Account-specific logo, adaptable in backend

[nhoening]

To support white-labeling, we need custom colors and logo. #471 is about the colors, here we deal with the logo.

In the end, users with role account-admin should be able to upload a logo, which gets saved to the database (in the account table). Of course, the size should be limited. The SO link here is a good inspiration for the whole roundtrip, but this issue only deals with making it possible for FlexMeasures admins to set the logo.

This requires:

• an extension of the accounts table with a logo field (the SO example used db.Column(db.LargeBinary) but I guess we can restrict the size here somewhat)
• extending the CLI command (pointing to a file?) might be a good way to test this without already having to write an upload form, probably not and maybe these two tickets require a new account editing form, but that
• when the logo field is set, the UI should show that logo in the upper left corner instead of the FlexMeasures logo. Currently, to set a custom logo we check the config variable which can contain a custom URL: in view_utils.py we do this: variables["menu_logo"] = current_app.config.get("FLEXMEASURES_MENU_LOGO_PATH"). Maybe we can add a Flask route account/ID/logo which serves the logo of an account (requiring users to be logged-in) and if the account has a logo and FLEXMEASURES_MENU_LOGO_PATH is not set, variables["menu_logo"] gets set to the URL for that view.

Not included: API endpoint to patch an account and a form to upload logo.

[joshuaunity]

Hi Nicolas, I was thinking what if we collect a URL instead of them uploading an actual image which we have to process?

[nhoening]

I forgot my counterargument. Maybe you are right and that is an easier path for now.