shell-scripting-templates/utilities/template_utils.bash

# Functions required to allow the script template and alert functions to be used

_acquireScriptLock_() {
    # DESC:
    #         Acquire script lock to prevent running the same script a second time before the
    #         first instance exits
    # ARGS:
    #         $1 (optional) - Scope of script execution lock (system or user)
    # OUTS:
    #         exports $SCRIPT_LOCK - Path to the directory indicating we have the script lock
    #         Exits script if lock cannot be acquired
    # NOTE:
    #         If the lock was acquired it's automatically released in _safeExit_()

    local _lockDir
    if [[ ${1:-} == 'system' ]]; then
        _lockDir="${TMPDIR:-/tmp/}$(basename "$0").lock"
    else
        _lockDir="${TMPDIR:-/tmp/}$(basename "$0").$UID.lock"
    fi

    if command mkdir "${LOCK_DIR}" 2>/dev/null; then
        readonly SCRIPT_LOCK="${_lockDir}"
        debug "Acquired script lock: ${tan}${SCRIPT_LOCK}${purple}"
    else
        if [ "$(declare -f "_safeExit_")" ]; then
            error "Unable to acquire script lock: ${yellow}${LOCK_DIR}${red}"
            fatal "If you trust the script isn't running, delete the lock dir"
        else
            printf "%s\n" "ERROR: Could not acquire script lock. If you trust the script isn't running, delete: ${LOCK_DIR}"
            exit 1
        fi

    fi
}

_makeTempDir_() {
    # DESC:
    #         Creates a temp directory to house temporary files
    # ARGS:
    #         $1 (Optional) - First characters/word of directory name
    # OUTS:
    #         Sets $TMP_DIR variable to the path of the temp directory
    # USAGE:
    #         _makeTempDir_ "$(basename "$0")"

    [ -d "${TMP_DIR:-}" ] && return 0

    if [ -n "${1:-}" ]; then
        TMP_DIR="${TMPDIR:-/tmp/}${1}.${RANDOM}.${RANDOM}.$$"
    else
        TMP_DIR="${TMPDIR:-/tmp/}$(basename "$0").${RANDOM}.${RANDOM}.${RANDOM}.$$"
    fi
    (umask 077 && mkdir "${TMP_DIR}") || {
        fatal "Could not create temporary directory! Exiting."
    }
    debug "\$TMP_DIR=${TMP_DIR}"
}

_safeExit_() {
    # DESC:
    #       Cleanup and exit from a script
    # ARGS:
    #       $1 (optional) - Exit code (defaults to 0)
    # OUTS:
    #       None

    if [[ -d ${SCRIPT_LOCK:-} ]]; then
        if command rm -rf "${SCRIPT_LOCK}"; then
            debug "Removing script lock"
        else
            warning "Script lock could not be removed. Try manually deleting ${yellow}'${LOCK_DIR}'"
        fi
    fi

    if [[ -n ${TMP_DIR:-} && -d ${TMP_DIR:-} ]]; then
        if [[ ${1:-} == 1 && -n "$(ls "${TMP_DIR}")" ]]; then
            command rm -r "${TMP_DIR}"
        else
            command rm -r "${TMP_DIR}"
            debug "Removing temp directory"
        fi
    fi

    trap - INT TERM EXIT
    exit ${1:-0}
}

_setPATH_() {
    # DESC:
    #         Add directories to $PATH so script can find executables
    # ARGS:
    #         $@ - One or more paths
    # OUTS:   Adds items to $PATH
    # USAGE:
    #         _setPATH_ "/usr/local/bin" "${HOME}/bin" "$(npm bin)"

    [[ $# == 0 ]] && fatal "Missing required argument to ${FUNCNAME[0]}"

    local _newPath

    for _newPath in "$@"; do
        if [ -d "${_newPath}" ]; then
            if ! echo "${PATH}" | grep -Eq "(^|:)${_newPath}($|:)"; then
                if PATH="${_newPath}:${PATH}"; then
                    debug "Added '${_newPath}' to PATH"
                else
                    return 1
                fi
            else
                debug "_setPATH_: '${_newPath}' already exists in PATH"
            fi
        else
            debug "_setPATH_: can not find: ${_newPath}"
            return 1
        fi
    done
    return 0
}