Add progress spinner animation during generation

[justinmayer]

I thought it would be nice to enhance Pelican's console output aesthetics via the Rich project, and adding an animated spinner during site generation is the most naive initial implementation I could conceive.

There are many other ways in which we could use Rich to enhance console output, including prettier text colors, nicer logging formatting, and more readable tracebacks.

I'd love to replace the Generating... spinner in this PR with per-task progress bars (generating, writing, etc.). If someone wants to submit a follow-up PR to implement that, I'd be most grateful! 🚀

[Lucas-C]

Interesting small aesthetics improvement! 😊

My humble feedback: is it worth pulling all those extra dependencies?
https://github.com/willmcgugan/rich/blob/master/pyproject.toml#L29

[minchinweb]

My humble feedback: is it worth pulling all those extra dependencies?

colorama would likely be required for any simple effort to provide cross platform color CLI output. I'll let others comment on the rest.

[iKevinY]

LGTM; I might've had the same comment as @Lucas-C re: whether it's worth pulling in dependencies, but I do like a good terminal spinner. 😄

[avaris]

It has a considerably smaller footprint than I anticipated.

[justinmayer]

My humble feedback: is it worth pulling all those extra dependencies?

Is it worth it, just to get an animated spinner, as provided by this very naive implementation? Probably not. But as I mentioned above, I think we could expand our Rich usage to a degree that would, in aggregate, be worth the extra dependencies. Besides, I don't think the extra dependencies really cost us very much, and if we later decide they aren't worth it, we can easily remove them.

I look forward to someone building on top of this effort to make the most of what Rich can offer us. ✨

[jvoisin]

In the wake of the log4j debacle, this is an interesting move :P

[justinmayer]

If you are suggesting that dependencies can be an attack vector, well sure they can — that’s not saying very much. Do I think Pelican users should be worried about Rich being such an attack vector? Nope.