`default_environment` can only be set in `meltano.yml`, not using `meltano config meltano set`

@tayloramurphy pointed out that meltano config meltano set default_environment prod or meltano config meltano unset default_environment doesn’t do anything.

This is because default_environment is not actually a setting, but a core property of meltano.yml: https://github.com/meltano/meltano/blob/dfd9650170ff97fd69fdff7ac8dc7dc0841bf663/src/meltano/core/meltano_file.py#L21

https://docs.meltano.com/concepts/environments#default-environments doesn’t suggest that meltano config meltano would work here, only setting it directly in meltano.yml. But https://docs.meltano.com/getting-started#view-and-activate-your-environments does call it a setting, and someone seeing it in meltano.yml could reasonably expect it to work just like the other keys in there like send_anonymous_usage_stats and project_id.

If we want to make it a proper setting, we should be able to define it in settings.yml and replace https://github.com/meltano/meltano/blob/main/src/meltano/cli/cli.py#L70 with ProjectSettingsService(project).get("default_environment").

[aaronsteers]

@DouweM and @tayloramurphy - This should be blocked by

• #6247

If we have that in place, and if we categorized this as a Meltano setting, this becomes doable as a top-level only setting that can be modified via .env, terminal env vars, and a top-level entry in meltano.yml.

[DouweM]

@edgarrmondragon Yeah, if default_environment is currently dev, meltano config meltano set default_environment prod would store that under environments: - dev, which would be confusing and may not actually stick, because the next time default_environment is read, it won’t know where to read from yet and would read from the root which wouldn’t have the key. In this case, it really doesn’t make any sense to store this anywhere other than the top-level of meltano.yml.

That’s another point in favor of not allowing top-level settings in envs, although I said in https://github.com/meltano/meltano/issues/3419#issuecomment-1150239801 that there are situations where that does make sense like with send_anonymous_usage_stats or ui.bind_port.