fix(errors): ensure unknown errors look nice

One of the complaints has been that the SDK now shows ugly unknown errors like this:

> Creating build... Error: Unknown Error (400): map[detail:Post http://localhost:5555/v2/test-61453435/blobs/uploads/: net/http: transport closed before response was received]

With this change, the error will dump the raw JSON output instead.

> Creating build... Error: Unknown Error (400): {"detail": "Post http://localhost:5555/v2/test-61453435/blobs/uploads/: net/http: transport closed before response was received"}

Author: Matthew Fisher

errors.go

@@ -92,11 +92,16 @@ func checkForErrors(res *http.Response) error {
 		res.Body.Close()
 	}()
 
+	out, err := ioutil.ReadAll(res.Body)
+	if err != nil {
+		return unknownServerError(res.StatusCode, err.Error())
+	}
+
 	switch res.StatusCode {
 	case 400:
 		bodyMap := make(map[string]interface{})
-		if err := json.NewDecoder(res.Body).Decode(&bodyMap); err != nil {
-			return unknownError(res.StatusCode, err)
+		if err := json.Unmarshal(out, &bodyMap); err != nil {
+			return unknownServerError(res.StatusCode, fmt.Sprintf("error decoding json response (%s): %s", err, string(out)))
 		}
 
 		if scanResponse(bodyMap, "username", []string{fieldReqMsg, invalidUserMsg}, true) {
@@ -166,8 +171,7 @@ func checkForErrors(res *http.Response) error {
 				return ErrTagNotFound
 			}
 		}
-
-		return unknownError(res.StatusCode, bodyMap)
+		return unknownServerError(res.StatusCode, string(out))
 	case 401:
 		return ErrUnauthorized
 	case 403:
@@ -183,11 +187,7 @@ func checkForErrors(res *http.Response) error {
 	case 500:
 		return ErrServerError
 	default:
-		out, err := ioutil.ReadAll(res.Body)
-		if err != nil {
-			return unknownError(res.StatusCode, err)
-		}
-		return unknownError(res.StatusCode, out)
+		return unknownServerError(res.StatusCode, string(out))
 	}
 }
 
@@ -224,8 +224,8 @@ func arrayContains(search string, completeMatch bool, array []string) bool {
 	return false
 }
 
-func unknownError(sc int, k interface{}) error {
-	return fmt.Errorf(formatErrUnknown, sc, k)
+func unknownServerError(statusCode int, message string) error {
+	return fmt.Errorf(formatErrUnknown, statusCode, message)
 }
 
 func scanResponse(

errors_test.go

@@ -2,6 +2,7 @@ package deis
 
 import (
 	"errors"
+	"fmt"
 	"io"
 	"net/http"
 	"testing"
@@ -257,12 +258,21 @@ func TestErrors(t *testing.T) {
 			},
 			expected: ErrServerError,
 		},
+		// ensure unknown errors at least look pretty
+		errorTest{
+			res: &http.Response{
+				StatusCode: 400,
+				Body:       readCloser(`{"detail":"unknown error"}`),
+			},
+			expected: errors.New(`Unknown Error (400): {"detail":"unknown error"}`),
+		},
 	}
 
 	for _, check := range tests {
 		actual := checkForErrors(check.res)
 
-		if actual != check.expected {
+		// specifically check error output rather than value comparison
+		if fmt.Sprintf("%v", actual) != fmt.Sprintf("%v", check.expected) {
 			t.Errorf(failureMessage, check.expected, actual)
 		}
 	}