Fix #434: Implement Uptime

[mathieucarbou]

Example in HA:

mqtt:
  sensor:
    - name: OpenEVSE Uptime
      unique_id: 55806B85-C3B9-4EF7-8DB3-2E6C28D97669
      icon: mdi:clock
      state_topic: "openevse/uptime"
      device_class: duration
      state_class: measurement
      unit_of_measurement: s
      value_template: "{{ value|int }}"
      expire_after: 40

In HA:

MQTT Integration: https://gist.github.com/mathieucarbou/92a3d5e0dc38d6b68aa1bdaf153a80c5

In MQTT:

/status:

/time:

[mathieucarbou]

reminder ;-)

[jeremypoulter]

There is no direct link to TIME_POLL_TIME and calling TimeManager::serialise and although chances are high that it would be called, you may want to add something explicit into the loop method. Also be aware that the loop method is only called regularly if SNTP is enabled.

[mathieucarbou]

True, I will add a more direct link because here, it works, but I rely on the whole call hierarchy.

@jeremypoulter Regarding the loop which could be disabled...

• should we then move the update stuff in its own cpp file with its own microtask ?
• should we couple the uptime code to another existing loop, which is less time-related ?
• should we keep the uptime code here, and accept the fact that time-related things need NTP ?

[mathieucarbou]

@jeremypoulter : I've updated the PR to move the uptime near the main loop, where the version and hardware info are.

[jeremypoulter]

Happy with this, thanks for the contribution