[proposal] Remove interfaces and functions from go-elasticsearch.Config about go-elasticsearch HOT 2 OPEN

How about:

Introduce a new StaticConfig struct within go-elasticsearch. This new struct doesn't include any functions and interfaces.
Then, use functional options in elasticsearch.New to allow building a new client with static config (from YAML), but also add other options such as RetryOnError.

type StaticConfig struct {
  Addresses []string `json:"addresses"`
}
myConfig := StaticConfig{}

client := elasticsearch.New(
  WithStaticConfig(myConfig),
)

With this, the user sets static config from the specified format.
I am specifying the JSON key in this struct here, as it's the easiest way to avoid folks from having to set their own config. But more complicated solutions using reflect may be possible if we want to be fancy.

If they want to specify function configs, which can't be specified from anything static, they can use other functional options:

client := elasticsearch.New(
  WithRetryOnError(func(*http.Request, error) bool {
    return false
  }),
)

Within the New method, a Config struct would be built, and every functional option would be passed to it. Each option decides what to do with the config (set one or multiple attributes).
If a specific functional option isn't passed, a default value has to be set.

from go-elasticsearch.

What I'm missing from the suggested StaticConfig approach is a proper solution for RetryOnError and RetryBackoff. In particular these two interfaces provide currently configuration options, that are essential for customers.
If they are implemented with the functional approach, like WithRetryOnError(..) I can see how this works from a developer perspective. But I think, every service - like apm-server, fleet-server & others - will come up with their own way to configure it and so I think, the purpose to unify go-elasticsearch.Config accross the Elastic ecosystem is missed.

from go-elasticsearch.