# Events management

LemonLDAP::NG has two kinds of events to propagate between its nodes:

- configuration updates

- session logout

By default, events aren’t really propagated but a timer permits to refresh such data.

Starting from version 2.20.0, LLNG adds an optional PUB/SUB system (not enabled by default) to replace this timers. This isn’t useful in classic deployments but may help big ones.

## Default events system

### Session reload

The default LLNG cache system keeps in memory sessions during 10mn, sessions are automatically refreshed after this delay.

### Configuration reload

After configuration is saved by Manager, LemonLDAP::NG will try to reload configuration on distant Handlers by sending an HTTP request to the servers. The servers and URLs can be configured in Manager, `General Parameters` > `reload configuration URLs`: keys are server names or IP the requests will be sent to, and values are the requested URLs.

You also have a parameter to adjust the timeout used to request reload URLs, it is be default set to 5 seconds.

Attention

If “Compact configuration file” option is enabled, all useless parameters are removed to limit file size. Typically, if SAMLv2 service is disabled, all relative parameters will be erased. To avoid useless parameters to be purged, you can disable this option.

These parameters can be overwritten in LemonLDAP::NG ini file, in the section `apply`.

Tip

You only need a reload URL per physical servers, as Handlers share the same configuration cache on each physical server.

The `reload` target is managed in Apache or Nginx configuration, inside a virtual host protected by LemonLDAP::NG Handler (see below examples in Apache->handler or Nginx->Handler).

Attention

You must allow access to declared URLs to your Manager IP.

Attention

If reload URL is served in HTTPS, to avoid “Error 500 (certificate verify failed)”, Go to :

`General Parameters > Advanced Parameters > Security > SSL options for server requests`

and set :

verify_hostname => 0

SSL_verify_mode => 0

Attention

If you want to use reload mechanism on a portal only host, you must install a handler in Portal host to be able to refresh local cache. Include `handler-nginx.conf` or `handler-apache2.conf` for example

Practical use case: configure reload in a LL::NG cluster. In this case you will have two servers (with IP 1.1.1.1 and 1.1.1.2), but you can keep only one reload URL (reload.example.com):

    /usr/share/lemonldap-ng/bin/lemonldap-ng-cli -yes 1 addKey \
    reloadUrls '1.1.1.1' 'http://reload.example.com/reload' \
    reloadUrls '1.1.1.2' 'http://reload.example.com/reload'

You also need to adjust the protection of the reload vhost, for example:

    <Location /reload>
        Require ip 127 ::1 1.1.1.1 1.1.1.2
        SetHandler perl-script
        PerlResponseHandler Lemonldap::NG::Handler::ApacheMP2->reload
    </Location>

## Using a Pub/Sub system

The message broker system replaces the previous system using an external Pub/Sub system.

When enabled, all LLNG process subscribe to `llng_events` channel which propagate “events”:

- configution update (`newConf`)

- logouts (`unlog`)

Such messages are read every 5 seconds, then logout and configuration updates are propagated in this delay. To modify this delay (10 seconds for example), set checkMsg=10 inside `lemonldap-ng.ini`, section `[all]`.

To configure the event system, go into “General Parameters » Advanced parameters » Events Management” and set Pub/Sub system to Redis, PostgreSQL or MQTT.

Then set into “Pub/Sub system options” the needed options depending on the chosen system (see below).

Note

The corresponding parameter inside `lemonldap-ng.ini` is `messageBroker` which takes as value: `::Redis` or `::Pg` or `::MQTT` (which are abbreviations of `Lemonldap::NG::Common::MessageBroker::<name>`).

Options take place into `messageBrokerOptions` parameter.

### Redis

See Redis options,

Example:

    server => "redis.example.com:3456"

### PostgreSQL

The following parameters are needed: * `dbiChain`: see DBD::Pg to know the syntax * `dbiUser`: the username to use to connect * `dbiPassword`: the password to use to connect

Example:

    dbiChain    => "dbi:Pg:dbname=llng;host=localhost;port=54432",
    dbiUser     => "llng",
    dbiPassword => "llng",

### MQTT

The following parameter can be set:

- `server` (default: ``localhost:1883``)

- `ssl`: set to 1 if SSL is available. Remember then to install IO::Socket::SSL (libio-socket-ssl-perl on Debian).

If `ssl` is set then these parameters are allowed:

- `user`: usernane to use for login

- `password`: password to use for login

- `SSL_ca_file`: file with certificate authorities (PEM encoded)

- `SSL_cert_file`: client certificate

- `SSL_key_file`: client private key

If `ssl` is set then these environment variables can be used also:

- `MQTT_SIMPLE_SSL_INSECURE`: Set to something other than 0 to disable SSL validation

- `MQTT_SIMPLE_SSL_CA`: Path to the CA certificate or a directory of certificates. IO::Socket::SSL can find the CA path automatically on some systems.

- `MQTT_SIMPLE_SSL_CERT`: Path to the client certificate file.

- `MQTT_SIMPLE_SSL_KEY`: Path to the client private key file.

### Web

LLNG provide a light pub/sub server, named llng-pubsub-server, designed to be used to manage LLNG events.

To use it, configure the message broker:

- `server` (default: ``localhost:8080``). To enable SSL, use `https://server:port`

- `token`: optional token to be set if the server requires a token

You can find llng-pubsub-server documentation into its manpage.