emonSD: emonhub log missing?

Simsala · 2019-02-14T21:33:05.096Z

Has the emonhub-log been moved? I just downloaded the latest emonSD image and after the first boot the latest updates were installed (e.g. emoncms 9.9.6). However, there are no log messages displayed under Setup → emonhub and there is no directory emonhub listed at /var/log.

sudo service emonhub status returns the last log entries, but where do they come from?

pb66 · 2019-02-14T23:46:46.156Z

Simsala:

Has the emonhub-log been moved?

Not that we have been made aware of.

We do not yet have a build guide for the Oct 2018 image so I cannot check on what should be where.

However! Trying to think what might of happened to them and not finding any changes on the emonhub repo, I have just recalled that @TrystanLea has made some changes to the emonSD in the emonPi update routine in respect of emonhub.

The service.unit that was not brought into mainstream use when it was merged last April has now been activated by the changes in the emonPi updates

github.com/openenergymonitor/emonpi

switch to systemd emonhub.service

committed 03:29PM - 07 Feb 19 UTC

+48 -2

If I recall correctly it was not previously used as it did not handle the logfile creation which the original init script does. I cannot find any sign of alternative arrangements having been made (yet?).

I fear emonhub may now need to be added to the long list of other softwares that do not start properly at boot time (due to log files not created) that are handled in the rc.local file. A shame really, since emonhub has been the only software to consistently and reliably manage it’s own logfiles without any problems for years. It has been essential and central to debugging untold issues.

There was functionality added to emonhub so it could send log data to syslog and there was also talk elsewhere about using systemctl logs rather than dedicated log files for services (such as MQTT etc) although I do not think that was aimed at emonhub, there has also been lengthy discussions about a custom logfile manager, using tmpfiles.d and my own suggestion of log2ram to over come the issues with managing logfiles when they are held in RAM (that didn’t affect emonhub prior to now), but I do not know where we are at with any of that, right now I believe the emonSD image still uses rc.local to create logfiles and folders with delays and service restarts.

I’m guessing that emonhub.log MIA is not intentional and will be making a return, as you point out is is used in emoncms and I’m not sure it will be quite so easy to parse/filter the syslog or systemctl logs for that purpose.

Is emonhub actually running? I cannot recall offhand if emonhub fails to start/run if it cannot create it’s log file, like mysql,mqtt and the rest, or if it can still run without a log file.

borpin · 2019-02-16T19:30:19.216Z

Simsala:

However, there are no log messages displayed

I have just fired up a brand new EmonSD image. Emonhub seems to start OK (even though I do not have an RFM board.

Log can be accessed via journalctl e.g.

 journalctl -u emonhub

The fact they do not appear interactively need to be raised as an issue.

Simsala:

sudo service emonhub status

As this is now a systemd service, strictly to view the status use systemctl as in

systemctl status emonhub.service

Simsala · 2019-02-17T08:55:47.913Z

Thank you both for the answer! Yes can confirm that emonhub runs smoothly.

So it is correct that the log file is no longer stored under /var/log/emonhub and only the emoncms-emonhub module has to be modified accordingly.

borpin · 2019-02-17T10:57:54.580Z

Simsala:

So it is correct that the log file is no longer stored under /var/log/emonhub and only the emoncms-emonhub module has to be modified accordingly.

Not sure. It needs investigating.

borpin · 2019-03-11T16:18:19.709Z

Solved in most recent update.

EmonHub log systemd emonHub

Ok, this issue has now been fixed. If a users runs emonPi update the emonhub log should start working again. Please let me know if it does. It may require a reboot for changes to take effect.