chore: change returned error from list to error (#5805)

pkg/query-service/rules/api_params.go

@@ -10,6 +10,7 @@ import (
 	"github.com/pkg/errors"
 	"go.signoz.io/signoz/pkg/query-service/model"
 	v3 "go.signoz.io/signoz/pkg/query-service/model/v3"
+	"go.uber.org/multierr"
 
 	"go.signoz.io/signoz/pkg/query-service/utils/times"
 	"go.signoz.io/signoz/pkg/query-service/utils/timestamp"
@@ -32,6 +33,12 @@ const (
 	RuleDataKindYaml RuleDataKind = "yaml"
 )
 
+var (
+	ErrFailedToParseJSON = errors.New("failed to parse json")
+	ErrFailedToParseYAML = errors.New("failed to parse yaml")
+	ErrInvalidDataType   = errors.New("invalid data type")
+)
+
 // this file contains api request and responses to be
 // served over http
 
@@ -72,31 +79,31 @@ type PostableRule struct {
 	OldYaml string `json:"yaml,omitempty"`
 }
 
-func ParsePostableRule(content []byte) (*PostableRule, []error) {
+func ParsePostableRule(content []byte) (*PostableRule, error) {
 	return parsePostableRule(content, "json")
 }
 
-func parsePostableRule(content []byte, kind string) (*PostableRule, []error) {
+func parsePostableRule(content []byte, kind RuleDataKind) (*PostableRule, error) {
 	return parseIntoRule(PostableRule{}, content, kind)
 }
 
 // parseIntoRule loads the content (data) into PostableRule and also
 // validates the end result
-func parseIntoRule(initRule PostableRule, content []byte, kind string) (*PostableRule, []error) {
+func parseIntoRule(initRule PostableRule, content []byte, kind RuleDataKind) (*PostableRule, error) {
 
 	rule := &initRule
 
 	var err error
-	if kind == "json" {
+	if kind == RuleDataKindJson {
 		if err = json.Unmarshal(content, rule); err != nil {
-			return nil, []error{fmt.Errorf("failed to load json")}
+			return nil, ErrFailedToParseJSON
 		}
-	} else if kind == "yaml" {
+	} else if kind == RuleDataKindYaml {
 		if err = yaml.Unmarshal(content, rule); err != nil {
-			return nil, []error{fmt.Errorf("failed to load yaml")}
+			return nil, ErrFailedToParseYAML
 		}
 	} else {
-		return nil, []error{fmt.Errorf("invalid data type")}
+		return nil, ErrInvalidDataType
 	}
 
 	if rule.RuleCondition == nil && rule.Expr != "" {
@@ -138,11 +145,11 @@ func parseIntoRule(initRule PostableRule, content []byte, kind string) (*Postabl
 		}
 	}
 
-	if errs := rule.Validate(); len(errs) > 0 {
-		return nil, errs
+	if err := rule.Validate(); err != nil {
+		return nil, err
 	}
 
-	return rule, []error{}
+	return rule, nil
 }
 
 func isValidLabelName(ln string) bool {
@@ -161,7 +168,9 @@ func isValidLabelValue(v string) bool {
 	return utf8.ValidString(v)
 }
 
-func (r *PostableRule) Validate() (errs []error) {
+func (r *PostableRule) Validate() error {
+
+	var errs []error
 
 	if r.RuleCondition == nil {
 		errs = append(errs, errors.Errorf("rule condition is required"))
@@ -200,7 +209,7 @@ func (r *PostableRule) Validate() (errs []error) {
 	}
 
 	errs = append(errs, testTemplateParsing(r)...)
-	return errs
+	return multierr.Combine(errs...)
 }
 
 func testTemplateParsing(rl *PostableRule) (errs []error) {

pkg/query-service/rules/manager.go

@@ -160,32 +160,20 @@ func (m *Manager) initiate() error {
 
 	for _, rec := range storedRules {
 		taskName := fmt.Sprintf("%d-groupname", rec.Id)
-		parsedRule, errs := ParsePostableRule([]byte(rec.Data))
+		parsedRule, err := ParsePostableRule([]byte(rec.Data))
 
-		if len(errs) > 0 {
-			if errs[0].Error() == "failed to load json" {
+		if err != nil {
+			if errors.Is(err, ErrFailedToParseJSON) {
 				zap.L().Info("failed to load rule in json format, trying yaml now:", zap.String("name", taskName))
 
 				// see if rule is stored in yaml format
-				parsedRule, errs = parsePostableRule([]byte(rec.Data), "yaml")
+				parsedRule, err = parsePostableRule([]byte(rec.Data), RuleDataKindYaml)
 
-				if parsedRule == nil {
+				if err != nil {
 					zap.L().Error("failed to parse and initialize yaml rule", zap.String("name", taskName), zap.Error(err))
 					// just one rule is being parsed so expect just one error
-					loadErrors = append(loadErrors, errs[0])
+					loadErrors = append(loadErrors, err)
 					continue
-				} else {
-					// rule stored in yaml, so migrate it to json
-					zap.L().Info("migrating rule from JSON to yaml", zap.String("name", taskName))
-					ruleJSON, err := json.Marshal(parsedRule)
-					if err == nil {
-						taskName, _, err := m.ruleDB.EditRuleTx(context.Background(), string(ruleJSON), fmt.Sprintf("%d", rec.Id))
-						if err != nil {
-							zap.L().Error("failed to migrate rule", zap.String("name", taskName), zap.Error(err))
-						} else {
-							zap.L().Info("migrated rule from yaml to json", zap.String("name", taskName))
-						}
-					}
 				}
 			} else {
 				zap.L().Error("failed to parse and initialize rule", zap.String("name", taskName), zap.Error(err))
@@ -236,12 +224,10 @@ func (m *Manager) Stop() {
 // datastore and also updates the rule executor
 func (m *Manager) EditRule(ctx context.Context, ruleStr string, id string) error {
 
-	parsedRule, errs := ParsePostableRule([]byte(ruleStr))
+	parsedRule, err := ParsePostableRule([]byte(ruleStr))
 
-	if len(errs) > 0 {
-		zap.L().Error("failed to parse rules", zap.Errors("errors", errs))
-		// just one rule is being parsed so expect just one error
-		return errs[0]
+	if err != nil {
+		return err
 	}
 
 	taskName, _, err := m.ruleDB.EditRuleTx(ctx, ruleStr, id)
@@ -337,12 +323,10 @@ func (m *Manager) deleteTask(taskName string) {
 // CreateRule stores rule def into db and also
 // starts an executor for the rule
 func (m *Manager) CreateRule(ctx context.Context, ruleStr string) (*GettableRule, error) {
-	parsedRule, errs := ParsePostableRule([]byte(ruleStr))
+	parsedRule, err := ParsePostableRule([]byte(ruleStr))
 
-	if len(errs) > 0 {
-		zap.L().Error("failed to parse rules", zap.Errors("errors", errs))
-		// just one rule is being parsed so expect just one error
-		return nil, errs[0]
+	if err != nil {
+		return nil, err
 	}
 
 	lastInsertId, tx, err := m.ruleDB.CreateRuleTx(ctx, ruleStr)
@@ -701,11 +685,9 @@ func (m *Manager) PatchRule(ctx context.Context, ruleStr string, ruleId string)
 	}
 
 	// patchedRule is combo of stored rule and patch received in the request
-	patchedRule, errs := parseIntoRule(storedRule, []byte(ruleStr), "json")
-	if len(errs) > 0 {
-		zap.L().Error("failed to parse rules", zap.Errors("errors", errs))
-		// just one rule is being parsed so expect just one error
-		return nil, errs[0]
+	patchedRule, err := parseIntoRule(storedRule, []byte(ruleStr), "json")
+	if err != nil {
+		return nil, err
 	}
 
 	// deploy or un-deploy task according to patched (new) rule state
@@ -753,11 +735,10 @@ func (m *Manager) PatchRule(ctx context.Context, ruleStr string, ruleId string)
 // sends a test notification. returns alert count and error (if any)
 func (m *Manager) TestNotification(ctx context.Context, ruleStr string) (int, *model.ApiError) {
 
-	parsedRule, errs := ParsePostableRule([]byte(ruleStr))
+	parsedRule, err := ParsePostableRule([]byte(ruleStr))
 
-	if len(errs) > 0 {
-		zap.L().Error("failed to parse rule from request", zap.Errors("errors", errs))
-		return 0, newApiErrorBadData(errs[0])
+	if err != nil {
+		return 0, newApiErrorBadData(err)
 	}
 
 	var alertname = parsedRule.AlertName
@@ -771,7 +752,6 @@ func (m *Manager) TestNotification(ctx context.Context, ruleStr string) (int, *m
 	parsedRule.AlertName = fmt.Sprintf("%s%s", alertname, TestAlertPostFix)
 
 	var rule Rule
-	var err error
 
 	if parsedRule.RuleType == RuleTypeThreshold {