v2.0

[biaks]

Major architecture overhaul — flat layout, unified API, prometheus-cpp compatibility

Breaking changes (fully backward-compatible via shims and aliases)

• Project restructured from core/simpleapi/3rdpatry to flat include/src/3rdparty
• CMake targets renamed:
  • prometheus-cpp-lite-core → prometheus-cpp-lite (header-only)
  • prometheus-cpp-simpleapi → prometheus-cpp-lite-full (static, with globals)
• SimpleAPI types moved from prometheus::simpleapi:: to prometheus:: namespace
• Core headers unified into core.h (registry.h, family.h, metric.h, builder.h, etc.)
• Networking headers renamed:
  • save_to_file.h → file_saver.h
  • push_to_server.h → http_pusher.h
  • gateway.h → http_pusher.h
• Networking library replaced: http-client-lite → ip-sockets-cpp-lite
• Umbrella header renamed: simpleapi.h → prometheus.h

New features

• HTTP pull server (http_server_t / Exposer) — new export mode with multi-endpoint support and auto-generated index page
• Info metric (info_t) for exposing build metadata as labels
• Benchmark metric (benchmark_t) for wall-clock profiling via start()/stop()
• Full prometheus-cpp API compatibility: BuildCounter(), Exposer, Gateway, Family, Add(), Increment(), RegisterCollectable()
• Custom user-defined metric types — follow the existing pattern to add your own (see add_custom_metric_class.cpp)
• Typed family wrappers (counter_family_t, etc.) with compile-time type safety
• Multiple value types: uint64_t (default counters), int64_t (default gauges), double, or any arithmetic type
• Global registry with pre-defined global exporters (http_server, http_pusher, file_saver) via prometheus-cpp-lite-full target
• Configurable socket log level for http_server_t and http_pusher_t
• 16 examples covering all API levels, export modes, class instrumentation, compatibility, and extensibility

Backward compatibility

All v1.0 code compiles and works without changes:

• Old CMake targets (prometheus-cpp-lite-core, prometheus-cpp-simpleapi) provided as aliases
• Old headers (registry.h, family.h, metric.h, builder.h, save_to_file.h, push_to_server.h, gateway.h, etc.) provided as shims with #pragma message deprecation notices
• Old class names (SaveToFile, PushToServer, Gateway) provided as [[deprecated]] type aliases
• prometheus::simpleapi:: namespace preserved with [[deprecated]] aliases
• simpleapi.h redirects to prometheus.h and provides all legacy aliases

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This discussion was created from the release v2.0.