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Asked: 2016-07-26 06:06:33 +0800 CST

Interactive App: Make sure certain output is found every 30 minutes

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So, due to some very poor design choices I'm stuck with a complex and unreplaceable interactive console application running forever on a Debian machine.

This apps does some tasks, repeatedly, and returns to stdout results like:

InvetoryOpt: Finished
PBridged: Finished
FLoot: ERROR

I need to make sure that every x minutes I get the string InvetoryOpt: Finished on the output of the program. If not I need to kill it, run other a script, start the program again and the check.

How may I accomplish this? I was thinking about expect but I don't have much experience with with and I'm not sure I'm able to check if output matches string every x minutes.

Notes:

  • The program also outputs lots of other garbage that I don't care about;
  • The program can output the same string InvetoryOpt: Finished multiple times in 30 minutes or just don't output anything at all. So tailing the end of a file won't do it because it would match the last output of that string.

Thank you.

bash command-line-interface

1 Answers

  1. Best Answer

    You can use the script below as a wrapper-controller. I assume bash is known, so no technical comments. I can add them if you want them.

    The variables PROGRAM and OTHER_SCRIPT for the script you mentioned need to be defined.

    The time control is rigid, ie. it doesn't reset the countdown to the last InvetoryOpt: Finished message time, just checks every 30 mins. I can think of a way to improve this if you need it.

    UPDATE: Trap added.

    #!/usr/bin/env bash

trap '
kill %1
rm $OUT
exit
' 2

#provide the program command below
PROGRAM=
#provide the other script below
OTHER_SCRIPT=
PHRASE="InvetoryOpt: Finished"
INTERVAL=1800
OUT=/tmp/out$$

message () {
    echo "$(basename "$0")": "$1"
}

start_app () {
    eval "$PROGRAM | tee $OUT &"
}

action () {
    if ! grep -q -e "$PHRASE" $OUT
    then
        message "Check failed. Restarting." >&2
        kill %1
        eval "$OTHER_SCRIPT"
        start_app
    else
        message "All fine."
    fi
    > $OUT
}

start_app
while true
    do {
        sleep $INTERVAL
        action
    }
    done
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