development.md

Development Notes

Uptime

What is uptime?

uptime should be defined as (time_normally_open - time_closed) / time_normally_open.

time_normally_open should be defined as the collective time that a lift should be open on a given day. If it's 0, we shouldn't try calculating the uptime (some lifts are closed on certain days).

time_closed should be defined as the collective time in a state other than 'Open' or 'For Scenic Rides Only' (every other state should be considered closed).

Time could be in minutes for ease of comparison

Example

In the summer, the Discovery Chair lift should be open from 9AM - 5PM PDT daily. That means the time_normally_open should be 480 minutes (8 hours).

Let's say that today the Discovery Chair was in the state 'Hold - Weather' from 1PM - 2PM PST. It's time_closed was 60 minutes (1 hour). We can then calculate it's uptime for the day as round(((480 - 60) / 480) * 100) or 88.

Gathering test data

select
  id,
  created_at at time zone 'utc' at time zone 'pdt' as created_at,
  updates
from latest_updates;

This query has a least a few lifts that were closed for weather on 2021-07-19.

select row_to_json(lift_data) from (
  select
    created_at at time zone 'utc' at time zone 'pdt' as created_at,
    updates
  from latest_updates
  where created_at
    between '2021-07-19 00:00' and '2021-07-20 00:00'
) lift_data;

Then replace \n with ,\n and wrap in [] to make it an array.