我正在处理错误处理并登录我的 bash 脚本。下面我提供了一个简化的代码片段来举例说明用例。
我想在我的脚本中实现以下目标:
- 陷阱退出信号应触发下面代码中的 onexit() 函数
- stderr 和 stdout 应发送到 log() 函数,该函数将确保根据特定日志格式将输出记录到日志文件(在下面的示例中进行了简化)
以下当前代码存在问题:
- 步骤 1 没有被 onexit 函数捕获,脚本继续执行步骤 2。很可能是因为 stderr 通过管道传输到 logStd()。如何将错误消息发送到 logStd() 但仍然在 onexit() 中捕获退出信号?
解决:
- Add
set -o pipefail
- 获取退出状态
onexit()
通过增加local exit_status=${1:-$?}
script.sh(解析后编辑)
#!/bin/bash -E
set -o pipefail
# Perform program exit housekeeping
function onexit {
local exit_status=${1:-$?}
log "onexit() called with param: $exit_status"
exit $1
}
# Simplified log function that sends input parameter to echo. This function is used within this script
# In real case this function would send log statement to log file according to specific log format
function log {
echo "log(): $1"
}
# Simplified log function that reads input stream and sends to log
# This function is used from commands
function logStd {
log "logStd() called"
while IFS= read -r line; do log "$line"; done
}
# http://linuxcommand.org/wss0160.php
# The trap command allows you to execute a command when a signal is received by your script.
# Usage: trap arg signals
# "signals" is a list of signals to intercept and "arg" is a command to execute when one of the signals is received
# arg can either be a command or a function name like clean_up below
trap onexit 1 2 3 15 ERR
# STEP 1 - should fail, send errors to logstd() and be trapped by onexit()
log "**Tarballing should fail, file doesn´t exist"
tar -czf /Users/ismar.slomic/shellscripting/unknownfile.txt.gz /Users/ismar.slomic/shellscripting/unknownfile.txt 2>&1 | logStd
# STEP 2 - should run successfully and send "tar: Removing leading '/' from member names" to logStd()
log "**Tarballing should run successfully"
tar -czf /Users/ismar.slomic/shellscripting/file.txt.gz /Users/ismar.slomic/shellscripting/file.txt 2>&1 | logStd
onexit
output:
log(): **Tarballing should fail, file doesn´t exist
log(): logStd() called
log(): tar: /Users/ismar.slomic/shellscripting/unknownfile.txt: Cannot stat: No such file or directory
log(): tar: Error exit delayed from previous errors.
log(): **Tarballing should run successfully
log(): logStd() called
log(): tar: Removing leading '/' from member names
log(): onexit() called with param:
你必须使用
set -o pipefail
看到这个相关的 StackOverflow 问题.
最小的例子:
#!/bin/bash
trap handler ERR
handler() { echo trapped ; }
echo 1
false | :
echo 2
set -o pipefail
false | :
Output:
$ bash test.sh
1
2
trapped
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