Python - Pydantic Configuration Management

Pydantic Configuration Management

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Overview

Sources:

• **

Code

• configurator.py:

import os
import sys
import site
from typing import Union, Type, Tuple
 
from pydantic import Field, computed_field
from pydantic_settings import (BaseSettings, SettingsConfigDict,
                               PydanticBaseSettingsSource)
 
USER_BASE = site.getuserbase()
SECRETS_DIR = ('/run/secrets'
               if os.path.exists('/.dockerenv')
               else f'{site.USER_BASE}/secrets')
PLATFORM = {
    'linux': 'Linux',
    'linux2': 'Linux',
    'win32': 'Windows',
    'darwin': 'MacOS'
}
ENVIRONMENT = os.getenv('ENVIRONMENT', MISSING_ENV)
MISSING_ENV = '>>> undefined ENV parameter <<<'
MISSING_SECRET = '>>> missing SECRETS file <<<'
 
if not os.path.exists('/.dockerenv'):
    os.makedirs(SECRETS_DIR, exist_ok=True)
 
 
class Common(BaseSettings):
    """ Common configuration parameters shared between all environments.
 
    Read configuration parameters defined in this class, and from
    ENVIRONMENT variables and from the .env file.
 
    The source priority is changed (from default) to the following
    order (from highest to lowest):
      - init_settings
      - dotenv_settings
      - env_settings
      - file_secret_settings
 
    The following environment variables should already be defined:
      - HOSTNAME (on Linux servers only - set by OS)
      - COMPUTERNAME (on Windows servers only - set by OS)
      - ENVIRONMENT (on all servers)
 
    Path where your <environment>.env file should be placed:
      - linux: /home/<user>/.local
      - darwin: /home/<user>/.local
      - win32: C:\\Users\\<user>\\AppData\\Roaming\\Python'
 
    Path where your secret files should be placed:
      - linux: /home/<user>/.local/secrets
      - darwin: /home/<user>/.local/secrets
      - win32: C:\\Users\\<user>\\AppData\\Roaming\\Python\\secrets'
    """
    model_config = SettingsConfigDict(extra='ignore',
                                      secrets_dir=SECRETS_DIR,
                                      env_file_encoding='utf-8',
                                      env_file=f'{USER_BASE}/.env')
 
    # constant parameters.
    routingDbPort: int = 8012
    trackingDbPort: int = 8006
    mqServer: str = 'P-W-MQ01'
    apiTimeout: tuple = (9.05, 60)
 
    # Environment depending parameters.
    env: str = ENVIRONMENT
    platform: str = PLATFORM.get(sys.platform, 'other')
 
    # Secrets depending parameters.
    serviceApiKey: str = Field(MISSING_SECRET, alias='service_api_key')
 
    @computed_field
    @property
    def hdrData(self) -> dict:
        """ Return updated API header (added serviceApiKey secret).
 
        :return: Updated API header.
        """
        return {'Content-Type': 'application/json',
                'X-API-Key': f'{self.serviceApiKey}'}
 
    @computed_field
    @property
    def server(self) -> str:
        """ Return local server name stripped of possible domain part.
 
        :return: Server name in upper case.
        """
        name = ('COMPUTERNAME' if sys.platform == 'win32' else 'HOSTNAME')
        return os.getenv(name, MISSING_ENV).upper().split('.')[0]
 
    @classmethod
    def settings_customise_sources(
            cls,
            settings_cls: Type[BaseSettings],
            init_settings: PydanticBaseSettingsSource,
            env_settings: PydanticBaseSettingsSource,
            dotenv_settings: PydanticBaseSettingsSource,
            file_secret_settings: PydanticBaseSettingsSource,
    ) -> Tuple[PydanticBaseSettingsSource, ...]:
        """ Change source priority order (env trumps environment). """
        return (init_settings, dotenv_settings,
                env_settings, file_secret_settings)
 
 
class Dev(Common):
    """ Configuration parameters for DEV environment.
 
    Values from dev.env supersede previous values when the file exists.
    """
    model_config = SettingsConfigDict(env_file=f'{USER_BASE}/{Common().env}.env')
 
    mqServer: str = 'localhost'
    dbServer: str = 'localhost:3306'
    apiRoot: str = 'http://localhost'
    mongoUrl: str = Field(MISSING_SECRET, alias=f'mongo_url_{Common().env}')
 
 
class Test(Common):
    """ Configuration parameters for TEST environment.
 
    Values from test.env supersedes previous values when the file exists.
    """
    model_config = SettingsConfigDict(env_file=f'{USER_BASE}/{Common().env}.env')
 
    dbServer: str = 't-l-docker01:3306'
    apiRoot: str = 'http://internal_api_test_host'
    mongoUrl: str = Field(MISSING_SECRET, alias=f'mongo_url_{Common().env}')
 
class Stage(Common):
    """ Configuration parameters for STAGE environment.
 
     Values from stage.env supersede previous values when the file exists.
     """
    model_config = SettingsConfigDict(env_file=f'{USER_BASE}/{Common().env}.env')
 
    routingDbPort: int = 8013
    trackingDbPort: int = 8007
    dbServer: str = 't-l-docker01:3307'
    apiRoot: str = 'http://internal_api_stage_host'
    mongoUrl: str = Field(MISSING_SECRET, alias=f'mongo_url_{Common().env}')
 
class Prod(Common):
    """ Configuration parameters for PROD environment.
 
    Values from prod.env supersedes previous values when the file exists.
    """
    model_config = SettingsConfigDict(env_file=f'{USER_BASE}/{Common().env}.env')
 
    dbServer: str = 'ocsemysqlcl:3306'
    apiRoot: str = 'http://internal_api_prod_host'
    mongoUrl: str = Field(MISSING_SECRET, alias=f'mongo_url_{Common().env}')
 
 
_setup = dict(
    dev=Dev,
    test=Test,
    prod=Prod,
    stage=Stage
)
 
# Validate and instantiate specified environment configuration.
config: Union[Dev, Test, Prod, Stage] = _setup[ENVIRONMENT]()

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See Also

• Python Map of Content
• Python Code
• Tool - Python
• Tool - Python Flask

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Appendix

Note created on 2024-04-15 and last modified on 2024-04-15.

Backlinks

LIST FROM [[Python - Pydantic Configuration Management]] AND -"CHANGELOG" AND -"04-RESOURCES/Code/Python/Python - Pydantic Configuration Management"

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