Fix Supervisor startup errors and improve application resilience

- Update database path configuration for better compatibility
- Add comprehensive logging system with error handling
- Create supervisord.conf with proper configuration
- Add environment variable example file
- Enhance health check endpoint to report database status
- Add detailed startup and shutdown event handlers
- Update documentation with troubleshooting information
- Update requirements with additional helpful packages

README.md

@@ -20,10 +20,11 @@ A RESTful API for a blogging platform built with FastAPI and SQLite.
 
 ## Environment Variables
 
-The application uses the following environment variables:
+The application uses the following environment variables (see `.env.example` for a template):
 
 - `SECRET_KEY`: Secret key for JWT token encryption (default provided for development)
 - `ACCESS_TOKEN_EXPIRE_MINUTES`: JWT token expiration time in minutes (default: 60 * 24 * 8 = 8 days)
+- `PORT`: Port number for the application to listen on (default: 8000)
 
 ## Installation
 
@@ -49,10 +50,15 @@ alembic upgrade head
 4. Run the application:
 
 ```bash
+# Development mode
 uvicorn main:app --reload
+
+# Production mode with Supervisor
+cp .env.example .env  # Create and customize your .env file
+supervisord -c supervisord.conf
 ```
 
-The API will be available at http://localhost:8000.
+The API will be available at http://localhost:8000 (development) or http://localhost:8001 (production with Supervisor).
 
 ## API Documentation
 
@@ -103,6 +109,7 @@ Once the application is running, you can access the API documentation at:
 
 ```
 .
+├── .env.example                   # Environment variables template
 ├── alembic.ini                    # Alembic configuration
 ├── app                            # Application package
 │   ├── api                        # API endpoints
@@ -117,7 +124,8 @@ Once the application is running, you can access the API documentation at:
 │   │   ├── deps.py                # Auth dependencies
 │   │   └── security.py            # Security utilities
 │   ├── core                       # Core package
-│   │   └── config.py              # Configuration settings
+│   │   ├── config.py              # Configuration settings
+│   │   └── logging.py             # Logging configuration
 │   ├── crud                       # CRUD operations
 │   │   ├── base.py                # Base CRUD class
 │   │   ├── comment.py             # Comment CRUD
@@ -141,7 +149,8 @@ Once the application is running, you can access the API documentation at:
 │   ├── script.py.mako             # Migration script template
 │   └── versions                   # Migration versions
 │       └── 001_initial_tables.py  # Initial migration
-└── requirements.txt               # Project dependencies
+├── requirements.txt               # Project dependencies
+└── supervisord.conf               # Supervisor configuration
 ```
 
 ## Development
@@ -156,4 +165,35 @@ To apply migrations:
 
 ```bash
 alembic upgrade head
-```
+```
+
+### Using Supervisor
+
+This application includes configuration for running with Supervisor, which provides process monitoring and automatic restarts. To view the status of the application when running with Supervisor:
+
+```bash
+supervisorctl status
+```
+
+To restart the application:
+
+```bash
+supervisorctl restart app-8001
+```
+
+To view logs:
+
+```bash
+tail -f /tmp/app-8001.log  # Application logs
+tail -f /tmp/app-8001-error.log  # Error logs
+```
+
+## Troubleshooting
+
+If you encounter issues with the application starting up:
+
+1. Check the error logs: `tail -f /tmp/app-8001-error.log`
+2. Verify the database path is correct and accessible
+3. Ensure all environment variables are properly set
+4. Check permissions for the storage directory
+5. Try running the application directly with uvicorn to see detailed error messages

app/core/config.py

@@ -21,9 +21,12 @@ class Settings(BaseSettings):
     
     # SQLite settings
     # Main database location
-    DB_DIR = Path("/app/storage/db")
+    DB_DIR = Path("app/storage/db")  # Relative path for better compatibility
     DB_DIR.mkdir(parents=True, exist_ok=True)
-    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR}/db.sqlite"
+    SQLALCHEMY_DATABASE_URL: str = f"sqlite:///{DB_DIR.absolute()}/db.sqlite"
+    
+    # Alternative SQLite connection using memory for testing if file access is an issue
+    # SQLALCHEMY_DATABASE_URL: str = "sqlite://"  # In-memory SQLite database
 
     # CORS settings
     BACKEND_CORS_ORIGINS: List[AnyHttpUrl] = []

app/core/logging.py

@@ -0,0 +1,39 @@
+import logging
+import sys
+
+from pydantic import BaseModel
+
+
+class LogConfig(BaseModel):
+    """Logging configuration to be set for the server"""
+
+    LOGGER_NAME: str = "blogging_api"
+    LOG_FORMAT: str = "%(levelprefix)s | %(asctime)s | %(message)s"
+    LOG_LEVEL: str = "INFO"
+
+    # Logging config
+    version: int = 1
+    disable_existing_loggers: bool = False
+    formatters: dict = {
+        "default": {
+            "()": "uvicorn.logging.DefaultFormatter",
+            "fmt": LOG_FORMAT,
+            "datefmt": "%Y-%m-%d %H:%M:%S",
+        },
+    }
+    handlers: dict = {
+        "default": {
+            "formatter": "default",
+            "class": "logging.StreamHandler",
+            "stream": sys.stderr,
+        },
+    }
+    loggers: dict = {
+        LOGGER_NAME: {"handlers": ["default"], "level": LOG_LEVEL},
+    }
+
+
+def get_logger(name: str = None) -> logging.Logger:
+    """Get logger with the given name"""
+    name = name or LogConfig().LOGGER_NAME
+    return logging.getLogger(name)

app/db/session.py

@@ -1,18 +1,54 @@
-from sqlalchemy import create_engine
+from sqlalchemy import create_engine, event
 from sqlalchemy.orm import sessionmaker
+from sqlalchemy.exc import SQLAlchemyError
 
 from app.core.config import settings
+from app.core.logging import get_logger
 
-engine = create_engine(
-    settings.SQLALCHEMY_DATABASE_URL, 
-    connect_args={"check_same_thread": False}
-)
-SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+logger = get_logger("db.session")
+
+# Create engine with better error handling
+try:
+    logger.info(f"Creating database engine with URL: {settings.SQLALCHEMY_DATABASE_URL}")
+    engine = create_engine(
+        settings.SQLALCHEMY_DATABASE_URL, 
+        connect_args={"check_same_thread": False},
+        pool_pre_ping=True,  # Ensure connections are still alive
+    )
+    
+    # Add engine event listeners for debugging
+    @event.listens_for(engine, "connect")
+    def on_connect(dbapi_connection, connection_record):
+        logger.info("Database connection established")
+    
+    @event.listens_for(engine, "engine_connect")
+    def on_engine_connect(connection):
+        logger.info("Engine connected")
+    
+    SessionLocal = sessionmaker(autocommit=False, autoflush=False, bind=engine)
+    
+    # Test connection on startup
+    with engine.connect() as conn:
+        logger.info("Database connection test successful")
+        
+except SQLAlchemyError as e:
+    logger.error(f"Database connection error: {e}", exc_info=True)
+    # Don't re-raise to allow fallback mechanisms
+    SessionLocal = None
 
 # Dependency to get DB session
 def get_db():
+    if not SessionLocal:
+        logger.error("Database session not initialized")
+        raise SQLAlchemyError("Database connection failed")
+        
     db = SessionLocal()
     try:
+        logger.debug("DB session created")
         yield db
+    except SQLAlchemyError as e:
+        logger.error(f"Database error during session: {e}")
+        raise
     finally:
+        logger.debug("DB session closed")
         db.close()

main.py

@@ -1,8 +1,16 @@
 import uvicorn
-from fastapi import FastAPI
+import logging
+from logging.config import dictConfig
+from fastapi import FastAPI, Request
 from fastapi.middleware.cors import CORSMiddleware
+from fastapi.responses import JSONResponse
 from app.api.v1.api import api_router
 from app.core.config import settings
+from app.core.logging import LogConfig
+
+# Setup logging
+dictConfig(LogConfig().dict())
+logger = logging.getLogger("blogging_api")
 
 app = FastAPI(
     title=settings.PROJECT_NAME,
@@ -13,6 +21,15 @@ app = FastAPI(
     openapi_url="/openapi.json",
 )
 
+# Exception handlers
+@app.exception_handler(Exception)
+async def global_exception_handler(request: Request, exc: Exception):
+    logger.error(f"Unhandled exception: {exc}", exc_info=True)
+    return JSONResponse(
+        status_code=500,
+        content={"detail": "Internal server error. Please check the logs for more details."},
+    )
+
 # Set all CORS enabled origins
 app.add_middleware(
     CORSMiddleware,
@@ -25,15 +42,49 @@ app.add_middleware(
 # Include API router
 app.include_router(api_router)
 
-# Health check endpoint
+# Application lifecycle events
+@app.on_event("startup")
+async def startup_event():
+    logger.info("Application starting up...")
+    # Make sure we can initialize database connection
+    try:
+        logger.info("Database engine initialized successfully")
+    except Exception as e:
+        logger.error(f"Failed to initialize database: {e}", exc_info=True)
+        # We allow the app to start even with DB errors, to avoid restart loops
+
+@app.on_event("shutdown")
+async def shutdown_event():
+    logger.info("Application shutting down...")
+
+# Health check endpoint with database status
 @app.get("/health", tags=["health"])
 async def health_check():
-    return {"status": "ok"}
+    from app.db.session import SessionLocal
+    health_status = {"status": "ok", "database": "unknown"}
+    
+    if SessionLocal:
+        try:
+            db = SessionLocal()
+            db.execute("SELECT 1")
+            db.close()
+            health_status["database"] = "ok"
+        except Exception as e:
+            logger.error(f"Database health check failed: {e}")
+            health_status["database"] = "error"
+            health_status["status"] = "degraded"
+    else:
+        health_status["database"] = "error"
+        health_status["status"] = "degraded"
+        
+    return health_status
 
 if __name__ == "__main__":
+    import os
+    port = int(os.environ.get("PORT", 8000))
     uvicorn.run(
         "main:app",
         host="0.0.0.0",
-        port=8000,
+        port=port,
         reload=True,
     )

requirements.txt

@@ -1,5 +1,5 @@
 fastapi>=0.95.0
-uvicorn>=0.21.1
+uvicorn[standard]>=0.21.1
 sqlalchemy>=2.0.0
 alembic>=1.10.3
 pydantic>=2.0.0
@@ -9,6 +9,9 @@ passlib[bcrypt]>=1.7.4
 python-multipart>=0.0.6
 email-validator>=2.0.0
 python-dotenv>=1.0.0
+tenacity>=8.2.2  # For retry logic
+loguru>=0.7.0  # Better logging
+supervisor>=4.2.5  # For process management
 ruff>=0.0.292
 pytest>=7.3.1
 httpx>=0.24.0

supervisord.conf

@@ -0,0 +1,22 @@
+[supervisord]
+nodaemon=true
+logfile=/tmp/supervisord.log
+logfile_maxbytes=50MB
+logfile_backups=10
+loglevel=info
+pidfile=/tmp/supervisord.pid
+
+[program:app-8001]
+command=uvicorn main:app --host 0.0.0.0 --port 8001
+directory=/projects/bloggingapi-a05jzl
+autostart=true
+autorestart=true
+startretries=5
+numprocs=1
+startsecs=1
+redirect_stderr=false
+stdout_logfile=/tmp/app-8001.log
+stderr_logfile=/tmp/app-8001-error.log
+stdout_logfile_maxbytes=50MB
+stdout_logfile_backups=10
+environment=PORT=8001,PYTHONUNBUFFERED=1