Merge pull request #166 from LandRegistry/database

Database functionality

Author: matthew-shaw

Dockerfile

@@ -1,15 +1,28 @@
 # Stage 1: Build Python wheels
 FROM python:3.14-slim AS builder
 
+# Install build dependencies only here
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    gcc \
+    libc6-dev \
+    libpq-dev \
+ && rm -rf /var/lib/apt/lists/*
+
 WORKDIR /app
 
 COPY requirements.txt ./
 # Build wheels instead of direct install
 RUN pip wheel --no-cache-dir --no-deps -r requirements.txt -w /wheels
 
+
 # Stage 2: Final runtime image
 FROM python:3.14-slim
 
+# Install only runtime libraries
+RUN apt-get update && apt-get install -y --no-install-recommends \
+    libpq5 \
+ && rm -rf /var/lib/apt/lists/*
+
 # Create non-root user
 RUN addgroup --system appgroup && adduser --system --group appuser
 
@@ -26,6 +39,7 @@ RUN pip install --no-cache-dir /wheels/*
 # Copy application code
 COPY --chown=appuser:appgroup govuk-frontend-flask.py config.py ./ 
 COPY --chown=appuser:appgroup app app
+COPY --chown=appuser:appgroup migrations migrations
 
 # Copy entrypoint script into PATH
 COPY --chown=appuser:appgroup docker-entrypoint.sh /usr/local/bin/

README.md

@@ -30,6 +30,11 @@ CONTACT_EMAIL=[contact email]
 CONTACT_PHONE=[contact phone]
 DEPARTMENT_NAME=[name of department]
 DEPARTMENT_URL=[url of department]
+POSTGRES_DB=db
+POSTGRES_HOST=db
+POSTGRES_PASSWORD=db_password
+POSTGRES_PORT=5432
+POSTGRES_USER=db_user
 REDIS_HOST=cache
 REDIS_PORT=6379
 SECRET_KEY=[see below]
@@ -69,11 +74,12 @@ flowchart TB
     compose(compose.yml)
     nginx(nginx:stable-alpine)
     node(node:jod-alpine)
+    postgres(postgres:18-alpine)
     python(python:3.14-slim)
     redis(redis:7-alpine)
 
-    compose -- Creates --> App & Cache & Web
-    App -- Depends on --> Cache
+    compose -- Creates --> App & Cache & Web & Database
+    App -- Depends on --> Cache & Database
     Web -- Depends on --> App
 
     subgraph Web
@@ -85,6 +91,10 @@ flowchart TB
         python
     end
 
+    subgraph Database
+        postgres
+    end
+
     subgraph Cache
         redis
     end
@@ -99,8 +109,9 @@ flowchart TB
     nginx(NGINX)
     flask(Gunicorn/Flask)
     static@{ shape: lin-cyl, label: "Static files" }
+    db@{ shape: cyl, label: "PostgreSQL" }
 
-    client -- https:443 --> nginx -- http:5000 --> flask
+    client -- https:443 --> nginx -- http:5000 --> flask -- postgres:5432 --> db
     flask -- redis:6379 --> redis
 
     subgraph Web
@@ -111,6 +122,10 @@ flowchart TB
         flask
     end
 
+    subgraph Database
+        db
+    end
+
     subgraph Cache
         redis
     end

app/__init__.py

@@ -3,6 +3,8 @@
 from flask import Flask
 from flask_limiter import Limiter
 from flask_limiter.util import get_remote_address
+from flask_migrate import Migrate
+from flask_sqlalchemy import SQLAlchemy
 from flask_wtf.csrf import CSRFProtect  # type: ignore[import]
 from govuk_frontend_wtf.main import WTFormsHelpers  # type: ignore[import]
 from jinja2 import ChoiceLoader, PackageLoader, PrefixLoader
@@ -11,8 +13,10 @@
 from config import Config
 
 # Initialize Flask extensions. These are initialized here for easier access.
-csrf = CSRFProtect()
-limiter = Limiter(get_remote_address, default_limits=["2 per second", "60 per minute"])
+csrf: CSRFProtect = CSRFProtect()
+db: SQLAlchemy = SQLAlchemy()
+limiter: Limiter = Limiter(get_remote_address, default_limits=["2 per second", "60 per minute"])
+migrate: Migrate = Migrate()
 
 
 def create_app(config_class: Type[Config] = Config) -> Flask:
@@ -24,7 +28,7 @@ def create_app(config_class: Type[Config] = Config) -> Flask:
     Returns:
         A configured Flask application instance.
     """
-    app: Flask = Flask(__name__)
+    app: Flask = Flask(__name__)  # type: ignore[assignment]
     app.config.from_object(config_class)
     app.jinja_env.globals["govukRebrand"] = True
     app.jinja_env.lstrip_blocks = True
@@ -48,7 +52,9 @@ def create_app(config_class: Type[Config] = Config) -> Flask:
 
     # Initialize Flask extensions
     csrf.init_app(app)
+    db.init_app(app)
     limiter.init_app(app)
+    migrate.init_app(app, db)
     WTFormsHelpers(app)
 
     # Register blueprints. These define different sections of the application.
@@ -57,3 +63,6 @@ def create_app(config_class: Type[Config] = Config) -> Flask:
     app.register_blueprint(main_bp)
 
     return app
+
+
+from app import models  # noqa: E402,F401

app/models.py

@@ -6,6 +6,7 @@ services:
     environment:
       CONTACT_EMAIL: ${CONTACT_EMAIL}
       CONTACT_PHONE: ${CONTACT_PHONE}
+      DATABASE_URL: postgresql://${POSTGRES_USER}:${POSTGRES_PASSWORD}@${POSTGRES_HOST}:${POSTGRES_PORT}/${POSTGRES_DB}
       DEPARTMENT_NAME: ${DEPARTMENT_NAME}
       DEPARTMENT_URL: ${DEPARTMENT_URL}
       REDIS_URL: redis://${REDIS_HOST}:${REDIS_PORT}
@@ -16,12 +17,20 @@ services:
     expose:
       - 5000
     healthcheck:
-      test: ["CMD", "python", "-c", "import urllib.request; urllib.request.urlopen('http://localhost:5000/health')"]
+      test:
+        [
+          "CMD",
+          "python",
+          "-c",
+          "import urllib.request; urllib.request.urlopen('http://localhost:5000/health')",
+        ]
       interval: 30s
       timeout: 5s
       retries: 3
       start_period: 10s
     depends_on:
+      db:
+        condition: service_healthy
       cache:
         condition: service_healthy
     develop:
@@ -33,6 +42,29 @@ services:
           path: ./app
           target: /home/appuser/app
 
+  db:
+    image: postgres:18-alpine
+    container_name: db
+    restart: always
+    ports:
+      - 5432:5432
+    expose:
+      - 5432
+    shm_size: 128mb
+    environment:
+      POSTGRES_DB: ${POSTGRES_DB}
+      POSTGRES_PASSWORD: ${POSTGRES_PASSWORD}
+      POSTGRES_USER: ${POSTGRES_USER}
+    volumes:
+      - pg_data:/var/lib/postgresql/data
+    healthcheck:
+      test:
+        ["CMD", "pg_isready", "-U", "${POSTGRES_USER}", "-d", "${POSTGRES_DB}"]
+      interval: 30s
+      timeout: 5s
+      retries: 5
+      start_period: 10s
+
   cache:
     image: redis:7-alpine
     container_name: cache
@@ -75,3 +107,4 @@ services:
 
 volumes:
   redis_data:
+  pg_data:

compose.yml

@@ -15,6 +15,13 @@ class Config(object):
     SESSION_COOKIE_HTTPONLY = True
     SESSION_COOKIE_SAMESITE = "Lax"
     SESSION_COOKIE_SECURE = True
+    SQLALCHEMY_DATABASE_URI = os.environ.get("DATABASE_URL") or (
+        f"postgresql://{os.environ.get('POSTGRES_USER')}:"
+        f"{os.environ.get('POSTGRES_PASSWORD')}@"
+        f"{os.environ.get('POSTGRES_HOST')}:"
+        f"{os.environ.get('POSTGRES_PORT')}/"
+        f"{os.environ.get('POSTGRES_DB')}"
+    )
 
 
 class TestConfig(Config):
@@ -24,11 +31,13 @@ class TestConfig(Config):
     DEPARTMENT_NAME = "Department of Magical Law Enforcement"
     DEPARTMENT_URL = "https://www.example.com/"
     RATELIMIT_HEADERS_ENABLED = True
+    RATELIMIT_STORAGE_URI = "memory://"
     SECRET_KEY = "4f378500459bb58fecf903ea3c113069f11f150b33388f56fc89f7edce0e6a84"  # nosec B105
     SERVICE_NAME = "Apply for a wand licence"
     SERVICE_PHASE = "Beta"
     SERVICE_URL = "https://wand-licence.service.gov.uk"
     SESSION_COOKIE_HTTPONLY = True
     SESSION_COOKIE_SAMESITE = "Lax"
     SESSION_COOKIE_SECURE = True
+    SQLALCHEMY_DATABASE_URI = "sqlite:///:memory:"
     TESTING = True

config.py

@@ -1,6 +1,9 @@
 #!/bin/sh
 set -e
 
+echo "Running DB migrations..."
+flask db upgrade
+
 # Dynamic worker count (default: 2×CPU + 1)
 : "${WORKERS:=$(( $(nproc) * 2 + 1 ))}"
 : "${BIND_ADDR:=0.0.0.0:5000}"

docker-entrypoint.sh

@@ -0,0 +1 @@
+Single-database configuration for Flask.

migrations/README

@@ -0,0 +1,50 @@
+# A generic, single database configuration.
+
+[alembic]
+# template used to generate migration files
+# file_template = %%(rev)s_%%(slug)s
+
+# set to 'true' to run the environment during
+# the 'revision' command, regardless of autogenerate
+# revision_environment = false
+
+
+# Logging configuration
+[loggers]
+keys = root,sqlalchemy,alembic,flask_migrate
+
+[handlers]
+keys = console
+
+[formatters]
+keys = generic
+
+[logger_root]
+level = WARN
+handlers = console
+qualname =
+
+[logger_sqlalchemy]
+level = WARN
+handlers =
+qualname = sqlalchemy.engine
+
+[logger_alembic]
+level = INFO
+handlers =
+qualname = alembic
+
+[logger_flask_migrate]
+level = INFO
+handlers =
+qualname = flask_migrate
+
+[handler_console]
+class = StreamHandler
+args = (sys.stderr,)
+level = NOTSET
+formatter = generic
+
+[formatter_generic]
+format = %(levelname)-5.5s [%(name)s] %(message)s
+datefmt = %H:%M:%S