DanfossAirUnit: Handling of lost connection

laursen · August 15, 2021, 6:21am

Once in a while this happens:

2021-08-11 21:14:54.842 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_ManualFanSpeed' changed from 10 to 0
2021-08-11 21:14:54.844 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_ExtractFanSpeed' changed from 2396 to 0
2021-08-11 21:14:54.845 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_SupplyFanSpeed' changed from 1868 to 0
2021-08-11 21:14:54.847 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_ExtractFanStep' changed from 77 to 0
2021-08-11 21:14:54.853 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_SupplyFanStep' changed from 55 to 0
2021-08-11 21:14:54.861 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_RoomTemperature' changed from 24.2 °C to 0 °C
2021-08-11 21:14:54.868 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_OutdoorTemperature' changed from 17.6 °C to 0 °C
2021-08-11 21:14:54.872 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Humidity' changed from 57.6 to 0.0
2021-08-11 21:14:54.875 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Recuperator_SupplyAirTemperature' changed from 25.2 °C to 0 °C
2021-08-11 21:14:54.877 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Recuperator_ExtractAirTemperature' changed from 25.8 °C to 0 °C
2021-08-11 21:14:54.879 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Recuperator_ExhaustAirTemperature' changed from 19.4 °C to 0 °C
2021-08-11 21:14:54.881 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Service_RemainingFilterLife' changed from 16.078432083129883 to 0.0

All values are set to 0. I have a rule for sending me a push notification when DanfossHRV_Service_RemainingFilterLife is changed to a value less than 10%, so this is something I’ll notice and take action upon. These have been my ways to mitigate:

Wait it out. Sometimes it happens when I’m sleeping or working, so I’ll not react in a timely manner, and when I attend to it, problem already resolved itself.
Other times it has helped to restart the binding.
A few times I have restarted the unit to fix the issue.
Restarting the unit felt too aggresive, so also tried pulling the Ethernet cable from my switch and put it back. Also seemed to resolve it.

I don’t know exactly why it happens (lost connection or unit acting strange?), but actually my question is if it would be possible to change the way it’s handled in the binding? Instead of zero’ing all values, would it be possible to mark the Thing as offline instead? This would still make it possible to detect the issue (e.g. from a rule), and persisted values wouldn’t become 0 and break graphs, statistics, calculations etc. IMHO it would be better to not update the values when no new values are available, which seems to be the case here.

Similar: [squeezebox] Map player connection state to thing status by maniac103 · Pull Request #10778 · openhab/openhab-addons ·

Best regards,
Jacob Laursen

laursen · September 1, 2021, 7:32pm

Created [danfossairunit] All channels updated to zero · Issue #11188 · openhab/openhab-addons · GitHub

laursen · September 22, 2021, 6:15pm

@pravussum - I finally found the reason for this and created a pull request with a proposed fix:

github.com/openhab/openhab-addons

[danfossairunit] Fix bug when connection is lost, leading to all channels being updated to zero values

openhab:main ← jlaur:11167-danfossairunit-fix-warnings

opened 02:03PM - 29 Aug 21 UTC

jlaur

+257 -96

### Main issue (bugfix) Once in while this happens: ``` 2021-09-01 18:44:…46.984 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_ManualFanSpeed' changed from 10 to 0 2021-09-01 18:44:46.990 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_ExtractFanSpeed' changed from 2660 to 0 2021-09-01 18:44:46.991 [INFO ] [openhab.event.ItemStateChangedEvent ] - Item 'DanfossHRV_Main_SupplyFanSpeed' changed from 2091 to 0 ``` etc. All values are set to 0, breaking rules, graphs etc. This is caused by an unchecked `read()` from InputStream with the result that the read buffer is uninitialized and no error handling or reconnect attempt takes place. After fixing this, in most cases connection will automatically be reestablished and nothing bad happens. In case of network issues preventing reconnection, channels will be updated to **Undefined** and thing will be taken offline. See #11188 for further details. ### Additionally some minor refactoring This PR has been repurposed to fix bug mentioned above, but additionally contains some refactoring to increase code quality: - Deleted some unused private methods. - Added constants for some hardcoded values. - Extracted interface from **DanfossAirUnitCommunicationController**. - Object is now created by **DanfossAirUnitHandler** and injected into **DanfossAirUnit** through constructor. Handler now takes responsibility for disconnecting without having to call cleanUp method in DanfossAirUnit. Object can be reused and mocked in tests. - Added testcases for some of the public **DanfossAirUnit** methods which documents their behavior. See #11167 for further details. ### Test Manual test: I have been running this version in production since September 1st without any issues.

pravussum · September 22, 2021, 7:18pm

Thanks a lot for taking the time to investigate and fix this!