Enhance Docker deployment: structured logging, health checks, resource limits, entrypoint script

- Add structured logging config with JSON/text format support
- Create docker-entrypoint.sh with dependency health checks
- Enhance /health endpoint with DB and Redis connectivity checks
- Add resource limits (CPU/memory) for all services
- Add network aliases for service discovery
- Add container hostnames for better identification
- Reduce health check timeout from 20s to 5s
- Add build metadata labels to Dockerfile
- Use ENTRYPOINT for dependency checking before app startup
- Log rotation: 50m per file, 5 files max

backend/app/core/logging_config.py

@@ -0,0 +1,97 @@
+"""
+Structured logging configuration for MTG Online backend.
+
+Supports JSON and text log formats with container metadata.
+Configured via MTG_LOG_LEVEL and MTG_LOG_FORMAT environment variables.
+"""
+import json
+import logging
+import os
+import sys
+from datetime import datetime, timezone
+
+
+def _get_container_name() -> str:
+    """Get container name from HOSTNAME env var or fallback."""
+    return os.environ.get("HOSTNAME", "unknown")
+
+
+class ContainerFormatter(logging.Formatter):
+    """Formatter that adds container metadata to log records.
+
+    Supports both text and JSON output formats.
+    """
+
+    SERVICE_NAME = "mtgonline-backend"
+
+    def __init__(self, fmt_type: str = "text"):
+        super().__init__()
+        self.fmt_type = fmt_type
+        self.container_name = _get_container_name()
+
+    def format(self, record: logging.LogRecord) -> str:
+        record.service = self.SERVICE_NAME
+        record.container = self.container_name
+
+        if self.fmt_type == "json":
+            return self._format_json(record)
+        return self._format_text(record)
+
+    def _format_text(self, record: logging.LogRecord) -> str:
+        return (
+            f"{self.formatTime(record)} [{record.service}] "
+            f"{record.levelname} - {record.getMessage()}"
+        )
+
+    def _format_json(self, record: logging.LogRecord) -> str:
+        log_entry = {
+            "timestamp": datetime.fromtimestamp(
+                record.created, tz=timezone.utc
+            ).isoformat(),
+            "level": record.levelname,
+            "service": record.service,
+            "container": record.container,
+            "logger": record.name,
+            "message": record.getMessage(),
+        }
+        if record.exc_info and record.exc_info[0] is not None:
+            log_entry["exception"] = self.formatException(record.exc_info)
+        return json.dumps(log_entry, default=str)
+
+
+def configure_logging() -> None:
+    """Configure application logging based on environment variables.
+
+    Reads:
+        MTG_LOG_LEVEL  - Log level (DEBUG, INFO, WARNING, ERROR, CRITICAL)
+        MTG_LOG_FORMAT - Output format ("text" or "json")
+    """
+    log_level = os.environ.get("MTG_LOG_LEVEL", "INFO").upper()
+    log_format = os.environ.get("MTG_LOG_FORMAT", "text").lower()
+
+    level = getattr(logging, log_level, logging.INFO)
+
+    formatter = ContainerFormatter(fmt_type=log_format)
+
+    handler = logging.StreamHandler(sys.stdout)
+    handler.setFormatter(formatter)
+
+    root_logger = logging.getLogger()
+    root_logger.setLevel(level)
+    root_logger.handlers.clear()
+    root_logger.addHandler(handler)
+
+    # Suppress noisy loggers unless DEBUG
+    if level != logging.DEBUG:
+        logging.getLogger("sqlalchemy.engine").setLevel(logging.WARNING)
+        logging.getLogger("sqlalchemy.pool").setLevel(logging.WARNING)
+
+    logger = logging.getLogger(__name__)
+    logger.info(
+        f"Logging configured: level={log_level}, "
+        f"format={log_format}, container={_get_container_name()}"
+    )
+
+
+# Auto-configure on import
+configure_logging()