avoid system settings in tiddlywebconfig.py

[FND]

currently bfwinstance produces a tiddlywebconfig.py that looks like this:

config = {
    'secret': '...',
    'twanager_plugins': ['tiddlywebplugins.tagdex', 'tiddlywebplugins.bfw'],
    'system_plugins': ['tiddlywebplugins.static', 'tiddlywebplugins.tagdex',
            'tiddlywebplugins.bfw'],
    'markdown.wiki_link_base': '',
    'markdown.extensions': (['markdown_checklist.extension'], {}),
}

only secret is actually specific to the respective instance and thus belongs into its tiddlywebconfig.py - the rest should be read directly from the BFW package to avoid manual intervention when upgrading that package:

from tiddlywebplugins.bfw.instance import merge_with_instance_config

merge_with_instance_config({
    'secret': '...'
})

(obviously this mechanism needs to allow for instance-specific plugins and other customizations)

seems like this is something that needs to be addressed by imaker, but I'm not sure exactly how - @cdent?

---

FWIW, this appears to work, but it's not something instance administrators should have to bother with:

instance_config = {
    'secret': '...'
}

from tiddlywebplugins.bfw.instance import instance_config as default_config
config = default_config.copy()
config.update(instance_config)

[cdent]

You seem to have some of your logic backwards. Have a look at how things like tank, tiddlyspace, maybe hoster and a few other plugins have an internal to the package config.py which is merged when the plugin is init().

tiddlywebconfig.py still must include server_plugins and twanager_plugins of at least the plugin which identifies the type of instance. That plugin can then be responsible for the loading of things like markdown settings.

[FND]

I had to go imperative in order to make this work: 4e92373b1d1d8f96926dd3022eb68569939d0c0b - though this might be due to my continued lack of understanding of this whole process, so suggestions welcome.