Offer redirection of micropip.install console messages and data

[bollwyvl]

References

• Remove "Python initialization complete" log line pyodide#3247 (comment)

Elevator pitch

Offer a way for programs to intercept and make use of micropip.install status and error information.

Motivation

During micropip.install, a lot of useful information is sent to the browser console which might actually be useful to display to users, such as drawing progress bars to indicate "5 of 10 packages are loading", or even "5MB of 50MB have been loaded".

But more crucially, having access to error conditions in a predictable manner instead of tracebacks in the browser console (if even reachable, e.g. on mobile) would help create more predictable experiences

Design Ideas

• accept error_callback and message_callback, similar to the typescript side
  • hand back some dict that includes a message, but ideally also some idea of progress, e.g. stage and total_packages, start_time, duration
  • these could be well-typed (even TypeDicts) or have a schema
• use a more pythonic approach, using a log=logger.getLogger()
  • potentially more featureful
    • less type-able
  • would make it easy to add DEBUG messages, etc. that shouldn't always be displayed without inventing some new system

[rth]

Thanks for the proposal! I certainly see the use case for this so +1 from me. Personally, I have no strong preferences between string and structured logging, it's mostly a question for downstream packages.

Someone would need to design the API and implement this though :)