AuroraMeter.Exporter.Item (Aurora Meter v1.0.0)

One thing to deliver, and everything an adapter is allowed to know about it.

The caller builds it, usually from a durable row, and it is immutable from that moment: the same struct is handed to AuroraMeter.Exporter.deliver/2 on the first attempt and on the twentieth, with only attempts moving. Build one with AuroraMeter.Exporter.item!/1 so a half-built struct cannot reach an adapter.

Field	What it is
`id`	the caller's row id, opaque to the adapter, and the key of the tuple the adapter returns
`subject_kind`	`:usage_window`, `:event` or `:correction`. The caller must not send a kind the adapter's `supports` list omits
`subject_ref`	the caller's stable business reference: an event id, or `"usage:<feature>:<period_start>:<from>:<to>"`
`tenant_key`	for logging, and for an adapter that must refuse an item belonging to another account
`payload`	a map with string keys, already JSON safe. This is the financial intent, and Aurora Meter never looks inside it
`attempts`	how many previous attempts this item has had; `0` on the first
`first_attempt_at`	when the first attempt was made, or `nil` before it. Stamped by the caller's database, not by a node clock

payload is where provider-specific fields live, and that is on purpose: an account id, a mode flag or a customer reference belongs there (or in the caller's own row), never in a field of this struct. Aurora Meter would then have to know what a provider is.

Summary

Types

t()

Types

t()

@type t() :: %AuroraMeter.Exporter.Item{
  attempts: non_neg_integer(),
  first_attempt_at: DateTime.t() | nil,
  id: String.t(),
  payload: %{optional(String.t()) => term()},
  subject_kind: AuroraMeter.Exporter.subject_kind(),
  subject_ref: String.t(),
  tenant_key: String.t()
}