Python Pydantic校验配置文件的示例详解

uv add -U pydantic
# python -m pip install -U pydantic

[service]
  host = "127.0.0.1"
  port = 8000
  env = "dev"  # dev, prod
[service.log]
  level = "DEBUG"  # DEBUG, INFO, WARNING, ERROR
  output = "BOTH"  # STDOUT, FILE, BOTH
  dir = "logs"
  # file_path = "logs/app.log"
  retention_days = 30  # days
  colorize = true
  diagnose = true
  backtrace = true
[database.postgres]
  host = "127.0.0.1"
  port = 5432
  user = "your_user"
  password = "your_password"
  dbname = "your_dbname"
  channel_name = "task_queue"
  pool_max_size = 10
  pool_min_size = 4

from typing import Annotated, Literal

from pydantic import BaseModel, Field


class ServiceLogConfig(BaseModel):
    level: Annotated[Literal["DEBUG", "INFO", "WARNING", "ERROR"], Field(default="INFO", description="日志级别")]
    dir: Annotated[str, Field(default="logs", description="日志文件目录")]
    output: Annotated[Literal["STDOUT", "FILE", "BOTH"], Field(default="STDOUT", description="日志输出方式")]
    retention_days: Annotated[int, Field(default=7, gt=0, le=30, description="日志文件轮转天数")]
    colorize: Annotated[bool, Field(default=True, description="是否启用颜色日志输出")]
    backtrace: Annotated[bool, Field(default=True, description="是否启用堆栈跟踪日志输出")]
    diagnose: Annotated[bool, Field(default=True, description="是否启用诊断日志输出")]


class ServiceConfig(BaseModel):
    host: Annotated[str, Field(default="127.0.0.1", description="服务监听地址")]
    port: Annotated[int, Field(default=8080, description="服务监听端口")]
    env: Annotated[Literal["dev", "prod"], Field(default="dev", description="服务环境")]
    log: ServiceLogConfig

from typing import Annotated
from urllib.parse import quote_plus

from pydantic import BaseModel, Field


class PostgresConfig(BaseModel):
    host: Annotated[str, Field(..., description="PostgreSQL host")]
    port: Annotated[int, Field(..., description="PostgreSQL port")]
    user: Annotated[str, Field(..., description="PostgreSQL user")]
    password: Annotated[str, Field(..., description="PostgreSQL password")]
    dbname: Annotated[str, Field(..., description="PostgreSQL database name")]
    pool_min_size: Annotated[int, Field(..., description="Minimum size of PostgreSQL connection pool")]
    pool_max_size: Annotated[int, Field(..., description="Maximum size of PostgreSQL connection pool")]

    def get_dsn(self) -> str:
        """Get PostgreSQL connection string (DSN)"""
        user = quote_plus(self.user)
        password = quote_plus(self.password)
        return f"postgresql://{user}:{password}@{self.host}:{self.port}/{self.dbname}"


class DatabaseConfig(BaseModel):
    postgres: PostgresConfig

from pathlib import Path
import tomllib

from pydantic import BaseModel, ValidationError

from .agent import AgentConfig
from .postgres import DatabaseConfig


class Config(BaseModel):
    service: ServiceConfig
    database: DatabaseConfig


def get_config() -> Config:
    """Get the global configuration instance."""
    config_file = Path(__file__).parent.parent.parent / "conf" / "config.toml"

    with open(config_file, "rb") as f:
        raw_config = tomllib.load(f)

    try:
        # pydantic v2中推荐用 model_validate 实现严格校验
        return Config.model_validate(raw_config)
    except ValidationError as e:
        raise RuntimeError(f"Failed to validate config: {e}") from e

from .config import get_config


cfg = get_config()

__all__ = ["cfg"]

from pkg.config import cfg

dsn = cfg.database.postgres.get_dsn()

RuntimeError: Failed to validate config: 1 validation error for Config
database.postgres.port
Input should be a valid integer, unable to parse string as an integer [type=int_parsing, input_value='5432qwer', input_type=str]
For further information visit https://errors.pydantic.dev/2.13/v/int_parsing