Hi all, This email presents my findings related to configuration packages in Golang for the Apache Synapse project.
I've been exploring various libraries for managing configurations from diverse sources and formats. I evaluated several options, including the widely used spf13/viper <https://github.com/spf13/viper>, go-ini/ini <https://github.com/go-ini/ini>, and knadh/koanf <https://github.com/knadh/koanf>. After careful consideration and extensive evaluation, I propose adopting the knadh/koanf <https://github.com/knadh/koanf> package as our primary configuration management solution. My primary reason for initially highlighting knadh/koanf over spf13/viper stemmed from its superior build size efficiency. knadh/koanf significantly reduces build sizes by minimizing unnecessary dependencies. This is a crucial factor for our project, as it leads to smaller binaries, faster deployment times, and reduced resource consumption. However, after further investigation, I found that knadh/koanf addresses other limitations I encountered not only with spf13/viper, but also with other libraries, such as go-ini/ini, which lacks the ability to merge configurations from multiple sources and live reloading. To provide a more comprehensive comparison, I've outlined the key differences between spf13/viper, go-ini/ini, and knadh/koanf in the table below: Feature/Metric spf13/viper go-ini/ini knadh/koanf Explanation/Benefit of koanf Build Size/Dependencies Larger, more dependencies Relatively small, but limited functionality Smaller, fewer dependencies Core Benefit: Significantly smaller binaries, faster deployments, reduced resource usage. Configuration Sources Wide range (files, env vars, remote, etc.) Primarily INI files Wide range (files, env vars, remote, etc.) Both viper and koanf support common sources, but koanf's modularity allows for only the needed providers. go-ini/ini is limited. Configuration Formats YAML, JSON, TOML, INI, etc. INI YAML, JSON, TOML, INI, etc. Both viper and koanf support common formats. go-ini/ini is limited to INI. Live Reloading (Watch) Limited/Requires External Libraries in some cases No built in support. Built-in Watch() for many providers Key Benefit: Dynamic configuration updates without restarts (e.g., log levels, feature flags). go-ini/ini lacks this feature. Simplicity/API Feature-rich, but can be complex Simple API, but limited functionality Simpler, more focused API Easier to learn, use, and maintain, especially for simpler configuration needs. go-ini/ini is simple, but lacks features. Performance Generally good, but can be slower due to overhead Relatively fast, but limited use cases. Optimized for speed and minimal overhead Faster configuration loading and access, especially important for high-performance applications. Extensibility Plugins/Customization possible, but can be complex Limited extensibility Highly extensible through pluggable providers Key Benefit: Modular design allows for easier integration of custom configuration sources and formats. Error Handling Can be verbose and sometimes complex Basic error handling More straightforward and predictable Easier to debug and handle configuration-related issues. Community/Maturity Mature, widely used Mature, but specific use case Growing, but still relatively newer Viper has a larger community, but koanf's design offers significant advantages. go-ini/ini is mature, but for a specific use case. Use Cases General-purpose configuration management Primarily INI file parsing Performance-sensitive, embedded, or microservice applications koanf is better suited for resource-constrained environments and general purpose use. Code Structure Monolithic Simple, but limited Modular Allows for a more maintainable code base. As you can see, while spf13/viper is a mature and widely used library, and go-ini/ini is excellent for simple INI files, knadh/koanf offers several key advantages, particularly in terms of build size efficiency, live reloading, simplicity, and performance. Its modular design allows for greater flexibility and extensibility, making it an ideal choice for Apache Synapse's configuration management needs. I welcome your feedback and discussion on this proposal. Thank you for your time and consideration. Sincerely, Thisara Weerakoon
