clients management

[Gianluca-Casagrande-Stiga]

Hi, I would like to build a broker clients management tool. My targets are:

• get clients list with their subscriptions
• force a client disconnection

I know that Ades object has "clients" property with every clients info. But in a Redis cluster scenario, this "clients" property is related only to that broker instance, isn't it? Is there a way to get every cluster clients info? Maybe from Redis?

thanks

[robertsLando]

You could build a generic one by just using aedes-persistence methods. For example in order to get all subscriptions you could call subscriptionsByTopic method with '#'.

In order to force a client disconnection you should use the subscription client id to get the client instance from aedes broker and call the close method.

Let me know if you build it we could add it to moscajs org if it is an OSS project :)

[robertsLando]

In a cluster env if you want to disconnect a specific clent but you dunno which broker instance have it you could use broker to publish on a specific $SYS topic like $SYS/clients/disconnect with client id as payload, on each instance simply subscribe broker to this topic and when a message is received do your disconnect logic by checking clients instances on that instance. Giving that $SYS topics are reserved for internal usage clients will never receive those messages

[Gianluca-Casagrande-Stiga]

Thank you Daniel for your hints.
Unfortunately I wasn't able to use subscriptionsByTopic# method on a Redis cluster solution. I've resolved my case with a broker subscription extension combined with a special client (ClientManager). This is my solution explanation:

Each broker of the cluster is subscribed to "$SYS/clients/list" and "$SYS/clients/disconnect" topics.
When a broker receives a message on "$SYS/clients/list", it publish every clients info on topic "$SYS/clients/list/ack".
When a broker receives a message on "$SYS/clients/disconnect", it try to close the client with the id contained in the payload; if the client is successfully closed, it returns an ack on "$SYS/clients/disconnect/ack".

ClientManager is an mqtt client with special auth that let it pub/sub on $SYS topics.
It can get the broker cluster client list publishing a "$SYS/clients/list" request and waiting the "$SYS/clients/list/ack" responses.
It can publish a "$SYS/clients/disconnect" request, waiting a "$SYS/clients/disconnect/ack" response.

[robertsLando]

Thanks for sharing :)