refactor: simplify app_config service and fix race conditions (#423)

backend/internal/model/app_config.go

@@ -1,17 +1,17 @@
 package model
 
 import (
+	"errors"
+	"fmt"
+	"reflect"
 	"strconv"
+	"strings"
 	"time"
 )
 
 type AppConfigVariable struct {
-	Key          string `gorm:"primaryKey;not null"`
-	Type         string
-	IsPublic     bool
-	IsInternal   bool
-	Value        string
-	DefaultValue string
+	Key   string `gorm:"primaryKey;not null"`
+	Value string
 }
 
 // IsTrue returns true if the value is a truthy string, such as "true", "t", "yes", "1", etc.
@@ -31,41 +31,153 @@ func (a *AppConfigVariable) AsDurationMinutes() time.Duration {
 
 type AppConfig struct {
 	// General
-	AppName             AppConfigVariable
-	SessionDuration     AppConfigVariable
-	EmailsVerified      AppConfigVariable
-	AllowOwnAccountEdit AppConfigVariable
+	AppName             AppConfigVariable `key:"appName,public"` // Public
+	SessionDuration     AppConfigVariable `key:"sessionDuration"`
+	EmailsVerified      AppConfigVariable `key:"emailsVerified"`
+	AllowOwnAccountEdit AppConfigVariable `key:"allowOwnAccountEdit,public"` // Public
 	// Internal
-	BackgroundImageType AppConfigVariable
-	LogoLightImageType  AppConfigVariable
-	LogoDarkImageType   AppConfigVariable
+	BackgroundImageType AppConfigVariable `key:"backgroundImageType,internal"` // Internal
+	LogoLightImageType  AppConfigVariable `key:"logoLightImageType,internal"`  // Internal
+	LogoDarkImageType   AppConfigVariable `key:"logoDarkImageType,internal"`   // Internal
 	// Email
-	SmtpHost                      AppConfigVariable
-	SmtpPort                      AppConfigVariable
-	SmtpFrom                      AppConfigVariable
-	SmtpUser                      AppConfigVariable
-	SmtpPassword                  AppConfigVariable
-	SmtpTls                       AppConfigVariable
-	SmtpSkipCertVerify            AppConfigVariable
-	EmailLoginNotificationEnabled AppConfigVariable
-	EmailOneTimeAccessEnabled     AppConfigVariable
+	SmtpHost                      AppConfigVariable `key:"smtpHost"`
+	SmtpPort                      AppConfigVariable `key:"smtpPort"`
+	SmtpFrom                      AppConfigVariable `key:"smtpFrom"`
+	SmtpUser                      AppConfigVariable `key:"smtpUser"`
+	SmtpPassword                  AppConfigVariable `key:"smtpPassword"`
+	SmtpTls                       AppConfigVariable `key:"smtpTls"`
+	SmtpSkipCertVerify            AppConfigVariable `key:"smtpSkipCertVerify"`
+	EmailLoginNotificationEnabled AppConfigVariable `key:"emailLoginNotificationEnabled"`
+	EmailOneTimeAccessEnabled     AppConfigVariable `key:"emailOneTimeAccessEnabled,public"` // Public
 	// LDAP
-	LdapEnabled                        AppConfigVariable
-	LdapUrl                            AppConfigVariable
-	LdapBindDn                         AppConfigVariable
-	LdapBindPassword                   AppConfigVariable
-	LdapBase                           AppConfigVariable
-	LdapUserSearchFilter               AppConfigVariable
-	LdapUserGroupSearchFilter          AppConfigVariable
-	LdapSkipCertVerify                 AppConfigVariable
-	LdapAttributeUserUniqueIdentifier  AppConfigVariable
-	LdapAttributeUserUsername          AppConfigVariable
-	LdapAttributeUserEmail             AppConfigVariable
-	LdapAttributeUserFirstName         AppConfigVariable
-	LdapAttributeUserLastName          AppConfigVariable
-	LdapAttributeUserProfilePicture    AppConfigVariable
-	LdapAttributeGroupMember           AppConfigVariable
-	LdapAttributeGroupUniqueIdentifier AppConfigVariable
-	LdapAttributeGroupName             AppConfigVariable
-	LdapAttributeAdminGroup            AppConfigVariable
+	LdapEnabled                        AppConfigVariable `key:"ldapEnabled,public"` // Public
+	LdapUrl                            AppConfigVariable `key:"ldapUrl"`
+	LdapBindDn                         AppConfigVariable `key:"ldapBindDn"`
+	LdapBindPassword                   AppConfigVariable `key:"ldapBindPassword"`
+	LdapBase                           AppConfigVariable `key:"ldapBase"`
+	LdapUserSearchFilter               AppConfigVariable `key:"ldapUserSearchFilter"`
+	LdapUserGroupSearchFilter          AppConfigVariable `key:"ldapUserGroupSearchFilter"`
+	LdapSkipCertVerify                 AppConfigVariable `key:"ldapSkipCertVerify"`
+	LdapAttributeUserUniqueIdentifier  AppConfigVariable `key:"ldapAttributeUserUniqueIdentifier"`
+	LdapAttributeUserUsername          AppConfigVariable `key:"ldapAttributeUserUsername"`
+	LdapAttributeUserEmail             AppConfigVariable `key:"ldapAttributeUserEmail"`
+	LdapAttributeUserFirstName         AppConfigVariable `key:"ldapAttributeUserFirstName"`
+	LdapAttributeUserLastName          AppConfigVariable `key:"ldapAttributeUserLastName"`
+	LdapAttributeUserProfilePicture    AppConfigVariable `key:"ldapAttributeUserProfilePicture"`
+	LdapAttributeGroupMember           AppConfigVariable `key:"ldapAttributeGroupMember"`
+	LdapAttributeGroupUniqueIdentifier AppConfigVariable `key:"ldapAttributeGroupUniqueIdentifier"`
+	LdapAttributeGroupName             AppConfigVariable `key:"ldapAttributeGroupName"`
+	LdapAttributeAdminGroup            AppConfigVariable `key:"ldapAttributeAdminGroup"`
+}
+
+func (c *AppConfig) ToAppConfigVariableSlice(showAll bool) []AppConfigVariable {
+	// Use reflection to iterate through all fields
+	cfgValue := reflect.ValueOf(c).Elem()
+	cfgType := cfgValue.Type()
+
+	res := make([]AppConfigVariable, cfgType.NumField())
+
+	for i := range cfgType.NumField() {
+		field := cfgType.Field(i)
+
+		key, attrs, _ := strings.Cut(field.Tag.Get("key"), ",")
+		if key == "" {
+			continue
+		}
+
+		// If we're only showing public variables and this is not public, skip it
+		if !showAll && attrs != "public" {
+			continue
+		}
+
+		fieldValue := cfgValue.Field(i)
+
+		res[i] = AppConfigVariable{
+			Key:   key,
+			Value: fieldValue.FieldByName("Value").String(),
+		}
+	}
+
+	return res
+}
+
+func (c *AppConfig) FieldByKey(key string) (string, error) {
+	rv := reflect.ValueOf(c).Elem()
+	rt := rv.Type()
+
+	// Find the field in the struct whose "key" tag matches
+	for i := range rt.NumField() {
+		// Grab only the first part of the key, if there's a comma with additional properties
+		tagValue, _, _ := strings.Cut(rt.Field(i).Tag.Get("key"), ",")
+		if tagValue != key {
+			continue
+		}
+
+		valueField := rv.Field(i).FieldByName("Value")
+		return valueField.String(), nil
+	}
+
+	// If we are here, the config key was not found
+	return "", AppConfigKeyNotFoundError{field: key}
+}
+
+func (c *AppConfig) UpdateField(key string, value string, noInternal bool) error {
+	rv := reflect.ValueOf(c).Elem()
+	rt := rv.Type()
+
+	// Find the field in the struct whose "key" tag matches, then update that
+	for i := range rt.NumField() {
+		// Separate the key (before the comma) from any optional attributes after
+		tagValue, attrs, _ := strings.Cut(rt.Field(i).Tag.Get("key"), ",")
+		if tagValue != key {
+			continue
+		}
+
+		// If the field is internal and noInternal is true, we skip that
+		if noInternal && attrs == "internal" {
+			return AppConfigInternalForbiddenError{field: key}
+		}
+
+		valueField := rv.Field(i).FieldByName("Value")
+		if !valueField.CanSet() {
+			return fmt.Errorf("field Value in AppConfigVariable is not settable for config key '%s'", key)
+		}
+
+		// Update the value
+		valueField.SetString(value)
+
+		// Return once updated
+		return nil
+	}
+
+	// If we're here, we have not found the right field to update
+	return AppConfigKeyNotFoundError{field: key}
+}
+
+type AppConfigKeyNotFoundError struct {
+	field string
+}
+
+func (e AppConfigKeyNotFoundError) Error() string {
+	return fmt.Sprintf("cannot find config key '%s'", e.field)
+}
+
+func (e AppConfigKeyNotFoundError) Is(target error) bool {
+	// Ignore the field property when checking if an error is of the type AppConfigKeyNotFoundError
+	x := AppConfigKeyNotFoundError{}
+	return errors.As(target, &x)
+}
+
+type AppConfigInternalForbiddenError struct {
+	field string
+}
+
+func (e AppConfigInternalForbiddenError) Error() string {
+	return fmt.Sprintf("field '%s' is internal and can't be updated", e.field)
+}
+
+func (e AppConfigInternalForbiddenError) Is(target error) bool {
+	// Ignore the field property when checking if an error is of the type AppConfigInternalForbiddenError
+	x := AppConfigInternalForbiddenError{}
+	return errors.As(target, &x)
 }