Certificate Expiry - Add attribute providing seconds until certificate expires

[whereisaaron]

Integration name

Certificate Expiry

Link to integration documentation on our website

https://www.home-assistant.io/integrations/cert_expiry/

Describe the enhancement

Add an attribute with seconds until cert expiry (this would be a negative value after expiry).

This integration works well, providing the timestamp when the certificate will expire. But in many or most use case for the integration the timestamp is not what you need, rather you what to know how long until the certificate expires. E.g. certificate will expire in 7 days.

Currently there is only the "Is valid" attribute, but it only changes when the certificate has already expired. You want to know e.g. 7 days before expiry.

Use cases

This would allow automation to decide whether to run the Let's Encrypt Add On to renew a certificate.

This would allow you to send notification e.g. 3 days before a certificate expires.

Anything else?

A current workaround is to create a template sensor that converts the expire timestamp to seconds until expiry. This is fine, but this use case is so common, that I think this values should be built into the integration.

https://community.home-assistant.io/t/hass-io-letsencrypt-renewal-and-reboot/295966/5

ssl_cert_expiry_seconds:
        entity_id: sensor.cert_expiry_timestamp_xxxxxxxx
        friendly_name: 'friendly name'
        value_template: '{{ ((as_timestamp(states("sensor.cert_expiry_timestamp_xxxxxxxx")[:16].replace("T"," ")) - as_timestamp(now())))  }}'
        unit_of_measurement: seconds

[github-actions[bot]]

🏷️ I've automatically added the integration: cert_expiry label to help categorize this feature request.

[whereisaaron]

Another workaround is to a time timestamp-offset trigger for an automation. Not clear how reliable this is if the exact trigger time is missed. Whereas a seconds attribute would enable trigger when expiry seconds is below X. You could add multiple triggers I guess?

alias: Renew certificate before expiry
description: ""
triggers:
  - trigger: time
    at:
      entity_id: sensor.my_certificate_name_cert_expiry
      offset: "-168:00:00"
conditions: []
actions:
  - action: hassio.addon_start
    data:
      addon: core_letsencrypt
  - delay:
      hours: 0
      minutes: 10
      seconds: 0
      milliseconds: 0
  - action: homeassistant.restart
    metadata: {}
    data: {}
mode: single

You really want to handle it with a condition check, like below, but for some reason, time conditions don't support an offset 😭

condition: time
after: sensor.my_certificate_name_cert_expiry
after_offset: "-168:00:00"

Message malformed: extra keys not allowed @ data['conditions'][0]['after_offset']

[mib1185]

Another workaround is to a time timestamp-offset trigger for an automation.

That's not a workaround, that's the solution 😉

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Adding an entity, which properly changes every second its state, will unnecessarily pollute your history database (that was the reason, why all uptime sensors got migrated to sensors with a timestamp long time ago - the frontend will take care to display these sensors properly in the dashboards and cards)