Issues with IClusterClient

[dandago]

1. Should we call Close() or Dispose() to clean up the client, or both?
2. IClusterClient has an awaitable Connect() method, whereas ISiloHost has an awaitable StartAsync(). That -Async() suffix is inconsistent. I know Microsoft recommends the -Async() suffix, but the Orleans team had decided against it a while back. Either way, it should be consistent. Personally, I prefer the -Async() suffix as it is immediately recognisable as needing an await (or other Task-based approach).

[sergeybykov]

We inherited StartAsync() from aspnet/Hosting#1163 via #3431. Hence "Async" in the method name. Otherwise, we try not to add the suffix.

I personally don't see a clean and easy way out of this compromise. It's too late for us to rename public methods anyway.

[ReubenBond]

@dandago Close() is graceful. Dispose() is identical to Abort(), which is ungraceful. So, if possible, always opt for await client.Close();

[ReubenBond]

Does this answer your question, @dandago?

[dandago]

Yes, although I'm very surprised at this design decision. This goes against a common convention in the .NET Framework of Close() and Dispose() being equivalent, and prevents people from wrapping their client in a using block.

[ReubenBond]

@dandago the client is intended to be long-lived, unlike a DbContext, which may be per-request. So the client typically lives for the duration of the app.

Close() is not identical to Dispose() because it's naturally async.

Here's the relationship between them:

                    graceful
           Close() +------------+
              (async)           |
                                |
                    ungraceful  v
           Abort() +----------> Stop(bool gracefully) (private)
           ^  (blocking)          * if graceful, shutdown gracefully
           |                      * clean up internal state
Dispose() ++                    

[dandago]

Why does Close() need to be async in this case? If it's doing cleanup, that will typically involve internal resources and no I/O operations.

[ReubenBond]

@dandago because it tells the cluster that the client is disconnecting, because it's graceful.

[dandago]

OK, got it.