prometheus/utility/strconv.go

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// Copyright 2013 Prometheus Team
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package utility
import (
"fmt"
"regexp"
"strconv"
"time"
)
var durationRE = regexp.MustCompile("^([0-9]+)([ywdhms]+)$")
// DurationToString formats a time.Duration as a string with the assumption that
// a year always has 365 days and a day always has 24h. (The former doesn't work
// in leap years, the latter is broken by DST switches, not to speak about leap
// seconds, but those are not even treated properly by the duration strings in
// the standard library.)
func DurationToString(duration time.Duration) string {
seconds := int64(duration / time.Second)
factors := map[string]int64{
"y": 60 * 60 * 24 * 365,
"d": 60 * 60 * 24,
"h": 60 * 60,
"m": 60,
"s": 1,
}
unit := "s"
switch int64(0) {
case seconds % factors["y"]:
unit = "y"
case seconds % factors["d"]:
unit = "d"
case seconds % factors["h"]:
unit = "h"
case seconds % factors["m"]:
unit = "m"
}
return fmt.Sprintf("%v%v", seconds/factors[unit], unit)
}
// StringToDuration parses a string into a time.Duration, assuming that a year
// always has 265d, a week 7d, a day 24h. See DurationToString for problems with
// that.
func StringToDuration(durationStr string) (duration time.Duration, err error) {
matches := durationRE.FindStringSubmatch(durationStr)
if len(matches) != 3 {
err = fmt.Errorf("not a valid duration string: %q", durationStr)
return
}
durationSeconds, _ := strconv.Atoi(matches[1])
duration = time.Duration(durationSeconds) * time.Second
unit := matches[2]
switch unit {
case "y":
duration *= 60 * 60 * 24 * 365
case "w":
duration *= 60 * 60 * 24 * 7
case "d":
duration *= 60 * 60 * 24
case "h":
duration *= 60 * 60
case "m":
duration *= 60
case "s":
duration *= 1
default:
panic("Invalid time unit in duration string.")
}
return
}