doc/packaging_apps_helpers.md

Application packaging

Shell helpers

Since YunoHost 2.4 release, new shell helpers are available to ease common packaging tasks like password generation, MySQL database creation…

Usage examples are available in the example application. We advise to use them.

You can find them on this repository.

To use them, you need to add following lines in the shell scripts:

# Source app helpers
source /usr/share/yunohost/helpers

Available helpers list (non exhaustive)

Database

ynh_mysql_execute_as_root SQL DB

Runs the SQL command SQL as database root user on DB database (this last argument is optional).

ynh_mysql_execute_file_as_root FILE DB

Runs the SQL commands listed inside FILE as root user on DB database (this last argument is optional).

ynh_mysql_create_db DB USER PWD

Create the DB database and grants all rights to USER (created on the fly with PASSWORD password).

ynh_mysql_drop_db DB

Delete the DB database.

ynh_mysql_drop_user USERNAME

Delete the USERNAME MySQL user.

ynh_mysql_dump_db DB > ./FILE

Exports the DB database into the FILE file.

Debian packages handling

ynh_package_is_installed PACKAGE

Tests if the Debian package PACKAGE is installed on the system. > Read command output to know the result. e.g:

if ! ynh_package_is_installed "yunohost" ; then
  echo "Oops, package is not installed"
else
  echo "Package is installed"
fi

ynh_package_version PACKAGE

Returns the installed version number of PACKAGE.

ynh_package_update

Updates the packages list (apt update) in a silent and non-interactive way.

Be careful, the following commands are to be avoided when possible. Installing (and even more removing) a package without handling conflicts and dependencies is risky. That will be improved in future Yunohost versions.

ynh_package_install PACKAGE1 PACKAGE2

Installs (apt install) PACKAGE1, PACKAGE2… packages, in a non interactive and silent way.

ynh_package_autoremove PACKAGE1 PACKAGE2

Removes (apt-get autoremove) PACKAGE1, PACKAGE2… packages in a silent and non-interactive way.

Apps configuration

ynh_app_setting_set APP KEY VALUE

Store the setting named KEY with value VALUE for the app APP. This allows to reuse it later (typically in the upgrade script), or so that YunoHost can autoconfigure the SSO. The settings are stored in the /etc/yunohost/apps/${APP}/settings.yml file. For example, to store the visibility setting (private or public app), you can use :

ynh_app_setting_set my_app is_public "yes"

The SSO uses app stored settings to allow or deny public access to HTTP resources. There are 6 configuration keys :

skipped_uris, unprotected_uris and protected_uris are relative to app path. Example:

ynh_app_setting_set app_name skipped_uris "/blog"

Matches the /blog path of the application: https://domain.tld/path_app/blog and everything under this path, but not https://domain.tld/path_app/.

skipped_uris An URL set with skipped_uris key will be totally ignored by the SSO, which means that the access will be public and the logged-in user information will not be passed to the app.

unprotected_uris An URL set with unprotected_uris key will be accessible publicly, but if an user is logged in, his information will be accessible (though HTTP headers) to the app.

protected_uris An URL set with protected_uris will be blocked by the SSO and accessible only to authenticated and authorized users.

skipped_regex, unprotected_uris and protected_regex are regex counterparts of the above keys.

The syntax is not the "standard" regex syntax (PCRE) but Lua patterns.

The regex patterns match the whole URL, unlike the string patterns (which match only the app-local part of the URL, as detailed above). This means you must write complete patterns including the domain and path.

For example, to use skipped_regex to match /blog followed by a 1+ digit number:

ynh_app_setting_set app_name skipped_regex "$domain$path/blog%?%d+$"

This may lead to an issue : if $domain or $path contain a dash (-), it will interpreted as a pattern magic char. That is why dashes must be escaped with a %.

domainregex=$(echo "$domain" | sed 's/-/\%&/g')
pathregex=$(echo "$path" | sed 's/-/\%&/g')
ynh_app_setting_set app_name skipped_regex "$domainregex$pathregex/blog%?%d+$"

ynh_app_setting_get APP KEY

Get the value of the setting named KEY for the APP app. Example :

is_public=$(ynh_app_setting_get app_name is_public)

ynh_app_setting_delete APP KEY

Delete the setting named KEY for the APP app.

Users management

ynh_user_exists USERNAME

Checks the existence of USERNAME user in YunoHost. Command return code must be checked to know the result. Example:

if ynh_user_exists "johndoe" ; then
  echo "This user exists!"
fi

ynh_user_get_info USERNAME KEY

Get the KEY information on USERNAME user. Possible KEY values are:

• firstname
• fullname
• lastname
• mail
• mail-aliases
• mailbox-quota Example:

mailadmin=$(ynh_user_get_info $admin mail)

ynh_system_user_exists USERNAME

Checks if the USERNAME unix user exists. Command return code must be checked to know the result. Example:

if ynh_system_user_exists "www-data" ; then
  echo "User exists on system!"
fi

Other commands

ynh_string_random LENGTH

Generates a random string of LENGTH chars (defaults to 24).

ynh_die MSG RETCODE

Displays the MSG message on stderr and exits the script with RETCODE return code (defaults to 1).

Following commands are to be replaced (or even deleted) in future YunoHost versions.

sudo yunohost app checkport <port>

This helper checks the port and returns an error if the port is already in use. Command return code must be checked to know the result. Example:

port=DEFAULT_PORT
while ! sudo yunohost app checkport $port ; do
    port=$((port+1))
done

sudo yunohost firewall allow [--no-upnp] {TCP,UDP,Both} PORT

Opens the port number PORT on the firewall, for TCP, UDP or both. Automatic port opening via upnp may be disabled on this port using --no-upnp

sudo yunohost firewall disallow {TCP,UDP,Both} PORT

Closes the port number PORT on the firewall for TCP, UDP or both.

sudo yunohost app checkurl DOMAINPATH -a APP

Checks DOMAIN/PATH url availability. Useful for web apps to make sure the chosen URL is not already taken by another app. If the URL is available, that commands register for the APP application. Note: do not prepend http:// or https:// to DOMAINPATH.

sudo yunohost app addaccess [--users=USER] APP

Allow the USER user to access APP.

sudo yunohost app removeaccess --users=USER APP

Remove the access authorization to APP from USER user.

sudo yunohost service remove NAME

Remove the service NAME from the YunoHost management interface.

sudo yunohost app ssowatconf

This commands rebuilds the SSO configuration. It is called automatically at the end of any script, but you may want to call it by hand before.