openbao-pydantic-settings-adapter 1.0.3

OpenBao/Vault secrets source for pydantic-settings with AppRole authentication

openbao-pydantic-settings-adapter

OpenBao/Vault secrets source for pydantic-settings with AppRole authentication, automatic token renewal, and graceful fallback to environment variables.

Features

• AppRole Authentication - Secure machine-to-machine authentication
• Automatic Token Renewal - TokenManager handles TTL-based token lifecycle
• Namespace Support - Multi-tenant isolation (team/project level)
• Two-Path Architecture - Separate secrets and supersecrets paths with deep merge
• SecretStr Validation - Enforces SecretStr for supersecrets to prevent log exposure
• Graceful Degradation - Falls back to .env when OpenBao is unavailable
• Type Safety - Full type annotations with py.typed marker (PEP 561)

Installation

pip install openbao-pydantic-settings-adapter

Note: The import name is openbao_settings:

from openbao_settings import OpenBaoSettingsSource

Quick Start

from pydantic import SecretStr
from pydantic_settings import BaseSettings, PydanticBaseSettingsSource

from openbao_settings import OpenBaoSettingsSource


class Settings(BaseSettings):
    database_url: str
    api_key: SecretStr  # Fields from supersecrets MUST use SecretStr

    @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, ...]:
        return (
            init_settings,
            OpenBaoSettingsSource(settings_cls),  # OpenBao has priority
            env_settings,
            dotenv_settings,
        )


settings = Settings()

Configuration

Configure via environment variables:

Variable	Description	Required
BAO_ADDR	OpenBao server URL (e.g., http://localhost:8200)	Yes
BAO_SECRET_PATH	Base path to secrets (e.g., myapp)	Yes
BAO_APPROLE_ROLE_ID	AppRole Role ID	Yes
BAO_APPROLE_SECRET_ID	AppRole Secret ID	Yes
BAO_NAMESPACE	OpenBao namespace for multi-tenant isolation	No
BAO_MOUNT_POINT	KV engine mount point (default: kv)	No
BAO_TIMEOUT	Connection timeout in seconds (default: 30)	No
BAO_TOKEN_RENEWAL_THRESHOLD	When to renew token (default: 0.75 = at 75% of TTL)	No

For Docker/Kubernetes, you can use file-based credentials:

• BAO_APPROLE_ROLE_ID_FILE
• BAO_APPROLE_SECRET_ID_FILE
• BAO_NAMESPACE_FILE

Secrets Architecture

The library reads from two paths and merges them:

kv/{BAO_SECRET_PATH}/secrets      - Regular secrets (developers can view/edit)
kv/{BAO_SECRET_PATH}/supersecrets - Sensitive secrets (admin only)

Important: Fields loaded from supersecrets MUST use SecretStr type annotation. The library validates this at runtime and raises SecurityMisconfigurationError if violated.

# Wrong - will raise SecurityMisconfigurationError
class Settings(BaseSettings):
    api_key: str  # Loaded from supersecrets but not SecretStr!

# Correct
class Settings(BaseSettings):
    api_key: SecretStr  # Properly protected

Token Lifecycle

TokenManager automatically handles token renewal:

1. Caches tokens per (namespace, role_id) combination
2. Renews at 75% of TTL (configurable via BAO_TOKEN_RENEWAL_THRESHOLD)
3. Thread-safe for multi-threaded applications
4. Graceful degradation if OpenBao becomes unavailable

from openbao_settings import TokenManager

# Manual token invalidation (e.g., for credential rotation)
TokenManager().invalidate()

# Check token health
TokenManager().is_healthy(namespace="myapp", role_id="...")

Diagnostics

Track where settings were loaded from:

from openbao_settings import get_last_source_info

info = get_last_source_info()
print(info["source"])  # "openbao" or "env"
print(info["details"])  # Human-readable description
print(info["openbao_keys_loaded"])  # Number of keys from OpenBao

API Reference

Classes

• OpenBaoSettingsSource - Main settings source for pydantic-settings
• OpenBaoClient - Low-level HTTP client for OpenBao API
• TokenManager - Singleton for token lifecycle management

Exceptions

• OpenBaoError - Base exception for all OpenBao errors
• InvalidPathError - Path not found (HTTP 404)
• InvalidRequestError - Invalid request/credentials (HTTP 400)
• ForbiddenError - Access denied (HTTP 403)
• InvalidResponseError - Unexpected API response structure
• SecurityMisconfigurationError - SecretStr validation failed

Response Models

• AppRoleLoginResponse - AppRole authentication response
• KvV2ReadResponse - KV v2 read response

License

This project is licensed under the PolyForm Noncommercial License 1.0.0.

You may use this software for noncommercial purposes only.

See LICENSE for the full license text, or visit polyformproject.org.