authZ: more fixes

- fix naming and formatting
- provide more context when erroring auth
- do not capitalize errors
- fix wrong documentation
- remove ugly remoteError{}

Signed-off-by: Antonio Murdaca <runcom@redhat.com>

plugins/client.go

@@ -20,15 +20,6 @@ const (
 	defaultTimeOut  = 30
 )
 
-type remoteError struct {
-	method string
-	err    string
-}
-
-func (e *remoteError) Error() string {
-	return fmt.Sprintf("Plugin Error: %s, %s", e.err, e.method)
-}
-
 // NewClient creates a new plugin client (http).
 func NewClient(addr string, tlsConfig tlsconfig.Options) (*Client, error) {
 	tr := &http.Transport{}
@@ -133,7 +124,7 @@ func (c *Client) callWithRetry(serviceMethod string, data io.Reader, retry bool)
 		if resp.StatusCode != http.StatusOK {
 			b, err := ioutil.ReadAll(resp.Body)
 			if err != nil {
-				return nil, &remoteError{method: serviceMethod, err: err.Error()}
+				return nil, fmt.Errorf("%s: %s", serviceMethod, err)
 			}
 
 			// Plugins' Response(s) should have an Err field indicating what went
@@ -144,13 +135,13 @@ func (c *Client) callWithRetry(serviceMethod string, data io.Reader, retry bool)
 			}
 			remoteErr := responseErr{}
 			if err := json.Unmarshal(b, &remoteErr); err != nil {
-				return nil, &remoteError{method: serviceMethod, err: err.Error()}
+				return nil, fmt.Errorf("%s: %s", serviceMethod, err)
 			}
 			if remoteErr.Err != "" {
-				return nil, &remoteError{method: serviceMethod, err: remoteErr.Err}
+				return nil, fmt.Errorf("%s: %s", serviceMethod, remoteErr.Err)
 			}
 			// old way...
-			return nil, &remoteError{method: serviceMethod, err: string(b)}
+			return nil, fmt.Errorf("%s: %s", serviceMethod, string(b))
 		}
 		return resp.Body, nil
 	}