Get Docker Size in MiB

get-docker-size-in-mib.sh

#!/bin/bash

function convert_to_mib {
    local mib=$1
    if [ $2 = "KB" ]
    then
        # if less than 1 MiB, just return 1 MiB
        mib=1
    fi

    if [ $2 = "GB" ]
    then
        # if GiB, convert to MiB
        mib=`echo "$1 * 1000" | bc -l`
    fi
    echo $mib
} 

function get_docker_size_in_mib {
    # get docker image size for a given name $1
    # if there are more than two images found for a given name, we will use the first appearing one
    # returned string would look like '3.98 MB'
    local size_string=`sudo docker images $1 --format "{{.Size}}" | head -1`
    
    # split at the space char, take the numeric portion, add 5, and round up
    # fixme: round up done using python script
    local size=`echo ${size_string} | awk -F' ' '{ print $1 }' | python -c "print int(round(float(raw_input()) + 5))"`

    # split at the space char, take the unit portion (e.g. B, KB, MB, GB)
    local size_unit=`echo ${size_string} | awk -F' ' '{ print $2 }'`

    # express in MiB
    size=$(convert_to_mib ${size} ${size_unit})

    echo ${size}
}

if [ -s "Singularity" ]
then
    echo "exists"
fi

size=$(get_docker_size_in_mib $1)
echo $size