[tarantool-patches] Re: [PATCH 1/3] Update only vshard part of a cfg on reload

[Vladislav Shpilevoy <v.shpilevoy@tarantool.org>]

Thanks for the patch! See 3 comments below.

> diff --git a/vshard/storage/init.lua b/vshard/storage/init.lua
> index 102b942..40216ea 100644
> --- a/vshard/storage/init.lua
> +++ b/vshard/storage/init.lua
> @@ -1553,18 +1553,19 @@ local function storage_cfg(cfg, this_replica_uuid)
>       --
>       -- If a master role of the replica is not changed, then
>       -- 'read_only' can be set right here.
> -    cfg.listen = cfg.listen or this_replica.uri
> -    if cfg.replication == nil and this_replicaset.master and not is_master then
> -        cfg.replication = {this_replicaset.master.uri}
> +    box_cfg.listen = box_cfg.listen or this_replica.uri
> +    if box_cfg.replication == nil and this_replicaset.master
> +       and not is_master then
> +        box_cfg.replication = {this_replicaset.master.uri}
>       else
> -        cfg.replication = {}
> +        box_cfg.replication = {}
>       end
>       if was_master == is_master then
> -        cfg.read_only = not is_master
> +        box_cfg.read_only = not is_master
>       end
>       if type(box.cfg) == 'function' then
> -        cfg.instance_uuid = this_replica.uuid
> -        cfg.replicaset_uuid = this_replicaset.uuid
> +        box_cfg.instance_uuid = this_replica.uuid
> +        box_cfg.replicaset_uuid = this_replicaset.uuid

1. All these box_cfg manipulations should be done under 'if not is_reload'
I think.

>       else
>           local info = box.info
>           if this_replica_uuid ~= info.uuid then
> @@ -1607,27 +1610,27 @@ local function storage_cfg(cfg, this_replica_uuid)
>           local_on_master_enable_prepare()
>       end
> 
> -    local box_cfg = table.copy(cfg)
> -    lcfg.remove_non_box_options(box_cfg)
> -    local ok, err = pcall(box.cfg, box_cfg)
> -    while M.errinj.ERRINJ_CFG_DELAY do
> -        lfiber.sleep(0.01)
> -    end
> -    if not ok then
> -        M.sync_timeout = old_sync_timeout
> -        if was_master and not is_master then
> -            local_on_master_disable_abort()
> +    if not is_reload then
> +        local ok, err = true, nil
> +        ok, err = pcall(box.cfg, box_cfg)

2. Why do you need to announce 'local ok, err' before
their usage on the next line?

> +        while M.errinj.ERRINJ_CFG_DELAY do
> +            lfiber.sleep(0.01)
>           end
> -        if not was_master and is_master then
> -            local_on_master_enable_abort()
> +        if not ok then
> +            M.sync_timeout = old_sync_timeout
> +            if was_master and not is_master then
> +                local_on_master_disable_abort()
> +            end
> +            if not was_master and is_master then
> +                local_on_master_enable_abort()
> +            end
> +            error(err)
>           end
> -        error(err)
> +        log.info("Box has been configured")
> +        local uri = luri.parse(this_replica.uri)
> +        box.once("vshard:storage:1", storage_schema_v1, uri.login, uri.password)
>       end
> 
> -    log.info("Box has been configured")
> -    local uri = luri.parse(this_replica.uri)
> -    box.once("vshard:storage:1", storage_schema_v1, uri.login, uri.password)
> -
>       lreplicaset.rebind_replicasets(new_replicasets, M.replicasets)
>       lreplicaset.outdate_replicasets(M.replicasets)
>       M.replicasets = new_replicasets
> @@ -1874,7 +1877,7 @@ if not rawget(_G, MODULE_INTERNALS) then
>       rawset(_G, MODULE_INTERNALS, M)
>   else
>       reload_evolution.upgrade(M)
> -    storage_cfg(M.current_cfg, M.this_replica.uuid)
> +    storage_cfg(M.current_cfg, M.this_replica.uuid, true)

3. I see that you have stored vshard_cfg in M.current_cfg. Not a full
config. So it does not have any box options. And it causes a question
- why do you need to separate reload from non-reload, if reload anyway
in such implementation is like 'box.cfg{}' call with no parameters?
And if you do not store box_cfg options how are you going to compare
configs when we will implement atomic cfg over cluster?

>       M.module_version = M.module_version + 1
>   end
>