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105 lines
2.6 KiB
Go
105 lines
2.6 KiB
Go
package pruning
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import (
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"fmt"
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"regexp"
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"sort"
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"time"
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"github.com/pkg/errors"
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"github.com/zrepl/zrepl/config"
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"github.com/zrepl/zrepl/pruning/retentiongrid"
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)
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// KeepGrid fits snapshots that match a given regex into a retentiongrid.Grid,
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// uses the most recent snapshot among those that match the regex as 'now',
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// and deletes all snapshots that do not fit the grid specification.
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type KeepGrid struct {
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retentionGrid *retentiongrid.Grid
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re *regexp.Regexp
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}
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func NewKeepGrid(in *config.PruneGrid) (p *KeepGrid, err error) {
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if in.Regex == "" {
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return nil, fmt.Errorf("Regex must not be empty")
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}
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re, err := regexp.Compile(in.Regex)
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if err != nil {
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return nil, errors.Wrap(err, "Regex is invalid")
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}
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// Assert intervals are of increasing length (not necessarily required, but indicates config mistake)
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lastDuration := time.Duration(0)
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for i := range in.Grid {
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if in.Grid[i].Length() < lastDuration {
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// If all intervals before were keep=all, this is ok
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allPrevKeepCountAll := true
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for j := i - 1; allPrevKeepCountAll && j >= 0; j-- {
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allPrevKeepCountAll = in.Grid[j].KeepCount() == config.RetentionGridKeepCountAll
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}
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if allPrevKeepCountAll {
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goto isMonotonicIncrease
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}
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err = errors.New("retention grid interval length must be monotonically increasing")
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return
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}
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isMonotonicIncrease:
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lastDuration = in.Grid[i].Length()
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}
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retentionIntervals := make([]retentiongrid.Interval, len(in.Grid))
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for i := range in.Grid {
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retentionIntervals[i] = &in.Grid[i]
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}
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return &KeepGrid{
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retentiongrid.NewGrid(retentionIntervals),
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re,
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}, nil
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}
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type retentionGridAdaptor struct {
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Snapshot
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}
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func (a retentionGridAdaptor) LessThan(b retentiongrid.Entry) bool {
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return a.Date().Before(b.Date())
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}
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// Prune filters snapshots with the retention grid.
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func (p *KeepGrid) KeepRule(snaps []Snapshot) (destroyList []Snapshot) {
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snaps = filterSnapList(snaps, func(snapshot Snapshot) bool {
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return p.re.MatchString(snapshot.Name())
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})
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if len(snaps) == 0 {
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return nil
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}
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// Build adaptors for retention grid
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adaptors := make([]retentiongrid.Entry, 0)
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for i := range snaps {
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adaptors = append(adaptors, retentionGridAdaptor{snaps[i]})
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}
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// determine 'now' edge
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sort.SliceStable(adaptors, func(i, j int) bool {
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return adaptors[i].LessThan(adaptors[j])
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})
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now := adaptors[len(adaptors)-1].Date()
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// Evaluate retention grid
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_, removea := p.retentionGrid.FitEntries(now, adaptors)
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// Revert adaptors
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destroyList = make([]Snapshot, len(removea))
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for i := range removea {
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destroyList[i] = removea[i].(retentionGridAdaptor).Snapshot
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}
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return destroyList
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}
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