add readonly tag (#190)

cli/mizu/config.go

@@ -21,6 +21,8 @@ import (
 const (
 	Separator      = "="
 	SetCommandName = "set"
+	FieldNameTag   = "yaml"
+	ReadonlyTag    = "readonly"
 )
 
 var allowedSetFlags = []string{
@@ -71,8 +73,8 @@ func GetConfigWithDefaults() (string, error) {
 		return "", err
 	}
 
-	// TODO: change to generic solution
-	defaultConf.AgentImage = ""
+	configElem := reflect.ValueOf(&defaultConf).Elem()
+	setZeroForReadonlyFields(configElem)
 
 	return uiUtils.PrettyYaml(defaultConf)
 }
@@ -110,16 +112,14 @@ func initFlag(f *pflag.Flag) {
 	}
 
 	if f.Name == SetCommandName {
-		mergeSetFlag(sliceValue.GetSlice())
+		mergeSetFlag(configElem, sliceValue.GetSlice())
 		return
 	}
 
 	mergeFlagValues(configElem, f.Name, sliceValue.GetSlice())
 }
 
-func mergeSetFlag(setValues []string) {
-	configElem := reflect.ValueOf(&Config).Elem()
-
+func mergeSetFlag(configElem reflect.Value, setValues []string) {
 	for _, setValue := range setValues {
 		if !strings.Contains(setValue, Separator) {
 			Log.Warningf(uiUtils.Warning, fmt.Sprintf("Ignoring set argument %s (set argument format: <flag name>=<flag value>)", setValue))
@@ -150,7 +150,7 @@ func mergeFlagValue(currentElem reflect.Value, flagKey string, flagValue string)
 			continue
 		}
 
-		if currentField.Tag.Get("yaml") != flagKey {
+		if getFieldNameByTag(currentField) != flagKey {
 			continue
 		}
 
@@ -176,7 +176,7 @@ func mergeFlagValues(currentElem reflect.Value, flagKey string, flagValues []str
 			continue
 		}
 
-		if currentField.Tag.Get("yaml") != flagKey {
+		if getFieldNameByTag(currentField) != flagKey {
 			continue
 		}
 
@@ -197,6 +197,10 @@ func mergeFlagValues(currentElem reflect.Value, flagKey string, flagValues []str
 	}
 }
 
+func getFieldNameByTag(field reflect.StructField) string {
+	return strings.Split(field.Tag.Get(FieldNameTag), ",")[0]
+}
+
 func getParsedValue(kind reflect.Kind, value string) (reflect.Value, error) {
 	switch kind {
 	case reflect.String:
@@ -282,3 +286,19 @@ func getParsedValue(kind reflect.Kind, value string) (reflect.Value, error) {
 
 	return reflect.ValueOf(nil), errors.New("value to parse does not match type")
 }
+
+func setZeroForReadonlyFields(currentElem reflect.Value) {
+	for i := 0; i < currentElem.NumField(); i++ {
+		currentField := currentElem.Type().Field(i)
+		currentFieldByName := currentElem.FieldByName(currentField.Name)
+
+		if currentField.Type.Kind() == reflect.Struct {
+			setZeroForReadonlyFields(currentFieldByName)
+			continue
+		}
+
+		if _, ok := currentField.Tag.Lookup(ReadonlyTag); ok {
+			currentFieldByName.Set(reflect.Zero(currentField.Type))
+		}
+	}
+}

cli/mizu/configStruct.go

@@ -19,7 +19,7 @@ type ConfigStruct struct {
 	Fetch                  configStructs.FetchConfig   `yaml:"fetch"`
 	Version                configStructs.VersionConfig `yaml:"version"`
 	View                   configStructs.ViewConfig    `yaml:"view"`
-	AgentImage             string                      `yaml:"agent-image,omitempty"`
+	AgentImage             string                      `yaml:"agent-image,omitempty" readonly:""`
 	MizuResourcesNamespace string                      `yaml:"mizu-resources-namespace" default:"mizu"`
 	Telemetry              bool                        `yaml:"telemetry" default:"true"`
 	DumpLogs               bool                        `yaml:"dump-logs" default:"false"`

cli/mizu/configStructs/tapConfig.go

@@ -34,7 +34,7 @@ type TapConfig struct {
 	Analysis                     bool     `yaml:"analysis" default:"false"`
 	AllNamespaces                bool     `yaml:"all-namespaces" default:"false"`
 	PlainTextFilterRegexes       []string `yaml:"regex-masking"`
-	HealthChecksUserAgentHeaders []string `yaml:"ignored-user-agents" default:"[]"`
+	HealthChecksUserAgentHeaders []string `yaml:"ignored-user-agents"`
 	DisableRedaction             bool     `yaml:"no-redact" default:"false"`
 	HumanMaxEntriesDBSize        string   `yaml:"max-entries-db-size" default:"200MB"`
 	Direction                    string   `yaml:"direction" default:"in"`

cli/mizu/config_test.go

@@ -0,0 +1,39 @@
+package mizu_test
+
+import (
+	"github.com/up9inc/mizu/cli/mizu"
+	"reflect"
+	"strings"
+	"testing"
+)
+
+func TestConfigWriteIgnoresReadonlyFields(t *testing.T) {
+	var readonlyFields []string
+
+	configElem := reflect.ValueOf(&mizu.ConfigStruct{}).Elem()
+	getFieldsWithReadonlyTag(configElem, &readonlyFields)
+
+	config, _ := mizu.GetConfigWithDefaults()
+	for _, readonlyField := range readonlyFields {
+		if strings.Contains(config, readonlyField) {
+			t.Errorf("unexpected result - readonly field: %v, config: %v", readonlyField, config)
+		}
+	}
+}
+
+func getFieldsWithReadonlyTag(currentElem reflect.Value, readonlyFields *[]string) {
+	for i := 0; i < currentElem.NumField(); i++ {
+		currentField := currentElem.Type().Field(i)
+		currentFieldByName := currentElem.FieldByName(currentField.Name)
+
+		if currentField.Type.Kind() == reflect.Struct {
+			getFieldsWithReadonlyTag(currentFieldByName, readonlyFields)
+			continue
+		}
+
+		if _, ok := currentField.Tag.Lookup(mizu.ReadonlyTag); ok {
+			fieldNameByTag := strings.Split(currentField.Tag.Get(mizu.FieldNameTag), ",")[0]
+			*readonlyFields = append(*readonlyFields, fieldNameByTag)
+		}
+	}
+}