g.raphaelli's weblog

Gearman can be handy for defeating security in situations like the one pictured:

Here, Host A can initiate connections to Host B but Host B is blocked by a firewall/router ACL/etc from initiating communications with Host A.

With gearman, you can call a service on Host A from Host B with a setup like this:

1. Run a gearmand job server on host B (or any host that A and B can both reach).
2. Register a gearman worker running on Host A with that job server.
3. Submit work from a client running on Host B to that job server.

This idea can be taken another step by chaining workers together such that calling abc() as depicted above creates a job that Host C, which can't reach or be reached by Host B at all, can ultimately execute. That kind of setup makes it increasingly difficult to track an individual task's real status but it can be handy in a pinch.