dashboard history: clean up dashboard version history

pkg/services/sqlstore/dashboard_version.go

@@ -1,13 +1,21 @@
 package sqlstore
 
 import (
+	"fmt"
+	"math"
+	"sort"
+	"strconv"
+	"strings"
+
 	"github.com/grafana/grafana/pkg/bus"
 	m "github.com/grafana/grafana/pkg/models"
+	"github.com/grafana/grafana/pkg/setting"
 )
 
 func init() {
 	bus.AddHandler("sql", GetDashboardVersion)
 	bus.AddHandler("sql", GetDashboardVersions)
+	bus.AddHandler("sql", DeleteExpiredVersions)
 }
 
 // GetDashboardVersion gets the dashboard version for the given dashboard ID and version number.
@@ -58,3 +66,92 @@ func GetDashboardVersions(query *m.GetDashboardVersionsQuery) error {
 	}
 	return nil
 }
+
+func DeleteExpiredVersions(cmd *m.DeleteExpiredVersionsCommand) error {
+	return inTransaction(func(sess *DBSession) error {
+		var expiredCount int64 = 0
+		var versions []DashboardVersionExp
+
+		// Don't clean up if user set versions_to_keep to 2147483647 (MaxInt32)
+		if versionsToKeep := setting.DashboardVersionsToKeep; versionsToKeep < math.MaxInt32 {
+			// Get dashboard ids to clean up
+			affectedDashboardsQuery := fmt.Sprintf(`SELECT dashboard_id FROM dashboard_version
+				GROUP BY dashboard_id HAVING COUNT(dashboard_version.id)>%d`, versionsToKeep)
+
+			err := x.Table("dashboard_version").
+				Select("dashboard_version.id, dashboard_version.version, dashboard_version.dashboard_id").
+				Where(fmt.Sprintf("dashboard_id IN (%s)", affectedDashboardsQuery)).
+				Find(&versions)
+
+			if err != nil {
+				return err
+			}
+
+			// Keep last versionsToKeep versions and delete other
+			versionIdsToDelete := getVersionIDsToDelete(versions, versionsToKeep)
+			versionIdsToDeleteStr := getVersionIDsToDeleteStr(versionIdsToDelete)
+			deleteExpiredSql := fmt.Sprintf("DELETE FROM dashboard_version WHERE id IN (%v)", strings.Join(versionIdsToDeleteStr, ", "))
+			expiredResponse, err := x.Exec(deleteExpiredSql)
+			if err != nil {
+				return err
+			}
+			expiredCount, _ = expiredResponse.RowsAffected()
+		}
+
+		sqlog.Debug("Deleted old/expired dashboard versions", "expired", expiredCount)
+		return nil
+	})
+}
+
+// Short version of DashboardVersion for getting expired versions
+type DashboardVersionExp struct {
+	Id          int64 `json:"id"`
+	DashboardId int64 `json:"dashboardId"`
+	Version     int   `json:"version"`
+}
+
+// Implement sort.Interface for []DashboardVersionExp (sort by Version field)
+type ByVersion []DashboardVersionExp
+
+func (v ByVersion) Len() int {
+	return len(v)
+}
+
+func (v ByVersion) Swap(i, j int) {
+	v[i], v[j] = v[j], v[i]
+}
+
+func (v ByVersion) Less(i, j int) bool {
+	return v[i].Version < v[j].Version
+}
+
+func getVersionIDsToDelete(versions []DashboardVersionExp, versionsToKeep int) []int64 {
+	dashboards := make(map[int64][]DashboardVersionExp)
+	for _, v := range versions {
+		elem, present := dashboards[v.DashboardId]
+		if present {
+			dashboards[v.DashboardId] = append(elem, v)
+		} else {
+			dashboards[v.DashboardId] = []DashboardVersionExp{v}
+		}
+	}
+
+	versionIds := make([]int64, 0)
+	for dashboard_id, versions := range dashboards {
+		sort.Sort(sort.Reverse(ByVersion(versions)))
+		dashboards[dashboard_id] = versions[versionsToKeep:]
+		for _, ver := range dashboards[dashboard_id] {
+			versionIds = append(versionIds, ver.Id)
+		}
+	}
+
+	return versionIds
+}
+
+func getVersionIDsToDeleteStr(versionIds []int64) []string {
+	var versionIdsToDeleteStr []string
+	for _, versionId := range versionIds {
+		versionIdsToDeleteStr = append(versionIdsToDeleteStr, strconv.FormatInt(versionId, 10))
+	}
+	return versionIdsToDeleteStr
+}