How to create custom chain of credential providers

[avishay28]

Hey,
How can I mimic this functionally from v1 sdk?

import (
	"github.com/aws/aws-sdk-go/aws/credentials"
	"github.com/aws/aws-sdk-go/aws/credentials/ec2rolecreds"
)

...

func GetCreds(accessKey, secretKey, token, region string) (*credentials.Credentials, error) {
	creds := credentials.NewChainCredentials([]credentials.Provider{
		&credentials.StaticProvider{Value: credentials.Value{
			AccessKeyID:     accessKey,
			SecretAccessKey: secretKey,
			SessionToken:    token,
		}},
		&credentials.EnvProvider{},
		&credentials.SharedCredentialsProvider{Filename: "", Profile: ""},
		&CustomProvider1{region: region, ExpiryWindow: 10 * time.Second},
		&ec2rolecreds.EC2RoleProvider{
			ExpiryWindow: 10 * time.Second,
			Client: ec2metadata.New(session.New(&aws.Config{
				Region: aws.String(region),
			})),
		},
		&CustomProvider2{Foo: "bar"},
	})

	_, err := creds.Get()
	if err != nil {
		return nil, err
	}

	return creds, nil
}

I couldn't find any way to do that in v2, it looks like a lof ot the credentials logic is hidden, I don't have any controll on the chain order.
Now I need to use LoadDefaultConfig which forcing the order of the providers.
I could try to create a customer provider which chains providers together and try to Retreive them in order, however it means I need to write in hand providers like SharedCredentialsProvider or EnvProvider which are not exist in v2.

As a general feedback- I feel like there's a bit of mess in everything that related to the way we working with credentials in v2 sdk. Some logic belongs to credentials package, some to aws package (like the Credentials struct or CredentialsCache, like.. why CredentialsCache logic is not part of credentials package?), some to config.
It was much easier to work with when everything was under github.com/aws/aws-sdk-go/aws/credentials