79 lines
2.2 KiB
Go
79 lines
2.2 KiB
Go
//go:build linux
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// +build linux
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/*
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Copyright 2018 The Kubernetes Authors.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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*/
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package util
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import (
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"context"
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"fmt"
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"os"
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"strconv"
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"strings"
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"time"
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"golang.org/x/sys/unix"
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"k8s.io/klog/v2"
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)
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// GetBootTime returns the time at which the machine was started, truncated to the nearest second.
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// It uses /proc/stat first, which is more accurate, and falls back to the less accurate
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// unix.Sysinfo if /proc/stat failed.
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func GetBootTime() (time.Time, error) {
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bootTime, err := getBootTimeWithProcStat()
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if err != nil {
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// TODO: it needs to be replaced by a proper context in the future
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ctx := context.TODO()
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logger := klog.FromContext(ctx)
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logger.Info("Failed to get boot time from /proc/uptime. Will retry with unix.Sysinfo.", "error", err)
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return getBootTimeWithSysinfo()
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}
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return bootTime, nil
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}
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func getBootTimeWithProcStat() (time.Time, error) {
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raw, err := os.ReadFile("/proc/stat")
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if err != nil {
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return time.Time{}, fmt.Errorf("error getting boot time: %w", err)
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}
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rawFields := strings.Fields(string(raw))
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for i, v := range rawFields {
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if v == "btime" {
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if len(rawFields) > i+1 {
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sec, err := strconv.ParseInt(rawFields[i+1], 10, 64)
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if err != nil {
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return time.Time{}, fmt.Errorf("error parsing boot time %s: %w", rawFields[i+1], err)
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}
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return time.Unix(sec, 0), nil
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}
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break
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}
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}
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return time.Time{}, fmt.Errorf("can not find btime from /proc/stat: %s", raw)
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}
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func getBootTimeWithSysinfo() (time.Time, error) {
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currentTime := time.Now()
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var info unix.Sysinfo_t
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if err := unix.Sysinfo(&info); err != nil {
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return time.Time{}, fmt.Errorf("error getting system uptime: %w", err)
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}
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return currentTime.Add(-time.Duration(info.Uptime) * time.Second).Truncate(time.Second), nil
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}
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