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Andreas 'ads' Scherbaum

openHAB is a stream of pure joy when it comes to debugging. Especially when all I want is a small display in the kitchen, working autonomous and without the need to restart it all the time or login to fix issues.

The latest installment of that endeavor was a black screen in the browser, with no way to even get to the usual HABpanel controls. After some debugging, it turns out that the file "habpanel.config" (/var/lib/openhab2/config/org/openhab/habpanel.config) on the openHAB server was destroyed, or more accurate: shortened to 4829 bytes. Lucky me I have this file in my Ansible playbooks, and whenever there is a change, a copy of this file is fetched to my Ansible host. From there it goes into my backups, and I can restore a couple dozen versions back, if needed. So not all is bad, but still something is not working as expected. First I installed a copy of this file from my backups - but turns out shortly later the file is shortened again. Later I figured that the file is always shortened when the openHAB service restarts. This particular instance was still running openHAB 2.4, and I used this opportunity to upgrade to 2.5, test my Playbooks (and exclude the one config file from everything) and see if the problem persists. It does. Except that after upgrading to 2.5 the file is no longer shortened to 4829 bytes, but to 4875 bytes.

Every time that happens, the file ends somewhere in the middle of the HABpanel panel configuration - and naturally the HABpanel service can no longer read that file and shows a blank screen. I would wish that it rather shows an error message, or does something useful here, but oh well.

For a while (and mostly because I was busy with other tasks) I helped myself by changing the owner of "habpanel.config" and the directory this files lives in to "root:root". This threw a couple other errors into the logfile, but helped somewhat because the config file got no longer destroyed when the service restarted.

Andreas 'ads' Scherbaum

About two years ago I blogged about how to create and renew Let's Encrypt certificates using Ansible. Back then, the "letsencrypt" module was State of the Art. This changed, and with all the Let's Encrypt API changes, the Ansible module changed quite a lot, and is now "acme_certificate". ACME stands for: Automatic Certificate Management Environment, and is the idea that every step along the way of creating and renewing certificates should be automated. No more manual creation of CSR (Certificate Signing Request), sending them per mail or manually uploading them to a CA website, enter your credit card details, and at some point get a mail back with the new signed certificate. All of this (except the credit card - you no longer need one) can be automated, and handled in a matter of seconds.

Time to write an updated blog post for the new module.

Andreas 'ads' Scherbaum

The 7" Raspberry display in the kitchen is nice, but unfortunately by default the installation comes with a screensaver enabled. After a while, the display goes dark. No one wants to stare at a blank display, and touch the screen in order to see crucial information.

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Our home automation got a nice 7" Raspberry display in the kitchen, showing the most relevant information (like temperature, weather, washing machine, dryer ect) on a dedicated screen. Quite handy, especially the temperature, and the one-click stop to the weather forecast.

While installing the Pi and setting everything up, I stumbled over the Icons which LXDE by default shows on the desktop. Not necessary, I want them removed. All I want on the desktop is the browser icon which directly goes to the HABpanel.

The reason is simple: if the Pi starts up, but the browser for unknown reasons doesn't come up, I don't want anyone to be confused by additional icons on the desktop. After all, usually the LXDE desktop is not seen by default.
 

Andreas 'ads' Scherbaum

Another Ansible upgrade deprecation warning, which appears in Ansible 2.8:

TASK [send email] *************************************************************************************************************************************************************************************************************************************************************
[DEPRECATION WARNING]: Use errors="ignore" instead of skip. This feature will be removed in version 2.12. Deprecation warnings can be disabled by setting deprecation_warnings=False in ansible.cfg.

Found so many in the last time that I added a new Tag: Deprecation.

Andreas 'ads' Scherbaum

In our Home Automation system, I read weather data from OpenWeatherMap. I blogged about the implementation before. The weather data provides an icon which can be used to show the current weather:

Image	homeCurrentIcon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:current#icon" }
Image	homef03Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours03#icon" }
Image	homef06Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours06#icon" }
Image	homef09Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours09#icon" }
Image	homef12Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours12#icon" }
Image	homef15Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours15#icon" }
Image	homef18Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours18#icon" }
Image	homef21Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours21#icon" }
Image	homef24Icon		"Icon"		{ channel="openweathermap:weather-and-forecast:home:forecastHours24#icon" }

On the openHAB server side, this reads the picture data into the Item itself:

2020-02-20 00:39:38.476 [vent.ItemStateChangedEvent] - homeCurrentIcon changed from raw type (image/png): 3801 bytes to raw type (image/png): 2773 bytes
2020-02-20 03:59:47.156 [vent.ItemStateChangedEvent] - homeCurrentIcon changed from raw type (image/png): 2773 bytes to raw type (image/png): 2565 bytes
2020-02-20 04:19:48.006 [vent.ItemStateChangedEvent] - homeCurrentIcon changed from raw type (image/png): 2565 bytes to raw type (image/png): 2922 bytes

The really interesting question is: how can I display this icon directly in HABpanel. The available documentation is sparse to non-existent.

Andreas 'ads' Scherbaum

The Ansible 2.8 upgrade brought a few failing Playbooks. I ran into the following error:

TASK [Demo Task] ************************************************************************************************************************************************************************************************************************************************
fatal: [localhost]: FAILED! => {"msg": "The task includes an option with an undefined variable. The error was: 'dict object' has no attribute '_ansible_item_label'\n\nThe error appears to be in '/path/to/ansible/playbook.yml': line 76, column 5, but may\nbe elsewhere in the file depending on the exact syntax problem.\n\nThe offending line appears to be:\n\n\n  - name: Demo Task\n    ^ here\n"}

Well, seems like another upgrade with another major change. Don't you like that?

Andreas 'ads' Scherbaum

The Raspberry Pi in the kitchen runs relatively stable, but recently the browser (which is showing the openHAB HABpanel) popped up a warning in the upper right corner. That's annoying, because this area in HABpanel shows the outside temperature.

Before investigating what's going on, I had to figure out a way to get a screenshot of the display - without running into the kitchen with my mobile phone. And without attaching a keyboard all the time (to press the "Print" button).

Andreas 'ads' Scherbaum

The openHAB HABpanel we have in the kitchen runs on a Raspberry Pi and uses a touchscreen display. The browser starts in fullscreen mode, and shows a specific HABpanel screen for this display. That's all nice, but by default the mouse cursor is in the way. Let's get rid of it.

Andreas 'ads' Scherbaum

In one of my earlier blog posts I reported that occasionally the HABpanel will disconnect from the server. Turns out it's not HABpanel, but it's the Pi itself which is causing the trouble. Part of the problem why it took me so long to investigate is that the display is in the kitchen, and someone had to have a look and spot the small red error message. To work around that problem, I hooked the device up in the network monitoring, and had an alarm triggered when the device is not reachable. Sure enough, that happens occasionally.

Because I moved /var/log to a small RAM disk to avoid wearing out the SDcard, all logs are lost once the device is rebooted. Had to bring keyboard and mouse to the kitchen in order to save the logfiles once the device was no longer reachable over the network.