Procd : adding something like sd_notify watchdog?

For Developers
1

I'm working on a new application for an OpenWRT device.

One of the features that I wish I had access to in OpenWRT is the ability to have procd terminate and restart a service, if that service fails to send procd an "I'm alive" message via a Unix Domain Socket periodically.

I've used this with applications on a desktop / server setting in the past, where systemd allows a service to be configured such that if the service failed to call sd_notify periodically (which, under the hood, just sends a message to a Unix Domain Socket), the service would be terminated and re-started.

This is great for network servers, to ensure that a programming bug hasn't caused the server to hang indefinitely.

I don't see any indication that this kind of functionality is supported by procd.

Is this functionality available?

If not, are there any patches that implement it?

If not, would OpenWRT accept a patch that implemented this feature?

2

Well this can be implemented in the application by using uloop or ubus

3

There is no indication of that anywhere on the OpenWRT development documentation. (Or the parts of the source code I read through)

Can you please elaborate?

4

uloop is part of the ubox library (if i remember correctly) It can be used to create a service that does operation every n second

5

Yes. Uloop is part of ubox. Ubox is a relatively tiny collection of c library functions.

I imagine that if procd ever supported a feature like SD_notify from systemd, it would be implemented using ubus like most other openwrt features.

That being said, ubus is simply Unix domain sockets under the hood, so while I appreciate the attempt at helping, I was really hoping for a more definitive answer on whether functionality like this exists, or is planned.

6

No.

No.

Yes.

7

Thank you!