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I have used this idea to create an event state history for timers which will allow me to differentiate between timer.started, timer.paused, timer.restarted, timer.cancelled, and timer.finished instead of the timer states of active, idle, and paused.
Thank you, again, for the seed.
Hi Taras,
Ive been using this for the last week, and it works just fine (though I had an interrupt upon first restart ;-0
I just can not be sure I fully understand the state template, more specifically the iif section. Could you please explain what that does and why? Why is the ‘shutdown’ also listed in thehomeassistant_started if?
thx,
Here’s its theory of operation:
When Home Assistant is shutdown gracefully, the sensor sets its state to shutdown.
On startup, the sensor checks its previous state.
shutdown, it changes its state to start.shutdown, it changes its state to interrupt.So if Home Assistant is not shutdown gracefully, the sensor never gets a chance to set its state to shutdown. It’s state remains as start (or unknown). On startup, the sensor detects that its previous state was not shutdown and reports interrupt.
The pseudo code for this:
{% if trigger.event.event_type == 'homeassistant_started' %}
{{ iif(this.state|default('unknown') == 'shutdown', 'start', 'interrupt') }}
{% else %}
shutdown
{% endif %}
would be something like this:
IF Home Assistant just started
THEN
IF my previous state was 'shutdown' (if I had no previous state then use 'unknown')
THEN
Set my state to 'start'
ELSE
Set my state to 'interrupt'
ELSE
Set my state to 'shutdown'
thanks for that last bit, because that (and the use of the ‘==’ operator) was what I am struggling with, especially given what is said in the warning box under:Templating - Home Assistant
I take it you’ve guarded that?
What it’s warning against is that it doesn’t care if the result of the test is true or false, it will always compute the values of if_true, if_false, and if_none.
This will work:
{{ x + 3 if x is defined else 3 }}
This will fail because it will attempt to evaluate x + 3 even when x is undefined.
{{ iif(x is defined, x + 3, 3) }}
The template I posted above isn’t affected by this behaviour because the values of its if_true and if_false are just strings.
thanks again Taras, that explains it very well.
I must admit I was thrown off by the ‘==’ and was looking for a closing ), but now see that the full
this.state|default('unknown') == 'shutdown'
compares to the
is_state('light.kitchen', 'on')
from the docs in the first iif example jut above that warning boxs…
btw, adding a unique_id to that trigger template makes it UI configurable, and I tried to create an extra on/off attribute, so we could easily use that in an automation trigger. Never sure if it updates to the latest state though, so I made this separate binary and that seems to operate correctly:
sensor:
- unique_id: graceful_shutdown_sensor
# name: Graceful shutdown sensor
state: >
{% if trigger.event.event_type == 'homeassistant_started' %}
{{ iif(this.state|default('unknown') == 'shutdown', 'start', 'interrupt') }}
{% else %}
shutdown
{% endif %}
icon: >
mdi:restart{{'-alert' if this.state == 'interrupt'}}
attributes:
history: >
{% set current = this.attributes.get('history', []) %}
{% set new = [{
"event": trigger.event.event_type[14:],
"time": now().isoformat() }] %}
{{ (new + current)[:10] }}
binary_sensor:
- unique_id: graceful_shutdown_sensor_binary
# name: Graceful shutdown
state: >
{{states('sensor.graceful_shutdown_sensor') != 'interrupt'}}
using a first time name during creation, and next commenting that, so the UI can take over.
note ‘interrupt’ at first launch/creation, and binary on, even though state is interrupt…? I have taken out the device_class afterwards though, as it is a positive binary, meaning ‘on’ is good…:
second restart:
I didn’t find a need for it given that a State Trigger with to: interrupt does the job.
yes, you are right.
I tend to create these binary ‘alerts’ so I can easily make frontend conditionals on those too, not only trigger automations. Even use those binary alerts in a container UI binary consisting of only binary_sensors…
but again, maybe I am overdoing things, and I could take several of these out. will scrutinize to see if deletion will bring me (back) some extra efficiency gain.
thanks anyways, its a very fine example of trigger based template and iif usage.
Should be in the docs!
@123 Even after multiples tries and reading of explanations, a plain copy/paste of the above code snippet doesn’t work : in the history attribute, I only see homeassistant_started events, no single homeassistant_stop events.
What could be missing to have it running like expected ?
I’m runing HA 2023.11.2 on Raspberry PI.
Big thanks if you can help !
Thanks for bringing this to my attention.
I have performed a test and was able to replicate your results. There’s no record of the sensor being able to detect Home Assistant’s homeassistant_stop event.
I modified the sensor’s code to use Homeassistant Trigger to detect the shutdown event but it still failed to detect it
- platform: homeassistant
event: shutdown
It appears that since I posted my example in March, something changed in Home Assistant that now prevents a Trigger-based Template Sensor from detecting any events involving the shutdown process.
I’ve also tried the homeassistant trigger with same result.
The positive of this is that we are now at least 2 sharing this issue.
What action do you recommend ? Bug reporting ?
Thanks,
missed that completely too.
its all the more frustrating, because now the state never changes from interrupt, rendering the sensor useless. While it was such an elegant solution.
Taras, will you file an issue on the matter? Maybe there’s an easy fix in core…
It seems like a bug. I wish I knew what changed that caused a Trigger-based Template entity to lose the ability to detect the shutdown event. Maybe the Template integration is already disabled by the time the shutdown event is fired.
just so this is checked in core: trigger based template sensor no longer triggers on 'shutdown' · Issue #104116 · home-assistant/core · GitHub
Thanks for posting it. Lately I have far less free time to contribute to this forum, reporting issues, etc.
I’m hoping the cause of the problem isn’t a design decision to shutdown the Template integration before issuing the homeassistant_stop event.
I tested 3 workarounds:
1 - Automation + MQTT: Create an MQTT sensor and update/check its status using start/shutdown events.
Problem: the sensor is not being read at start, despite the MQTT state being correct, the sensor remains unknown, causing the automation to set the state to interrupted. Any idea?
2 - Automation + text helper: Same logic as above.
Problem: Strange behavior, it always returns to the state before it was shutdown, it seems that the state set by the automation is not persistent.
3 - Automation + shell command + python_script:
It seems to be working well:
It seems that homeassistant_stop event works again, at least in 2023.12.1.
There is one more caveat when using a template sensor, though. Home Assistant itself does not immediately write the new sensor state to the disk after it has been changed (e.g. set to start after a graceful reboot). If a power failure happens at this moment, upon the next startup the state of the sensor will be start instead of ‘interrupt’ because the recent stored value in entity registry was shutdown.
That’s good news. I’ll check it when I upgrade from 2023.11.
Has this ever happened to you?
Because this alleged behavior hasn’t been observed and reported since the example was posted in March 2023.
in 2024.1 beta a pr was made to the Trigger Home Assistant shutdown automations right before the stop event instead of during it by tetele · Pull Request #91165 · home-assistant/core · GitHub
short discussion suggested to use
trigger:
- platform: homeassistant
event: shutdown
- platform: homeassistant
event: start
so hopefully this would be fixed now?
can confirm this to work (note I added a trigger.id as there are no trigger variables to the homeassistant platform to use?). See the top 2 attributes in the screen tp be the result of this latest version:
template:
- trigger:
# platform: event
# event_type:
# - homeassistant_started
# - homeassistant_stop
- platform: homeassistant
event: shutdown
id: shutdown
- platform: homeassistant
event: start
id: start
sensor:
- unique_id: graceful_shutdown_sensor
state: >
{% if trigger.id == 'start' %}
{{iif(this.state|default('unknown') == 'shutdown','start','interrupt')}}
{% else %}
shutdown
{% endif %}
icon: >
mdi:restart{{'-alert' if this.state == 'interrupt'}}
attributes:
history: >
{% set current = this.attributes.get('history',[]) %}
{% set new = [{
"event": trigger.id,
"time": now().isoformat()}] %}
{{(new + current)[:10]}}
The shutdown trigger is fixed in 2024.1 and should be used preferably. do keep in mind what Frenck mentioned in the beta:
unless the automation takes over 20 seconds, in that case, the automation is aborted to not block the shutdown process
