Add support for customizable precedence in Settings Module
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MR: Pending
## Description
Add support for customizable precedence in Settings Module.
There may be cases where we want different settings in the settings module to have different precedence rules, and rather than be stuck with a one-size-fits-all, lets go ahead and add support for making the precedence rules configurable on a per-setting basis.
This will have the additional benefit of further abstracting/standardizing the existing support for determining "relevant settings" for a given step, which currently relies on manual per-step logic and guard clauses.
See related discussion in [this thread](https://gitlab.com/groups/gitlab-org/-/work_items/14186#note_2052379090).
- See https://gitlab.com/groups/gitlab-org/-/epics/14186+ for overview and more context
- See [Related Issues and MRs section in that epic](https://gitlab.com/groups/gitlab-org/-/epics/14186#related-issues-and-mrs) for related issues and MRs
## Acceptance Criteria
- [ ] Precedence rules can be configured on a per-setting basis
## Technical Requirements
Here is an initial idea of what this API might look like:
```ruby
module RemoteDevelopment
module Settings
class DefaultSettings
def self.default_settings
{
some_setting: {
default_value: 1,
type: Integer,
sources: [SomeSettingsReader, SomeOtherSettingsReader]
},
# ...
}
end
end
end
end
module RemoteDevelopment
module Settings
class SomeSettingsReader
def self.read(context)
err_result = nil
SettingsBuilder.provide_settings_values(step_class: self, context: context) do |setting_name, values_from_previous_steps|
# NOTE: values_from_previous_steps can be used if this step needs to know the values of other settings
begin
ClassToReadSomeSetting.read(setting_name) # read and return setting value from some source, to contribute to context
rescue
err_result = Gitlab::Fp::Result.err(SettingsSomeSettingsReadFailed.new(details: "Some failure for #{setting_name}"))
break
end
# provide_settings_values will take the returned setting value, and add it to the list of "contributed" settings
end
return err_result if err_result
Gitlab::Fp::Result.ok(context)
end
end
end
end
module RemoteDevelopment
module Settings
class SettingsPrecedenceSorter # last step in the Settings Module ROP chain
def self.sort(context)
context[:settings] = SettingsBuilder.sort(context) # sort out the settings based on order of sources
context
end
end
end
end
```
## Design Requirements
None, no UI changes.
issue