1.\" 2.\" SPDX-License-Identifier: BSD-2-Clause 3.\" 4.\" Copyright (c) 2018 Kyle Evans <kevans@FreeBSD.org> 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 15.\" THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND 16.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 17.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 18.\" ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE 19.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 20.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 21.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 22.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 23.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 24.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 25.\" SUCH DAMAGE. 26.\" 27.\" $FreeBSD$ 28.\" 29.Dd April 28, 2020 30.Dt HOOK.LUA 8 31.Os 32.Sh NAME 33.Nm hook.lua 34.Nd FreeBSD hook module 35.Sh DESCRIPTION 36.Nm 37contains functionality for defining hook types and attaching hooks. 38Hooks are functions used to attach custom behaviors at pre-defined points in 39loader execution. 40These pre-defined points are what we refer to as 41.Dq hook types . 42Hooks may also take an optional data parameter, which may or may not be 43populated by the caller. 44.Pp 45Before using the functionality provided by 46.Nm , 47it must be included with a statement such as the following: 48.Pp 49.Dl local hook = require("hook") 50.Ss Exported functions 51The following functions are exported from 52.Nm : 53.Bl -tag -width hook.registerType -offset indent 54.It Fn hook.registerType hooktype 55Adds 56.Ev hooktype 57as a recognized hook type. 58This allows functions to be added to run when hooks of this type are invoked 59using 60.Fn hook.runAll hooktype . 61.It Fn hook.register hooktype hookfunc 62Register 63.Ev hookfunc 64to be run when hooks of type 65.Ev hooktype 66are invoked. 67.It Fn hook.runAll hooktype 68Invoke all hooks registered for type 69.Ev hooktype . 70Hooks are invoked in the order in which they are registered. 71.El 72.Ss Hook Naming Guidelines 73Hook names should consist of the name of the module they are defined in, as well 74as a verb describing when the hook is executed, separated by a period. 75For example, 76.Dq config.reloaded 77is defined in the 78.Xr config.lua 8 79module and run when the configuration is reloaded. 80.Sh EXAMPLES 81To register a hook to be run when configuration is reloaded: 82.Pp 83.Bd -literal -offset indent -compact 84local hook = require("hook") 85 86local function configuration_was_reloaded() 87 print("Configuration was reloaded!") 88end 89 90hook.register("config.reloaded", configuration_was_reloaded) 91.Ed 92.Sh AUTHORS 93The 94.Nm 95file was originally written by 96.An Kyle Evans Aq Mt kevans@FreeBSD.org . 97