add-pkg

#!/bin/sh

set -e # Exit immediately if a command exits with a non-zero status.

usage() {
    echo "usage: $(basename "$0") [--virtual NAME ] PKG [PKG...]"
}

trap : TERM QUIT INT
trap "cleanup" EXIT

#
# Alpine functions
#

is_pkg_installed_alpine() {
    apk info 2>/dev/null | grep -v "^WARNING" | grep -q "^$1\$"
}

install_pkg_alpine() {
    VIRTUAL_PKG="$1"
    shift

    APK_EXTRA_OPTS=
    if [ "$VIRTUAL_PKG" -eq 1 ]; then
        APK_EXTRA_OPTS="--virtual"
    fi

    apk --no-cache add $APK_EXTRA_OPTS "$@"
}

cleanup_alpine() {
    rm -rf /var/cache/misc/*
}

#
# Debian functions
#

is_pkg_installed_debian() {
    dpkg --status "$1" 2>&1 | grep -q "^Status: install ok installed"
}

install_pkg_debian() {
    VIRTUAL_PKG="$1"
    shift

    if [ "$VIRTUAL_PKG" -eq 1 ]; then
        VIRTUAL_PKG_NAME=$1
        shift

        if [ -f /var/lib/apt/$VIRTUAL_PKG_NAME.virtual ]; then
            echo "ERROR: Virtual package '$VIRTUAL_PKG_NAME' already exists."
            exit 1
        fi

        echo "$*" > /var/lib/apt/$VIRTUAL_PKG_NAME.virtual
    fi

    if [ -n "$1" ]; then
        apt-get -q update
        apt-get -q install -y --no-install-recommends "$@"
    fi
}

cleanup_debian() {
    apt-get -q clean
        rm -rf /var/lib/apt/lists/* \
               /var/log/dpkg.log \
               /var/log/alternatives.log \
               /var/log/apt/*
}

#
# OS agnostic functions
#

is_pkg_installed() {
    if [ -n "$(which apk)" ]; then
        is_pkg_installed_alpine "$@"
    else
        is_pkg_installed_debian "$@"
    fi
}

install_pkg() {
    if [ -n "$(which apk)" ]; then
        install_pkg_alpine "$@"
    else
        install_pkg_debian "$@"
    fi
}

cleanup() {
    if [ -n "$(which apk)" ]; then
        cleanup_alpine
    else
        cleanup_debian
    fi
}

#
# Main
#

if [ -z "$1" ]; then
    usage
    exit 1
fi

VIRTUAL_PKG=
if [ "$1" = "--virtual" ]; then
    shift
    if [ -z "$1" ]; then
        echo "Virtual package name missing."
        usage
        exit 1
    fi
    VIRTUAL_PKG="$1"
    shift
fi

if [ -n "$VIRTUAL_PKG" ]; then
    PKGS="$VIRTUAL_PKG"
    for PKG in "$@"
    do
        if ! is_pkg_installed $PKG; then
            PKGS="$PKGS $PKG"
        fi
    done
    install_pkg 1 $PKGS
else
    install_pkg 0 "$@"
fi