config.py

from pathlib import Path
from pydantic import BaseModel, Field
import yaml


class DevDBConfig(BaseModel):
    container_host: str
    container_name: str = Field(min_length=1)
    container_port: int = Field(ge=1024, le=65535)
    postgres_db: str | None = Field(min_length=1, default=None)
    postgres_user: str = Field(min_length=1)
    postgres_password: str = Field(min_length=1)


class Config(BaseModel):
    dev_db: DevDBConfig

    @property
    def conn_str(self) -> str:
        """ Connection string for Psycopg. """
        return f"postgresql://" + self._conn_str_params()
    
    @property
    def sqlalchemy_url(self) -> str:
        """ Connection string for SQLAlchemy. """
        return f"postgresql+psycopg://" + self._conn_str_params()
    
    def _conn_str_params(self) -> str:
        """ Connection string without a URI scheme. """
        return \
            f"{self.dev_db.postgres_user}:{self.dev_db.postgres_password}" + \
            f"@{self.dev_db.container_host}:{self.dev_db.container_port}" + \
            f"/{self.dev_db.postgres_db}"


class TestDBConfig(Config):
    """
    Subclass of `Config`, which contains parameters of a test database.
    Added mainly for a better typing semantics.
    """
    pass


def load_config() -> Config:
    path = Path(__file__).parent / "config.yml"
    with open(path) as f:
        data = yaml.safe_load(f)
    return Config(**data)