feat: Create openfeature pull command

[jsalaber]

Summary

• init command creates a .openfeature.yaml to store flagSourceUrl using the --flag-source-url
• adds a new pull command that fetches a flag configuration from a flagSourceUrl configured in the init command
• pull command prompts the user for default values if the source configuration doesn't define default values
• overwrites the manifest with the source url flags

Related Issues

#3

Notes

• refactored out the Load function from flagset due to circular dependency when trying to use flagset type in the manifest package
• new LoadFromSourceFlags takes the type from a source configuration and compares it to different types that could match, e.g. Boolean, bool, boolean

Todo

• Support different auth types other than auth token as a header, and figure out a way to store it securely without needing to pass it in as a flag in the pull command

[beeme1mr]

For anyone interested in testing this locally:

go run main.go pull --flagSourceUrl https://gist.githubusercontent.com/beeme1mr/f74bc892c9651d029fa804657e847237/raw/b1a21304df3a9b99e13c4c91b42245e56d90dffa/flags

Note

You also need to comment out the auth header on line 17 in fetchFlags.go.

[kriscoleman]

I love the UX here, well done 🥇

[kriscoleman]

I'm wondering if we could drop the switch statements if we take the map from unmarshal and do a key/value lookup on it.

Then maybe we could return with something like this:

	value, exists := config[key]
	if !exists {
		return "", fmt.Errorf("unknown key: %s", key)
	}

	return value, nil
	```

[kriscoleman]

good call, I think moving this logic here makes sense 👍

EDIT: on second thought, I mistakenly thought this returned a Manifest obj, and I was going to use it in my branch, but it looks like it loads the manifest from path into a flagset obj.

I would expect if I call manifest.Load() it would return a manifest, just some food for thought.

Perhaps we could keep this in flagset, and I would suggest maybe naming it flagset.LoadFromManifest; or, if we keep it here, I suggest naming it manifest.LoadFlagset()

[jsalaber]

that's a good point, the problem I had keeping it in the flagset file was a circular dependency occurring where I needed the type defined in flagset in this package, but the flagset file also imported the manifest package

I wouldn't mind renaming this to be more specific to loading the flagset though!

[kriscoleman]

looking great to me so far 😄

[beeme1mr]

Sorry @jsalaber, this automatically closed when I merged my other PR but I'm not sure why. Could you please reopen it when you have moment?

[jsalaber]

@beeme1mr yep, recreating it against main