$ show go-kratos/kratos
Kratos is a production-grade Go microservices framework designed for cloud-native applications. It provides a unified transport layer supporting both HTTP (gorilla/mux) and gRPC, with a composable middleware chain for cross-cutting concerns like logging, tracing, authentication, rate limiting, and circuit breaking. The framework is protobuf-first: service definitions are written in proto files, and code generators (protoc-gen-go-http, protoc-gen-go-errors) produce HTTP stubs and structured error types. It includes a pluggable configuration system with support for multiple sources (file, etcd, consul, nacos, apollo, kubernetes, polaris), a service registry abstraction with implementations for etcd, consul, nacos, eureka, zookeeper, kubernetes, polaris, and others, and a load balancing selector with algorithms like random, weighted round-robin, and power of two choices (p2c). Observability is integrated via OpenTelemetry (tracing, metrics, logging) and Sentry error tracking. The CLI tool `kratos` scaffolds new projects, manages proto generation, and handles upgrades. The architecture is modular: core packages are minimal and extensible, with contrib packages as separate Go modules. The codebase demonstrates strong engineering practices, clean interfaces, and well-tested core components.
The LLM identified 5 files worth highlighting for reuse:
Implements the SRE circuit breaker pattern using a sliding window rolling counter. It tracks success/failure counts and opens the circuit when the failure ratio exceeds a threshold. The implementation is self-contained, uses only internal rolling counter utilities, and can be extracted for use in any Go service requiring circuit breaking.
Implements the BBR (Bottleneck Bandwidth and Round-trip propagation time) rate limiting algorithm. It dynamically adjusts the request limit based on CPU usage and in-flight request counts. The algorithm is standalone and can be reused in any Go application needing adaptive rate limiting.
Provides a weighted node implementation using Exponentially Weighted Moving Average (EWMA) to calculate dynamic weights based on latency and success rate. This enables adaptive load balancing in client-side service discovery. The node logic is decoupled from the selector framework and can be reused in custom load balancers.
Decodes URL query parameters into protobuf messages, supporting nested messages, repeated fields, and well-known types. This is a non-trivial utility that solves a common problem in HTTP APIs. It is self-contained and can be extracted for use in any Go project that needs to parse form data into protobuf structs.
Builds HTTP paths from protobuf field masks and query parameters, supporting resource name patterns and field selection. This utility is essential for RESTful API design with protobuf. It is isolated and can be reused in other Go HTTP frameworks for path construction.