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package main
import (
"fmt"
"io/ioutil"
"log"
"sort"
"strings"
"time"
)
type backup struct {
Name string
Time time.Time
}
var (
keep_yearly = 1
keep_monthly = 6
keep_weekly = 4
keep_daily = 14
patterns = map[string]string{
"daily": "2006-01-02",
"weekly": "", // See special case in keepers()
"monthly": "2006-01",
"yearly": "2006",
}
)
func enumerate_backups() []backup {
var backups []backup
files, err := ioutil.ReadDir("./test/data")
if err != nil {
log.Fatal(err)
}
for _, file := range files {
name := file.Name()
time, err := time.Parse(time.RFC3339, strings.Split(name, "@")[1])
if err != nil {
log.Fatalf("Failed to parse timestamp in %s\n", name)
continue
}
backups = append(backups, backup{name, time})
}
return backups
}
func keepers(backups []backup, rule string, keepCnt int) []backup {
var keep []backup
var last string
for _, backup := range backups {
var period string
// Special case because there is no support for "week number" in Time.Format
if rule == "weekly" {
year, week := backup.Time.Local().ISOWeek()
period = fmt.Sprintf("%d-%d", year, week)
} else {
period = backup.Time.Local().Format(patterns[rule])
}
// fmt.Printf("rule: %s, pattern: %s, t: %s, format: %s\n", rule, patterns[rule], backup.Time.Local(), period)
if period != last {
last = period
keep = append(keep, backup)
if len(keep) == keepCnt {
break
}
}
}
return keep
}
func main() {
backups := enumerate_backups()
sort.Slice(backups, func(i, j int) bool {
return backups[i].Time.After(backups[j].Time)
})
fmt.Println("============== DAILY ==============")
for _, kept := range keepers(backups, "daily", keep_daily) {
fmt.Printf("%s\n", kept.Name)
}
fmt.Println("============== WEEKLY ==============")
for _, kept := range keepers(backups, "weekly", keep_weekly) {
fmt.Printf("%s\n", kept.Name)
}
fmt.Println("============== MONTHLY ==============")
for _, kept := range keepers(backups, "monthly", keep_monthly) {
fmt.Printf("%s\n", kept.Name)
}
fmt.Println("============== YEARLY ==============")
for _, kept := range keepers(backups, "yearly", keep_yearly) {
fmt.Printf("%s\n", kept.Name)
}
}
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