"""Configuration management for EMS MCP server.
Uses pydantic-settings for environment variable loading with validation.
"""
from functools import lru_cache
from typing import Annotated
from pydantic import SecretStr, field_validator
from pydantic_settings import BaseSettings, SettingsConfigDict
class EMSSettings(BaseSettings):
"""EMS MCP server settings loaded from environment variables.
Required environment variables:
EMS_BASE_URL: Base URL of EMS API server (e.g., https://ems.example.com)
EMS_USERNAME: Username for authentication
EMS_PASSWORD: Password for authentication
Optional environment variables:
EMS_DEFAULT_SYSTEM: Default EMS system ID
EMS_CACHE_TTL: Cache time-to-live in seconds (default: 3600)
EMS_REQUEST_TIMEOUT: Request timeout in seconds (default: 120)
EMS_LOG_LEVEL: Logging level (default: INFO)
EMS_MAX_RETRIES: Maximum retry attempts (default: 3)
"""
model_config = SettingsConfigDict(
env_prefix="EMS_",
case_sensitive=False,
)
# Required settings
base_url: str
username: str
password: SecretStr
# Optional settings with defaults
default_system: int | None = None
cache_ttl: Annotated[int, "Cache TTL in seconds"] = 3600
request_timeout: Annotated[int, "Request timeout in seconds"] = 120
log_level: str = "INFO"
max_retries: Annotated[int, "Maximum retry attempts"] = 3
@field_validator("base_url")
@classmethod
def normalize_base_url(cls, v: str) -> str:
"""Normalize base URL: remove trailing slash, upgrade HTTP to HTTPS.
Also removes a trailing '/api' if present, as the client and token manager
add it themselves.
"""
url = v.rstrip("/")
if url.lower().endswith("/api"):
url = url[:-4]
if url.startswith("http://"):
url = "https://" + url[7:]
return url
@field_validator("log_level")
@classmethod
def validate_log_level(cls, v: str) -> str:
"""Validate log level is a valid Python logging level."""
valid_levels = {"DEBUG", "INFO", "WARNING", "ERROR", "CRITICAL"}
upper = v.upper()
if upper not in valid_levels:
raise ValueError(f"Invalid log level: {v}. Must be one of {valid_levels}")
return upper
@lru_cache
def get_settings() -> EMSSettings:
"""Get singleton settings instance.
Returns:
EMSSettings instance loaded from environment variables.
Raises:
ValidationError: If required environment variables are missing or invalid.
"""
return EMSSettings() # type: ignore[call-arg]
