[jira] [Commented] (CASSANDRA-14754) Add verification of state machine in StreamSession

["Benjamin Lerer (Jira)" <ji...@apache.org>]

    [ https://issues.apache.org/jira/browse/CASSANDRA-14754?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17066591#comment-17066591 ] 

Benjamin Lerer commented on CASSANDRA-14754:
--------------------------------------------

My understanding of the possible states transition is the following:
{code}
 
      +-------------+----------> FAILED <---------+
      |             |              ^              |              
      |             |              |              |                
INITIALIZED --> PREPARING --> STREAMING --> WAIT_COMPLETE ---> COMPLETED    
      |             |                             ^                ^
      |             |     if preview              |                |
      |             +-----------------------------+                |
      |           nothing to request or to transfer                |
      +------------------------------------------------------------+ 
                  nothing to request or to transfer 

{code}

It should not be possible for example to go from {{INITIALIZED}} to {{STREAMING}}.
The current patch does not check that type of state transitions and it might be good if it does.

Otherwise, the patch is firing an `IllegalStateException` in case of invalid state transition. It seems fine to me but I am not an expert in this part of the code.
[~jasobrown], [~djoshi] do you have any concerns with the approach?

> Add verification of state machine in StreamSession
> --------------------------------------------------
>
>                 Key: CASSANDRA-14754
>                 URL: https://issues.apache.org/jira/browse/CASSANDRA-14754
>             Project: Cassandra
>          Issue Type: Task
>          Components: Legacy/Streaming and Messaging
>            Reporter: Jason Brown
>            Assignee: ZhaoYang
>            Priority: Normal
>             Fix For: 4.0
>
>
> {{StreamSession}} contains an implicit state machine, but we have no verification of the safety of the transitions between states. For example, we have no checks to ensure we cannot leave the final states (COMPLETED, FAILED).
> I propose we add some program logic in {{StreamSession}}, tests, and documentation to ensure the correctness of the state transitions.



--
This message was sent by Atlassian Jira
(v8.3.4#803005)

---------------------------------------------------------------------
To unsubscribe, e-mail: commits-unsubscribe@cassandra.apache.org
For additional commands, e-mail: commits-help@cassandra.apache.org