[Spread-users] Re: partition detection

Guido van Rossum guido at python.org
Mon Apr 22 15:33:51 EDT 2002


> 1) JOIN: This means a single member joined the group. Noone failed and the
> the new member received no messages to the group prior to the join and will
> receive all messages after the join. Everyone is told which member joined.
> 
> 2) LEAVE: A single member left the group (someone called SP_leave). the
> leaving member received all messages prior to this leave message (althought
> spread guarantees nothing about what the program DID with those messages it
> received) and wil receive no more messages from the group. Everyone is told
> which member left.
> 
> 3) DISCONNECT: A single member 'disconnected' from the daemon it had been
> connected to. This could be because the client called SP_disconnect() or it
> could be because the TCP or Unix Domain Socket returned a closed connection
> to the daemon (something between the client and daemon failed and caused a
> network reset, or the client process crashed, or something else). In this
> case everyone else (other then the disconnected member) will get a message
> indicating who was disconnected. It is not clear what messages the client
> received prior to the disconnet event as it is not know where the failure
> occured. 

I believe the API provides for multiple members joining, leaving or
disconnecting in this way.  Does Spread guarantee that you get a
separate message for each join/leave/disconnect event?  Could this
change in the future?  (IOW should I write code that can handle
multiple members, or can I safely assume this will never happen?)

--Guido van Rossum (home page: http://www.python.org/~guido/)





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