Continuously make and run an artifact, ignoring files according to git and make.

makew

#!/bin/bash
# --- NEEDLE-HELP-START ---
# NAME
#     makew - makew continuously run make upon source files changes.
#
# SYNOPSYS
#     makew [TARGET ...] [--cmd <command|file>] [--no-cmd] [--no-git] [--gitignore] [--exclude <regex>] [-h|--help]
#
# DESCRIPTION
#     makew calls make with the provided TARGET(s) (or none), and continue doing so whenever a source file changes.
#     makew executes the rightmost executable TARGET, and restarts it when make succeeds.
#
#     make considers source files changes if:
#       - it is not ignored by git
#       - at least one target is not up to date according to make
#
# OPTIONS
#     --cmd=<command>
#     --cmd=<file>
#         Execute the provided command or file instead of guessing what to execute.
#     --no-cmd
#         Only build and don't try to execute anything.
#     --no-git
#         Consider all files changes, even if they're ignored by git (still ignores the directory .git).
#     --gitignore
#         Don't even watch ignored files.
#         makew watch all files (except .git/*) and then queries git to know which files to ignore upon file system events.
#         But a large ignored directory may be slow to watch.
#         This option transforms .gitignore into a regex that inotify will respect...
#         But it's not possible to implement bang rules (starting with !) with POSIX extended regex.
#         makew will miss events on such files... if they were created after its initial start.
#     --exclude=<regex>
#         Append the POSIX extended regex to inotify --exclude option.
#     -h | --help
#         Print this help message.
# --- NEEDLE-HELP-END ---

# TODO option --cmd <command>
# TODO option --cmd <file>
# TODO option --no-cmd
# TODO option --no-git
# TODO option --no-git-regex
# TODO option --exclude see inotifywait --exclude
set -e
ARGS=($@)

cmd=
pid=
trap 'trap - ERR SIGINT SIGTERM EXIT; cyan "cleaning up..."; kill -- -$$;' ERR SIGINT SIGTERM EXIT

function cyan() {
    echo $(tput setaf 6)$@$(tput sgr0)
}
function magenta() {
    echo $(tput setaf 5)$@$(tput sgr0)
}
function red() {
    echo $(tput setaf 1)$@$(tput sgr0)
}

function killRunningCommand() {
    if [ "$pid" ] && isMyPID "$pid"; then
        cyan "kill $cmd ($pid)"
        kill -15 "$pid"
    fi
    pid=
}

# checks this script owns the PID ($1) to avoid killing a random process.
function isMyPID() {
    if [ -z "$1" ]; then
        return 2
    elif [ "$1" -eq 1 ]; then
        return 1
    elif [ "$1" -eq $$ ]; then
        return 0
    fi
    isMyPID $(ps -o ppid= -p "$1" 2>/dev/null)
}

function makeThenRun() {
    cyan "make ${ARGS[@]}"
    if make ${ARGS[@]}; then
        killRunningCommand
        if [ ${#ARGS[@]} -eq 0 ]; then
            executable=$(find $(grep -Pom1 '^[[:print:]]+(?=:)' [Mm]akefile) -type f -executable | tail -1)
        else
            executable=$(find ${ARGS[@]} -type f -executable | tail -1)
        fi
        if [ -z "$executable" ]; then
            return
        fi
        ./$executable &
        cmd=$executable
        pid=$!
        cyan "running $executable ($pid)"
    else
        red "failed to make"
    fi
}

makeThenRun
inotifywait -m -q --exclude './.git/.*' --format '%w%f' -e create -e modify -e delete -r . |
while read filename; do
    if ! git check-ignore -q "$filename" && ! make -q ${ARGS[@]}; then
        if [ -d "$filename" ]; then
            filename="$filename/"
        fi
        magenta "${filename#*/} changed"
        makeThenRun
    fi
done