Quartz's query: http_request query endpoint

[gshif]

Test quartz's query (defined in https://github.com/influxdata/quartz/blob/cloud-two-dev/lib/quartz/two/billing/organization_usage.ex):

def get_reads_usage(org_id, start, stop) do
    """
    from(bucket: "system_usage")
    |> range(start: #{start}, stop: #{stop})
    |> filter(fn: (r) =>
    r.org_id != ""
    and r.org_id == "#{org_id}"
    and r._measurement == "http_request"
    and r._field == "resp_bytes"
    and r.endpoint == "/api/v2/query"
    )
    |> group()
    |> aggregateWindow(every: 1h, fn: sum)
    |> keep(columns: ["_time", "_value", "_start"])
    |> fill(column: "_value", value: 0)
    |> rename(columns: {_value: "reads_b"})
    |> yield(name: "reads_b")
    """
  end

[Nlyandres]

This query is covered in test_metrics_usage.py test suite