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

…onvert (#1429) (#1487)

* fix: improve error messaging when mandatory flag is missing in file convert (#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.

* add a reusable validation function for strings

* assert converted file contents and address review feedback

* limit file convert tests to yaml format for now

cmd/file_convert.go

@@ -113,6 +113,22 @@ 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 {
+			validSourceFormats := []string{string(convert.FormatKongGateway), string(convert.FormatKongGateway2x)}
+			validDestinationFormats := []string{string(convert.FormatKonnect), string(convert.FormatKongGateway3x)}
+
+			err := validateInputFlag("from", convertCmdSourceFormat, validSourceFormats, "")
+			if err != nil {
+				return err
+			}
+
+			err = validateInputFlag("to", convertCmdDestinationFormat, validDestinationFormats, "")
+			if err != nil {
+				return err
+			}
+
+			return nil
+		},
 	}
 
 	sourceFormats := []convert.Format{convert.FormatKongGateway, convert.FormatKongGateway2x}

cmd/utils.go

@@ -1,6 +1,10 @@
 package cmd
 
 import (
+	"errors"
+	"fmt"
+	"slices"
+
 	"github.com/fatih/color"
 	"github.com/kong/go-database-reconciler/pkg/cprint"
 	"github.com/kong/go-database-reconciler/pkg/diff"
@@ -30,3 +34,16 @@ func addSilenceEventsFlag(set *pflag.FlagSet) {
 	set.BoolVar(&silenceEvents, "silence-events", false,
 		"disable printing events to stdout")
 }
+
+func validateInputFlag(flagName string, flagValue string, allowedValues []string, errorMessage string) error {
+	if slices.Contains(allowedValues, flagValue) {
+		return nil
+	}
+
+	if errorMessage != "" {
+		return errors.New(errorMessage)
+	}
+
+	return fmt.Errorf("invalid value '%s' found for the '%s' flag. Allowed values: %v",
+		flagValue, flagName, allowedValues)
+}

tests/integration/file_convert_test.go

@@ -0,0 +1,73 @@
+package integration
+
+import (
+	"os"
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"sigs.k8s.io/yaml"
+)
+
+func Test_FileConvert(t *testing.T) {
+	tests := []struct {
+		name                        string
+		convertCmdSourceFormat      string
+		convertCmdDestinationFormat string
+		errorExpected               bool
+		errorString                 string
+		expectedOutputFile          string
+	}{
+		{
+			name:                        "Valid source and destination format",
+			convertCmdSourceFormat:      "kong-gateway-2.x",
+			convertCmdDestinationFormat: "kong-gateway-3.x",
+			errorExpected:               false,
+			expectedOutputFile:          "testdata/file-convert/001-kong-gateway-config/kong-gateway-3-x.yaml",
+		},
+		{
+			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) {
+			output, 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)
+
+				return
+			}
+
+			assert.NoError(t, err)
+
+			var expectedOutput interface{}
+			var currentOutput interface{}
+			content, err := os.ReadFile(tc.expectedOutputFile)
+			assert.NoError(t, err)
+
+			err = yaml.Unmarshal(content, &expectedOutput)
+			assert.NoError(t, err)
+			err = yaml.Unmarshal([]byte(output), &currentOutput)
+			assert.NoError(t, err)
+			assert.Equal(t, expectedOutput, currentOutput)
+		})
+	}
+}

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

tests/integration/testdata/file-convert/001-kong-gateway-config/kong-gateway-3-x.yaml

@@ -0,0 +1,10 @@
+_format_version: "3.0"
+services:
+- connect_timeout: 60000
+  id: 58076db2-28b6-423b-ba39-a797193017f7
+  host: mockbin.org
+  name: svc1
+  port: 80
+  protocol: http
+  read_timeout: 60000
+  retries: 5