A janky script to sync system time from various public APIs in case NTP is unusable

time-sync.service

[Unit]
Description=Sync system time from various network APIs

[Service]
User=root
Type=oneshot
ExecStart=/usr/local/lib/time-sync.sh

time-sync.sh

#!/bin/bash

function timestamp_to_time {
    date -d "@$1" "+%F %T"
}

function time_to_timestamp {
    date -d "$1" "+%s"
}

function timestamp_taobao {
    local ts=$(curl -s 'http://api.m.taobao.com/rest/api3.do?api=mtop.common.getTimestamp' | jq -r '.data.t')
    echo $(( $ts / 1000 ))
}

function timestamp_tencent {
    local ts=$(curl -s 'http://vv.video.qq.com/checktime?otype=json')
    ts="${ts/QZOutputJson\=/}"
    ts="${ts/\;/}"
    echo "$ts" | jq -r '.t'
}

function timestamp_suning {
    local ts=$(curl -s 'http://f.m.suning.com/api/ct.do' | jq -r '.currentTime')
    echo $(( $ts / 1000 ))
}

function timestamp_suning_2 {
    time_to_timestamp "$(curl -s 'http://quan.suning.com/getSysTime.do' | jq -r '.sysTime2')"
}

declare -a fns=(
timestamp_taobao
timestamp_tencent
timestamp_suning
timestamp_suning_2
)

for fn in "${fns[@]}"
do
    ts="-1"
    echo "Trying API ${fn} ..."
    ts=$("${fn}")
    echo "Got timestamp: ${ts}"
    if [ "${ts}" -gt "1700000000" ]
    then
        echo "Timestamp seems valid, set to system time ..."
        date -s "@${ts}"
        exit 0
    fi
done

time-sync.timer

[Unit]
Description=Run time-sync daily

[Timer]
OnCalendar=*-*-* 01:00:00
Persistent=true

[Install]
WantedBy=timers.target