html_url,issue_url,id,node_id,user,user_label,created_at,updated_at,author_association,body,reactions,issue,issue_label,performed_via_github_app
https://github.com/simonw/datasette/issues/1384#issuecomment-869074701,https://api.github.com/repos/simonw/datasette/issues/1384,869074701,MDEyOklzc3VlQ29tbWVudDg2OTA3NDcwMQ==,2670795,brandonrobertz,2021-06-26T23:45:18Z,2021-06-26T23:45:37Z,CONTRIBUTOR,"> Here's where the plugin hook is called, demonstrating the `fallback=` argument:
> 
> https://github.com/simonw/datasette/blob/05a312caf3debb51aa1069939923a49e21cd2bd1/datasette/app.py#L426-L472
> 
> I'm not convinced of the use-case for passing `fallback=` to the hook here - is there a reason a plugin might care whether fallback is `True` or `False`, seeing as the `metadata()` method already respects that fallback logic on line 459?

I think you're right. I can't think of a reason why the plugin would care about the `fallback` parameter since plugins are currently mandated to return a full, global metadata dict.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",930807135,Plugin hook for dynamic metadata,
https://github.com/simonw/datasette/issues/1384#issuecomment-869074182,https://api.github.com/repos/simonw/datasette/issues/1384,869074182,MDEyOklzc3VlQ29tbWVudDg2OTA3NDE4Mg==,2670795,brandonrobertz,2021-06-26T23:37:42Z,2021-06-26T23:37:42Z,CONTRIBUTOR,"> > Hmmm... that's tricky, since one of the most obvious ways to use this hook is to load metadata from database tables using SQL queries.
> > @brandonrobertz do you have a working example of using this hook to populate metadata from database tables I can try?
> 
> Answering my own question: here's how Brandon implements it in his `datasette-live-config` plugin: https://github.com/next-LI/datasette-live-config/blob/72e335e887f1c69c54c6c2441e07148955b0fc9f/datasette_live_config/__init__.py#L50-L160
> 
> That's using a completely separate SQLite connection (actually wrapped in `sqlite-utils`) and making blocking synchronous calls to it.
> 
> This is a pragmatic solution, which works - and likely performs just fine, because SQL queries like this against a small database are so fast that not running them asynchronously isn't actually a problem.
> 
> But... it's weird. Everywhere else in Datasette land uses `await db.execute(...)` - but here's an example where users are encouraged to use blocking calls instead.

_Ideally_ this hook would be asynchronous, but when I started down that path I quickly realized how large of a change this would be, since metadata gets used synchronously across the entire Datasette codebase. (And calling async code from sync is non-trivial.)

In my live-configuration implementation I use synchronous reads using a persistent sqlite connection. This works pretty well in practice, but I agree it's limiting. My thinking around this was to go with the path of least change as `Datasette.metadata()` is a critical core function.","{""total_count"": 0, ""+1"": 0, ""-1"": 0, ""laugh"": 0, ""hooray"": 0, ""confused"": 0, ""heart"": 0, ""rocket"": 0, ""eyes"": 0}",930807135,Plugin hook for dynamic metadata,