Alerting: Provisioning API - Notification Policies (#46755)

* Base-line API for provisioning notification policies

* Wire API up, some simple tests

* Return provenance status through API

* Fix missing call

* Transactions

* Clarity in package dependencies

* Unify receivers in definitions

* Fix issue introduced by receiver change

* Drop unused internal test implementation

* FGAC hooks for provisioning routes

* Polish, swap names

* Asserting on number of exposed routes

* Don't bubble up updated object

* Integrate with new concurrency token feature in store

* Back out duplicated changes

* Remove redundant tests

* Regenerate and create unit tests for API layer

* Integration tests for auth

* Address linter errors

* Put route behind toggle

* Use alternative store API and fix feature toggle in tests

* Fixes, polish

* Fix whitespace

* Re-kick drone

* Rename services to provisioning

pkg/services/ngalert/api/api_provisioning.go

@@ -0,0 +1,51 @@
+package api
+
+import (
+	"context"
+	"errors"
+	"net/http"
+
+	"github.com/grafana/grafana/pkg/api/response"
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/models"
+	apimodels "github.com/grafana/grafana/pkg/services/ngalert/api/tooling/definitions"
+	domain "github.com/grafana/grafana/pkg/services/ngalert/models"
+	"github.com/grafana/grafana/pkg/services/ngalert/provisioning"
+	"github.com/grafana/grafana/pkg/services/ngalert/store"
+	"github.com/grafana/grafana/pkg/util"
+)
+
+type ProvisioningSrv struct {
+	log      log.Logger
+	policies NotificationPolicyService
+}
+
+type NotificationPolicyService interface {
+	GetPolicyTree(ctx context.Context, orgID int64) (provisioning.EmbeddedRoutingTree, error)
+	UpdatePolicyTree(ctx context.Context, orgID int64, tree apimodels.Route, p domain.Provenance) error
+}
+
+func (srv *ProvisioningSrv) RouteGetPolicyTree(c *models.ReqContext) response.Response {
+	policies, err := srv.policies.GetPolicyTree(c.Req.Context(), c.OrgId)
+	if errors.Is(err, store.ErrNoAlertmanagerConfiguration) {
+		return ErrResp(http.StatusNotFound, err, "")
+	}
+	if err != nil {
+		return ErrResp(http.StatusInternalServerError, err, "")
+	}
+
+	return response.JSON(http.StatusOK, policies)
+}
+
+func (srv *ProvisioningSrv) RoutePostPolicyTree(c *models.ReqContext, tree apimodels.Route) response.Response {
+	// TODO: lift validation out of definitions.Rotue.UnmarshalJSON and friends into a dedicated validator.
+	err := srv.policies.UpdatePolicyTree(c.Req.Context(), c.OrgId, tree, domain.ProvenanceApi)
+	if errors.Is(err, store.ErrNoAlertmanagerConfiguration) {
+		return ErrResp(http.StatusNotFound, err, "")
+	}
+	if err != nil {
+		return ErrResp(http.StatusInternalServerError, err, "")
+	}
+
+	return response.JSON(http.StatusAccepted, util.DynMap{"message": "policies updated"})
+}