Is there a way to remove a dictionary with merge?

[josecelano]

Context

In my app I have a TOML file with a default configuration:

[http_api]
enabled = true
bind_address = "HTTP://127.0.0.1:1212"

# ...

The dictionary http_api contains config values about that service. By default, the service is enabled in the app. Right now, I can disable it just by overriding the key value enabled, but the whole dictionary is still there.

I'm loading the configuration with:

Figment::from(Serialized::defaults(Configuration::default()))
    .merge(Toml::file(&info.config_toml_path))
    .merge(Env::prefixed(CONFIG_OVERRIDE_PREFIX).split(CONFIG_OVERRIDE_SEPARATOR))

That allows me to define a default configuration (with the enabled HTTP API service) and disable the API overriding the enabled key with env vars.

Question

What I want to do is get rid of the enabled key. I would like to represent that the API is not enabled just not including that part of the configuration. However, I would like to include it in the default configuration.

The only solution I see now is to remove the http_api dict in the default configuration, but that forces the user to always override that part.

Is there a way to remove a whole dictionary with merge?

cc @da2ce7

[SergioBenitez]

What is the functionality that you're looking for? At the moment, it feels like your two asks are in conflict with each-other: you want to simultaneously provide a default, which implies a configuration should exist when one isn't provided, but also not use a configuration when one isn't provided. Can you perhaps provide several examples (that is, configurations and their expected extraction) that demonstrate what you're trying to achieve?

[josecelano]

What is the functionality that you're looking for? At the moment, it feels like your two asks are in conflict with each-other: you want to simultaneously provide a default, which implies a configuration should exist when one isn't provided, but also not use a configuration when one isn't provided. Can you perhaps provide several examples (that is, configurations and their expected extraction) that demonstrate what you're trying to achieve?

Hi @SergioBenitez sorry, I was thinking in a way to "unset" a default value, but trying to thinking about a concrete example I see all solutions would be custom uses of TOML and Figment, but It does not make sense. What I finally did was to remove the whole dict form the default, even if that implies that users have to explicitly added it in other cases. The only clean alternative is to add the "enable" field I wanted to remove.

Sorry to bother you :-/.

[josecelano]

Just to clarify, I was thinking about something like a difference set operation. Merge and join are "union", this new would be "difference" and in the future even "intersection" could be implemented. But the solution with "difference" would imply to inject a second toml file. And that would be more complex or verbose than the other alternatives, at least in this case.