はじめに
FastAPIとpostgresqlの環境構築を行いました。
LaravelやRailsのフレームワークに慣れていたのもあり、FastAPIを導入する際に少し面倒くさく感じたので、
備忘録を兼ねて環境構築の手順を書きました。
各コードの詳細については省いてます。
忙しい人のために最終的なソースです。
https://github.com/nonamenme/docker-fastapi-postgres
こちらをdocker-compose up -dで立ち上げれば、とりあえずFastAPIの環境は完成します。
1. 準備
以下の構成でファイルを用意
─── project
├── docker-compose.yml
├── Dockerfile
├── requirements.txt
└── fastapi
└── main.py
・各ファイルの中身
docker-compose.yml
version: '3.7'
services:
fastapi:
build: .
volumes:
- ./fastapi:/app
ports:
- 8000:8000
restart: always
tty: true
depends_on:
- db
db:
image: postgres:15
container_name: postgres-db
volumes:
- postgres_data:/var/lib/postgresql/data/
environment:
- POSTGRES_USER=postgres
- POSTGRES_PASSWORD=password
ports:
- 5432:5432
volumes:
postgres_data:
・コンテナ名などは必要に応じて変更
dockerfile
FROM python:3.9-alpine
ENV LANG C.UTF-8
ENV TZ Asia/Tokyo
WORKDIR /app
# pip installs
COPY ./requirements.txt requirements.txt
RUN apk add --no-cache postgresql-libs \
&& apk add --no-cache --virtual .build-deps gcc musl-dev postgresql-dev \
&& python3 -m pip install -r /app/requirements.txt --no-cache-dir \
&& apk --purge del .build-deps
COPY . /app
# FastAPIの起動
CMD ["uvicorn", "main:app", "--reload", "--host", "0.0.0.0", "--port", "8000"]
・"--reload"をつけることで、main.pyに変更が入った際に即時反映することができる
main.py
import uvicorn
from fastapi import FastAPI
app = FastAPI()
@app.get("/")
async def root():
return {"message": "Hello World"}
if __name__ == "__main__":
uvicorn.run(app, host="0.0.0.0", port=8000)
requirements.txt
fastapi
uvicorn
SQLAlchemy==1.3.22
SQLAlchemy-Utils==0.41.1
alembic==1.5.2
psycopg2==2.8.6
psycopg2-binary==2.9.3
pydantic[email]==1.6.1
python-jose[cryptography]==3.2.0
python-multipart==0.0.6
python-dotenv==1.0.0
2. コンテナを立ち上げる
$ docker-compose up -d
3. コンテナが立ち上がっているか確認
$ docker-compose ps
Name Command State Ports
------------------------------------------------------------------------------------
fast-api_fastapi_1 uvicorn main:app --reload ... Up 0.0.0.0:8000->8000/tcp
postgres-db docker-entrypoint.sh postgres Up 0.0.0.0:5432->5432/tcp
この時点でアプリは立ち上がっている。
http://localhost:8000 をブラウザで開くと
{"message":"Hello World"}
と表示されているはず。
また、http://localhost:8000/docs をブラウザで開くと、SwaggerUIで参照も出来る。
4. alembicでmigrationを作成
ここが少し面倒くさかった・・・。
・alembicはDBマイグレーションツール
4-1. アプリコンテナに入る
$ docker-compose exec fastapi sh
4-2. alembic initでmigration環境の作成
/app # alembic init migration
Creating directory /app/migration ... done
Creating directory /app/migration/versions ... done
Generating /app/migration/script.py.mako ... done
Generating /app/migration/README ... done
Generating /app/alembic.ini ... done
Generating /app/migration/env.py ... done
Please edit configuration/connection/logging settings in '/app/alembic.ini' before proceeding.
ここまで完了すると、以下のようなファイル構成ができている。
─── project
├── docker-compose.yml
├── Dockerfile
├── requirements.txt
└── fastapi
├── main.py
+ ├── alembic.ini
+ └── migration
+ ├── versions
+ ├── env.py
+ ├── README
+ └── script.py.mako
4-3. dbの接続先を変更する
4-3-1. .envの作成
/app # touch .env
.env
DATABASE_URL=postgresql://postgres:password@postgres-db:5432/postgres
4-3-2. core/config.pyの作成
/app # mkdir core
/app # touch config.py
4-3-3. 環境変数を読み込む為の設定ファイルを作成
core/config.py
import os
from functools import lru_cache
from pydantic import BaseSettings
PROJECT_ROOT = os.path.dirname(os.path.dirname(os.path.abspath(__file__)))
class Environment(BaseSettings):
""" 環境変数を読み込む
"""
database_url: str
class Config:
env_file = os.path.join(PROJECT_ROOT, '.env')
@lru_cache
def get_env():
""" @lru_cacheで.envの結果をキャッシュする
"""
return Environment()
4-3-4. 接続先のDBを設定
migration/env.py
+ import sys
+ # 相対パスでcoreディレクトリが参照できないので、読み取れるように
+ sys.path = ['', '..'] + sys.path[1:]
+ import os
+ from core.config import PROJECT_ROOT
+ from dotenv import load_dotenv
from logging.config import fileConfig
from sqlalchemy import engine_from_config
from sqlalchemy import pool
from alembic import context
# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config
# Interpret the config file for Python logging.
# This line sets up loggers basically.
fileConfig(config.config_file_name)
# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
target_metadata = None
# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.
+ load_dotenv(dotenv_path=os.path.join(PROJECT_ROOT, '.env'))
+ config.set_main_option('sqlalchemy.url', os.getenv('DATABASE_URL'))
def run_migrations_offline():
...
4-4. 生成されるmigrationファイルのファイル名を変更する
alembic.ini
# A generic, single database configuration.
[alembic]
# path to migration scripts
script_location = migration
# template used to generate migration files
# file_template = %%(rev)s_%%(slug)s
+ file_template = %%(year)d%%(month).2d%%(day).2d%%(hour).2d%%(minute).2d_%%(slug)s
# timezone to use when rendering the date
# within the migration file as well as the filename.
# string value is passed to dateutil.tz.gettz()
# leave blank for localtime
# timezone =
+ timezone = Asia/Tokyo
# max length of characters to apply to the
# "slug" field
# truncate_slug_length = 40
...
4-5. migrationファイルを作成
/app # alembic revision -m "create users table"
Generating /app/migration/versions/202305121847_create_users_table.py ... done
これでmigration/version/配下にmigrationファイルが生成される。
5. migrationの実行
5-1. migrationファイルの変更
xxxx_create_users_table.py
"""create users table
Revision ID: xxxxxxxx
Revises:
Create Date: YYYY-MM-dd hh:ss:mm.ssssss
"""
from alembic import op
import sqlalchemy as sa
# revision identifiers, used by Alembic.
revision = 'xxxxxxxx'
down_revision = None
branch_labels = None
depends_on = None
def upgrade():
- pass
+ op.create_table(
+ 'users',
+ sa.Column('id', sa.Integer, primary_key=True),
+ sa.Column('name', sa.String(50), nullable=False),
+ sa.Column('login_id', sa.String(50), nullable=False),
+ sa.Column('password', sa.Text(), nullable=False),
+ )
def downgrade():
- pass
+ op.drop_table('users')
5-2. migrationの実行
/app # alembic upgrade head
INFO [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO [alembic.runtime.migration] Will assume transactional DDL.
INFO [alembic.runtime.migration] Running upgrade -> xxxxxxxx, create users table
これでmigrationが実行され、postgresqlのDBへusersテーブルが作成される。
6. Modelを元にmigrationファイルを生成するように
6-1. models.pyを作成
/app # touch migration/models.py
migration/models.py
from datetime import datetime
from sqlalchemy import create_engine, Column, String, Integer, Text, DateTime
from sqlalchemy.ext.declarative import declarative_base
from core.config import get_env
# Engine の作成
Engine = create_engine(
get_env().database_url,
encoding="utf-8",
echo=False
)
BaseModel = declarative_base()
6-2. Userモデルを作成
migration/models.py
from datetime import datetime
from sqlalchemy import create_engine, Column, String, Integer, Text, DateTime
from sqlalchemy.ext.declarative import declarative_base
from core.config import get_env
# Engine の作成
Engine = create_engine(
get_env().database_url,
encoding="utf-8",
echo=False
)
BaseModel = declarative_base()
+ class User(BaseModel):
+ __tablename__ = 'users'
+
+ id = Column(Integer, primary_key=True)
+ name = Column(String(50), nullable=False)
+ login_id = Column(String(50), unique=True, nullable=False)
+ password = Column(Text, nullable=False)
+ created_at = Column(DateTime, default=datetime.now, nullable=False) # 追加分
+ updated_at = Column(DateTime, default=datetime.now, nullable=False) # 追加分
・ migrationファイルとの差分は created_atとupdated_at
6-3. 作成したmodelをalembicで呼び出すように設定する
migration/env.py
import sys
sys.path = ['', '..'] + sys.path[1:]
import os
from core.config import PROJECT_ROOT
from dotenv import load_dotenv
from logging.config import fileConfig
- from sqlalchemy import engine_from_config
- from sqlalchemy import pool
from alembic import context
+ from migration.models import BaseModel, Engine
# this is the Alembic Config object, which provides
# access to the values within the .ini file in use.
config = context.config
# Interpret the config file for Python logging.
# This line sets up loggers basically.
fileConfig(config.config_file_name)
# add your model's MetaData object here
# for 'autogenerate' support
# from myapp import mymodel
# target_metadata = mymodel.Base.metadata
- target_metadata = None
+ # target_metadata = None
+ target_metadata = BaseModel.metadata
# other values from the config, defined by the needs of env.py,
# can be acquired:
# my_important_option = config.get_main_option("my_important_option")
# ... etc.
load_dotenv(dotenv_path=os.path.join(PROJECT_ROOT, '.env'))
config.set_main_option('sqlalchemy.url', os.getenv('DATABASE_URL'))
def run_migrations_offline():
"""Run migrations in 'offline' mode.
This configures the context with just a URL
and not an Engine, though an Engine is acceptable
here as well. By skipping the Engine creation
we don't even need a DBAPI to be available.
Calls to context.execute() here emit the given string to the
script output.
"""
url = config.get_main_option("sqlalchemy.url")
context.configure(
url=url,
target_metadata=target_metadata,
literal_binds=True,
dialect_opts={"paramstyle": "named"},
)
with context.begin_transaction():
context.run_migrations()
def run_migrations_online():
"""Run migrations in 'online' mode.
In this scenario we need to create an Engine
and associate a connection with the context.
"""
- connectable = engine_from_config(
- config.get_section(config.config_ini_section),
- prefix="sqlalchemy.",
- poolclass=pool.NullPool,
- )
+ # connectable = engine_from_config(
+ # config.get_section(config.config_ini_section),
+ # prefix="sqlalchemy.",
+ # poolclass=pool.NullPool,
+ # )
+ url = config.get_main_option("sqlalchemy.url")
+ connectable = Engine
with connectable.connect() as connection:
context.configure(
+ url=url,
connection=connection,
target_metadata=target_metadata
)
with context.begin_transaction():
context.run_migrations()
if context.is_offline_mode():
run_migrations_offline()
else:
run_migrations_online()
6-4. migrationファイルの生成
/app # alembic revision --autogenerate -m "add columns"
INFO [alembic.runtime.migration] Context impl PostgresqlImpl.
INFO [alembic.runtime.migration] Will assume transactional DDL.
INFO [alembic.ddl.postgresql] Detected sequence named 'users_id_seq' as owned by integer column 'users(id)', assuming SERIAL and omitting
INFO [alembic.autogenerate.compare] Detected added column 'users.created_at'
INFO [alembic.autogenerate.compare] Detected added column 'users.updated_at'
INFO [alembic.autogenerate.compare] Detected added unique constraint 'None' on '['login_id']'
Generating /app/migration/versions/YYYYMMddHHmm_add_columns.py ... done
--autogenerateオプションをつけることで、models.pyを元にすでにあるmigrationファイルとの差分のmigrationファイルを作成してくれる。
YYYYMMddHHmm_add_columns.py
"""add columns
Revision ID: xxxxxxx
Revises: yyyyyyyyy
Create Date: YYYY-MM-dd HH:mm:ss.ssssss+09:00
"""
from alembic import op
import sqlalchemy as sa
# revision identifiers, used by Alembic.
revision = 'xxxxxxx'
down_revision = 'yyyyyyyyy'
branch_labels = None
depends_on = None
def upgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.add_column('users', sa.Column('created_at', sa.DateTime(), nullable=False))
op.add_column('users', sa.Column('updated_at', sa.DateTime(), nullable=False))
op.create_unique_constraint(None, 'users', ['login_id'])
# ### end Alembic commands ###
def downgrade():
# ### commands auto generated by Alembic - please adjust! ###
op.drop_constraint(None, 'users', type_='unique')
op.drop_column('users', 'updated_at')
op.drop_column('users', 'created_at')
# ### end Alembic commands ###
6-5. migrationの実行
alembic upgrade head
7. 完了
ここまでで環境構築としては完了。
初めてのFastAPIでの環境構築で戸惑いまくりでしたが、楽しかったです。
参考リンク
https://qiita.com/Butterthon/items/a55daa0e7f168fee7ef0
https://qiita.com/penpenta/items/c993243c4ceee3840f30
https://qiita.com/hkyo/items/65321d7015121ccf369f