home-manager/home-manager/home-manager

#!@bash@/bin/bash

# This code explicitly requires GNU Core Utilities and we therefore
# need to ensure they are prioritized over any other similarly named
# tools on the system.
PATH=@coreutils@/bin:$PATH

set -euo pipefail

# Attempts to set the HOME_MANAGER_CONFIG global variable.
#
# If no configuration file can be found then this function will print
# an error message and exit with an error code.
function setConfigFile() {
    if [[ -v HOME_MANAGER_CONFIG ]] ; then
        if [[ ! -e "$HOME_MANAGER_CONFIG" ]] ; then
            echo "No configure file found at $HOME_MANAGER_CONFIG"
            exit 1
        fi

        HOME_MANAGER_CONFIG="$(realpath "$HOME_MANAGER_CONFIG")"
        return
    fi

    local confFile
    for confFile in "$HOME/.config/nixpkgs/home.nix" \
                    "$HOME/.nixpkgs/home.nix" ; do
        if [[ -e "$confFile" ]] ; then
            HOME_MANAGER_CONFIG="$confFile"
            return
        fi
    done

    echo "No configuration file found. " \
         "Please create one at ~/.config/nixpkgs/home.nix"
    exit 1
}

function setHomeManagerModulesPath() {
    local modulesPath
    for modulesPath in "@MODULES_PATH@" \
                       "$HOME/.nixpkgs/home-manager/modules" ; do
        if [[ -e "$modulesPath" ]] ; then
            export NIX_PATH="$NIX_PATH${NIX_PATH:+:}home-manager=$modulesPath"
            return
        fi
    done
}

function doBuild() {
    if [[ -z "$1" ]]; then
        echo "Need to provide generation output path."
        exit 1
    fi

    if [[ -e "$1" ]]; then
        echo "The output path $1 already exists."
        exit 1
    fi

    setConfigFile
    setHomeManagerModulesPath

    output="$(realpath "$1")"

    if [[ $? -ne 0 ]]; then
        exit 1
    fi

    export NIX_PATH="$NIX_PATH${NIX_PATH:+:}home-manager=@MODULES_PATH@"

    local extraArgs
    extraArgs=""

    for p in "${EXTRA_NIX_PATH[@]}"; do
        extraArgs="$extraArgs -I $p"
    done

    if [[ -v VERBOSE ]]; then
        extraArgs="$extraArgs --show-trace"
    fi

    nix-build $extraArgs \
              "@HOME_MANAGER_EXPR_PATH@" \
              --argstr confPath "$HOME_MANAGER_CONFIG" \
              -A activation-script \
              -o "$output"
}

function doSwitch() {
    local wrkdir
    wrkdir="$(mktemp -d)"

    if doBuild "$wrkdir/generation" ; then
        "$wrkdir/generation/activate"
    fi

    rm -r "$wrkdir"
}

function doListGens() {
    pushd "/nix/var/nix/profiles/per-user/$USER" > /dev/null
    ls --color=yes -gG --sort time home-manager-*-link \
        | cut -d' ' -f 4-
    popd > /dev/null
}

function doListPackages() {
    local outPath
    outPath="$(nix-env -q --out-path | grep -o '/.*home-manager-path$')"
    if [[ -n "$outPath" ]] ; then
        nix-store -q --references "$outPath" | sed 's/[^-]*-//'
    else
        echo "No home-manager packages seem to be installed."
    fi
}

function doHelp() {
    echo "Usage: $0 [OPTION] COMMAND"
    echo
    echo "Options"
    echo
    echo "  -f FILE      The home configuration file."
    echo "               Default is '~/.config/nixpkgs/home.nix'."
    echo "  -I PATH      Add a path to the Nix expression search path."
    echo "  -v           Verbose output"
    echo "  -n           Do a dry run, only prints what actions would be taken"
    echo "  -h           Print this help"
    echo
    echo "Commands"
    echo "  help         Print this help"
    echo "  build        Build configuration into result directory"
    echo "  switch       Build and activate configuration"
    echo "  generations  List all home environment generations"
    echo "  packages     List all packages installed in home-manager-path"
}

EXTRA_NIX_PATH=()

while getopts f:I:vnh opt; do
    case $opt in
        f)
            HOME_MANAGER_CONFIG="$OPTARG"
            ;;
        I)
            EXTRA_NIX_PATH+=("$OPTARG")
            ;;
        v)
            export VERBOSE=1
            ;;
        n)
            export DRY_RUN=1
            ;;
        h)
            doHelp
            exit 0
            ;;
        *)
            echo "Unknown option -$OPTARG" >&2
            doHelp >&2
            exit 1
            ;;
    esac
done

# Get rid of the options.
shift "$((OPTIND-1))"

cmd="$*"

case "$cmd" in
    build)
        doBuild "result"
        ;;
    switch)
        doSwitch
        ;;
    generations)
        doListGens
        ;;
    packages)
        doListPackages
        ;;
    help|--help)
        doHelp
        ;;
    *)
        echo "Unknown command: $cmd"
        doHelp >&2
        exit 1
        ;;
esac