Alerting: Add traceability headers for alert queries (#57127)

* Define EvaluationContext

* Refactor ConditionEval to use new context struct

* Refactor QueriesAndExpressionsEval to use EvaluationContext

* Remove dead field from AlertExecCtx

* Refactor Validate to use EvaluationContext

* Get rid of privately used AlertExecCtx

* Move EvaluationContext to new file and add helper

* Add builder pattern and bind rule info to context

* Extract header logic and add rule UID header

* Fix missing call

pkg/services/ngalert/api/api_ruler.go

@@ -10,10 +10,10 @@ import (
 
 	"github.com/grafana/grafana/pkg/services/accesscontrol"
 	"github.com/grafana/grafana/pkg/services/dashboards"
+	"github.com/grafana/grafana/pkg/services/ngalert/eval"
 	"github.com/grafana/grafana/pkg/services/ngalert/provisioning"
 	"github.com/grafana/grafana/pkg/services/ngalert/store"
 	"github.com/grafana/grafana/pkg/services/quota"
-	"github.com/grafana/grafana/pkg/services/user"
 	"github.com/grafana/grafana/pkg/setting"
 
 	"github.com/prometheus/common/model"
@@ -30,7 +30,7 @@ import (
 
 type ConditionValidator interface {
 	// Validate validates that the condition is correct. Returns nil if the condition is correct. Otherwise, error that describes the failure
-	Validate(ctx context.Context, user *user.SignedInUser, condition ngmodels.Condition) error
+	Validate(ctx eval.EvaluationContext, condition ngmodels.Condition) error
 }
 
 type RulerSrv struct {
@@ -308,7 +308,7 @@ func (srv RulerSrv) RoutePostNameRulesConfig(c *models.ReqContext, ruleGroupConf
 	}
 
 	rules, err := validateRuleGroup(&ruleGroupConfig, c.SignedInUser.OrgID, namespace, func(condition ngmodels.Condition) error {
-		return srv.conditionValidator.Validate(c.Req.Context(), c.SignedInUser, condition)
+		return srv.conditionValidator.Validate(eval.Context(c.Req.Context(), c.SignedInUser), condition)
 	}, srv.cfg)
 	if err != nil {
 		return ErrResp(http.StatusBadRequest, err, "")