Changelog

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All notable changes to Aurora Meter are documented here. The format is based on Keep a Changelog, and this project adheres to Semantic Versioning.

[0.3.0] - 2026-09-07

No migration required (schema version stays 2).

Added

  • Cluster-wide counters. Every node still meters into its own ETS table, but the flusher now writes deltas (value = value + Δ) and re-bases on the total Postgres returns, so nodes add up instead of overwriting each other. Nodes exchange deltas over PubSub every :broadcast_interval and announce flushed totals every :flush_interval; a value read on any node is the true total minus at most the other nodes' last tick of increments. See docs/clustering.md and ADR 0004.
  • AuroraMeter.Cluster — the supervised process behind it; config cluster_sync: true (default).
  • AuroraMeter.Storage.add_counters/1 and add_history/1 (new required callbacks on the behaviour) alongside the absolute upsert_*.
  • AuroraMeter.Test — reset!/0, flush!/0, broadcast!/0, unique_tenant/1, checkout/1, simulate_node/3, simulate_flush/2 and a use AuroraMeter.Test macro, replacing the boilerplate the testing guide used to ask hosts to copy.
  • One-step installer. With igniter in your deps, mix igniter.install aurora_meter (or mix aurora_meter.install) writes the config, adds AuroraMeter to your supervision tree after the repo and PubSub, creates a starter plans module and generates the migration. Without Igniter the task keeps printing the steps.
  • Telemetry: [:aurora_meter, :cluster, :apply] and [:aurora_meter, :flush, :error]; [:aurora_meter, :flush] gains delta_sum, [:aurora_meter, :broadcast] gains deltas.

Changed

  • ETS counter rows are now {key, value, pending_flush, pending_gossip} (anyone reading :aurora_meter_counters directly needs the new shape).
  • With cluster_sync on, tenant usage broadcasts are node-local: each node informs its own LiveViews from its own converged view.
  • A failed flush no longer crashes the flusher: taken deltas are restored and re-marked dirty, the error is logged and reported via telemetry.
  • AuroraMeter.check/2 is documented as advisory (a read then a compare); use reserve/3 or with_quota/4 to enforce a hard limit atomically.

[0.2.0] - 2026-09-07

Schema version 2. Existing installs add one migration:

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.