Oops is a Go library for structured error handling that serves as a drop-in replacement for the standard error type. It provides a fluent builder pattern to attach rich contextual information (error codes, domains, tags, key-value attributes, user/tenant data, HTTP request/response, timestamps, durations, hints, ownership) to errors, along with automatic stack trace capture and optional source code fragment extraction. The library implements the standard error interface, supports error wrapping and chaining, panic recovery, assertions, and integrates with major Go logging libraries (zap, zerolog, logrus, slog) via separate formatter packages. Its architecture centers on an immutable option chain (functional options) that defers stack frame symbolization to first read, minimizing allocation overhead for errors that are created but never inspected. Key entry points are the package-level functions (Wrap, Wrapf, New, Errorf, Join, Recover, Recoverf, Assert, Assertf) and the OopsErrorBuilder chainable methods. External dependencies are minimal: only github.com/oklog/ulid/v2, github.com/samber/lo, and go.opentelemetry.io/otel/trace for optional OpenTelemetry span context extraction. The codebase is well-tested, benchmarked, and follows Go best practices with comprehensive linting and security scanning.
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).