Settings: Encapsulate settings within an extensible provider (#32219)

* Encapsulate settings with a provider with support for runtime reloads

* SettingsProvider: reload is controlled by the services

* naive impl of reload handlers for settings

* working naive detection on new changes

* Trigger settings reload from API endpoint

* validation step added

* validation of settings

* Fix linting errors

* Replace DB_Varchar by DB_NVarchar

* Reduce settings columns (section, key) lenghts

* wip db update logic

* Db Settings: separate updates and removals

* Fix: removes incorrectly added code

* Minor code improvements

* Runtime settings: moved oss -> ee

* Remove no longer used setting.Cfg SAML-related fields

* Rename file setting/settings.go => setting/provider.go

* Apply suggestions from code review

Co-authored-by: Agnès Toulet <35176601+AgnesToulet@users.noreply.github.com>

* Minor code improvements on OSS settings provider

* Fix some login API tests

* Correct some GoDoc comments

* Apply suggestions from code review

Co-authored-by: Agnès Toulet <35176601+AgnesToulet@users.noreply.github.com>

Co-authored-by: Leonard Gram <leo@xlson.com>
Co-authored-by: Agnès Toulet <35176601+AgnesToulet@users.noreply.github.com>

pkg/setting/provider.go

@@ -0,0 +1,141 @@
+package setting
+
+import (
+	"errors"
+	"strings"
+	"time"
+
+	"gopkg.in/ini.v1"
+)
+
+var (
+	ErrOperationNotPermitted = errors.New("operation not permitted")
+)
+
+type ValidationError struct {
+	Errors []error
+}
+
+func (v ValidationError) Error() string {
+	builder := strings.Builder{}
+
+	for i, e := range v.Errors {
+		builder.WriteString(e.Error())
+		if i != len(v.Errors)-1 {
+			builder.WriteString(", ")
+		}
+	}
+
+	return builder.String()
+}
+
+// Provider is a settings provider abstraction
+// with thread-safety and runtime updates.
+type Provider interface {
+	// Update
+	Update(updates SettingsBag, removals SettingsRemovals) error
+	// KeyValue returns a key-value abstraction
+	// for the given pair of section and key.
+	KeyValue(section, key string) KeyValue
+	// Section returns a settings section
+	// abstraction for the given section name.
+	Section(section string) Section
+	// RegisterReloadHandler registers a handler for validation and reload
+	// of configuration updates tied to a specific section
+	RegisterReloadHandler(section string, handler ReloadHandler)
+}
+
+// Section is a settings section copy
+// with all of its pairs of keys-values.
+type Section interface {
+	// KeyValue returns a key-value
+	// abstraction for the given key.
+	KeyValue(key string) KeyValue
+}
+
+// KeyValue represents a settings key-value
+// for a given pair of section and key.
+type KeyValue interface {
+	// Key returns pair's key.
+	Key() string
+	// Value returns pair's value.
+	Value() string
+
+	// MustString returns the value's string representation
+	// If empty, then it returns the given default.
+	MustString(defaultVal string) string
+	// MustBool returns the value's boolean representation
+	// Otherwise returns the given default.
+	MustBool(defaultVal bool) bool
+	// MustDuration returns the value's time.Duration
+	// representation. Otherwise returns the given default.
+	MustDuration(defaultVal time.Duration) time.Duration
+}
+
+// ReloadHandler defines the expected behaviour from a
+// service that have support for configuration reloads.
+type ReloadHandler interface {
+	// Reload handles reloading of configuration changes.
+	Reload(section Section) error
+
+	// Validate validates the configuration, if the validation
+	// fails the configuration will not be updated neither reloaded.
+	Validate(section Section) error
+}
+
+type SettingsBag map[string]map[string]string
+type SettingsRemovals map[string][]string
+
+type OSSImpl struct {
+	Cfg *Cfg `inject:""`
+}
+
+func (o OSSImpl) Init() error {
+	return nil
+}
+
+func (OSSImpl) Update(SettingsBag, SettingsRemovals) error {
+	return errors.New("oss settings provider do not have support for settings updates")
+}
+
+func (o *OSSImpl) KeyValue(section, key string) KeyValue {
+	return o.Section(section).KeyValue(key)
+}
+
+func (o *OSSImpl) Section(section string) Section {
+	return &sectionImpl{section: o.Cfg.Raw.Section(section)}
+}
+
+func (OSSImpl) RegisterReloadHandler(string, ReloadHandler) {}
+
+type keyValImpl struct {
+	key *ini.Key
+}
+
+func (k *keyValImpl) Key() string {
+	return k.key.Name()
+}
+
+func (k *keyValImpl) Value() string {
+	return k.key.Value()
+}
+
+func (k *keyValImpl) MustString(defaultVal string) string {
+	return k.key.MustString(defaultVal)
+}
+
+func (k *keyValImpl) MustBool(defaultVal bool) bool {
+	return k.key.MustBool(defaultVal)
+}
+
+func (k *keyValImpl) MustDuration(defaultVal time.Duration) time.Duration {
+	return k.key.MustDuration(defaultVal)
+}
+
+type sectionImpl struct {
+	section *ini.Section
+}
+
+func (s *sectionImpl) KeyValue(key string) KeyValue {
+	return &keyValImpl{s.section.Key(key)}
+}

pkg/setting/setting.go

@@ -297,10 +297,6 @@ type Cfg struct {
 	// OAuth
 	OAuthCookieMaxAge int
 
-	// SAML Auth
-	SAMLEnabled             bool
-	SAMLSingleLogoutEnabled bool
-
 	// JWT Auth
 	JWTAuthEnabled       bool
 	JWTAuthHeaderName    string
@@ -1175,10 +1171,6 @@ func readAuthSettings(iniFile *ini.File, cfg *Cfg) (err error) {
 	SigV4AuthEnabled = auth.Key("sigv4_auth_enabled").MustBool(false)
 	cfg.SigV4AuthEnabled = SigV4AuthEnabled
 
-	// SAML auth
-	cfg.SAMLEnabled = iniFile.Section("auth.saml").Key("enabled").MustBool(false)
-	cfg.SAMLSingleLogoutEnabled = iniFile.Section("auth.saml").Key("single_logout").MustBool(false)
-
 	// anonymous access
 	AnonymousEnabled = iniFile.Section("auth.anonymous").Key("enabled").MustBool(false)
 	cfg.AnonymousEnabled = AnonymousEnabled