Show HN: Laboratory, a Python port of GitHub's Scientist library for refactoring

by buttscicles • 10 years ago

153 13 10 years ago

agentultra• 10 years ago

Cool! Thanks for the tool!

Imagine you've implemented a complex caching strategy for some objects in your database and a stale cache is simply not acceptable.

I hope you have a formal specification of that cache. That will help ensure your design is correct in the first place before you even get to running it in code.

I shall be playing with this soon. Cheers!

lasdfas• 10 years ago

I imagine this can only work on getters? How do you use this when code makes state changes?

tomtompl• 10 years ago

It only should be used for code which doesn't have side effects. According to original github lib.

chucksmash• 10 years ago

From Github's Scientist [1]:

Because `enabled?` and `run_if` determine when a candidate runs, it's impossible to guarantee that it will run every time. For this reason, Scientist is only safe for wrapping methods that aren't changing data.

When using Scientist, we've found it most useful to modify both the existing and new systems simultaneously anywhere writes happen, and verify the results at read time with `science`.

[1] https://github.com/github/scientist/blob/master/README.md#de...

jonathankoren• 10 years ago

Python? Isn't Python dying? ;) https://news.ycombinator.com/item?id=11100251

nubs• 10 years ago

Here's some other ports of Scientist I've come across as well:

PHP

https://github.com/LartTyler/Analyst

Javascript

https://github.com/trello/scientist

https://github.com/Runnable/scientist

https://github.com/jirwin/labrat

taspeotis• 10 years ago

.NET

http://haacked.com/archive/2016/01/20/scientist/

jack_jennings• 10 years ago

Before clicking the link I wondered how this would translate the block-based Ruby API into Python. Using Python's with statement is quite nice here, I think.

The with statement is one of my favorite additions to the language. It's a really flexible syntax to encapsulate control flow, exceptions, necessary cleanup steps… etc. etc.

chronial• 10 years ago

I would argue that python provides even simpler syntax to enable functionality like this.

  @experiment.with(new_function)
  def old_function()
      ...

shoyer• 10 years ago

Agreed -- a decorator seems like a much cleaner way to handle this.

ByteJuggler• 10 years ago

Another Python one: https://github.com/staticshock/scientist.py

Show HN: Laboratory, a Python port of GitHub's Scientist library for refactoring

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