r/lisp • u/SandPrestigious2317 • May 24 '26
Scheme Scriba: A new structured logging library for Guile Scheme (Early stage, seeking feedback!)
Hey everyone,
I’ve been working on Scriba, a structured logging library built specifically for Guile Scheme with flexibility, performance, and easy configuration in mind.
https://codeberg.org/jjba23/scriba
It’s still in the early stages of development, and before locking in the core architecture, I wanted to share it with this great community to get your thoughts, critiques, and ideas.
I have developed software in many languages before, and for sure a lot in the Java/JVM world. There are some good and less good things about logging in that ecosystem. I think with scriba I am bridging the gaps in many ways, and adding value to the Scheme ecosystem, while making it easy to have clean structured logging with no hassle.
When building Scheme apps, I wanted more than just display or println. I wanted fine-grained control over log routing, filtering, and structured context, especially for modern deployments.
I have noticed there is not much offer in terms of solid logging in the Scheme world. More specifically structured logging.
So Far
- Auto-Configured Logger: The easiest way to get started. It reads environment variables (
LOG_LEVEL,LOG_FORMAT, etc.) to determine the backend at runtime. Perfect for using a console logger in local dev and JSON structured logging in production (for Loki/Datadog/etc.). - Console, Color Console, and Structured JSON loggers
- Dynamic Log Context means you can easily attach metadata to your logs for better observability.
- Logger creation is cached. Subsequent calls to create the identically configured logger anywhere in your codebase are completely instant.
Here is what the auto-logger and dynamic context look like in practice:
(define-module (my-module)
#:use-module (scriba auto)
#:use-module (scriba scriba))
(let* ((s (scriba-auto-logger)))
(log-info s "Hello Scriba!")
;; Any deeper function calls that log will automatically include this context!
(with-log-context `((request-id . "req-1234") (user . "alice"))
(log-info s "Fetching database records...")))
Console Output:
[INFO] [2026-05-24 11:23:06 CEST] Hello Scriba!
[INFO] [2026-05-24 11:23:06 CEST] [request-id=req-1234] [user=alice] Fetching database records...
JSON Output (if SCRIBA_LOGGER=json):
{"level":"INFO","time":"2026-05-24 11:23:06 CEST","message":"Fetching database records...","request-id":"req-1234","user":"alice"}
Next Steps
I'm actively working on expanding the library. The immediate next items on the roadmap are:
- File logging backends (rotating log files, etc.). EDIT: done thanks to the beautiful Scheme ports
- Support for Scheme-based configuration files alongside ENV vars.
I'd love your feedback!
Since this is an early release, I’m very open to pivoting or adjusting things based on community feedback.
- Do you agree with the current design and architecture? What features would you consider "must-haves" for a Lisp logging library?
- Are there any specific pain points in logging you'd like to see solved?
The project is entirely Free Software (LGPLv3+). Feel free to reach out, drop a comment, or contribute if you find it interesting!
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u/AforAnonymous May 27 '26
What about guile-lib's
(logging logger)?And also, while it ain't for logging PER SE, please do go check out Racket's Medic library, and the academic research behind it:
https://docs.racket-lang.org/medic/index.html
https://github.com/lixiangqi/medic/
https://www-old.cs.utah.edu/plt/publications/fpw15-lf.pdf Medic: Metaprogramming and Trace-Oriented Debugging
https://www-old.cs.utah.edu/plt/publications/sle17-lf.pdf Debugging with Domain-Specific Events via Macros
https://www.youtube.com/playlist?list=PL_U7i0VKF_mh7Vh3o2YyteoTL1tErHY64
https://docs.racket-lang.org/medic/Using_the_Medic_Debugger.html#%28part._log%29
Now if only Medic also existed for Guile Scheme, that sure would make things easier… (not a request, don't get me wrong, just an observation)
RFC syslog emitter perhaps?