Gnocchi: implement resource types List method

[ozerovandrei]

Add new resourcetypes package with List method.
Add tests and a documentation example.

Code references:
https://github.com/gnocchixyz/gnocchi/blob/stable/4.2/gnocchi/rest/api.py#L953
https://github.com/gnocchixyz/gnocchi/blob/stable/4.2/gnocchi/indexer/sqlalchemy.py#L485
https://github.com/gnocchixyz/gnocchi/blob/stable/4.2/gnocchi/resource_type.py#L264

For #54

[jtopjian]

@ozerovandrei I apologize for the delay.

I've left one inline comment. In addition, I think the Attribute type might need some changes. According to the REST API docs there are a set amount of "types": string, bool, number, etc. This is reflected in the code, too:

• https://github.com/gnocchixyz/gnocchi/blob/stable/4.2/gnocchi/resource_type.py#L132
• https://github.com/gnocchixyz/gnocchi/blob/stable/4.2/gnocchi/resource_type.py#L164

Each type can have different attributes. For example, a "number" type has min and max but a "string" does not.

I wonder if it would be best to model Attribute like:

type Attribute {
  Type string
  Required bool
  Extra map[string]interface{}
}

Thoughts?

[jtopjian]

Can we call this Attribute?

[ozerovandrei]

@jtopjian Hello.
Attribute was tricky. I haven't started implementing another PR for the #54, because I haven't been sure about current implementation.
Will try to change it according to your request.

[jtopjian]

Sounds good. Another option is to leave Attribute as a generic map[string]interface{}. I guess it depends on if the attributes will be usable or just for informational purposes.

[ozerovandrei]

@jtopjian I made changes related to Attribute field. I think that it's better to have at least Name and Type as separate fields inside the structure because they're common between all attribute types.

[jtopjian]

@ozerovandrei This still felt a little strange to me and then I realized it is because we're trying to convert a map of values into an array.

How about something like this: jtopjian@89b3bbb

[ozerovandrei]

@jtopjian it's because I've tried to do a very strong structure types without any maps from the beginning of that PR. Some Go developer told me to so so once: #issuecomment-362023884 😉

But yeah, I can change this, why not.

[jtopjian]

That discussion is still applicable. :)

What I'm proposing is modeling the data in its normal map/object/hash/dict form and not coalescing it into an array/list/slice.

[ozerovandrei]

@jtopjian I thought about it and I think that your variant is better, because it looks more similar to actual Gnocchi response structure.
I've applied those changes.

[jtopjian]

LGTM!

[jtopjian]

@ozerovandrei Just to confirm: you're finished with this and it's mergeable?

[ozerovandrei]

@jtopjian yes, it is ready.