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Saqib Ali
Asked: 2018-05-09 10:42:17 +0800 CST

Sending an alert email if time for a curl command exceeds 1 sec

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I am trying to a write one liner for sending an alert email if the time taken for curl command exceeds 1 sec.

if time curl {URI} > 1; then mailx -r [email protected] -s ALERT; fi

How since time command returns more than just a numeric value, this fails.

Any ideas on how I can achieve this?

command-line bash time

3 Answers

  1. From the look of it, the result of curl does not seem to matter.

    So I propose to kill the command if it spans more than one second by using timeout. Here is the one-liner:

    timeout 1s curl {URI} || mailx -r [email protected] -s ALERT

    If it timeouts, it returns an error and the mailx command is run.

    No tested but that should work.

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  2. I'd save the PID of the curl process, sleep a second and just test whether it's still running with kill:

    curl … &
pid=$!
sleep 1
if kill -0 $pid &>/dev/null; then
  mailx -r [email protected] -s ALERT
fi

    You can test this easily with sleep 1 or sleep 2 respectively:

    $ sleep 1 & pid=$!; sleep 1; if kill -0 $pid &>/dev/null; then echo running; fi
[1] 27520
[1]+  Done                    sleep 1
$ sleep 2 & pid=$!; sleep 1; if kill -0 $pid &>/dev/null; then echo running; fi
[1] 27599
running
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  3. Curl has an option for this, --max-time (and --connect-time, if you want to control time spend in the connect phase on the session). If timeout occurs, curl will return error-code 28.

    So something like this:

    curl --max-time 60 <URL>
if [ $? -eq 28 ]
then 
  mailx -r [email protected] -s ALERT
fi

    should do it.

    I found this site Everything Curl which describes the capabilities of Curl.

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