feat: config deprecation

[mathnogueira]

This PR allows us to deprecate configuration fields and notify the user about them.

Checklist

• tested locally
• added new dependencies
• updated the docs
• added a test

[mathnogueira]

Added this so we have a warning about this setting.

[schoren]

Great work! I think the test relying on writing files to disk needs to be improved, but I like the new apprach!

[schoren]

you can unexport this, I don't think any external clients will depend on this

[schoren]

nice name!

[schoren]

Is it ok if we noramlize tests naming in CamelCase? so we follow the convention from the test func

[schoren]

This test is a bit too complex, and the approach of persisting configs to a file on runtime is prone to race conditions and other kinds of errors.

Given that the config options are defined once for all the souces (file, env, flags), you can leverage the flags to allow concurrent tests. This also allows to reuse the testdata/basic.yaml test file, so we don't have to maintain another basic example here.

Here's an example of a simpler implementation of this test. It also verifies the complete output messages, so the coverage is more complete.

Suggested change

	type deprecatedOptionTest struct {
	name string
	fileContent string
	expectedDeprecatedKeys []string
	}
	type logger struct {
	messages []string
	}
	func (l *logger) Println(in ...any) {
	message := fmt.Sprintf("%s", in...)
	l.messages = append(l.messages, message)
	}
	func (l *logger) GetMessages() []string {
	return l.messages
	}
	func TestDeprecatedOptions(t *testing.T) {
	testCases := []deprecatedOptionTest{
	{
	name: "should_not_detect_any_deprecated_config",
	expectedDeprecatedKeys: []string{},
	fileContent: `
	postgres:
	host: localhost
	port: 5432
	`,
	},
	{
	name: "should_detect_any_deprecated_config",
	expectedDeprecatedKeys: []string{"postgresConnString"},
	fileContent: `
	postgresConnString: "this is deprecated"
	postgres:
	host: localhost
	port: 5432
	`,
	},
	}
	executeDeprecationTestCase(t, testCases)
	}
	func executeDeprecationTestCase(t *testing.T, testCases []deprecatedOptionTest) {
	for _, testCase := range testCases {
	testCase.fileContent = strings.ReplaceAll(testCase.fileContent, "\t", "")
	fileName := "tracetest.yaml"
	err := ioutil.WriteFile(fileName, []byte(testCase.fileContent), 0644)
	require.NoError(t, err)
	defer os.Remove(fileName)
	logger := logger{
	messages: []string{},
	}
	config.New(nil, &logger)
	warnings := make([]string, 0)
	for _, line := range logger.GetMessages() {
	if line == "" {
	continue
	}
	warnings = append(warnings, line)
	}
	assert.Len(t, warnings, len(testCase.expectedDeprecatedKeys))
	for _, message := range testCase.expectedDeprecatedKeys {
	assertSlicesContainsString(t, warnings, message)
	}
	}
	}
	func assertSlicesContainsString(t *testing.T, slice []string, str string) {
	for _, item := range slice {
	if strings.Contains(item, str) {
	return
	}
	}
	assert.Fail(t, fmt.Sprintf("%s was not found", str))
	}
	import (
	"strings"
	"testing"
	"github.com/kubeshop/tracetest/server/config"
	"github.com/stretchr/testify/assert"
	"github.com/stretchr/testify/require"
	)
	type logger struct {
	messages []string
	}
	func (l *logger) Println(in ...any) {
	l.messages = append(l.messages, strings.Join(in))
	}
	func TestDeprecatedOptions(t *testing.T) {
	testCases := []struct {
	name string
	flags []string
	expectedMessages []string
	}{
	{
	name: "NoDeprecations",
	flags: []string{"--config", "./testdata/basic.yaml"},
	expectedMessages: []string{""},
	},
	{
	name: "Deprecated/postgresConnString",
	flags: []string{"--postgresConnString", "some conn string"},
	expectedMessages: []string{`config "postgresConnString" is deprecated. Use the new postgres config structure instead`},
	},
	}
	configFromFlagsWithLogger := func(logger *logger, inputFlags []string) *config.Config {
	flags := pflag.NewFlagSet("fake", pflag.ExitOnError)
	config.SetupFlags(flags)
	err := flags.Parse(inputFlags)
	require.NoError(t, err)
	cfg, err := config.New(flags, logger)
	require.NoError(err)
	return cfg
	}
	for _, testCase := range testCases {
	t.Run(testCase.name, func(t *testing.T) {
	testCase := testCase
	t.Parallel()
	logger := &logger{}
	cfg := configFromFlagsWithLogger(testCase.flags)
	assert.DeepEqual(t, testCase.expectedMessages, logger.messages)
	})
	}
	}

[schoren]

LGTM! Thanks for dealing with my annoying request!