This apt-get wrapper script (bash) is intended mainly for use with Dockerfile. It allows to detect apt-get network errors and to avoid distracting "red" apt-get output.

apt-get-wrapper

#!/usr/bin/env bash
#
#   "apt-get" wrapper that detects STDERR messages with the prefixes "W:" and "E:"
#   and redirect some apt-get STDERR messages to STDOUT.
#
#   Returns exit status 120 in case of non-zero apt-get exit status
#   or in case of detection of STDERR message with the prefix "W:" or "E:".
#
#   The wrapper is intended mainly for use with Dockerfile.
#   It allows to detect apt-get network errors
#   and to avoid distracting "red" apt-get output.
#
#   See also "Advanced Bash−Scripting Guide":
#   Chapter 16. I/O Redirection
#   Chapter 22. Process Substitution
#   Chapter 11. Internal Commands and Builtins ('read' command)

declare -r  MYEXECNAME="${BASH_SOURCE[0]##*/}"
declare -r  MYSUCCESS='@@@zZ:^&?@%#:#%@?&^:Zz@@@'
declare -u  myupper=
declare     myok=
declare     mystatus=
declare     myerr=
declare     myline=

exec 10>&1  #  Link file descriptor #10 with STDOUT

while IFS= read -r myline
do
    #   Handle apt-get STDERR line
    #   (customize redirecting to STDOUT according to your needs)
    if   [ "$myline" = "$MYSUCCESS" ]; then
        myok=1
    elif [ -z "$myline" ]; then
        :
    elif [ "${myline#*Extracting templates from packages: 100%}" != "$myline" ]; then
        echo 'Extracting templates from packages: 100%'
    elif [ "${myline#debconf: delaying package configuration}" != "$myline" ]; then
        echo "$myline"
    else
        echo "$myline" 1>&2
        myupper="${myline:0:2}"
        if [ "$myupper" = 'E:' -o "$myupper" = 'W:' ]; then
            myerr=1
        fi
    fi
done  < <(
    # This is subshell environment ...

    # Redirect apt-get STDERR to the pipe and STDOUT to the #10:
    apt-get "$@" 2>&1 >&10
    mystatus="$?"

    echo    # Terminate possible pipe line before echo "$MYSUCCESS"
    if [ "$mystatus" = 0 ] ; then
        echo "$MYSUCCESS"
    else
        echo "${MYEXECNAME}: apt-get" "$@" "- Exit Status ${mystatus}"
    fi
)

exec 10>&- # Close file descriptor #10

if   [ "$myok" != 1 ]; then
    exit 120
elif [ "$myerr" = 1 ]; then    
    echo "FAILURE: ${MYEXECNAME}: apt-get error/warning message is detected" 1>&2 
    exit 120
fi
exit 0