libprotoconf

.//libprotoconf

Runtime configuration made easy with protocol-buffers.

Goals

Developers can define their desired configuration struct in a proto file, then get all sorts of ways to load that configuration into their software runtime:

• Populate config from environment variables
• Get a flag.FlagSet instance
• Read and merge configs from global, user and workspace locations (/etc/mypackage/, $USER/.mypackage/, $(pwd)/.mypackage/)
• Allow configuration changes dynamically
  • Reload on Signals
  • Reload on file change (inotify)
  • gRPC/rest configuration endpoints
  • key-value stores (consul, etcd, zookeeper, redis)
  • protoconf gRPC streaming agent
• Formats:
  • JSON (.json)
  • YAML (.yaml, .yml)
  • pbtext (.pb)
  • pb binary (.data)
  • pb binary with base64 encoding (.base64, .b64)
  • jsonnet (.jsonnet)
  • toml (.toml)
  • hcl (.hcl)
  • cue (.cue)
• Pre/Post hooks for dynamic changes
• Debugging features
  • ShowConfig() method (available via gRPC/rest)
  • ConfigMetadata() method (available via gRPC/rest)
    • Where a specific variable was set (env/flag/which file/key value store/rpc)
    • When was the change applied to runtime
    • When was the change made (if made before the process was starting)
    • Who made the change (if data available)
  • /varz http endpoint
  • /metrics http endpoint for prometheus (with ConfigMetadata() information available)

Implementations

• First implementation will be in Go. This implementation will also include the protoconf gRPC streaming agent, so developers of any language can use the dynamic reload features as a sidecar agent.
• Future implementations (please vote!)
  • Rust (will probably replace Go for the agent implementation)
  • Python
  • JavaScript
  • Java
  • C++
  • Suggest other languages