Firefly
Firefly is a C++20 logging library built to illuminate what is happening inside engine and application code without tying either one to a specific output format or logging implementation.
- Technology
- C++20 / Infrastructure
- Status
- In use
Frame-by-frame visibility quickly becomes noise.
A useful engine logger has to serve humans during development and structured tooling after the fact. It also needs to handle repeated frame-by-frame messages without flooding its output, and preserve recent context when a process fails.
Treat each log as structured evidence.
A small logger interface accepts entries and delegates formatting to replaceable sinks. Named channels separate engine and game output, configurable deduplication controls repetition, and a ring-buffer crash sink preserves the events leading up to a failure.
What it does.
- 01
Trace through fatal severity levels
- 02
Named loggers and a concise macro API
- 03
Plain text, CSV, JSON, and NDJSON sinks
- 04
Configurable message deduplication windows
- 05
A last-N crash-dump ring buffer
How decisions
get made.
Separate data from format
Log entries are value snapshots; sinks decide how they are represented.
Integrate through adapters
Umbra consumes Firefly behind its own logger interface.
Keep the signal visible
Deduplication and named channels prevent useful events from disappearing into noise.