Re: [Tarantool-patches] [PATCH] box: allow upgrading from version 1.6

[Vladimir Davydov via Tarantool-patches <tarantool-patches@dev.tarantool.org>]

On Fri, Aug 13, 2021 at 02:20:23AM +0300, Serge Petrenko wrote:
> > > +local function on_init_set_recovery_triggers()
> > > +    log.info("Recovering snapshot with schema version %s", snap_version)
> > > +    for _, trig_tbl in ipairs(recovery_triggers) do
> > > +        if trig_tbl.version >= snap_version then
> > > +            for space, trig in pairs(trig_tbl.tbl) do
> > > +                box.space[space]:before_replace(trig)
> > > +                log.info("Set recovery trigger on space '%s' to comply with "..
> > > +                         "version %s format", space, trig_tbl.version)
> > > +            end
> > > +        end
> > > +    end
> > > +end
> > > +
> > > +local function set_recovery_triggers(version)
> > > +    snap_version = version
> > > +    box.ctl.on_schema_init(on_init_set_recovery_triggers)
> > > +end
> > 
> > Please don't use a global variable for this - it's bad for encapsulation
> > and generally make code more difficult to follow. Pass version
> > explicitly to all functions that need it.
> 
> I can't do that for an on_schema_init trigger, unfortunately.
> Am I missing something? Looks like there's no way to pass trigger.data
> for lua triggers.

You can capture a value in a lambda:

box.ctl.on_schema_init(function()
    on_init_set_recover_triggers(snap_version)
end)