How to Mock AWS Secrets Manager in Python

import json
from typing import Optional


class MockSecretsManager:
    """A simple mock of AWS Secrets Manager's get_secret_value API."""

    def __init__(self):
        self._secrets: dict[str, str] = {}

    def create_secret(self, secret_id: str, secret_value: str) -> None:
        """Store a secret value under a given ID."""
        self._secrets[secret_id] = secret_value

    def get_secret_value(self, secret_id: str) -> Optional[str]:
        """Fetch a secret's string value by ID, or None if not found."""
        return self._secrets.get(secret_id)


if __name__ == "__main__":
    mock_client = MockSecretsManager()

    # Seed with sample data
    mock_client.create_secret("prod/db/password", "s3cr3t-p@ssw0rd")
    mock_client.create_secret("dev/api/key", "dev_key_12345")

    # Fetch and display results
    db_secret = mock_client.get_secret_value("prod/db/password")
    api_secret = mock_client.get_secret_value("dev/api/key")
    missing_secret = mock_client.get_secret_value("nonexistent/secret")

    print(f"DB password: {db_secret}")
    print(f"API key: {api_secret}")
    print(f"Missing secret: {missing_secret}")

    # Demonstrate parsing as JSON
    mock_client.create_secret("service/config", json.dumps({"timeout": 30, "retries": 3}))
    config_raw = mock_client.get_secret_value("service/config")
    config = json.loads(config_raw) if config_raw else {}
    print(f"Config timeout: {config.get('timeout')}")