Mfrhtyj

I've encouter some problems with my scripts.

So to make it short and clear, I'm in an internship and my boss gave me an assignement to make a Probe for Nagios.

The purpose of this Probe is to check on all our hosts if a package is missing from the repo if yes then we have a Warning on Nagios with the list of missing packages.

This Probe can include a Whitelist if we want to keep a package which is not in whatever repo but we're not using it.

Here is my script:

#!/bin/bash



STATE_OK=0

STATE_WARNING=1

STATE_CRITICAL=2



which apt-show-versions >/dev/null

STATE=$?



declare -a WHITELIST=( host1:elasticsearch:all host2:elasticsearch:all)

PACKAGES=()

NOT_AVAILABLE=()

HOST=$(hostname)





#while [ -f /var/lib/apt/lists/lock ]

#do

#  sleep 2

#done





if [ "$STATE" = 0 ] #Verifie la condition apt-show-version = installer

then



    packets=$(apt-show-versions | grep 'No available version in archive' | cut -d" " -f1)



    for packet in $packets;do

        PACKAGES+=("${HOST}:$packet")

    done



    for package in "${PACKAGES[@]}"; do

        if [ "${WHITELIST[*]}" != "${package}" ]; then

            NOT_AVAILABLE+=("$package")

        fi

    done



    if [ -z "$NOT_AVAILABLE" ]; then

        #Ok dans Nagios

        echo "There is no package without version in archive"

        exit $STATE_OK

    else

        #Warning dans Nagios

        echo "Some package have no available version in archive"

        echo ${NOT_AVAILABLE[*]//"${HOST}":}

        exit $STATE_WARNING

    fi

else

    #Critical dans nagios

    echo "Package apt-show-versions is missing"

    exit $STATE_CRITICAL

fi

And there is the message that is coming frome Nagios :

Remote command execution failed: Failed to open file /var/lib/apt/lists//security.debian.org_dists_stretch_updates_InRelease for reading: Permission denied

I tried to play with lock file in my script but it doesn't work, I got like an infinite loop.

I already gave a look at this question
and tried to make a wrapper but he didn't worked or I missed something since I'm student and this is my first step in the shell scripting world.

I looked at this, too but it's kinda old.

Consider using lsof to check if the file is in use, as recommended on related Serverfault post. You could do something like this:

while [ "x$(lsof /var/lib/apt/lists/lock)" != "x" ] ; do

    # if lsof returns output, that means some apt task is running

    # wait 60 seconds and check again

    sleep 60

done

Another command would be fuser (and IMHO better than lsof). According to documentation:

fuser returns a non-zero return code if none of the specified files is accessed or in case of a fatal error. If at least one access has been found, fuser returns zero.

This means you can rely on exit status in the loop, which makes the syntax nicer:

while fuser /var/lib/apt/lists/lock > /dev/null ; do

    sleep 60

done

Ideally, you probably should use fnctl() type of function to see if file is locked, either via C or Python.

See also:

• Is there a faster way to check if a file is in use?