Let `python-etcd3` renew auth token when expired between calling `Lock.acquire` and `Lock.release`

[WilliamDEdwards]

How do I let python-etcd3 renew my auth token when it has expired between calling Lock.acquire and Lock.release?

Context:

When calling Lock.release more than 5 minutes after calling Lock.acquire, the call fails as the auth token has expired:

grpc._channel._InactiveRpcError: <_InactiveRpcError of RPC that terminated with:
        status = StatusCode.UNAUTHENTICATED
        details = "etcdserver: invalid auth token"
        debug_error_string = "UNKNOWN:Error received from peer ipv6:%5B2a0c:eb00:0:f7:ede:aae:eee:eee%5D:2379 {grpc_message:"etcdserver: invalid auth token", grpc_status:16, created_time:"2023-10-06T14:36:22.040952303+02:00"}"
>

This is expected, because etcd's simple token expires after the aforementioned 5 minutes.

FWIW:

• From etcd 3.5, the simple token expiration period can be configured with --auth-token-ttl. However:
• • I am on etcd 3.4. And cannot upgrade, as 3.5 is not available in the Debian repositories.
• • Increasing the auth token TTL to be higher than the highest possible lock TTL is not sustainable.
• • As a workaround, I could use JWT and set –auth-token jwt,ttl=...'. But JWT support #779 being the very only mention of JWT for this client implies that it is not supported.
• I have not found a definitive answer on how this client renews the auth token. Not in the documentation nor in the code.
• I also tried re-creating the Lock object to call release() on, rather than re-using the Lock object that I called acquire() on (and setting uuid to the previous object's, as Lock.release requires it to match), but that causes the same error.
• Periodically causing Lock.refresh does not refresh the auth token.