openstack/manila
Code Issues Proposed changes
4e25ce5a0c
manila/doc/source/devref/share_hooks.rst
Goutham Pacha Ravi f14808a2d1 Add doc for Share Replication 
- Document extra_spec and capabilities involved
- Document driver interfaces properly to please Sphinx
- Document scheduler behavior
- Document replica and snapshot workflows
- Fix trailing white spaces in the descriptions of capabilities

Change-Id: I054aebda9618968ab8bd3881ccdd8164e1283682
Closes-Bug: #1544812
2016-04-14 16:11:52 -04:00

3.3 KiB
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Manila share driver hooks

Manila share driver hooks are designed to provide additional possibilities for each manila-share service; such as any kind of notification and additional actions before and after share driver calls.

Possibilities

  • Perform actions before some share driver method calls.
  • Perform actions after some share driver method calls with results of

    driver call and preceding hook call.

  • Call additional 'periodic' hook each 'N' ticks.
  • Possibility to update results of driver's action by post-running hook.

Features

  • Errors in hook execution can be suppressed.
  • Any hook can be disabled.
  • Any amount of hook instances can be run at once for each manila-share

    service.

Limitations

  • Hooks approach is not asynchronous. That is, if we run hooks, and

    especially, more than one hook instance, then all of them will be executed in one thread.

Implementation in share drivers

Share drivers can [re]define method get_periodic_hook_data that runs with each execution of 'periodic' hook and receives list of shares (as parameter) with existing access rules. So, each share driver, for each of its shares can add/update some information that will be used then in the periodic hook.

What is required for writing new 'hook' implementation?

All implementations of 'hook' interface are expected to be in 'manila/share/hooks'. Each implementation should inherit class 'manila.share.hook:HookBase' and redefine its abstract methods.

How to use 'hook' implementations?

Just set config option 'hook_drivers' in driver's config group. For example:

[MY_DRIVER]
hook_drivers=path.to:FooClass,path.to:BarClass

Then all classes defined above will be initialized. In the same config group, any config option of hook modules can be redefined too.

Note

More info about common config options for hooks can be found in module manila.share.hook

Driver methods that are wrapped with hooks

  • allow_access
  • create_share_instance
  • create_snapshot
  • delete_share_instance
  • delete_share_server
  • delete_snapshot
  • deny_access
  • extend_share
  • init_host
  • manage_share
  • publish_service_capabilities
  • shrink_share
  • unmanage_share
  • create_share_replica
  • promote_share_replica
  • delete_share_replica
  • update_share_replica
  • create_replicated_snapshot
  • delete_replicated_snapshot
  • update_replicated_snapshot

Above list with wrapped methods can be extended in future.

The manila.share.hook.py Module

manila.share.hook