This is the official NATS C client library (nats.c), a production-grade C library providing full support for the NATS messaging system. It implements core publish/subscribe, request-reply, queue groups, and advanced features including JetStream (streams, consumers, key-value store, object store), a microservices framework, and legacy NATS Streaming support. The library is designed for high performance and reliability, with built-in reconnection, TLS/SSL, authentication (NKeys, JWT), and event loop integration (libevent, libuv). It exposes a comprehensive C API with hundreds of functions, and includes extensive examples and documentation. The codebase is well-structured with platform abstractions for Unix and Windows, and internal modules for protocol parsing, connection management, threading, and memory management. While the library is actively maintained and widely used, it carries some technical debt from legacy Streaming support and a large, tightly-coupled internal architecture.
This is a Prometheus exporter for NATS server monitoring. It polls NATS server HTTP monitoring endpoints (varz, connz, subz, routez, healthz, jsz, etc.) and exposes metrics in Prometheus format. The architecture is a standalone binary with an embeddable library API. Key entry points are the CLI (main.go) and the exporter.NewExporter function. Data flow: on each scrape, collectors make HTTP requests to NATS monitoring endpoints, parse JSON responses, and convert them to Prometheus gauge metrics. The exporter supports TLS, basic auth, custom metric prefixes, and multiple NATS servers (though one per exporter is recommended). It includes pre-built Grafana dashboards for both NATS core and JetStream metrics. The codebase is well-structured with separate packages for collectors, exporter, and test utilities. It uses reflection-based metric extraction for simple endpoints and custom collectors for complex ones like JetStream, connections, and gateways. The project is actively maintained with recent commits and modern dependencies.