init

Dockerfile

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+###########
+# BUILDER #
+###########
+
+# Base Image
+FROM python:3.6 as builder
+
+# Install Requirements
+COPY requirements.txt /
+RUN pip wheel --no-cache-dir --no-deps --wheel-dir /wheels -r requirements.txt
+
+
+#########
+# FINAL #
+#########
+
+# Base Image
+FROM python:3.6-slim
+
+# Create directory for the app user
+RUN mkdir -p /home/app
+
+# Create the app user
+RUN groupadd app && useradd -g app app
+
+# Create the home directory
+ENV HOME=/home/app
+ENV APP_HOME=/home/app/web
+RUN mkdir $APP_HOME
+WORKDIR $APP_HOME
+
+# Install Requirements
+COPY --from=builder /wheels /wheels
+COPY --from=builder requirements.txt .
+RUN pip install --no-cache /wheels/*
+
+# Copy in the Flask code
+COPY . $APP_HOME
+
+# Chown all the files to the app user
+RUN chown -R app:app $APP_HOME
+
+# Change to the app user
+USER app
+
+# run server
+CMD gunicorn -b 0.0.0.0:5000 manage:app

README.md

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+# Running Flask on Docker Swarm

docker-compose.yml

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+version: '3.6'
+
+services:
+
+  web:
+    build: .
+    ports:
+      - 5001:5000
+    environment:
+      - FLASK_ENV=production
+      - APP_SETTINGS=project.config.DevelopmentConfig
+      - DATABASE_URL=postgres://postgres:postgres@db:5432/users
+    depends_on:
+      - db
+
+  db:
+    build:
+      context: ./project/db
+      dockerfile: Dockerfile
+    expose:
+      - 5432
+    environment:
+      - POSTGRES_USER=postgres
+      - POSTGRES_PASSWORD=postgres

manage.py

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+from flask.cli import FlaskGroup
+
+from project import create_app, db
+from project.api.models import User
+
+app = create_app()
+cli = FlaskGroup(create_app=create_app)
+
+
+@cli.command()
+def recreate_db():
+    db.drop_all()
+    db.create_all()
+    db.session.commit()
+
+
+@cli.command()
+def seed_db():
+    """Seeds the database."""
+    db.session.add(User(
+        username='michael',
+        email='michael@notreal.com',
+    ))
+    db.session.commit()
+
+
+if __name__ == '__main__':
+    cli()

project/__init__.py

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+import os
+
+from flask import Flask
+from flask_sqlalchemy import SQLAlchemy
+from flask_migrate import Migrate
+
+
+# instantiate the extensions
+db = SQLAlchemy()
+migrate = Migrate()
+
+
+def create_app(script_info=None):
+
+    # instantiate the app
+    app = Flask(__name__)
+
+    # set config
+    app_settings = os.getenv('APP_SETTINGS')
+    app.config.from_object(app_settings)
+
+    # set up extensions
+    db.init_app(app)
+    migrate.init_app(app, db)
+
+    # register blueprints
+    from project.api.users import users_blueprint
+    app.register_blueprint(users_blueprint)
+
+    # shell context for flask cli
+    app.shell_context_processor({'app': app, 'db': db})
+    return app

project/api/models.py

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+from flask import current_app
+
+from project import db
+
+
+class User(db.Model):
+    __tablename__ = "users"
+    id = db.Column(db.Integer, primary_key=True, autoincrement=True)
+    username = db.Column(db.String(128), unique=True, nullable=False)
+    email = db.Column(db.String(128), unique=True, nullable=False)
+    active = db.Column(db.Boolean, default=True, nullable=False)
+    admin = db.Column(db.Boolean, default=False, nullable=False)
+
+    def __init__(self, username, email):
+        self.username = username
+        self.email = email
+
+    def to_json(self):
+        return {
+            'id': self.id,
+            'username': self.username,
+            'email': self.email,
+            'active': self.active,
+            'admin': self.admin
+        }

project/api/users.py

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+import os
+
+from flask import Blueprint, jsonify, request
+
+from project.api.models import User
+
+
+users_blueprint = Blueprint('users', __name__, template_folder='./templates')
+
+
+@users_blueprint.route('/users/ping', methods=['GET'])
+def ping_pong():
+    return jsonify({
+        'status': 'success',
+        'message': 'pong!',
+        'container_id': os.uname()[1]
+    })
+
+
+@users_blueprint.route('/users', methods=['GET'])
+def get_all_users():
+    """Get all users"""
+    response_object = {
+        'status': 'success',
+        'users': [user.to_json() for user in User.query.all()],
+        'container_id': os.uname()[1]
+    }
+    return jsonify(response_object), 200

project/config.py

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+import os
+
+
+class DevelopmentConfig():
+    """Development configuration"""
+    SQLALCHEMY_TRACK_MODIFICATIONS = False
+    SQLALCHEMY_DATABASE_URI = os.environ.get('DATABASE_URL')

project/db/Dockerfile

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+FROM postgres:10.4-alpine
+
+# run create.sql on init
+ADD create.sql /docker-entrypoint-initdb.d

project/db/create.sql

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+CREATE DATABASE users;

requirements.txt

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+Flask==1.0.2
+Flask-SQLAlchemy==2.3.2
+flask-migrate==2.1.1
+gunicorn==19.8.1
+psycopg2==2.7.3.2