Add option registry to config package

config/get.go

@@ -43,6 +43,19 @@ func GetAsString(name string, fallback string) func() string {
 	}
 }
 
+// GetAsStringArray returns a function that returns the wanted string with high performance.
+func GetAsStringArray(name string, fallback []string) func() []string {
+	valid := getValidityFlag()
+	value := findStringArrayValue(name, fallback)
+	return func() []string {
+		if !valid.IsSet() {
+			valid = getValidityFlag()
+			value = findStringArrayValue(name, fallback)
+		}
+		return value
+	}
+}
+
 // GetAsInt returns a function that returns the wanted int with high performance.
 func GetAsInt(name string, fallback int64) func() int64 {
 	valid := getValidityFlag()
@@ -55,3 +68,16 @@ func GetAsInt(name string, fallback int64) func() int64 {
 		return value
 	}
 }
+
+// GetAsBool returns a function that returns the wanted int with high performance.
+func GetAsBool(name string, fallback bool) func() bool {
+	valid := getValidityFlag()
+	value := findBoolValue(name, fallback)
+	return func() bool {
+		if !valid.IsSet() {
+			valid = getValidityFlag()
+			value = findBoolValue(name, fallback)
+		}
+		return value
+	}
+}

config/get_test.go

@@ -9,7 +9,10 @@ func TestGet(t *testing.T) {
 	err := SetConfig(`
   {
     "monkey": "1",
-    "elephant": 2
+		"zebra": ["black", "white"],
+    "elephant": 2,
+		"hot": true,
+		"cold": false
   }
   `)
 	if err != nil {
@@ -28,14 +31,30 @@ func TestGet(t *testing.T) {
 	}
 
 	monkey := GetAsString("monkey", "none")
-	elephant := GetAsInt("elephant", -1)
 	if monkey() != "1" {
 		t.Fatalf("monkey should be 1, is %s", monkey())
 	}
+
+	zebra := GetAsStringArray("zebra", []string{})
+	if len(zebra()) != 2 || zebra()[0] != "black" || zebra()[1] != "white" {
+		t.Fatalf("zebra should be [\"black\", \"white\"], is %v", zebra())
+	}
+
+	elephant := GetAsInt("elephant", -1)
 	if elephant() != 2 {
 		t.Fatalf("elephant should be 2, is %d", elephant())
 	}
 
+	hot := GetAsBool("hot", false)
+	if !hot() {
+		t.Fatalf("hot should be true, is %v", hot())
+	}
+
+	cold := GetAsBool("cold", true)
+	if cold() {
+		t.Fatalf("cold should be false, is %v", cold())
+	}
+
 	err = SetConfig(`
   {
     "monkey": "3"
@@ -48,10 +67,14 @@ func TestGet(t *testing.T) {
 	if monkey() != "3" {
 		t.Fatalf("monkey should be 0, is %s", monkey())
 	}
+
 	if elephant() != 0 {
 		t.Fatalf("elephant should be 0, is %d", elephant())
 	}
 
+	zebra()
+	hot()
+
 }
 
 func BenchmarkGetAsStringCached(b *testing.B) {

config/layers.go

@@ -3,8 +3,10 @@ package config
 import (
 	"errors"
 	"sync"
+	"fmt"
 
 	"github.com/tidwall/gjson"
+	"github.com/tidwall/sjson"
 )
 
 var (
@@ -15,6 +17,9 @@ var (
 
 	// ErrInvalidJSON is returned by SetConfig and SetDefaultConfig if they receive invalid json.
 	ErrInvalidJSON = errors.New("json string invalid")
+
+	// ErrInvalidOptionType is returned by SetConfigOption and SetDefaultConfigOption if given an unsupported option type.
+	ErrInvalidOptionType = errors.New("invalid option value type")
 )
 
 // SetConfig sets the (prioritized) user defined config.
@@ -45,7 +50,115 @@ func SetDefaultConfig(json string) error {
 	return nil
 }
 
-// findValue find the correct value in the user or default config
+func validateValue(name string, value interface{}) error {
+	optionsLock.RLock()
+	defer optionsLock.RUnlock()
+
+	option, ok := options[name]
+	if !ok {
+		switch value.(type) {
+		case string:
+			return nil
+		case []string:
+			return nil
+		case int:
+			return nil
+		case bool:
+			return nil
+		default:
+			return ErrInvalidOptionType
+		}
+	}
+
+	switch v := value.(type) {
+	case string:
+		if option.OptType != OptTypeString {
+			return fmt.Errorf("expected type string for option %s, got type %T", name, v)
+		}
+		if option.compiledRegex != nil {
+			if !option.compiledRegex.MatchString(v) {
+				return fmt.Errorf("validation failed: string \"%s\" did not match regex for option %s", v, name)
+			}
+		}
+		return nil
+	case []string:
+		if option.OptType != OptTypeStringArray {
+			return fmt.Errorf("expected type string for option %s, got type %T", name, v)
+		}
+		if option.compiledRegex != nil {
+			for pos, entry := range v {
+				if !option.compiledRegex.MatchString(entry) {
+					return fmt.Errorf("validation failed: string \"%s\" at index %d did not match regex for option %s", entry, pos, name)
+				}
+			}
+		}
+		return nil
+	case int:
+		if option.OptType != OptTypeInt {
+			return fmt.Errorf("expected type int for option %s, got type %T", name, v)
+		}
+		return nil
+	case bool:
+		if option.OptType != OptTypeBool {
+			return fmt.Errorf("expected type bool for option %s, got type %T", name, v)
+		}
+		return nil
+	default:
+		return ErrInvalidOptionType
+	}
+}
+
+// SetConfigOption sets a single value in the (prioritized) user defined config.
+func SetConfigOption(name string, value interface{}) error {
+	configLock.Lock()
+	defer configLock.Unlock()
+
+	var err error
+	var newConfig string
+
+	if value == nil {
+		newConfig, err = sjson.Delete(userConfig, name)
+	} else {
+		err = validateValue(name, value)
+		if err == nil {
+			newConfig, err = sjson.Set(userConfig, name, value)
+		}
+	}
+
+	if err == nil {
+		userConfig = newConfig
+		resetValidityFlag()
+	}
+
+	return err
+}
+
+// SetDefaultConfigOption sets a single value in the (fallback) default config.
+func SetDefaultConfigOption(name string, value interface{}) error {
+	configLock.Lock()
+	defer configLock.Unlock()
+
+	var err error
+	var newConfig string
+
+	if value == nil {
+		newConfig, err = sjson.Delete(defaultConfig, name)
+	} else {
+		err = validateValue(name, value)
+		if err == nil {
+			newConfig, err = sjson.Set(defaultConfig, name, value)
+		}
+	}
+
+	if err == nil {
+		defaultConfig = newConfig
+		resetValidityFlag()
+	}
+
+	return err
+}
+
+// findValue find the correct value in the user or default config.
 func findValue(name string) (result gjson.Result) {
 	configLock.RLock()
 	defer configLock.RUnlock()
@@ -57,7 +170,7 @@ func findValue(name string) (result gjson.Result) {
 	return result
 }
 
-// findStringValue validates and return the value with the given name
+// findStringValue validates and returns the value with the given name.
 func findStringValue(name string, fallback string) (value string) {
 	result := findValue(name)
 	if !result.Exists() {
@@ -69,7 +182,26 @@ func findStringValue(name string, fallback string) (value string) {
 	return result.String()
 }
 
-// findIntValue validates and return the value with the given name
+// findStringArrayValue validates and returns the value with the given name.
+func findStringArrayValue(name string, fallback []string) (value []string) {
+	result := findValue(name)
+	if !result.Exists() {
+		return fallback
+	}
+	if !result.IsArray() {
+		return fallback
+	}
+	results := result.Array()
+	for _, r := range results {
+		if r.Type != gjson.String {
+			return fallback
+		}
+		value = append(value, r.String())
+	}
+	return value
+}
+
+// findIntValue validates and returns the value with the given name.
 func findIntValue(name string, fallback int64) (value int64) {
 	result := findValue(name)
 	if !result.Exists() {
@@ -80,3 +212,19 @@ func findIntValue(name string, fallback int64) (value int64) {
 	}
 	return result.Int()
 }
+
+// findBoolValue validates and returns the value with the given name.
+func findBoolValue(name string, fallback bool) (value bool) {
+	result := findValue(name)
+	if !result.Exists() {
+		return fallback
+	}
+	switch result.Type {
+	case gjson.True:
+		return true
+	case gjson.False:
+		return false
+	default:
+		return fallback
+	}
+}

config/layers_test.go

@@ -2,50 +2,186 @@ package config
 
 import "testing"
 
-func TestLayers(t *testing.T) {
+func TestLayersGetters(t *testing.T) {
 
 	err := SetConfig("{invalid json")
 	if err == nil {
-		t.Fatal("expected error")
+		t.Error("expected error")
 	}
 
 	err = SetDefaultConfig("{invalid json")
 	if err == nil {
-		t.Fatal("expected error")
+		t.Error("expected error")
 	}
 
 	err = SetConfig(`
-    {
+		{
-      "monkey": "banana",
+			"monkey": "1",
-      "elephant": 3
+			"zebra": ["black", "white"],
-    }
+			"weird_zebra": ["black", -1],
+			"elephant": 2,
+			"hot": true
+		}
     `)
 	if err != nil {
-		t.Fatal(err)
+		t.Error(err)
 	}
 
 	// Test missing values
 
 	missingString := GetAsString("missing", "fallback")
 	if missingString() != "fallback" {
-		t.Fatal("expected fallback value: fallback")
+		t.Error("expected fallback value: fallback")
+	}
+
+	missingStringArray := GetAsStringArray("missing", []string{"fallback"})
+	if len(missingStringArray()) != 1 || missingStringArray()[0] != "fallback" {
+		t.Error("expected fallback value: [fallback]")
 	}
 
 	missingInt := GetAsInt("missing", -1)
 	if missingInt() != -1 {
-		t.Fatal("expected fallback value: -1")
+		t.Error("expected fallback value: -1")
+	}
+
+	missingBool := GetAsBool("missing", false)
+	if missingBool() {
+		t.Error("expected fallback value: false")
 	}
 
 	// Test value mismatch
 
 	notString := GetAsString("elephant", "fallback")
 	if notString() != "fallback" {
-		t.Fatal("expected fallback value: fallback")
+		t.Error("expected fallback value: fallback")
+	}
+
+	notStringArray := GetAsStringArray("elephant", []string{"fallback"})
+	if len(notStringArray()) != 1 || notStringArray()[0] != "fallback" {
+		t.Error("expected fallback value: [fallback]")
+	}
+
+	mixedStringArray := GetAsStringArray("weird_zebra", []string{"fallback"})
+	if len(mixedStringArray()) != 1 || mixedStringArray()[0] != "fallback" {
+		t.Error("expected fallback value: [fallback]")
 	}
 
 	notInt := GetAsInt("monkey", -1)
 	if notInt() != -1 {
-		t.Fatal("expected fallback value: -1")
+		t.Error("expected fallback value: -1")
+	}
+
+	notBool := GetAsBool("monkey", false)
+	if notBool() {
+		t.Error("expected fallback value: false")
+	}
+
+}
+
+func TestLayersSetters(t *testing.T) {
+
+	Register(&Option{
+		Name:            "name",
+		Key:             "monkey",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         OptTypeString,
+		DefaultValue:    "banana",
+		ValidationRegex: "^(banana|water)$",
+	})
+	Register(&Option{
+		Name:            "name",
+		Key:             "zebra",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         OptTypeStringArray,
+		DefaultValue:    []string{"black", "white"},
+		ValidationRegex: "^[a-z]+$",
+	})
+	Register(&Option{
+		Name:            "name",
+		Key:             "elephant",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         OptTypeInt,
+		DefaultValue:    2,
+		ValidationRegex: "",
+	})
+	Register(&Option{
+		Name:            "name",
+		Key:             "hot",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         OptTypeBool,
+		DefaultValue:    true,
+		ValidationRegex: "",
+	})
+
+	// correct types
+	if err := SetConfigOption("monkey", "banana"); err != nil {
+		t.Error(err)
+	}
+	if err := SetConfigOption("zebra", []string{"black", "white"}); err != nil {
+		t.Error(err)
+	}
+	if err := SetDefaultConfigOption("elephant", 2); err != nil {
+		t.Error(err)
+	}
+	if err := SetDefaultConfigOption("hot", true); err != nil {
+		t.Error(err)
+	}
+
+	// incorrect types
+	if err := SetConfigOption("monkey", []string{"black", "white"}); err == nil {
+		t.Error("should fail")
+	}
+	if err := SetConfigOption("zebra", 2); err == nil {
+		t.Error("should fail")
+	}
+	if err := SetDefaultConfigOption("elephant", true); err == nil {
+		t.Error("should fail")
+	}
+	if err := SetDefaultConfigOption("hot", "banana"); err == nil {
+		t.Error("should fail")
+	}
+	if err := SetDefaultConfigOption("hot", []byte{0}); err == nil {
+		t.Error("should fail")
+	}
+
+	// validation fail
+	if err := SetConfigOption("monkey", "dirt"); err == nil {
+		t.Error("should fail")
+	}
+	if err := SetConfigOption("zebra", []string{"Element649"}); err == nil {
+		t.Error("should fail")
+	}
+
+	// unregistered checking
+	if err := SetConfigOption("invalid", "banana"); err != nil {
+		t.Error(err)
+	}
+	if err := SetConfigOption("invalid", []string{"black", "white"}); err != nil {
+		t.Error(err)
+	}
+	if err := SetConfigOption("invalid", 2); err != nil {
+		t.Error(err)
+	}
+	if err := SetConfigOption("invalid", true); err != nil {
+		t.Error(err)
+	}
+	if err := SetConfigOption("invalid", []byte{0}); err != ErrInvalidOptionType {
+		t.Error("should fail with ErrInvalidOptionType")
+	}
+
+	// delete
+	if err := SetConfigOption("monkey", nil); err != nil {
+		t.Error(err)
+	}
+	if err := SetDefaultConfigOption("elephant", nil); err != nil {
+		t.Error(err)
+	}
+	if err := SetDefaultConfigOption("invalid_delete", nil); err != nil {
+		t.Error(err)
 	}
 
 }

config/registry.go

@@ -0,0 +1,67 @@
+package config
+
+import (
+	"errors"
+	"fmt"
+	"regexp"
+	"sync"
+)
+
+// Variable Type IDs for frontend Identification. Values over 100 are free for custom use.
+const (
+	OptTypeString      uint8 = 1
+	OptTypeStringArray uint8 = 2
+	OptTypeInt         uint8 = 3
+	OptTypeBool        uint8 = 4
+
+	ExpertiseLevelUser      int8 = 1
+	ExpertiseLevelExpert    int8 = 2
+	ExpertiseLevelDeveloper int8 = 3
+)
+
+var (
+	optionsLock sync.RWMutex
+	options     = make(map[string]*Option)
+
+	// ErrIncompleteCall is return when RegisterOption is called with empty mandatory values.
+	ErrIncompleteCall = errors.New("could not register config option: all fields, except for the validationRegex are mandatory")
+)
+
+// Option describes a configuration option.
+type Option struct {
+	Name            string
+	Key             string
+	Description     string
+	ExpertiseLevel  uint8
+	OptType         uint8
+	DefaultValue    interface{}
+	ValidationRegex string
+	compiledRegex   *regexp.Regexp
+}
+
+// Register registers a new configuration option.
+func Register(option *Option) error {
+
+	if option.Name == "" ||
+		option.Key == "" ||
+		option.Description == "" ||
+		option.ExpertiseLevel == 0 ||
+		option.OptType == 0 {
+		return ErrIncompleteCall
+	}
+
+	if option.ValidationRegex != "" {
+		var err error
+		option.compiledRegex, err = regexp.Compile(option.ValidationRegex)
+		if err != nil {
+			return fmt.Errorf("config: could not compile option.ValidationRegex: %s", err)
+		}
+	}
+
+	optionsLock.Lock()
+	defer optionsLock.Unlock()
+
+	options[option.Key] = option
+
+	return nil
+}

config/registry_test.go

@@ -0,0 +1,45 @@
+package config
+
+import (
+	"testing"
+)
+
+func TestRegistry(t *testing.T) {
+
+	if err := Register(&Option{
+		Name:            "name",
+		Key:             "key",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         OptTypeString,
+		DefaultValue:    "default",
+		ValidationRegex: "^(banana|water)$",
+	}); err != nil {
+		t.Error(err)
+	}
+
+	if err := Register(&Option{
+		Name:            "name",
+		Key:             "key",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         0,
+		DefaultValue:    "default",
+		ValidationRegex: "^[A-Z][a-z]+$",
+	}); err == nil {
+		t.Error("should fail")
+	}
+
+	if err := Register(&Option{
+		Name:            "name",
+		Key:             "key",
+		Description:     "description",
+		ExpertiseLevel:  1,
+		OptType:         OptTypeString,
+		DefaultValue:    "default",
+		ValidationRegex: "[",
+	}); err == nil {
+		t.Error("should fail")
+	}
+
+}