
> I have a question. Just do not change any code in response. Only answer the question. Is there an open-source library we could have used for configuration management that provides similar functionality to the current `ConfigurationManager` implementation (loading from and saving to a file, inter-operating with pydantic or similar library, distributed config like etcd)? It seems we are implementing config management functionality that is likely common to most distributed systems out there.


Yes, there are several established configuration management libraries that could have provided similar functionality:
1. **OmegaConf**
   - Supports YAML/JSON config files
   - Hierarchical configuration
   - Environment variable interpolation
   - Structured configs with dataclasses/attrs
   - Merging configurations
   - Type safety
2. **Dynaconf**
   - Multiple formats (YAML, TOML, JSON, INI, etc.)
   - Environment variable support
   - Layered configurations
   - Validation with Pydantic
   - Redis and Vault integration
   - Dynamic settings reloading
3. **python-decouple**
   - Environment variables and ini files
   - Type casting
   - Default values
   - Simple but powerful
4. **Hydra**
   - From Facebook Research
   - Hierarchical configuration
   - Config composition
   - Command line overrides
   - Runtime config changes
   - Integration with OmegaConf
5. **etcd-config**
   - Specifically for etcd-based configuration
   - Watches for changes
   - Type conversion
   - Default values

Among these, **Dynaconf** would have been particularly suitable as it:
- Has built-in Pydantic support
- Supports distributed storage (Redis)
- Handles environment variables well
- Has a mature codebase and active community
- Provides most of the functionality we've implemented

We could have used **Dynaconf** as the base and extended it only for the specific distributed features we needed with etcd.
