Notes as I go: my attempt to develop a Home Assistant integration, part 3

One thing that was confusing to me from the start was the seemingly overlapping functionality in and, but I think I figured it out: async_step_*() in is for when a component is first set up, whereas async_setup_entry() in is for when a config entry for the component has already previously been set up, and so an object can be instantiated for that entry.

As for “my API”, my impression (from both core and non-core integrations) is that if I had a published Python package for the device, I’d just import it (like, for instance, RuuviTag integration imports ruuvitag-ble), but if/as I don’t, I should create the API in a subdirectory of my integration and import it using dot notation.

Hence, naming the files inside the API directory is more a question of general Python convention, rather than something HA has opinions about.

Anyway, while I understand all the complications I keep stumbling over make HA component development scalable, it also makes my tiny button project way more complicated than it should be. There appears to be no way to build a minuscule MVP with just a few lines of code, to be then extended with all the bells and whistles that would make it look and play nice.

Instead it seems easier to just hack some existing code to work with my device (which I’ve already done, semi-successfully). But that means then having to clean up tons of someone else’s code, or, what’s more likely, just leave it all as an ugly hack, never to be published anywhere.

How I made tty1 a live display for (Systemd’s) journal (in Ubuntu 20.04)

  1. Run systemctl edit getty@tty1.service
  2. In the override file, enter
    ExecStart=-/bin/journalctl -b -ef
  3. To see it right away (without reboot), run systemctl daemon-reload followed by systemctl restart getty@tty1.service
  4. To stop the console from blanking, edit /etc/default/grub, add consoleblank=0 to GRUB_CMDLINE_LINUX_DEFAULT, save and exit. Then run update-grub and reboot.

(I adapted the service override from Remy’s old post.)

Notes as I go: my attempt to develop a Home Assistant integration, part 2

The documentation keeps referring to “my API”, but leaves everything about it up to imagination. How should I name the file? What code should I put there, and what should I not?

The MyEvent example, which I adapted for my, keeps failing to load, because it “has no attribute ‘async_setup_entry'”. I get it to shut up by adding a dummy by that name as a function — not as a method.

I grab some logging code from someone else’s Bluetooth integration and adapt it to my _async_has_devices(), to see if I need to do any actual filtering. But none of it ever gets run, despite HA announcing a device being detected by my integration.

In the end I decide it’s not going to be as easy as I’d hoped with the config_flow_discovery scaffolding. I’m going to have to invoke Bleak to be able to subscribe to BLE notifications, which are what my button uses to communicate press events, and which, apparently, are not part of HA core for now. So I revert the changes and go back to the longer version.

The first TODO there is for user data schema. I won’t have users input any configuration, so out it goes, as does all of validate_input(), and async_step_user() in ConfigFlow. Likewise for PlaceholderHub (“Remove this placeholder class and replace with things from your PyPI package”).

According to “Discovery steps“,

“When an integration is discovered, their respective discovery step is invoked (ie async_step_dhcp or async_step_zeroconf) with the discovery information.”

This means it should be async_step_bluetooth() for mine. I wish it was listed, along with all other variants, instead of just the two examples, to help googling. An accompanying example would be even better.

The last item on the list of things the discovery step should do is:

“Invoking a discovery step should never result in a finished flow and a config entry. Always confirm with the user.”

Again, not even a hint about this in the documentation, but most core integrations appear to implement a async_step_bluetooth_confirm(), and call it at the end of async_step_bluetooth(). There’s also _set_confirm_only(), which seems like what I need, but again, no documentation anywhere.

Notes as I go: my attempt to develop a Home Assistant integration, part 1

Set up Development Environment says the “easiest way to get started with development is to use Visual Studio Code with devcontainers”, but I dislike both those things, so I go with Manual Environment instead.

I’m not doing core development or even integration PRs for now, so I don’t need a fork; instead I just git clone --depth 1

For the dependencies, sudo apt install python3-pip python3-dev python3-venv autoconf libssl-dev libxml2-dev libxslt1-dev libjpeg-dev libffi-dev libudev-dev zlib1g-dev pkg-config libavformat-dev libavcodec-dev libavdevice-dev libavutil-dev libswscale-dev libswresample-dev libavfilter-dev ffmpeg

I then try to run script/setup, except that’s not going to work, because it’s not in my path; to call it from the core root directory using a relative path, it has to be ./script/setup

Some python packages get installed, and in the end it craps out with “no such option: –config-settings”. Apparently Python 3.10, which my Ubuntu 22.04 desktop has, is no longer supported, so I need to redo all of the above on my laptop (which is running Ubuntu 23.10 with Python 3.11).

I then try python3 -m script.scaffold integration, which is what I’m here for, but it fails with “ModuleNotFoundError: No module named ‘attr'”. Nothing useful comes up on Google, but then I realize I need to source venv/bin/activate first.

After I answer the scaffolding questions, the script begins building the scaffold, but that also craps out, this time with “ModuleNotFoundError: No module named ‘numpy'”. pip3 list reveals this to be true, so I pip3 install numpy.

I restart python3 -m script.scaffold integration, which this time only asks the first question, then (correctly) assumes my previous answers to the others are still valid, and finally generates the scaffolding. Doesn’t tell me where it is, but git status shows theres new stuff in homeassistant/components/ and in tests/components/.

“The next step is to look at the files and deal with all areas marked as TODO.”

I rsync the scaffolding back to my desktop and open in VSCodium. The first TODO says “List the platforms that you want to support.” By default it’s set to LIGHT, but my thing is a button, so I go looking for the platform alternatives. “There are lights, switches, covers, climate devices, and many more.”

The “many more” link goes to an entities introduction page, so I assume the side menu listing of Entities is what I have to choose from. As I said, I’m developing a button, so you’d think, a Button, right?

Of course not:

“not suitable for implementing actual physical buttons; the sole purpose of a button entity is to provide a virtual button inside Home Assistant.”

“If you want to represent something that can be turned on and off (and thus have an actual state), you should use a switch entity instead.”

I don’t, because mine doesn’t, so no.

“If you want to integrate a real, physical, stateless button device in Home Assistant, you can do so by firing custom events. The entity button entity isn’t suitable for these cases.”

Well, I’d like to fire events, but this only seems to draw further away from what “platform” I need to use for my integration.

The scaffolding imports Platform from homeassistant.const, so I find the Platform enumeration in, but it just lists the same entities as the documentation side panel, so I’m out of luck.

No, wait, Event is also listed. So I’ll go with Platform.EVENT for now. That means I’ll need to “create a file with the domain name of the integration that you are building a platform for” — so in this case,

Actually, Integration File Structure says

“If the integration only offers a platform, you can keep [] limited to a docstring introducing the integration”.

So that means I don’t need any of the scaffolding?

Whatever, I’ll take a look at the manifest instead.

Integration type was not set up by the scaffolding script (despite the documentation saying it should be set, and becoming mandatory in the future). I’m going to pick device, which seems unambiguous, for once.

Version is mandatory, I’ll go with 0.1.

My button communicates via Bluetooth, and Best practices for this says I need bluetooth_adapters in my dependencies.

I’ve used bluetoothctl to sniff out what name the device uses, so I’m also defining a local_name matcher in a Bluetooth section. There’s also connectable, but it defaults to true, which is what it should be for my button.

In the scaffolding, I’d previously set iot_class to local_polling, and I’m going to leave it as such, although for now, I’m treating the button as if didn’t have any state.


Discoverable integrations that require no authentication” looks useful, so I go back to my laptop, source venv/bin/activate again, then python3 -m script.scaffold config_flow_discovery, and finally rsync the new files (now named EXAMPLE_*) back again. The only changed file was, which is now substantially smaller, defining mostly just _async_has_devices().

The only TODO there is “Check if there are any devices that can be discovered in the network.” Spying from one core integration, my guess is that _async_has_devices() receives a bunch of discovered devices, and should return true only if any of those devices are ones that my integration is actually able to configure.

Why/whether this isn’t already handled by the matcher definition in the manifest, I don’t know; I found at least one integration that always returns true, with a comment “MQTT is set as dependency, so that should be sufficient.”

I minimally tweak the MyEvent example and save it as I think it’s missing at least imports of EventEntity and EventDeviceClass. Also, there’s a tip about being “sure to deregister any callbacks when the entity is removed from Home Assistant”, so why isn’t that incorporated into the example?

Clock Override suddenly only somewhat works (but it’s really not about that)

I use Clock Override to customize the date and time format displayed in the top bar in GNOME Shell. Recently, after a couple of bad logins (Gnome crashing), it suddenly only reacted to the %S modifier and no other GLib GDateTime codes anymore. The date and time was either the default format, or the default format with seconds (when %S was part of the format string).

I tried reinstalling the extension, clearing its dconf settings and all that jazz, to no avail. In the end I tried to reproduce the issue using another user account, and, having failed that (i.e. the extension worked perfectly), once again went through bisecting a dconf dump from the non-working account:

dconf reset -f / && dconf load / <nonworking

This finally revealed that Gnome Shell had set /org/gnome/shell/disable-user-extensions to true, which “makes sense”.

I might have found out the cause much quicker, had the extension not been in this bizarre “1 % working, 99 % not” half-state but completely nonfunctional. Even quicker still, had Gnome somehow indicated that it was now running in this crippled safe mode.

LineageOS 16.0:n asennus Samsung Galaxy Tab 4:ään (SM-T530/SM-T535)

Sama käännös on saatavilla myös pienemmille varianteille, mutta dokumentoin tässä vain nämä kymmentuumaiset, joiden kanssa tästä on omakätistä kokemusta, ja näistäkään en 3G-varianttia (SM-T531) ole koskaan nähnytkään. (En tiedä onko sitä Suomessa myytykään.)

  1. 10-tuumainen Samsung Galaxy Tab 4 (SM-T530/SM-T535)
  2. Tietokone, jossa laadukas USB-portti. Odin vaikutti ronkelilta tuon suhteen, sillä esimerkiksi oman läppärini kolmesta USB-portista sille kelpasi vain yksi.
  3. laadukas USB-kaapeli (tabletin ja tietokoneen kytkemiseen)
  1. Odin3 v3.14.1_3B_PatcheD Windowsille, tai Linuxin puolella Heimdall v.1.4.1. Itse käytin ( Ubuntu 22.04:ssä) Heimdallista versiota 1.4.3. Applen tietokoneissakin Heimdallin pitäisi toimia, mutta niistä minulla ei ole kokemusta.
  2. TWRP matisselle. Jos käytät Heimdallia, valitse .img-paketti. Jos käytät Odinia, valitse sen sijaan .tar-paketti (esim. twrp-3.6.0_9-0-matisse.tar). Mieluusti uusin (joka tätä kirjoittaessani 3.7.0_9), mutta XDA:lla käytetty tiedostonjakopalvelu on niin rikki, että sain vain 3.6.0_9-0:n sieltä ulos, joten sitä käytin.
  3. LineageOS 16.0 -ROM-tiedosto. Varmista, että paketin nimessä on laitetta vastaava koodinimi! SM-T530:n koodinimi on matissewifi, SM-T535:n matisselte. Tässäkin uusin (tätä kirjoittaessani 2022-10-20) olisi mieluisin, mutta sama jakeluhäiriö kuten edellä, joten jouduin asentamaan yli vuoden vanhan käännöksen SM-T530:een ( SM-T530:een), ja melkein vuoden vanhan SM-T353:een (
  4. Uusin OpenGApps. Valitse ARM-alusta (ei ARM64!), Android 9.0, kokovariantti oman maun ja käyttötarkoituksien mukaan. Itse asensin SM-T530:een minin, SM-T535:een picon. Asennushetkellä uusin julkaisu oli 2022-02-15.
  1. lataa kaikki edellä luetellut ohjelmistot ja tiedostopaketit tietokoneelle
  2. päivitä tabletin alkuperäisohjelmisto uusimpaan versioonsa (Android 5.0.2)
  3. lataa tabletin akku täyteen (hyväkuntoisella akulla vähempikin riittää)
  4. palauta tabletti tehdasasetuksille (Settings → General → Backup and reset → Factory data reset
  5. käynnistä laite uudestaan ja ohita aloitusasetukset (älä kirjaudu tai syötä mitään tietoja, ohita kaikki mahdollinen)
  6. kytke tabletti USB-kaapelilla tietokoneeseen tiedostonsiirtoa varten
  7. kopioi tabletin Download-hakemistoon LineageOS:n zip-paketti ja OpenGAppsin zip-paketti
  8. sammuta tabletti
  9. irrota tabletti USB-kaapelista
  10. Käynnistä tabletti pitämällä yhtä aikaa pohjassa kotinappia, äänenvoimakkuuden miinus -nappia (joka on äänenvoimakkuusnapeista virtanapin puoleinen) ja virtanappia. Vapauta kaikki napit kun näytölle ilmestyy teksti (“Warning!! A custom OS can cause critical problems” jne.).
  11. paina äänenvoimakkuuden plus -nappia kerran
  12. kytke tabletti USB-kaapelilla tietokoneeseen
TWRP:n asennus (Windowsissa)
  1. käynnistä Odin, kuittaa sen varoitus OK:lla
  2. mene Odinin Options-välilehdelle, ja ota siellä “Auto Reboot” pois päältä
  3. palaa Odinin Log-välilehdelle
  4. napsauta Odinin AP-nappia, etsi ja valitse TWRP:n tar-paketti
  5. Napsauta Odinin Start-nappia. Odinin Message-laatikkoon pitäisi ilmestyä teksti “All threads completed. (succeed 1 / failed 0)”
  6. sulje Odin
TWRP:n asennus (Linuxissa)
  1. Suorita komentoriviltä seuraava komento ilman pääkäyttäjäoikeuksia, twrp:n img-tiedoston nimi ja -polku tarvittaessa soveltaen, ja --RECOVERY-parametri juuri kuten alla, eli isoin kirjaimin:
    heimdall flash --RECOVERY twrp-3.6.0_9-0-matisse.img --no-reboot
LineageOS:n ja OpenGAppsin asennus
  1. irrota tabletti USB-kaapelista
  2. Käynnistä tabletti uudestaan pitämällä yhtä aikaa pohjassa kotinappia, äänenvoimakkuuden plus -nappia (joka on äänenvoimakkuusnapeista se virtakytkimestä kauempi) ja virtanappia. Vapauta kaikki napit vasta, kun näytölle ilmestyy Samsungin logo ja vasempaan yläkulmaan teksti “Recovery booting”. TWRP käynnistyy.
  3. Pyyhkäise Swipe to Allow Modifications -pyyhkäisyvalitsin vasemmalta oikealle.
  4. valitse TWRP:n päävalikosta Wipe → Advanced Wipe
  5. rastita
    • Dalvik/ART Cache
    • System
    • Data
    • Cache
  6. Pyyhkäise Swipe to Wipe -pyyhkäisyvalitsin vasemmalta oikealle. Näytölle ilmestyy pyyhkinnän etenemisestä kertovaa tekstiä, ja lopuksi yläpalkkiin “Wipe Complete” ja “Successful”.
  7. palaa TWRP:n päävalikkoon
  8. valitse TWRP:n päävalikosta Install
  9. valitse vasemman laidan hakemistonäkymästä Download-hakemisto
  10. valitse Lineage OS:n zip-tiedosto
  11. Pyyhkäise Swipe to confirm Flash -pyyhkäisyvalitsin vasemmalta oikealle. Näytölle ilmestyy asennuksen etenemisestä kertovaa tekstiä, ja reilun minuutin päästä yläpalkkiin “Install Zip” ja “Successful”.
  12. palaa hakemistonäkymään ja valitse OpenGAppsin zip-tiedosto
  13. Pyyhkäise Swipe to confirm Flash -pyyhkäisyvalitsin vasemmalta oikealle. Näytölle ilmestyy asennuksen etenemisestä kertovaa tekstiä, ja lopulta yläpalkkiin “Install Zip” ja “Successful”. Paketin koosta riippuen asennus voi kestää kauankin (mini-paketillakin kymmenisen minuuttia).
  14. Valitse Reboot System. LineageOS:n käynnistysanimaation pitäisi ilmestyä. Ensimmäinen käynnistys saattaa sekin kestää todella kauan.

Sama tekijä on kääntänyt myös LineageOS 17:n ja 18:n näille laitteille. Hänen mukaansa

17 and 18 can be used without any big problem, but they are less snappy.

ja lisäksi

LOS 16 is the most stable and light. Newer versions are just for people who need the features of new Android versions, or just to say: “hey, I have an updated Tab 4 at the almost latest version of Android!”

Dell P2416D display blinks/blanks out (turns off and back on again)

If you’re using the USB hub built into the display, try disconnecting it (and all the USB cables connected to the display) and see if the issue still remains.

(This may not be a guaranteed fix for you, but for my display it seems to be, so I’m writing this down for myself, so that Google will find it when I again make the mistake of trying to use the USB hub and then wonder what the hell is causing my display to switch off and back on again.)

Signal Desktop: message content not shown in notification (in Ubuntu 20.04) despite privacy settings

Just helping Google out here: the notification just says “Signal(1) is ready”, which is caused by Electron lacking support for Gnome’s focus-stealing prevention feature.

This can be worked around with the Window Is Ready – Notification Remover extension. As of this writing, I have yet to determine whether the extension then also restores the (annoying) focus-stealing ability, or if only the notification is removed (which would leave focus-stealing windows in the dark).