fix: improve error messaging when mandatory flag is missing in file c…

…onvert (#1429)

When mandatory flags for file convert are missing, the error message is not helpful. In this commit, we have added additional validation to communicate more details in the message.

cmd/file_convert.go

@@ -113,6 +113,19 @@ into another compatible format. For example, a configuration for 'kong-gateway-2
 can be converted into a 'kong-gateway-3.x' configuration file.`,
 		Args: validateNoArgs,
 		RunE: execute,
+		PreRunE: func(_ *cobra.Command, _ []string) error {
+			if convertCmdSourceFormat != string(convert.FormatKongGateway) &&
+				convertCmdSourceFormat != string(convert.FormatKongGateway2x) {
+				return fmt.Errorf("invalid value '%s' found for the 'from' flag. Allowed values: [%s, %s]",
+					convertCmdSourceFormat, string(convert.FormatKongGateway), string(convert.FormatKongGateway2x))
+			}
+			if convertCmdDestinationFormat != string(convert.FormatKonnect) &&
+				convertCmdDestinationFormat != string(convert.FormatKongGateway3x) {
+				return fmt.Errorf("invalid value '%s' found for the 'to' flag. Allowed values: [%s, %s]",
+					convertCmdDestinationFormat, string(convert.FormatKonnect), string(convert.FormatKongGateway3x))
+			}
+			return nil
+		},
 	}
 
 	sourceFormats := []convert.Format{convert.FormatKongGateway, convert.FormatKongGateway2x}

tests/integration/file_convert_test.go

@@ -0,0 +1,56 @@
+package integration
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+)
+
+func Test_FileConvert(t *testing.T) {
+	tests := []struct {
+		name                        string
+		convertCmdSourceFormat      string
+		convertCmdDestinationFormat string
+		errorExpected               bool
+		errorString                 string
+	}{
+		{
+			name:                        "Valid source and destination format",
+			convertCmdSourceFormat:      "kong-gateway-2.x",
+			convertCmdDestinationFormat: "kong-gateway-3.x",
+			errorExpected:               false,
+		},
+		{
+			name:                        "Invalid source format",
+			convertCmdSourceFormat:      "random-value",
+			convertCmdDestinationFormat: "kong-gateway-3.x",
+			errorExpected:               true,
+			errorString: "invalid value 'random-value' found for the 'from' flag." +
+				" Allowed values: [kong-gateway, kong-gateway-2.x]",
+		},
+		{
+			name:                        "Invalid destination format",
+			convertCmdSourceFormat:      "kong-gateway-2.x",
+			convertCmdDestinationFormat: "random-value",
+			errorExpected:               true,
+			errorString: "invalid value 'random-value' found for the 'to' flag." +
+				" Allowed values: [konnect, kong-gateway-3.x]",
+		},
+	}
+	for _, tc := range tests {
+		t.Run(tc.name, func(t *testing.T) {
+			_, err := fileConvert(
+				"--from", tc.convertCmdSourceFormat,
+				"--to", tc.convertCmdDestinationFormat,
+				"--input-file", "testdata/file-convert/001-kong-gateway-config/kong-gateway-2-x.yaml",
+			)
+
+			if tc.errorExpected {
+				assert.Error(t, err)
+				assert.Contains(t, err.Error(), tc.errorString)
+			} else {
+				assert.NoError(t, err)
+			}
+		})
+	}
+}

tests/integration/test_utils.go

@@ -342,6 +342,28 @@ func lint(opts ...string) (string, error) {
 	return stripansi.Strip(string(out)), cmdErr
 }
 
+func fileConvert(opts ...string) (string, error) {
+	deckCmd := cmd.NewRootCmd()
+	args := []string{"file", "convert"}
+	if len(opts) > 0 {
+		args = append(args, opts...)
+	}
+	deckCmd.SetArgs(args)
+
+	// capture command output to be used during tests
+	rescueStdout := os.Stdout
+	r, w, _ := os.Pipe()
+	os.Stdout = w
+
+	cmdErr := deckCmd.ExecuteContext(context.Background())
+
+	w.Close()
+	out, _ := io.ReadAll(r)
+	os.Stdout = rescueStdout
+
+	return stripansi.Strip(string(out)), cmdErr
+}
+
 func ping(opts ...string) error {
 	deckCmd := cmd.NewRootCmd()
 	args := []string{"gateway", "ping"}

tests/integration/testdata/file-convert/001-kong-gateway-config/kong-gateway-2-x.yaml

@@ -0,0 +1,10 @@
+_format_version: "1.1"
+services:
+- connect_timeout: 60000
+  id: 58076db2-28b6-423b-ba39-a797193017f7
+  host: mockbin.org
+  name: svc1
+  port: 80
+  protocol: http
+  read_timeout: 60000
+  retries: 5