pyyaml, uritemplate を install

settings.DEFAULT_SCHEMA_CLASS が指定されていたら、 default の rest_framework.schemas.openapi.AutoSchema に戻しておく

以下のコマンドを実行する

$ python manage.py generateschema --title="fumi23API" --description="[DFR標準] OpenAPI document 自動生成をテスト" --urlconf='fumi23.urls' > openapi-schema.yaml

もしくは URLconf に以下を追記して、 runserver => http://localhost:8000/openapi-schema/ にアクセス

# urls.py (今回は ROOT_CONF に記載)
from rest_framework.schemas import get_schema_view
from rest_framework import permissions
from rest_framework.renderers import OpenAPIRenderer
from django.views.generic.base import TemplateView

urlpatterns += [
    # yaml file download
    path('openapi-schema/', get_schema_view(
        title="fumi23 API",
        description="[DFR標準] OpenAPI document 自動生成をテスト",
        version="1.0.0",
        public=True,
        urlconf='fumi23.urls',
        renderer_classes=[OpenAPIRenderer],
        permission_classes=(permissions.AllowAny,),
    ), name='openapi-schema'),
    # Swagger UI view
    # ここ https://www.django-rest-framework.org/topics/documenting-your-api/#a-minimal-example-with-swagger-ui に記載の template も用意する
    path('docs/', TemplateView.as_view(
        template_name='swagger-ui.html',
        extra_context={'schema_url': 'openapi-schema'}
    ), name='swagger-ui'),
]

drf-yasg を install

settings.INSTALLED_APPS に drf_yasg を追記

URLconf に以下を追記して runserver => http://localhost:8000/swagger/ にアクセス

from django.urls import re_path
from rest_framework import permissions
from drf_yasg.views import get_schema_view
from drf_yasg import openapi

schema_view = get_schema_view(
    openapi.Info(
        title="fumi23 API",
        default_version='v3',
        description="[drf-yasg] OpenAPI document 自動生成をテスト",
    ),
    url='http://localhost:8000',
    urlconf='fumi23.urls',
    public=True,
    permission_classes=(permissions.AllowAny,),
)

    urlpatterns += [
        # yaml or json file download
        re_path(r'^swagger(?P<format>\.json|\.yaml)$', schema_view.without_ui(cache_timeout=0), name='schema-json'),
        # Swagger UI view
        path('swagger/', schema_view.with_ui('swagger', cache_timeout=0), name='schema-swagger-ui'),
        # ReDoc view
        path('redoc/', schema_view.with_ui('redoc', cache_timeout=0), name='schema-redoc'),
    ]