Instruments.RateTracker (Instruments v2.12.0)

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RateTracker will track how often you are reporting metrics that are not backed by a "fast" implementation.

RateTracker is designed to catch cases where you have inadvertently reported a metric "too" frequently, as some metrics require hitting statsd directly for every reported value. Doing so in hot loops can result in your application slowing significantly.

Summary

Types

callback()
t()

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

dump_rates()

Dump the currently tracked rates

init(atom)

Callback implementation for GenServer.init/1.

start_link(_ \\ [])
subscribe(callback)

Add a callback to be notified that you are reporting a metric "too" frequently.

Types

callback()

@type callback() :: ({String.t(), Statix.options()}, non_neg_integer() -> term())

t()

@type t() :: %Instruments.RateTracker{
  callbacks: [callback()],
  last_update_time: integer(),
  table_count: non_neg_integer()
}

Functions

child_spec(init_arg)

Returns a specification to start this module under a supervisor.

See Supervisor.

dump_rates()

@spec dump_rates() :: [{{String.t(), Keyword.t()}, non_neg_integer()}]

Dump the currently tracked rates

init(atom)

Callback implementation for GenServer.init/1.

start_link(_ \\ [])

subscribe(callback)

@spec subscribe(callback()) :: :ok

Add a callback to be notified that you are reporting a metric "too" frequently.

In order to receive notifications, you must set :instruments -> :rate_tracker_callback_threshold to the per-second rate that you want to be notified at. This value will be different for every system, and will require experimentation to determine. You can use dump_rates() in a remote console to see what values are currently tracked for your metrics.

This callback should be short-lived.