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.Dd April 28, 2020 28.Dt HOOK.LUA 8 29.Os 30.Sh NAME 31.Nm hook.lua 32.Nd FreeBSD hook module 33.Sh DESCRIPTION 34.Nm 35contains functionality for defining hook types and attaching hooks. 36Hooks are functions used to attach custom behaviors at pre-defined points in 37loader execution. 38These pre-defined points are what we refer to as 39.Dq hook types . 40Hooks may also take an optional data parameter, which may or may not be 41populated by the caller. 42.Pp 43Before using the functionality provided by 44.Nm , 45it must be included with a statement such as the following: 46.Pp 47.Dl local hook = require("hook") 48.Ss Exported functions 49The following functions are exported from 50.Nm : 51.Bl -tag -width hook.registerType -offset indent 52.It Fn hook.registerType hooktype 53Adds 54.Ev hooktype 55as a recognized hook type. 56This allows functions to be added to run when hooks of this type are invoked 57using 58.Fn hook.runAll hooktype . 59.It Fn hook.register hooktype hookfunc 60Register 61.Ev hookfunc 62to be run when hooks of type 63.Ev hooktype 64are invoked. 65.It Fn hook.runAll hooktype 66Invoke all hooks registered for type 67.Ev hooktype . 68Hooks are invoked in the order in which they are registered. 69.El 70.Ss Hook Naming Guidelines 71Hook names should consist of the name of the module they are defined in, as well 72as a verb describing when the hook is executed, separated by a period. 73For example, 74.Dq config.reloaded 75is defined in the 76.Xr config.lua 8 77module and run when the configuration is reloaded. 78.Sh EXAMPLES 79To register a hook to be run when configuration is reloaded: 80.Pp 81.Bd -literal -offset indent -compact 82local hook = require("hook") 83 84local function configuration_was_reloaded() 85 print("Configuration was reloaded!") 86end 87 88hook.register("config.reloaded", configuration_was_reloaded) 89.Ed 90.Sh AUTHORS 91The 92.Nm 93file was originally written by 94.An Kyle Evans Aq Mt kevans@FreeBSD.org . 95