Webcore pistons stop working

Webcore on hubitat stops executing many pistons regularly. Some pistons keep working, not always the same.
I use webcore almost exclusively for automation (>100 devices and 40 pistons).
Are there limitations to resources? Is there a way to check this? Should I adopt RM for simple automations? Any other ideas to build stability?

Using the simplest app for your automations is always the best bet, start by using Basic Rules for anything that only needs that kind of power and go up from there, Room Lighting, Motion Lighting and then Rule Machine.

At first I started by going the RM way for everything and soon found out as I added and replaced stuff, it was getting harder and harder to modify the Rules. So I started looking at the simpler apps and now most are now on Basic Rules. When I need more complexe stuff then I go the RM way or just write my own app and make it specific for the task(s) if nothing is available.


There are some limits on resources, but it's hard to know where to start troubleshooting without additional information. Your best clues would be in Logs on Hubitat. I'd first check for any errrors your apps or devices might be throwing, either under Current Logs or (more likely since you probably didn't have the page open when these happened) Past Logs.

Besides that, if resources are indeed the concern, this page can help with that too. Check out the Device Stats and (more likely if a webCoRE piston is really it) App Stats tabs. There are no hard and fast rules here, but I normally start with anything that is a large percent of total, abnormally long average ms (most apps should wake and exit within a few hundred), or perhaps excessively large count (number of wakes/runs) or state size. Percent of busy is not something I look at as much, as a single app taking up a large chunk of that isn't necessarily a problem if the hub itself isn't super-busy. Keep in mind you can hide/show various columns ("Show/hide app settings" at the top, and the checkboxes that appear when shown) and sort columns.

There used to be some warning against webCoRE, but the current de facto Hubitat fork maintainer has done a good job of optimizing it, and I haven't heard of any problems like some had back in the early days. That being said, it is certainly possible to write a piston (or rule or app driver or really anything) that will bring the hub to its knees if poorly written; if that's the case, the above stats may single something out.

Regarding RM or other options, I'd say: up to you! Lots of users get by with just RM, though some ST converts prefer webCoRE for familiarity, and even new users may prefer its editing interface (it is quite nice, given that it's not subject to the constraints of the mobile-first Groovy-generated app UIs that Hubitat "inherited"). But Rule Machine is a lot more powerful now than it was in the early days, and personally, after about Rule 4.0 or so, I was able to do anything I did in webCoRE in RM. RM is also part of the platform, so there's official support behind it (though again, not to say that webCoRE doesn't have a great community developer behind it now!). Ultimately, up to you and your comfort with using custom code, preferences for how you want to view or edit rules/pistons, and all that.

PS - I also second the advice above to consider other built-in options besides Rule Machine. On ST, there weren't a lot of these, and they weren't very powerful, so many users turned to custom solutions. Hubitat has a lot of apps built-in that are quite powerful and built for specific purposes in mind (e.g., the Notifications app or Room Lighting), so you may find the need to write custom rules/pistons/etc. less on Hubitat than on ST in the first place.


webcore should have logs if it is seeing errors (HE console -> logs)

I have not see it run some and not others.

Something you can look at is hub information driver by @thebearmay
many folks use this in general to monitor memory and if needed have a reboot happen if memory gets low.

I run over 250 pistons, + echo speaks, home bridge v2 without issue on my C5. If you are up to date with webcore and HE firmware, I would expect a week or so before needing a reboot.

If memory is getting low, I not sure switching automations as a known path to use less memory....


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