Annotation: Add clean up job for old annotations (#26156)

Co-authored-by: Marcus Efraimsson <marcus.efraimsson@gmail.com>
Co-authored-by: Diana Payton <52059945+oddlittlebird@users.noreply.github.com>
Co-authored-by: Arve Knudsen <arve.knudsen@gmail.com>

pkg/services/sqlstore/annotation_cleanup.go

@@ -0,0 +1,87 @@
+package sqlstore
+
+import (
+	"context"
+	"fmt"
+	"time"
+
+	"github.com/grafana/grafana/pkg/infra/log"
+	"github.com/grafana/grafana/pkg/setting"
+)
+
+// AnnotationCleanupService is responseible for cleaning old annotations.
+type AnnotationCleanupService struct {
+	batchSize int64
+	log       log.Logger
+}
+
+const (
+	alertAnnotationType     = "alert_id <> 0"
+	dashboardAnnotationType = "dashboard_id <> 0 AND alert_id = 0"
+	apiAnnotationType       = "alert_id = 0 AND dashboard_id = 0"
+)
+
+// CleanAnnotations deletes old annotations created by
+// alert rules, API requests and human made in the UI.
+func (acs *AnnotationCleanupService) CleanAnnotations(ctx context.Context, cfg *setting.Cfg) error {
+	err := acs.cleanAnnotations(ctx, cfg.AlertingAnnotationCleanupSetting, alertAnnotationType)
+	if err != nil {
+		return err
+	}
+
+	err = acs.cleanAnnotations(ctx, cfg.APIAnnotationCleanupSettings, apiAnnotationType)
+	if err != nil {
+		return err
+	}
+
+	return acs.cleanAnnotations(ctx, cfg.DashboardAnnotationCleanupSettings, dashboardAnnotationType)
+}
+
+func (acs *AnnotationCleanupService) cleanAnnotations(ctx context.Context, cfg setting.AnnotationCleanupSettings, annotationType string) error {
+	if cfg.MaxAge > 0 {
+		cutoffDate := time.Now().Add(-cfg.MaxAge).UnixNano() / int64(time.Millisecond)
+		deleteQuery := `DELETE FROM annotation WHERE id IN (SELECT id FROM (SELECT id FROM annotation WHERE %s AND created < %v ORDER BY id DESC %s) a)`
+		sql := fmt.Sprintf(deleteQuery, annotationType, cutoffDate, dialect.Limit(acs.batchSize))
+
+		err := acs.executeUntilDoneOrCancelled(ctx, sql)
+		if err != nil {
+			return err
+		}
+	}
+
+	if cfg.MaxCount > 0 {
+		deleteQuery := `DELETE FROM annotation WHERE id IN (SELECT id FROM (SELECT id FROM annotation WHERE %s ORDER BY id DESC %s) a)`
+		sql := fmt.Sprintf(deleteQuery, annotationType, dialect.LimitOffset(acs.batchSize, cfg.MaxCount))
+		return acs.executeUntilDoneOrCancelled(ctx, sql)
+	}
+
+	return nil
+}
+
+func (acs *AnnotationCleanupService) executeUntilDoneOrCancelled(ctx context.Context, sql string) error {
+	for {
+		select {
+		case <-ctx.Done():
+			return ctx.Err()
+		default:
+			var affected int64
+			err := withDbSession(ctx, func(session *DBSession) error {
+				res, err := session.Exec(sql)
+				if err != nil {
+					return err
+				}
+
+				affected, err = res.RowsAffected()
+
+				return err
+			})
+			if err != nil {
+				return err
+			}
+
+			if affected == 0 {
+				return nil
+			}
+		}
+	}
+}