---
title: Hooks
template: docs
taxonomy:
category: docs
routes:
default: '/packaging_apps_hooks'
---
YunoHost includes a hook mechanism triggered on a lot of operation changing the system. You can use this mechanism in order to extend the behaviour of a yunohost command.
## How to add a hooks
!!! Bellow we imagine we want to run a command after each user creation to add the user to samba user.
You should create a directory with the name of the hooks into `/etc/yunohost/hooks.d/`:
```
mkdir -p /etc/yunohost/hooks.d/post_user_create
```
Next create a bash script inside this directory prefixed by 2 numbers and a dash:
```bash
nano /etc/yunohost/hooks.d/post_user_create/05-add-user-to-samba
```
## Hooks referencies
### User and permissions
#### post_user_create
[details summary="Triggered after user creation" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost user create` or equivalent action in webadmin.
##### Environment variables
- YNH_USER_USERNAME: The username of the created user
- YNH_USER_MAIL: The mail of the created user
- YNH_USER_PASSWORD: The **clear** password of the created user
- YNH_USER_FIRSTNAME: The firstname of the created user ([should be removed in future](https://github.com/YunoHost/issues/issues/296))
- YNH_USER_LASTNAME: The lastname of the created user ([should be removed in future](https://github.com/YunoHost/issues/issues/296))
##### Positionnal arguments (deprecated)
- $1: The username of the created user
- $2: The mail of the created user
##### No waited return
##### Examples
###### Send automatically a mail to new user
```bash
#!/bin/bash
domain=$(cat /etc/hostname)
message="Hello $YNH_USER_FIRSTNAME,
Welcome on $domain !
Feel free to change your password.
Let me know if you have a problem,
The admin of $domain
"
echo $message | mail -s "Welcome on $domain !" $YNH_USER_MAIL
```
###### Add the user to samba
##### Hook changelog
-
[/details]
#### post_user_delete
[details summary="Triggered at the end of user deletion" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost user delete` or equivalent action in webadmin.
##### No environment variables
##### Positionnal arguments
- $1: The username of the user deleted
- $2: True if --purge option is used
##### No waited return
##### Examples
######
```bash
#!/bin/bash
```
##### Hook changelog
-
[/details]
### post_user_update
[details summary="Triggered at the end of the user update" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost user update` or equivalent action in webadmin.
##### Environment variables
! Only arguments given to the cli/api are given as environment variable.
- YNH_USER_USERNAME: The username of the updated user
- YNH_USER_FIRSTNAME: The firstname of the updated user ([should be removed in future](https://github.com/YunoHost/issues/issues/296))
- YNH_USER_LASTNAME: The lastname of the updated user ([should be removed in future](https://github.com/YunoHost/issues/issues/296))
- YNH_USER_PASSWORD: The new password of the updated user
- YNH_USER_MAILS: The mail and mail aliases of the updated user seperated by comma
- YNH_USER_MAILFORWARDS: The list of forward mails of the updated user separated by comma
- YNH_USER_MAILQUOTA: The quota of the updated user (could be 0 or a number following by one of this unit: b, k, M, G or T)
##### No positionnal arguments
##### No waited return
##### Examples
###### Send a mail on password changing
```bash
#!/bin/bash
"
domain=$(cat /etc/hostname)
message="Hello,
Your password has been successfully changed on $domain.
If you have not asked for changing your password, you probably should contact the admin of $domain.
"
echo $message | mail -s "Your password has been changed on $domain !" $YNH_USER_USERNAME
```
##### Hook changelog
-
[/details]
### post_app_addaccess
[details summary="Triggered after adding a permission to users or groups " class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost user permission add` or equivalent action in webadmin.
##### No environment variables
##### Positionnal arguments (deprecated)
- $1: The app name
- $2: The list of users added separated by comma
- $3: The name of the sub permission (`main`, `admin`, etc.)
- $4: The list of groups added separated by comma
##### No waited return
##### Examples
##### Hook changelog
-
[/details]
### post_app_removeaccess
[details summary="Triggered after removing a pemission to users or groups" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost user permission remove` or equivalent action in webadmin.
##### No environment variables
##### Positionnal arguments (deprecated)
- $1: The app name
- $2: The list of users removed from the permission separated by comma
- $3: The name of the sub permission (`main`, `admin`, etc.)
- $4: The list of groups removed from the permission separated by comma
##### No waited return
##### Examples
##### Hook changelog
-
[/details]
## Domain, certificates and DNS
### post_domain_add
[details summary="Triggered at the end of the domain add operation" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost domain add` or equivalent action in webadmin.
##### No environment variable
##### Positionnal arguments (deprecated)
- $1: The domain added
##### No waited return
##### Examples
######
```bash
```
##### Hook changelog
-
[/details]
### post_domain_remove
[details summary="Triggered after removing the domain" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost domain remove` or equivalent action in webadmin.
##### No environment variable
##### Positionnal arguments (deprecated)
- $1: The domain removed
##### No waited return
##### Examples
######
```bash
```
##### Hook changelog
-
[/details]
### post_cert_update
[details summary="Triggered after Let's encrypt certificate update" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost domain cert update` or equivalent action in webadmin.
##### No environment variable
##### Positionnal arguments
- $1: The domain for which we have updated the certificate
##### No waited return
##### Examples
###### Restart a service after cert renewal
```bash
systemctl restart gemserv
```
##### Hook changelog
-
[/details]
### custom_dns_rules
[details summary="Customized your DNS rules for your domains" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost domain dns suggest` or equivalent action in webadmin.
Thanks to this hooks you can customize
##### No environment variable
##### Positionnal arguments
- $1: The base domain for which we want to build a DNS suggestion
##### Waited return
The script should return a JSON array with dictionnary in this format:
```json
[
{
'type': 'SRV',
'name': 'stuff.foo.bar',
'value': 'yoloswag',
'ttl': 3600
}
]
```
##### Examples
###### Validate Let's Encrypt DNS challenge with a YunoHost DynDNS domain
```bash
#!/bin/bash
if [[ "$1" == "XXXX.nohost.me" ]] ; then
echo "[
{
'type': 'TXT',
'name': '_acme-challenge',
'value': 'LETSENCRYPT_VALUE',
'ttl': 3600
}
]"
fi
```
##### Hook changelog
-
[/details]
## Apps
### post_app_change_url
[details summary="Triggered after an app has changed of URL" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost app change-url` or equivalent action in webadmin.
##### Environment variables
- YNH_APP_OLD_DOMAIN: The old domain of the app
- YNH_APP_OLD_PATH: The old path of the app
- YNH_APP_NEW_DOMAIN: The new domain of the app
- YNH_APP_NEW_PATH: The new path of the app
##### No positionnal arguments
##### No waited return
##### Examples
######
```bash
```
##### Hook changelog
-
[/details]
### post_app_upgrade
[details summary="Triggered on app upgrade" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost app upgrade` or equivalent action in webadmin.
##### Environment variables
- YNH_APP_ID: The app id (for example nextcloud)
- YNH_APP_INSTANCE_NAME: The app instance name (for example nextcloud__2)
- YNH_APP_INSTANCE_NUMBER: The app instance number (for example 2)
- YNH_APP_MANIFEST_VERSION: The app manifest version (for example 1 or ?)
- YNH_ARCH: The arch as returned by `dpkg --print-architecture`
- YNH_APP_UPGRADE_TYPE: The type of upgrade (UPGRADE_PACKAGE, UPGRADE_APP, UPGRADE_FULL)
- YNH_APP_MANIFEST_VERSION: The version number
- YNH_APP_CURRENT_VERSION: The version number of the app (in the yunohost format)
- NO_BACKUP_UPGRADE: 1 if we don't want to backup else 0
##### No positionnal arguments
##### No waited return
##### Examples
###### Change a settings in an app config file (unmanaged by config panel)
```bash
#!/bin/bash
source /usr/share/yunohost/helpers
app=$YNH_APP_INSTANCE_NAME
if [[ "$app" == "etherpad_mypads" ]]; then
ynh_write_var_in_file --file=/var/www/etherpad_mypads/settings.json --key=max --value=100 --after=importExportRateLimiting
systemctl restart etherpad_mypads
fi
```
##### Hook changelog
-
[/details]
### post_app_install
[details summary="Triggered at the end of an app installation" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost app install` or equivalent action in webadmin.
##### Environment variables
- YNH_APP_ID: The app id (for example nextcloud)
- YNH_APP_INSTANCE_NAME: The app instance name (for example nextcloud__2)
- YNH_APP_INSTANCE_NUMBER: The app instance number (for example 2)
- YNH_APP_MANIFEST_VERSION: The app manifest version (for example 1 or ?)
- YNH_ARCH: The arch as returned by `dpkg --print-architecture`
- YNH_APP_ARG_XXXXXXX: The argument of the manifest
##### No positionnal arguments
##### No waited return
##### Examples
######
```bash
#!/bin/bash
```
##### Hook changelog
-
[/details]
### post_app_remove
[details summary="Triggered after removing an app" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost app remove` or equivalent action in webadmin.
##### Environment variables
- YNH_APP_ID: The app id (for example nextcloud)
- YNH_APP_INSTANCE_NAME: The app instance name (for example nextcloud__2)
- YNH_APP_INSTANCE_NUMBER: The app instance number (for example 2)
- YNH_APP_MANIFEST_VERSION: The app manifest version (for example 1 or ?)
- YNH_ARCH: The arch as returned by `dpkg --print-architecture`
- YNH_APP_PURGE: 1 if the --purge option has been activated
##### No positionnal arguments
##### No waited return
##### Examples
######
```bash
#!/bin/bash
```
##### Hook changelog
-
[/details]
## Backup / Restore
### backup
[details summary="Add some files to backup" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost backup create` or equivalent action in webadmin.
##### Environment variables
- YNH_BACKUP_DIR: The work dir in which we can store temporary data to backup like database dump
- YNH_BACKUP_CSV: The CSV in which we add the things to backup. Don't use this directly and use ynh_backup helper instead.
- YNH_APP_BACKUP_DIR: To document
##### Positionnal arguments
- $1: The work dir in which we can store temporary data to backup like database dump
##### No waited return
##### Examples
###### Backup some files in more (for example your custom hooks)
```bash
#!/bin/bash
# Source YNH helpers
source /usr/share/yunohost/helpers
ynh_backup_dest (){
YNH_CWD="${YNH_BACKUP_DIR%/}/$1"
mkdir -p $YNH_CWD
cd "$YNH_CWD"
}
# Exit hook on subcommand error or unset variable
ynh_abort_if_errors
# MISC
ynh_backup_dest "conf/custom/misc"
ynh_backup "/etc/sysctl.d/noipv6.conf"
ynh_backup "/usr/local/bin/"
ynh_backup "/etc/yunohost/hooks.d/backup/99-conf_custom"
ynh_backup "/etc/yunohost/hooks.d/restore/99-conf_custom"
```
##### Hook changelog
-
[/details]
### restore
[details summary="Restore some files" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost backup restore` or equivalent action in webadmin.
##### Environment variables
- YNH_BACKUP_DIR: The work dir in which we can store temporary data to backup like database dump
- YNH_BACKUP_CSV: The CSV in which we add the things to backup. Don't use this directly and use ynh_backup helper instead.
##### Positionnal arguments
- $1: The work dir in which we can store temporary data to backup like database dump
##### No waited return
##### Examples
######
```bash
#!/bin/bash
# Source YNH helpers
source /usr/share/yunohost/helpers
ynh_restore_dest (){
YNH_CWD="${YNH_BACKUP_DIR%/}/$1"
cd "$YNH_CWD"
}
# Exit hook on subcommand error or unset variable
ynh_abort_if_errors
# MISC
ynh_restore_dest "conf/custom/misc"
ynh_restore_file "/etc/sysctl.d/noipv6.conf"
ynh_restore_file "/usr/local/bin/"
ynh_restore_file "/etc/yunohost/hooks.d/backup/99-conf_custom"
ynh_restore_file "/etc/yunohost/hooks.d/restore/99-conf_custom"
```
##### Hook changelog
-
[/details]
### backup_method
[details summary="Define a new way to backup and restore files" class="helper-card-subtitle text-muted"]
This hooks is run during the command `yunohost backup create` or equivalent action in webadmin.
This hook is called several times with different action keywords.
##### No environment variables
##### Positionnal arguments
- $1: The action ("need_mount", "backup", "mount")
- $2: The work dir
- $3: The name of the backup
- $4: The repository in which the backup should be done
- $5: An estimation size of the files to backup
- $6: A description of the archive
##### No waited return
##### Examples
###### A very simple backup on rotationnal disks
```bash
#!/bin/bash
set -euo pipefail
work_dir="$2"
name="$3"
repo="$4"
size="$5"
description="$6"
case "$1" in
need_mount)
# Set false if your method can itself put files in good place in your archive
true
;;
backup)
mount /dev/sda1 /mnt/hdd
if [[ "$(df /mnt/hdd | tail -n1 | cut -d" " -f1)" != "/dev/sda1" ]]
then
exit 1
fi
pushd "$work_dir"
current_date=$(date +"%Y-%m-%d_%H:%M")
cp -a "${work_dir}" "/mnt/hdd/${current_date}_$name"
popd
umount /mnt/hdd
;;
*)
echo "hook called with unknown argument \`$1'" >&2
exit 1
;;
esac
exit 0
```
##### Hook changelog
-
[/details]
## Configuration and firewall
### post_iptable_rules
[details summary="Triggered after reloaded the firewall rules" class="helper-card-subtitle text-muted"]
This hooks is run at the end of the command `yunohost firewall reload` or equivalent action in webadmin.
##### No environment variables
##### Positionnal arguments
- $1: True if upnp has succeeded
- $2: True if ipv6 is available
##### No waited return
##### Examples
###### Forbid completely the outgoing 25 port
```bash
#!/bin/bash
iptables -A OUTPUT -p tcp -m tcp --dport 25 -j ACCEPT
```
##### Hook changelog
-
[/details]
### conf_regen
[details summary="Change configuration suggested as default config in regen-conf mechanism" class="helper-card-subtitle text-muted"]
This hooks is run during the command `yunohost tools regen-conf` or equivalent action in webadmin.
This hook is called several times with different actions keywords (pre and post operations).
##### Environment variables
- YNH_DOMAINS: The list of domains managed by Yunohost separated by comma
- YNH_MAIN_DOMAINS: The list of main domains separated by comma
##### Positionnal arguments
- $1: The pre or post action
- $2: Empty string due to legacy
- $3: Empty string due to legacy
- $4: In post mode the list of file which should be modified. In pre mode the dir in which we store pending configuration
##### No waited return
##### Examples
###### Fix the warning about postfix compatibility mode in postfix logs
```bash
#!/bin/bash
action=$1
pending_dir=$4
postfix_conf=$pending_dir/../postfix/etc/postfix/main.cf
[[ "$action" == "pre" ]] || exit 0
[[ -e $postfix_conf ]] || exit 0
echo '
compatibility_level = 2' >> $postfix_conf
```
##### Hook changelog
-
[/details]