Enhance the ErrWrongConfig error

This changes the name of ErrWrongConfig to ErrInvalidConfig, and also
adds the `What` field. This allows a user of the error to supply context
as to how configuration was incorrect.

Change-Id: I476ef9ed737e9a4eee7bef9f3b0f3417ebff60f6

pkg/bootstrap/isogen/command.go

@@ -71,13 +71,15 @@ func GenerateBootstrapIso(settings *environment.AirshipCTLSettings, args []strin
 
 func verifyInputs(cfg *config.Bootstrap) error {
 	if cfg.Container.Volume == "" {
-		log.Print("Specify volume bind for ISO builder container")
-		return config.ErrWrongConfig{}
+		return config.ErrMissingConfig{
+			What: "Must specify volume bind for ISO builder container",
+		}
 	}
 
 	if (cfg.Builder.UserDataFileName == "") || (cfg.Builder.NetworkConfigFileName == "") {
-		log.Print("UserDataFileName or NetworkConfigFileName are not specified in ISO builder config")
-		return config.ErrWrongConfig{}
+		return config.ErrMissingConfig{
+			What: "UserDataFileName or NetworkConfigFileName are not specified in ISO builder config",
+		}
 	}
 
 	vols := strings.Split(cfg.Container.Volume, ":")
@@ -85,8 +87,9 @@ func verifyInputs(cfg *config.Bootstrap) error {
 	case len(vols) == 1:
 		cfg.Container.Volume = fmt.Sprintf("%s:%s", vols[0], vols[0])
 	case len(vols) > 2:
-		log.Print("Bad container volume format. Use hostPath:contPath")
-		return config.ErrWrongConfig{}
+		return config.ErrInvalidConfig{
+			What: "Bad container volume format. Use hostPath:contPath",
+		}
 	}
 	return nil
 }

pkg/bootstrap/isogen/command_test.go

@@ -130,26 +130,49 @@ func TestVerifyInputs(t *testing.T) {
 	defer cleanup(t)
 
 	tests := []struct {
+		name        string
 		cfg         *config.Bootstrap
 		args        []string
 		expectedErr error
 	}{
 		{
+			name: "missing-container-field",
 			cfg: &config.Bootstrap{
 				Container: &config.Container{},
 			},
-			expectedErr: config.ErrWrongConfig{},
+			expectedErr: config.ErrMissingConfig{
+				What: "Must specify volume bind for ISO builder container",
+			},
 		},
 		{
+			name: "missing-filenames",
 			cfg: &config.Bootstrap{
 				Container: &config.Container{
 					Volume: tempVol + ":/dst",
 				},
 				Builder: &config.Builder{},
 			},
-			expectedErr: config.ErrWrongConfig{},
+			expectedErr: config.ErrMissingConfig{
+				What: "UserDataFileName or NetworkConfigFileName are not specified in ISO builder config",
+			},
 		},
 		{
+			name: "invalid-host-path",
+			cfg: &config.Bootstrap{
+				Container: &config.Container{
+					Volume: tempVol + ":/dst:/dst1",
+				},
+				Builder: &config.Builder{
+					UserDataFileName:      "user-data",
+					NetworkConfigFileName: "net-conf",
+				},
+			},
+			expectedErr: config.ErrInvalidConfig{
+				What: "Bad container volume format. Use hostPath:contPath",
+			},
+		},
+		{
+			name: "success",
 			cfg: &config.Bootstrap{
 				Container: &config.Container{
 					Volume: tempVol,
@@ -161,22 +184,13 @@ func TestVerifyInputs(t *testing.T) {
 			},
 			expectedErr: nil,
 		},
-		{
-			cfg: &config.Bootstrap{
-				Container: &config.Container{
-					Volume: tempVol + ":/dst:/dst1",
-				},
-				Builder: &config.Builder{
-					UserDataFileName:      "user-data",
-					NetworkConfigFileName: "net-conf",
-				},
-			},
-			expectedErr: config.ErrWrongConfig{},
-		},
 	}
 
 	for _, tt := range tests {
-		actualErr := verifyInputs(tt.cfg)
-		assert.Equal(t, tt.expectedErr, actualErr)
+		tt := tt
+		t.Run(tt.name, func(subTest *testing.T) {
+			actualErr := verifyInputs(tt.cfg)
+			assert.Equal(subTest, tt.expectedErr, actualErr)
+		})
 	}
 }

pkg/config/errors.go

@@ -60,12 +60,13 @@ func (e ErrBootstrapInfoNotFound) Error() string {
 	return fmt.Sprintf("Bootstrap info %q not found", e.Name)
 }
 
-// ErrWrongConfig returned in case of incorrect configuration
-type ErrWrongConfig struct {
+// ErrInvalidConfig returned in case of incorrect configuration
+type ErrInvalidConfig struct {
+	What string
 }
 
-func (e ErrWrongConfig) Error() string {
-	return "Wrong configuration"
+func (e ErrInvalidConfig) Error() string {
+	return fmt.Sprintf("Invalid configuration: %s", e.What)
 }
 
 // ErrMissingConfig returned in case of missing configuration