Correlations: Add CreateCorrelation HTTP API (#51630)

* Correlations: add migration

* Correlations: Add CreateCorrelation API

* Correlations: Make correlations work with provisioning

* Handle version changes

* Fix lining error

* lint fixes

* rebuild betterer results

* add a UID to each correlation

* Fix lint errors

* add docs

* better wording in API docs

* remove leftover comment

* handle ds updates

* Fix error message typo

* add bad data test

* make correlations a separate table

* skip readonly check when provisioning correlations

* delete stale correlations when datasources are deleted

* restore provisioned readonly ds

* publish deletion event with full data

* generate swagger and HTTP API docs

* apply source datasource permission to create correlation API

* Fix tests & lint errors

* ignore empty deletion events

* fix last lint errors

* fix more lint error

* Only publish deletion event if datasource was actually deleted

* delete DS provisioning deletes correlations, added & fixed tests

* Fix unmarshalling tests

* Fix linting errors

* Fix deltion event tests

* fix small linting error

* fix lint errors

* update betterer

* fix test

* make path singular

* Revert "make path singular"

This reverts commit 420c3d315e.

* add integration tests

* remove unneeded id from correlations table

* update spec

* update leftover references to CorrelationDTO

* fix tests

* cleanup tests

* fix lint error

pkg/services/correlations/correlations.go

@@ -0,0 +1,74 @@
+package correlations
+
+import (
+	"context"
+
+	"github.com/grafana/grafana/pkg/api/routing"
+	"github.com/grafana/grafana/pkg/bus"
+	"github.com/grafana/grafana/pkg/events"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/services/accesscontrol"
+	"github.com/grafana/grafana/pkg/services/datasources"
+	"github.com/grafana/grafana/pkg/services/sqlstore"
+)
+
+func ProvideService(sqlStore *sqlstore.SQLStore, routeRegister routing.RouteRegister, ds datasources.DataSourceService, ac accesscontrol.AccessControl, bus bus.Bus) *CorrelationsService {
+	s := &CorrelationsService{
+		SQLStore:          sqlStore,
+		RouteRegister:     routeRegister,
+		log:               log.New("correlations"),
+		DataSourceService: ds,
+		AccessControl:     ac,
+	}
+
+	s.registerAPIEndpoints()
+
+	bus.AddEventListener(s.handleDatasourceDeletion)
+
+	return s
+}
+
+type Service interface {
+	CreateCorrelation(ctx context.Context, cmd CreateCorrelationCommand) (Correlation, error)
+	DeleteCorrelationsBySourceUID(ctx context.Context, cmd DeleteCorrelationsBySourceUIDCommand) error
+	DeleteCorrelationsByTargetUID(ctx context.Context, cmd DeleteCorrelationsByTargetUIDCommand) error
+}
+
+type CorrelationsService struct {
+	SQLStore          *sqlstore.SQLStore
+	RouteRegister     routing.RouteRegister
+	log               log.Logger
+	DataSourceService datasources.DataSourceService
+	AccessControl     accesscontrol.AccessControl
+}
+
+func (s CorrelationsService) CreateCorrelation(ctx context.Context, cmd CreateCorrelationCommand) (Correlation, error) {
+	return s.createCorrelation(ctx, cmd)
+}
+
+func (s CorrelationsService) DeleteCorrelationsBySourceUID(ctx context.Context, cmd DeleteCorrelationsBySourceUIDCommand) error {
+	return s.deleteCorrelationsBySourceUID(ctx, cmd)
+}
+
+func (s CorrelationsService) DeleteCorrelationsByTargetUID(ctx context.Context, cmd DeleteCorrelationsByTargetUIDCommand) error {
+	return s.deleteCorrelationsByTargetUID(ctx, cmd)
+}
+
+func (s CorrelationsService) handleDatasourceDeletion(ctx context.Context, event *events.DataSourceDeleted) error {
+	return s.SQLStore.InTransaction(ctx, func(ctx context.Context) error {
+		if err := s.deleteCorrelationsBySourceUID(ctx, DeleteCorrelationsBySourceUIDCommand{
+			SourceUID: event.UID,
+		}); err != nil {
+			return err
+		}
+
+		if err := s.deleteCorrelationsByTargetUID(ctx, DeleteCorrelationsByTargetUIDCommand{
+			TargetUID: event.UID,
+		}); err != nil {
+			return err
+		}
+
+		return nil
+	})
+}