Comparison of method of using WeeWX

[Remy Lavabre]

Good morning,

Small question(s) for a PIP installation:

1/ Is there a difference between:
- the use of the weewx daemon
- the weewxd command placed in the contrab at the RPi starting
- the manually typed command "nohup weewxd &"?

2/What is the interest/advantage of one method compared to others?

THANKS

[Invisible Man]

To my understanding, the commands are the same in terms of "what they do", i.e start weewx.
The difference lies in how easy it is to manage weewx.

1. If you use weewx as a service, you can easily start/stop/restart/mask (etc) your service with the systemctl commands. This includes for example restarting weewx if it has stopped. Also, you can ensure at boot time that weewx only tries to start once your host has network for example.

2. Crontab. IMHO, a crontab is useful to start periodic tasks, like "do a backup at 5am". If your idea is to use a crontab just to start weewx at boot time, the /etc/rcX.d directories are probably better suited. If you want the crontab to periodically check weewx is running and restart it if it's down, then yes, you can do it with the crontab, but you'll  have to write the script that detects weewx is up or down and restart if necessary. This is automatically handled by the systemctl service configuration, so you are kind of re-inventing the wheel IMHO.

3. nohup weewxd. This works and it's sometimes handy because it's simple and easy to debug. But if your weewx dies for some reason, you have no way to restart it. Also, it's not that easy to see if you already have a weewxd running (you'll  have to do "ps aex" and grep for example) so you might launch several instances by error. Finally, the logs go where you launched the command, they are not centralized in journalctl like systemctl option, or in /var/log/syslog.

Hope it helps. There might be other differences I am missing.

[vince]

There are almost infinite ways to start a process on Linux/unix.

Just use way your os dictates which is likely systemd on a modern system.

[cric...@pobox.com]

Since I detest systemd and friends, I wrote a perl script to run as a cron job to start weewx as needed.

Suites me just fine.  Since weewx is so stable, it rarely has to be restarted.  I use the same basic script

for several other things, and quite happy with it.  Oh, and the cron job is OS-agnostic, which is a plus for me.

Chris