[tarantool-patches] Re: [PATCH] Make `tarantoolctl start` work withiout box.cfg in init script

[Konstantin Osipov]

* Max Melentiev <dmarc-noreply at freelists.org> [19/08/09 11:12]:
> `box.cfg` may not be called inside init script and tarantool
> will not be daemonized (forcing `background = true` in hijacked `box.cfg`),
> so we need to fork tarantool before running this script.
> 
> To find out the moment when tarantool finishes startup it waits for `READY=1`
> message on NOTIFY_SOCKET which is emitted after init script is finished.

Thanks for the patch.

Most of this patch has to be done on the server level.

Please prepare a patch that allows a user to override box.cfg with
environment variables. Since this is a user-visible change, it
needs an issue at github.


Basically I should be able to say: 

setenv TARANTOOL_WAL_DIR="path" and this would override box.cfg
setting, if any.

The same is true for all variables which are overrides in
/etc/default:

https://github.com/tarantool/tarantool/blob/master/extra/dist/default/tarantool.in

Alternatively, you could have a single environment variable to
force box.cfg to look at /etc/default/tarantool file, or some
other file, for these defaults:

TARANTOOL_DEFAULT_FILE=

Please check with the solutions team which approach is better - I
prefer the second one, since it requires less maintenance when new
defaults are added to /etc/default.

Once this patch is in place, tarantoolctl should be changed to
exec() instance file, not dofile() it.

This will solve most of the problems reflected this patch tries to
address (and a few more).

The next patch should split daemon features away from box.cfg, so
that it would be possible to become daemon before calling box.cfg.
We already can configure logger before box.cfg, and on the road of
making listen independent of box.cfg. Daemon is an easy step in
the same direction. This patch is also against the core server,not
against tarantoolctl.

It is easy to do, take a look here:

https://github.com/tarantool/tarantool/blob/master/src/main.cc#L387

This function needs to become available via
io.daemon(pid_file_path).

io.daemon() should fail and do nothing if the logging subsystem is
not initialized.

There should be a test case in app-tap.

Please feel free to solicit help from the core team for this
patch.

If io.daemon() has been called, box.cfg.background=true/false
should be ignored when box.cfg is called. 


io.daemon() should respect sysctl events if sysctl socket is
provided.


-- 
Konstantin Osipov, Moscow, Russia