$ show uber-go/zap
Uber-go/zap is a high-performance, structured logging library for Go. It provides two primary logger types: the zero-allocation, reflection-free Logger for hot-path usage and the ergonomic SugaredLogger for printf-style logging. The library emphasizes minimal allocations through object pooling, lazy field evaluation, and efficient encoders (JSON and console). It includes advanced features like sampling, dynamic level adjustment via AtomicLevel, hook systems for extensibility, and integration with testing, gRPC, and standard library. The architecture is modular, separating public API (zap), core implementation (zapcore), testing utilities (zaptest), and experimental features (exp).
The LLM identified 5 files worth highlighting for reuse:
Implements a sync.Pool for byte buffers to minimize allocations in high-frequency logging. The pool is pre-sized for log entry buffers and demonstrates a reusable pattern for any scenario requiring temporary buffer reuse with minimal allocation overhead.
Provides Lazy fields that defer computation until a log entry is actually emitted (if the level is enabled). This avoids expensive field serialization when logging is suppressed, showcasing a reusable pattern for conditional expensive operations in performance-critical paths.
Defines CheckPreWriteHook and CheckWriteHook interfaces allowing registration of functions to execute before/after log entry writing. This enables cross-cutting concerns (e.g., filtering, metrics) without modifying core logic, demonstrating a clean extensibility pattern via callbacks.
Implements a token bucket sampler to log a representative subset of entries while reducing volume. The sampler preserves statistical properties of the log stream and demonstrates a reusable rate-limiting pattern applicable to any event stream requiring sampling.
Provides AtomicLevel for runtime log level changes using atomic operations for safe concurrent updates. This enables dynamic configuration without logger recreation and showcases a reusable pattern for any runtime-configurable threshold requiring thread-safe updates.