Instruments.Probe behaviour (Instruments v2.4.0)
A behavior for a Probe.
Modules that define probes are expected to implement all of the functions in this behaviour.
A probe is created via the call to Instruments.Probe.probe_init/3, and is
then called every sample_interval milliseconds via the
Instruments.Probe.probe_sample/1 function. The probe can then update its
internal state and do any processing it requires.
Every report_interval milliseconds, the probe is expected to emit its metric
value.
Link to this section Summary
Callbacks
Called at least every report_interval milliseconds. This call reads the
value of the probe, which is reported to the underlying statistics system.
Called when the probe's runner process receives an unknown message.
Called when the probe is created. The callback is passed the name of the probe, what kind of metric it's producing and the options the probe was created with.
Resets the probe's state.
Called every sample_interval milliseconds. When called, the probe should
perform its measurement and update its internal state.
Link to this section Types
datapoint()
@type datapoint() :: String.t()
probe_options()
@type probe_options() :: [ sample_rate: pos_integer(), tags: [String.t(), ...], report_interval: pos_integer(), sample_interval: pos_integer(), function: (-> {:ok, state()}), mfa: {module(), atom(), [term()]}, module: module(), keys: [atom()] ]
probe_type()
@type probe_type() :: :counter | :spiral | :gauge | :histogram | :timing | :set
probe_value()
state()
@type state() :: any()
Link to this section Callbacks
probe_get_value(state)
@callback probe_get_value(state()) :: {:ok, probe_value()}
Called at least every report_interval milliseconds. This call reads the
value of the probe, which is reported to the underlying statistics system.
Return values can either take the form of a single numeric value, or a keyword list keys -> numeric values. Nil values won't be reported to the statistics system.
probe_handle_message(any, state)
Called when the probe's runner process receives an unknown message.
You must return {:ok, state}. Any other return values will cancel further
execution of the probe.
probe_init(t, probe_type, probe_options)
@callback probe_init(String.t(), probe_type(), probe_options()) :: {:ok, state()}
Called when the probe is created. The callback is passed the name of the probe, what kind of metric it's producing and the options the probe was created with.
You must return {:ok, state}. The state will be passed back to you on
subsequent callbacks. Any other return values will cancel further
execution of the probe.
probe_reset(state)
Resets the probe's state.
You must return {:ok, state}. Any other return values will cancel further
execution of the probe.
probe_sample(state)
Called every sample_interval milliseconds. When called, the probe should
perform its measurement and update its internal state.
You must return {:ok, state}. Any other return values will cancel further
execution of the probe.
Link to this section Functions
define!(name, type, options)
See Instruments.Probe.Definitions.define!/3.
define(name, type, options)
See Instruments.Probe.Definitions.define/3.