Allow identity of user attached to connection/agent to change in real time

[korydraughn]

• main
• 4-3-stable

---

Feature

iRODS connections tie the identity of a user to the socket. This is fine for one-off commands, but not for situations where there can be hundreds to thousands of concurrent users. Creating a new connection for every user will quickly drain resources.

Therefore, iRODS should provide a way to change the user identity tied to the connection object. This would lead to huge improvements regarding performance, scalability, and resource management.

This would also improve support for client applications because the client libraries would finally be able to implement real connection pooling for iRODS connections.

Requirements

The only API requirement is ... switching the user tied to the connection object requires rodsadmin level privileges.

Challenges

The primary challenge with implementing this has to do with long running agents.

When an agent is forked, depending on the operation being carried out, the agent may choose to use the catalog or local memory. If information is fetched from local memory, then we run the risk of using out-of-date information. This situation applies to resource hierarchies, rule engine plugins, and likely other things.

So, to support this feature means iRODS must guarantee that long running agents see important changes. The question now becomes, when do iRODS agents sync with the catalog and how?

Other

Add support to the following libraries:

• client_connection.hpp
• connection_pool.hpp

---

Related issues: #5060

[korydraughn]

See PR #6593