[tarantool-patches] [PATCH 2/2] On ctl event trigger
Vladimir Davydov
vdavydov.dev at gmail.com
Thu Aug 30 15:38:07 MSK 2018
On Tue, Aug 28, 2018 at 07:19:13PM +0300, Georgy Kirichenko wrote:
> Introduce a ctl event trigger fired in cases of a bootstrap/recovery status
> changes, a space create/alter/drop action, an applier state change and
> shutdown. Trigger could be set with box.ctl_event even before the first
> box.cfg invocation to control recovery and bootstrap behavior.
>
> Event constants accessible via box.ctl_event.const()
> There are events:
> - RECOVERY
> - SPACE
> - SHUTDOWN
> - APPLIER
>
> A recovery event might have a status:
> * RECOVERY_SNAPSHOT_START
> * RECOVERY_SNAPSHOT_DONE
> * RECOVERY_HOT_STANDBY_START
> * RECOVERY_HOT_STANDBY_DONE
> * RECOVERY_XLOGS_DONE
> * RECOVERY_BOOTSTRAP_START
> * RECOVERY_BOOTSTRAP_DONE
> * RECOVERY_INITIAL_JOIN_START
> * RECOVERY_INITIAL_JOIN_DONE
> * RECOVERY_FINAL_JOIN_DONE
>
> A space event consists of space identifier and action:
> * SPACE_CREATE
> * SPACE_ALTER
> * SPACE_DELETE
>
> An applier event contains peer uuid and state:
> * APPLIER_OFF
> * APPLIER_CONNECT
> * APPLIER_CONNECTED
> * APPLIER_AUTH
> * APPLIER_READY
> * APPLIER_INITIAL_JOIN
> * APPLIER_FINAL_JOIN
> * APPLIER_JOINED
> * APPLIER_SYNC
> * APPLIER_FOLLOW
> * APPLIER_STOPPED
> * APPLIER_DISCONNECTED
> * APPLIER_LOADING
I can't review this patch properly, because ctl_event.[hc] are missing,
but I've a few notes about the API.
First, I don't understand why you need two kinds of constants. I mean
SPACE and SPACE_CREATE, or RECOVERY and RECOVERY_SNAPSHOT_START. IMO
there should be just one set of constants.
Second, IMO the event trigger should be installed with box.ctl.on_event
(not box.ctl_event.on_ctl_event), and constants should be defined in
box.ctl.event (not box.ctl_event.const()).
Third, let's start with fewer events, only ones that we need to right
now (e.g. for replication conflict resolution with before_replace).
We can add other events later, when we need to.
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