin
    build:
      context: .
      dockerfile: ./deploy/docker/local/py/Dockerfile
    volumes:
      - .:/py
    ports:
      - "8000:8000"
    env_file:
      - .env
    tty: true
    stdin_open: true

$ docker compose build --no-cache

docker compose run --rm django poetry init

$ docker compose run --rm django poetry add django "psycopg[binary]"
$ docker compose run --rm django poetry add --dev ruff

$ docker compose run --rm django poetry run django-admin startproject myapp ./src

"""
Django settings for myapp project.

Generated by 'django-admin startproject' using Django 6.0.

For more information on this file, see
https://docs.djangoproject.com/en/6.0/topics/settings/

For the full list of settings and their values, see
https://docs.djangoproject.com/en/6.0/ref/settings/
"""

import os
from pathlib import Path

# Build paths inside the project like this: BASE_DIR / 'subdir'.
BASE_DIR = Path(__file__).resolve().parent.parent


# Quick-start development settings - unsuitable for production
# See https://docs.djangoproject.com/en/6.0/howto/deployment/checklist/

# SECURITY WARNING: keep the secret key used in production secret!
SECRET_KEY = 'django-insecure-jr21o1cjct+97fvqon)d$hdjm8oo7h0ko_th=dlv!8@ts#4!&5'

# SECURITY WARNING: don't run with debug turned on in production!
DEBUG = True

ALLOWED_HOSTS = []


# Application definition

INSTALLED_APPS = [
    'django.contrib.admin',
    'django.contrib.auth',
    'django.contrib.contenttypes',
    'django.contrib.sessions',
    'django.contrib.messages',
    'django.contrib.staticfiles',
    # プロジェクトのディレクトリ追加
    'myapp'
]

MIDDLEWARE = [
    'django.middleware.security.SecurityMiddleware',
    'django.contrib.sessions.middleware.SessionMiddleware',
    'django.middleware.common.CommonMiddleware',
    'django.middleware.csrf.CsrfViewMiddleware',
    'django.contrib.auth.middleware.AuthenticationMiddleware',
    'django.contrib.messages.middleware.MessageMiddleware',
    'django.middleware.clickjacking.XFrameOptionsMiddleware',
]

ROOT_URLCONF = 'myapp.urls'

TEMPLATES = [
    {
        'BACKEND': 'django.template.backends.django.DjangoTemplates',
        'DIRS': [],
        'APP_DIRS': True,
        'OPTIONS': {
            'context_processors': [
                'django.template.context_processors.request',
                'django.contrib.auth.context_processors.auth',
                'django.contrib.messages.context_processors.messages',
            ],
        },
    },
]

WSGI_APPLICATION = 'myapp.wsgi.application'


# Database
# https://docs.djangoproject.com/en/6.0/ref/settings/#databases

DATABASES = {
    # PostgreSQLへの接続設定
    'default': {
        'ENGINE': 'django.db.backends.postgresql',
        'NAME': os.environ['DB_NAME'],
        'USER': os.environ['DB_USER'],
        'PASSWORD': os.environ['DB_PASSWORD'],
        'HOST': os.environ['DB_HOST'],
        'PORT': '5432',
    }
}


# Password validation
# https://docs.djangoproject.com/en/6.0/ref/settings/#auth-password-validators

AUTH_PASSWORD_VALIDATORS = [
    {
        'NAME': 'django.contrib.auth.password_validation.UserAttributeSimilarityValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.MinimumLengthValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.CommonPasswordValidator',
    },
    {
        'NAME': 'django.contrib.auth.password_validation.NumericPasswordValidator',
    },
]


# Internationalization
# https://docs.djangoproject.com/en/6.0/topics/i18n/

# 日本語化設定
LANGUAGE_CODE = 'ja'
TIME_ZONE = 'Asia/Tokyo'

USE_I18N = True

USE_TZ = True


# Static files (CSS, JavaScript, Images)
# https://docs.djangoproject.com/en/6.0/howto/static-files/

STATIC_URL = 'static/'

FROM python:3.14.0-slim-trixie

# タイムゾーン設定
ENV TZ=Asia/Tokyo

# パッケージ管理用のpoetryをインストール
RUN pip3 install --no-cache-dir poetry

# [開発用] 仮想環境を作成
RUN poetry config virtualenvs.in-project true

WORKDIR /py

# poetry.lockから依存関係をインストール
COPY pyproject.toml poetry.lock .
RUN poetry install --no-root

COPY ./src ./src

EXPOSE 8000

services:
  django:
    container_name: django-admin
    build:
      context: .
      dockerfile: ./deploy/docker/local/py/Dockerfile
    command: poetry run python ./src/manage.py runserver 0.0.0.0:8000
    volumes:
      - ./pyproject.toml:/py/pyproject.toml
      - ./poetry.lock:/py/poetry.lock
      - ./src:/py/src
    ports:
      - "8000:8000"
    env_file:
      - .env
    tty: true
    stdin_open: true
    depends_on:
      - db-django
  db-django:
    container_name: django-db
    build:
      context: .
      dockerfile: ./deploy/docker/local/db/Dockerfile
    environment:
      POSTGRES_DB: ${DB_NAME}
      POSTGRES_USER: ${DB_USER}
      POSTGRES_PASSWORD: ${DB_PASSWORD}
      TZ: Asia/Tokyo
      # ローカル環境でもパスワードを有効化する設定
      POSTGRES_INITDB_ARGS: --auth-local=scram-sha-256 --auth-host=scram-sha-256
    volumes:
      - ./deploy/docker/local/db/init:/docker-entrypoint-initdb.d
      - db-django-data:/var/lib/postgresql
    ports:
      - "5432:5432"
    env_file:
      - .env
volumes:
  db-django-data:

$ docker compose down
$ docker compose build --no-cache
$ docker compose up -d

$ docker compose exec django poetry run python ./src/manage.py inspectdb > ./src/myapp/models.py

from django.db import models
from django.utils.translation import gettext_noop

class Users(models.Model):
    id = models.BigAutoField(primary_key=True)
    uid = models.CharField(unique=True)
    last_name = models.CharField()
    first_name = models.CharField()
    email = models.CharField(unique=True)
    # 作成日と更新日を自動設定するように修正
    created_at = models.DateTimeField(auto_now_add=True)
    updated_at = models.DateTimeField(auto_now=True)
    deleted_at = models.DateTimeField(blank=True, null=True)

    class Meta:
        managed = False
        db_table = 'users'
        # 表示設定（日本語化で翻訳されないようにgettext_noopを使用）
        verbose_name = gettext_noop("User")
        verbose_name_plural = gettext_noop("Users")

$ touch src/myapp/admin.py

from django.contrib import admin
from django.contrib.admin.models import LogEntry
from .models import Users

# サイト名の設定
admin.site.site_header = "Django Admin"
admin.site.site_title = "Django Admin"

# 操作履歴用にデフォルトであるモデルを管理画面に追加
admin.site.register(LogEntry)

# DBスキーマに関するモデルを管理画面に追加
admin.site.register(Users)

$ docker compose exec django poetry run python ./src/manage.py migrate

$ docker compose exec django poetry run python ./src/manage.py createsuperuser

$ docker compose down
$ docker compose up -d

from django.contrib import admin
from django.contrib.admin.models import LogEntry
from django.utils import timezone

from .models import Users

# サイト名の設定
admin.site.site_header = "Django Admin"
admin.site.site_title = "Django Admin"


###############################
# 操作履歴をメニューに追加する設定
###############################


# デフォルトで存在するモデルを使用する
@admin.register(LogEntry)
class LogEntryAdmin(admin.ModelAdmin):
    # 一覧画面に表示するフィールド設定
    list_display = (
        "action_time",
        "user",
        "content_type",
        "object_repr",
        "action_flag",
    )

    # 一覧画面のフィルター設定
    list_filter = ("action_flag", "content_type")

    # 検索用の対象フィールド
    search_fields = ("object_repr", "change_message", "user__username")

    # 変更不可フィールド設定
    readonly_fields = (
        "action_time",
        "user",
        "content_type",
        "object_repr",
        "action_flag",
    )

    # 詳細画面の表示設定
    fieldsets = (
        (
            None,
            {
                "fields": (
                    "action_time",
                    "user",
                    "content_type",
                    "object_repr",
                    "action_flag",
                ),
            },
        ),
    )


###############################
# 共通フィルター用のクラス定義
###############################


# 削除日用のクラス定義
class DeletedAtFilter(admin.SimpleListFilter):
    title = "削除日（deleted_at）"
    parameter_name = "deleted"

    # 選択肢の設定
    def lookups(self, request, model_admin):
        return (
            ("alive", "未削除"),
            ("deleted", "削除済み"),
        )

    # 選択肢に対するクエリ設定
    def queryset(self, request, queryset):
        value = self.value()
        if value == "alive":
            return queryset.filter(deleted_at__isnull=True)
        if value == "deleted":
            return queryset.filter(deleted_at__isnull=False)
        return queryset


###############################
# DBモデルをメニューに追加する設定
###############################


# usersの設定
@admin.register(Users)
class UsersAdmin(admin.ModelAdmin):
    # 一覧画面に表示するフィールド設定
    list_display = [field.name for field in Users._meta.get_fields()]

    # 一覧画面のフィルター設定
    list_filter = ((DeletedAtFilter),)

    # 検索用の対象フィールド
    search_fields = ("id", "uid", "last_name", "first_name", "email")

    # 変更不可フィールド設定
    readonly_fields = ("id", "created_at", "updated_at")

    # 詳細画面の表示設定
    fieldsets = (
        (
            None,
            {
                "fields": (
                    "id",
                    "uid",
                    "last_name",
                    "first_name",
                    "email",
                    "created_at",
                    "updated_at",
                    "deleted_at",
                ),
            },
        ),
    )

    # 単体用の論理削除設定
    def delete_model(self, request, obj):
        obj.updated_at = timezone.now()
        obj.deleted_at = timezone.now()
        obj.save()

    # 一括用の論理削除設定
    def delete_queryset(self, request, queryset):
        queryset.update(updated_at=timezone.now(), deleted_at=timezone.now())

$ docker compose exec django poetry run ruff format .
$ docker compose exec django poetry run ruff check . --select I --fix

$ docker compose exec django poetry run ruff check .