Handled more errors during db initialization

Dockerfile

@@ -1,5 +1,6 @@
-FROM python:3.11.7-slim-bookworm
+FROM python:3.11.7-alpine
 WORKDIR /app
 COPY api .
+RUN apk add --no-cache curl
 RUN pip install -r requirements.txt
 CMD python3 app.py

api/app.py

@@ -4,6 +4,7 @@ from flask_jwt_extended import JWTManager
 from jwt import ExpiredSignatureError
 from models import db, RevokedToken
 import os
+from tech_views import tech_bp
 from utils import init_db, wait_for_db
 from views import user_bp
 from werkzeug.exceptions import HTTPException
@@ -26,6 +27,7 @@ def create_app(config_name="default"):
 
     # Blueprints registration
     app.register_blueprint(user_bp)
+    app.register_blueprint(tech_bp)
 
     # Database and JWT initialization
     db.init_app(app)
@@ -53,7 +55,7 @@ def create_app(config_name="default"):
 
     # Fill database by initial values (only if we are not testing)
     with app.app_context():
-        wait_for_db()
+        wait_for_db(max_retries=100)
         db.create_all()
         if config_name != "testing":
             init_db()

api/tech_views.py

@@ -0,0 +1,20 @@
+from flask import Blueprint, jsonify
+from models import db
+from sqlalchemy import text
+from utils import db_ready
+
+# Blueprint with technical endpoints
+tech_bp = Blueprint('tech_bp', __name__)
+
+@tech_bp.route('/health', methods=['GET'])
+def health_check():
+    "Check if service works and database is functional"
+    try:
+        with db.engine.connect() as connection:
+            connection.execute(text("SELECT 1"))
+        return jsonify(status="healthy"), 200
+    except Exception:
+        if db_ready:
+            return jsonify(status="unhealthy"), 500
+        else:
+            return jsonify(status="starting"), 503

api/utils.py

@@ -3,19 +3,21 @@ from flask_jwt_extended import get_jwt_identity
 from models import User, db
 import os
 from sqlalchemy import text
-from sqlalchemy.exc import DatabaseError
+from sqlalchemy.exc import DatabaseError, InterfaceError
 import time
 from werkzeug.security import generate_password_hash
 
+db_ready = False
 
 def admin_required(user_id, message='Access denied.'):
+    "Check if common user try to make administrative action."
     user = db.session.get(User, user_id)
     if user is None or user.role != "Administrator":
         abort(403, message)
 
 
 def validate_access(owner_id, message='Access denied.'):
-    # Check if user try to access or edit resource that does not belong to them 
+    "Check if user try to access or edit resource that does not belong to them."
     logged_user_id = int(get_jwt_identity())
     logged_user_role = db.session.get(User, logged_user_id).role
     if logged_user_role != "Administrator" and logged_user_id != owner_id:
@@ -30,20 +32,18 @@ def get_user_or_404(user_id):
     return user
 
 
-MAX_RETRIES = 100
-
-def wait_for_db():
-    for retries in range(MAX_RETRIES):
+def wait_for_db(max_retries):
+    "Try to connect with database <max_retries> times."
+    global db_ready
+    for _ in range(max_retries):
         try:
             with db.engine.connect() as connection:
                 connection.execute(text("SELECT 1"))
-            print("Successfully connected with database.")
+            db_ready = True
             return
-        except DatabaseError:
-            print(f"Waiting for database... (retry {retries + 1})")
+        except DatabaseError | InterfaceError:
             time.sleep(3)
-    print("Failed to connect to database.")
-    raise Exception("Database not ready after multiple retries.")
+    raise Exception("Failed to connect to database.")
 
 
 def init_db():

docker-compose.yml

@@ -7,9 +7,24 @@ services:
     build: .
     env_file:
       - api/.env
+    ports:
+      - 80:80
+    healthcheck:
+      test: ["CMD", "curl", "-f", "http://localhost/health"]
+      interval: 10s
+      timeout: 5s
+      retries: 5
+      start_period: 15s
   db:
     container_name: db
     hostname: db
     image: mysql:latest
     env_file:
       - db/.env
+    ports:
+      - 3306:3306
+    healthcheck:
+      test: ["CMD", "mysqladmin", "ping", "-h", "localhost"]
+      interval: 10s
+      timeout: 5s
+      retries: 5