etcd provider does not work as expected

[bamoo456]

Expected Behavior

Based on the README.md, the following execution should work.

ETCDCTL_ENDPOINTS=x.x.x.x:2379 ETCDCTL_USER=read ETCDCTL_PASSWORD teller show

Current Behavior

The above command gave me:

FATA[0000] could not load all variables from the given existing providers  error="etcdserver: user name is empty"

Possible Solution

I would suggest explicitly add a username and password while instantiating a etcd client, for example: Update the code to be following:

	cfg := clientv3.Config{
		TLS:       tr,
		Endpoints: eps,
		Username:  os.Getenv("ETCDCTL_USER"),
		Password:  os.Getenv("ETCDCTL_PASSWORD"),
	}

Steps to Reproduce

1. Dowload the latest release version 1.5.6.
2. Execute the teller by: ETCDCTL_ENDPOINTS=x.x.x.x:2379 ETCDCTL_USER=read ETCDCTL_PASSWORD teller show
3. You should see the unexpected errors.

Context

The issue is the etcd provider was not work as expected, so we need a fix for people using etcd.

Specifications

• Version:

Teller 1.5.6
Revision 7b714bc2f1d5e14920f2add828fdf7425148ff6b, date: 2022-10-13T08:02:44Z

• Platform: Ubuntu 22.04