AuroraMeter.
View Source
The hot path: atomic ETS counter operations.
Increments use :ets.update_counter/3 (lock-free, concurrency-safe). A cold key
is seeded once from the last flushed database value (ensure_seeded/4) so the
in-ETS value is always absolute; after that first touch the path is pure ETS.
Every mutation marks the key dirty for the flusher.
Summary
Functions
Returns a map of feature => value for a tenant's warm counters in a period.
Removes a single key from the dirty set.
Snapshots the current set of dirty keys.
Increments a counter by qty and returns the new value.
Marks a counter key dirty so the flusher persists it.
Releases a previously reserved qty (rollback on a raised function).
Atomically reserves qty against an optional hard limit.
Returns the current value for a counter (rehydrating from the database if cold).
Types
@type key() :: {String.t(), atom(), DateTime.t()}
A counter key: {tenant_key, feature, period_start}.
Functions
@spec all_for(String.t(), DateTime.t()) :: %{required(atom()) => integer()}
Returns a map of feature => value for a tenant's warm counters in a period.
@spec clear_dirty(key()) :: :ok
Removes a single key from the dirty set.
@spec dirty_keys() :: [key()]
Snapshots the current set of dirty keys.
@spec incr(String.t(), atom(), integer(), DateTime.t()) :: integer()
Increments a counter by qty and returns the new value.
@spec mark_dirty(key()) :: :ok
Marks a counter key dirty so the flusher persists it.
@spec release(String.t(), atom(), integer(), DateTime.t()) :: :ok
Releases a previously reserved qty (rollback on a raised function).
@spec reserve(String.t(), atom(), integer(), DateTime.t(), non_neg_integer() | nil) :: :ok | {:error, :limit_exceeded}
Atomically reserves qty against an optional hard limit.
Increments first; if the new value exceeds limit it rolls the increment back
and returns {:error, :limit_exceeded}. A nil limit always succeeds.
@spec value(String.t(), atom(), DateTime.t()) :: integer()
Returns the current value for a counter (rehydrating from the database if cold).