42 lines
1.5 KiB
ReStructuredText
42 lines
1.5 KiB
ReStructuredText
=====================
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Group Membership
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=====================
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Basic operations
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===================
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One of the feature provided by the coordinator is the ability to handle
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group membership. Once a group is created, any coordinator can join the
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group and become a member of it. Any coordinator can be notified when a
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members joins or leaves the group.
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.. literalinclude:: ../../../examples/group_membership.py
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:language: python
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Note that all the operation are asynchronous. That means you cannot be sure
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that your group has been created or joined before you call the
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:meth:`tooz.coordination.CoordAsyncResult.get` method.
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You can also leave a group using the
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:meth:`tooz.coordination.CoordinationDriver.leave_group` method. The list of
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all available groups is retrievable via the
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:meth:`tooz.coordination.CoordinationDriver.get_groups` method.
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Watching Group Changes
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======================
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It's possible to watch and get notified when the member list of a group
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changes. That's useful to run callback functions whenever something happens
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in that group.
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.. literalinclude:: ../../../examples/group_membership_watch.py
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:language: python
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Using :meth:`tooz.coordination.CoordinationDriver.watch_join_group` and
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:meth:`tooz.coordination.CoordinationDriver.watch_leave_group` your
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application can be notified each time a member join or leave a group. To
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stop watching an event, the two methods
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:meth:`tooz.coordination.CoordinationDriver.unwatch_join_group` and
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:meth:`tooz.coordination.CoordinationDriver.unwatch_leave_group` allow to
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unregister a particular callback.
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