Merge pull request #67 from ovh/dev/rbeuque/errors

feat(errors): improve readability of error messages

ovh/error.go

@@ -1,6 +1,9 @@
 package ovh
 
-import "fmt"
+import (
+	"fmt"
+	"strings"
+)
 
 // APIError represents an error that can occurred while calling the API.
 type APIError struct {
@@ -16,10 +19,33 @@ type APIError struct {
 	QueryID string
 }
 
-func (err *APIError) Error() string {
-	if err.Class == "" {
-		return fmt.Sprintf("HTTP Error %d: %q", err.Code, err.Message)
+// Let's make sure that APIError always satisfies the fmt.Stringer and error interfaces
+var _ fmt.Stringer = APIError{}
+var _ error = APIError{}
+
+func (err APIError) Error() string {
+	var sb strings.Builder
+	sb.Grow(128)
+
+	// Base message
+	fmt.Fprint(&sb, "OVHcloud API error (status code ", err.Code, "): ")
+
+	// Append class if any
+	if err.Class != "" {
+		fmt.Fprint(&sb, err.Class, ": ")
+	}
+
+	// Real error message, quoted
+	fmt.Fprintf(&sb, "%q", err.Message)
+
+	// QueryID if any
+	if err.QueryID != "" {
+		fmt.Fprint(&sb, " (X-OVH-Query-Id: ", err.QueryID, ")")
 	}
 
-	return fmt.Sprintf("HTTP Error %d: %s: %q (X-OVH-Query-Id: %s)", err.Code, err.Class, err.Message, err.QueryID)
+	return sb.String()
+}
+
+func (err APIError) String() string {
+	return err.Error()
 }

ovh/error_test.go

@@ -8,17 +8,27 @@ import (
 )
 
 func TestErrorString(t *testing.T) {
-	err := &APIError{
+	err := APIError{
 		Code:    http.StatusBadRequest,
-		Message: "Bad request",
+		Message: "An input error occurred",
 	}
-	td.CmpString(t, err, `HTTP Error 400: "Bad request"`)
+	expected := `OVHcloud API error (status code 400): "An input error occurred"`
+	td.Cmp(t, err.Error(), expected)
+	td.Cmp(t, err.String(), expected)
 
-	err = &APIError{
+	err = APIError{
 		Code:    http.StatusConflict,
 		Message: `the cart id "foobar" already exists`,
 		Class:   "CartAlreadyExists",
 		QueryID: "EU.ext-99.foobar",
 	}
-	td.CmpString(t, err, `HTTP Error 409: CartAlreadyExists: "the cart id \"foobar\" already exists" (X-OVH-Query-Id: EU.ext-99.foobar)`)
+	expected = `OVHcloud API error (status code 409): CartAlreadyExists: "the cart id \"foobar\" already exists" (X-OVH-Query-Id: EU.ext-99.foobar)`
+	td.Cmp(t, err.Error(), expected)
+	td.Cmp(t, err.String(), expected)
+
+	err.Class = ""
+	expected = `OVHcloud API error (status code 409): "the cart id \"foobar\" already exists" (X-OVH-Query-Id: EU.ext-99.foobar)`
+	td.Cmp(t, err.Error(), expected)
+	td.Cmp(t, err.String(), expected)
+
 }