wrap apt-get to handle lock contention due to unattended upgrades etc.

apt-get.sh

#!/usr/bin/env bash

set -uoe pipefail

function apt-get() {
    # wrap apt-get to handle lock contention due to unattended upgrades etc.
    # retry on lock contention up to three times. on other errors, exit without retry
    local i=0

    while true;
    do
        i=$((i + 1))

        # capture stderr in a temp file
        stderr_log=$(mktemp -t apt-get-std-err-XXXXXX)

        exit_code=0

        command apt-get "$@" 2> >(tee "$stderr_log" >&2) || exit_code=$?

        if [[ -z $exit_code ]]; then
            # success
            return 0
        fi

        if [[ $i == 3 ]]; then
            echo "all attempts failed!" >&2
            return "$exit_code"
        fi

        if grep -qF "held by process" "$stderr_log"; then
            # another process has the apt lock
            pid=$(grep -o '[0-9]\+' "$stderr_log")
            echo "waiting for process $pid to complete ..." >&2
            tail --pid="$pid" -f /dev/null
            # retry
            continue
        fi

        # some other error
        return "$exit_code"

    done
}

function sudo {
    # declare and export apt-get for use in sudo shells
    # sudo options = ${@:1:$#-1} ie: all except last arg
    # sudo command = ${!#} ie: last arg
    command sudo "${@:1:$#-1}" bash -c "$(declare -f apt-get); export -f apt-get; ${!#}"
}