Add a config flag for ED to customize the location of config.json

[pmaier1]

Your use case

What would you like to do?

Add a config flag for ED to customize the location of config.json such that it can point to the one exposed by ESS. This way the admin can live edit it using e.g., admin console or other hooks. Customer admins can set the flag via their ED installer (e.g., MSI).

Why would you like to do it?

• There are certain configurations that administrators will set in ESS (example)
• For EW we can just change config.json on-the-fly ✔️
• Currently there is no (simple) way to automatically propagate them to ED since ED relies on a hardcoded local config.json (if I'm not mistaken)

How would you like to achieve it?

The idea is that there would be something like a build flag (e.g., in MSI for Windows) such that administrators can roll out ED with a pre-configured location for config.json. This way we imagine that changes in ESS will automatically propagate to ED instances.

@daniellekirkwood @langleyd

Have you considered any alternatives?

No response

Additional context

No response

[t3chguy]

By location do you mean system file path or do you mean web URL? If the latter we'd need designs for the state for when the config cannot be loaded. I guess we'd need that if the config file was missing on the filesystem too.

Related #731
Related element-hq/element-web#13678

[Half-Shot]

@pmaier1 @t3chguy does #1921 solve this?

[davidegirardi]

In my opinion yes and we also avoid building different packages for different configuration paths.