64

如何重试 bash 命令直到其状态正常或达到超时？

我最好的镜头（我正在寻找更简单的东西）：

NEXT_WAIT_TIME=0
COMMAND_STATUS=1
until [ $COMMAND_STATUS -eq 0 || $NEXT_WAIT_TIME -eq 4 ]; do
  command
  COMMAND_STATUS=$?
  sleep $NEXT_WAIT_TIME
  let NEXT_WAIT_TIME=NEXT_WAIT_TIME+1
done
4

6 回答 6

78

command您可以通过正确地进行测试并以不同的方式进行增量来简化事情。否则脚本看起来不错：

NEXT_WAIT_TIME=0
until [ $NEXT_WAIT_TIME -eq 5 ] || command; do
    sleep $(( NEXT_WAIT_TIME++ ))
done
[ $NEXT_WAIT_TIME -lt 5 ]
于 2012-09-07T16:13:45.487 回答
35

一条线，最短，也许是最好的方法：

timeout 12h bash -c 'until ssh root@mynewvm; do sleep 10; done'

归功于http://jeromebelleman.gitlab.io/posts/devops/until/

于 2019-11-08T03:32:01.247 回答
16

重试功能来自：

http://fahdshariff.blogspot.com/2014/02/retrying-commands-in-shell-scripts.html

#!/bin/bash

# Retries a command on failure.
# $1 - the max number of attempts
# $2... - the command to run
retry() {
    local -r -i max_attempts="$1"; shift
    local -r cmd="$@"
    local -i attempt_num=1

    until $cmd
    do
        if (( attempt_num == max_attempts ))
        then
            echo "Attempt $attempt_num failed and there are no more attempts left!"
            return 1
        else
            echo "Attempt $attempt_num failed! Trying again in $attempt_num seconds..."
            sleep $(( attempt_num++ ))
        fi
    done
}

# example usage:
retry 5 ls -ltr foo

如果你想在你的脚本中重试一个函数，你应该这样做：

# example usage:
foo()
{
   #whatever you want do.
}

declare -fxr foo
retry 3 timeout 60 bash -ce 'foo'
于 2016-03-14T00:56:55.823 回答
13

把一些工具放在一起。

重试：https ://github.com/kadwanev/retry

超时： http: //manpages.courier-mta.org/htmlman1/timeout.1.html

然后看看魔法

retry timeout 3 ping google.com

PING google.com (173.194.123.97): 56 data bytes
64 bytes from 173.194.123.97: icmp_seq=0 ttl=55 time=13.982 ms
64 bytes from 173.194.123.97: icmp_seq=1 ttl=55 time=44.857 ms
64 bytes from 173.194.123.97: icmp_seq=2 ttl=55 time=64.187 ms
Before retry #1: sleeping 0.3 seconds
PING google.com (173.194.123.103): 56 data bytes
64 bytes from 173.194.123.103: icmp_seq=0 ttl=55 time=56.549 ms
64 bytes from 173.194.123.103: icmp_seq=1 ttl=55 time=60.220 ms
64 bytes from 173.194.123.103: icmp_seq=2 ttl=55 time=8.872 ms
Before retry #2: sleeping 0.6 seconds
PING google.com (173.194.123.103): 56 data bytes
64 bytes from 173.194.123.103: icmp_seq=0 ttl=55 time=25.819 ms
64 bytes from 173.194.123.103: icmp_seq=1 ttl=55 time=16.382 ms
64 bytes from 173.194.123.103: icmp_seq=2 ttl=55 time=3.224 ms
Before retry #3: sleeping 1.2 seconds
PING google.com (173.194.123.103): 56 data bytes
64 bytes from 173.194.123.103: icmp_seq=0 ttl=55 time=58.438 ms
64 bytes from 173.194.123.103: icmp_seq=1 ttl=55 time=94.828 ms
64 bytes from 173.194.123.103: icmp_seq=2 ttl=55 time=61.075 ms
Before retry #4: sleeping 2.4 seconds
PING google.com (173.194.123.103): 56 data bytes
64 bytes from 173.194.123.103: icmp_seq=0 ttl=55 time=43.361 ms
64 bytes from 173.194.123.103: icmp_seq=1 ttl=55 time=32.171 ms
...

检查最终通过/失败的退出状态。

于 2015-03-26T19:39:31.577 回答
0

对于任何想要真正等到一段时间过去的人来说，考虑到你的命令时间可能很重要：

TIMEOUT_SEC=180
start_time="$(date -u +%s)"
while [ condition_or_just_true ]; do
  current_time="$(date -u +%s)"
  elapsed_seconds=$(($current_time-$start_time))
  if [ $elapsed_seconds -gt $TIMEOUT_SEC ]; then
    echo "timeout of $TIMEOUT_SEC sec"
    exit 1
  fi
  echo "another attempt (elapsed $elapsed_seconds sec)"
  some_command_and_maybe_sleep
done
于 2021-12-15T10:25:11.943 回答
-1

我对这个答案进行了一些调整，让您可以切换是否达到超时，或者命令是否成功。此外，在此版本中，每秒重试一次：

ELAPSED=0
started=$(mktemp)
echo "False" > $started
until the_command_here && echo "True" > $started || [ $ELAPSED -eq 30 ]
do
   sleep 1
   (( ELAPSED++ ))
done

if [[ $(cat $started) == "True" ]]                                                                                                                                                                                                                            
then                                                                                                                    
    echo "the command completed after $ELAPSED seconds"                                                                                              
else                                                                                                                    
    echo "timed out after $ELAPSED seconds"                                                                               
    exit 111                                                                                                            
fi
于 2019-10-16T05:09:50.353 回答