After review commit

docs/configuration/advanced-configuration.md

@@ -319,19 +319,6 @@ you can set the authorization configuration in the `DOCKER_AUTH_CONFIG`
 [variable]. It can be set in both GitLab Variables section of
 a project and in the `config.toml` file.
 
-Docker credentials helper can be configured using `config.json` file in `.docker` folder
-in runner's home directory, if you are using self hosted runners:
-
-```json
-{
-    "credHelpers": {
-        "aws_account_id.dkr.ecr.region-1.amazonaws.com": "ecr-login",
-        "aws_account_id.dkr.ecr.region-2.amazonaws.com": "ecr-login",
-        "gcr.io": "gcr"
-    }
-}
-```
-
 For a detailed example, visit the [Using Docker images documentation][priv-example].
 
 The steps performed by the Runner can be summed up to:

helpers/docker/auth_config.go

@@ -114,30 +114,34 @@ func ReadAuthConfigsFromReader(r io.Reader) (map[string]types.AuthConfig, error)
 		}
 		addAll(auths, authsFromCredentialsHelpers)
 	}
+
 	return auths, nil
 }
 
 func readAuthConfigsFromCredentialsStore(config *configfile.ConfigFile) (map[string]types.AuthConfig, error) {
 	store := credentials.NewNativeStore(config, config.CredentialsStore)
-
 	newAuths, err := store.GetAll()
-
 	if err != nil {
 		return nil, err
 	}
+
 	return newAuths, nil
 }
 
 func readAuthConfigsFromCredentialsHelper(config *configfile.ConfigFile) (map[string]types.AuthConfig, error) {
 	helpersAuths := make(map[string]types.AuthConfig)
+
 	for registry, helper := range config.CredentialHelpers {
 		store := credentials.NewNativeStore(config, helper)
+
 		newAuths, err := store.Get(registry)
 		if err != nil {
 			return nil, err
 		}
+
 		helpersAuths[registry] = newAuths
 	}
+
 	return helpersAuths, nil
 }