aurora_meter

# Changelog

All notable changes to Aurora Meter are documented here. The format is based on
[Keep a Changelog](https://keepachangelog.com/en/1.1.0/), and this project adheres
to [Semantic Versioning](https://semver.org/spec/v2.0.0.html).

## [0.2.0] - 2026-09-07

Schema version 2. Existing installs add one migration:

```elixir
def up, do: AuroraMeter.Migration.up(from: 2)
def down, do: AuroraMeter.Migration.down(to: 2)
```

(`mix aurora_meter.gen.migration -r MyApp.Repo --from 2` generates it.)

### Added

- **Usage history** — UTC day buckets are maintained next to the period counter
  (same ETS hot path, flushed to the new `aurora_meter_history` table) and read
  back with `AuroraMeter.history/3`, giving charts without durable events.
  Off with `config :aurora_meter, history: false`.
- **`AuroraMeter.quota/2`** — one dashboard-ready map per feature: kind, used,
  limit / included, remaining, overage, percent and the current period.
- **`AuroraMeter.period/1`** — the tenant's current billing window.
- **Subscription cache** — `AuroraMeter.Subscriptions` memoises the plan lookup
  in ETS (`:subscription_cache_ttl`, default 5 s) and evicts on every
  `Storage.put_subscription/1`, locally and across nodes via PubSub. `check/2`,
  `reserve/3` and `with_quota/4` no longer touch the database per call.
- **Versioned migrations** — `AuroraMeter.Migration.up/1` and `down/1` take
  `:version`, `:from` and `:to`; every version is idempotent.
- **Telemetry** — `[:aurora_meter, :reserve]` with `%{qty}` and the outcome
  (`:ok`, `:limit_exceeded`, `:not_entitled`) in metadata.
- `AuroraMeter.Schema.Subscription.entitled_statuses/0` and `entitled?/1`.

### Fixed

- The flusher now traps exits, so the final flush actually runs on shutdown; a
  deploy no longer drops up to one flush interval of usage.
- Live updates could be lost when a flush landed between a `track` and the next
  broadcast tick; the broadcaster now keeps its own touched set.
- A subscription in a non-entitled status (`canceled`, `unpaid`, `incomplete`,
  ...) kept granting its plan; it now falls back to the default plan.
- `mix aurora_meter.gen.migration` failed in a host app because the repo was
  never loaded; it now calls `Mix.Ecto.ensure_repo/2` first.
- `usage_meter/1` shows the included allowance and overage for metered features
  and the enabled state for boolean features instead of a bare count.

## [0.1.0] - 2026-07-11

Initial release of the free core.

### Added

- **Metering** — `AuroraMeter.track/4`, `usage/2`, `usage_all/1`. ETS-backed
  atomic counters (`:ets.update_counter`), never touching the database on the hot
  path; ~8M increments/sec aggregate. Interval `Flusher` persists absolute-value
  snapshots (idempotent); interval `Broadcaster` fans live values over PubSub.
  Per-feature `:durable` mode also writes a raw event row.
- **Entitlements** — `check/2`, `allowed?/2`, `entitled?/2`, `remaining/2`,
  `reserve/2,3`, and `with_quota/3,4` (atomic reserve + release-on-raise; correct
  hard-limit enforcement under concurrency). Hard limits block; metered features
  allow overage; undeclared features are permissive.
- **Plans** — a compile-time DSL (`use AuroraMeter.Plans`) with `plan`, `price`,
  `limit`, `metered`, and `feature`, validated at compile time.
- **Subscriptions** — local `subscribe/2` and `plan/1`, with a configurable
  default plan.
- **Billing seam** — `AuroraMeter.Billing.Provider` behaviour + `Noop` default +
  a `Billing` facade, so the core works standalone and Pro plugs in.
- **LiveView** — `usage_meter/1` and `usage_summary/1` components (behind the
  optional LiveView deps) and `AuroraMeter.LiveView.subscribe/1`.
- **Storage** — `AuroraMeter.Storage` behaviour + Ecto/Postgres adapter;
  `AuroraMeter.Migration` and `mix aurora_meter.gen.migration` / `install`.
- **Config** — `NimbleOptions`-validated configuration (fail fast at boot).
- **Telemetry** — `[:aurora_meter, :track | :flush | :broadcast]`.
- **Bench** — `mix aurora_meter.bench`.