View Source PrometheusExometer.Metrics (prometheus_exometer v0.3.1)

Interface functions to update Exometer metrics with labels.

The underlying Exometer API to set values is simple. It doesn't change depending on the type of the metric, you can call the update/3 function for everything. This function is a simple wrapper which calls combine_name_labels/2 on its arguments, then calls :exometer.update_or_create/2. Calling e.g. inc/3 if you are incrementing a counter makes the intent clearer, though.

There are convenience functions to help with duration calculations as well.

This interface largely implements the recommended public API for Prometheus client libraries

Differences with the Prometheus API recommendations:

Erlang handles times in microseconds internally, so that's what we store, and that's the default output unit instead of seconds.

Summary

Types

error()

labels()

name()

value()

Functions

combine_name_labels(name, labels)

Combine base metric name with labels.

dec(name)

dec(name, labels)

dec(name, labels, value)

Decrement counter or gauge metric.

ensure_child(name, labels)

Ensure that a metric exists with the specified keyword under the parent metric

get_value(name)

Get Exometer metric value

get_value(name, labels)

Get Exometer metric value with labels

inc(name)

inc(name, labels)

inc(name, labels, value)

Increment counter or gauge metric.

observe(name, value)

observe(name, labels, value)

Observe current value for histogram or summary.

observe_duration(name, start_time)

Observe time difference in ms between starting time and current time.

observe_duration(name, labels, start_time)

set(name, value)

set(name, labels, value)

Set gauge to specified value.

set_duration(name, start_time)

Set metric to the difference between the specified timestamp and the current time in ms.

set_duration(name, labels, start_time)

set_to_current_time(name)

set_to_current_time(name, labels)

Set metric to the current Unix time in seconds.

tc(name, mod, fun, args)

Record duration in ms of a function call, like Erlang :timer.tc/3

tc(name, labels, mod, fun, args)

update(name, tuple_value)

update(name, labels, value)

Update Exometer metric with labels

Types

error()

@type error() :: {:error, any()}

labels()

@type labels() :: Keyword.t()

name()

@type name() :: :exometer.name()

value()

@type value() :: any()

Functions

combine_name_labels(name, labels)

@spec combine_name_labels(name(), labels()) :: name()

Combine base metric name with labels.

dec(name)

@spec dec(name()) :: :ok

dec(name, labels)

@spec dec(name(), labels() | value()) :: :ok

dec(name, labels, value)

@spec dec(name(), labels(), value()) :: :ok

Decrement counter or gauge metric.

Returns :ok.

Examples

iex> PrometheusExometer.Metrics.dec([:active_requests])
:ok

ensure_child(name, labels)

@spec ensure_child(name(), labels()) :: :ok | error()

Ensure that a metric exists with the specified keyword under the parent metric

get_value(name)

@spec get_value(name()) :: {:ok, any()} | {:error, :not_found}

Get Exometer metric value

get_value(name, labels)

@spec get_value(name(), labels()) :: {:ok, any()} | {:error, :not_found}

Get Exometer metric value with labels

inc(name)

@spec inc(name()) :: :ok

inc(name, labels)

@spec inc(name(), labels() | value()) :: :ok

inc(name, labels, value)

@spec inc(name(), labels(), value()) :: :ok

Increment counter or gauge metric.

Returns :ok.

Examples

Increment simple requests metric by one:

iex> PrometheusExometer.Metrics.inc([:requests])
:ok

observe(name, value)

@spec observe(name(), value()) :: :ok | error()

observe(name, labels, value)

@spec observe(name(), labels(), number()) :: :ok | error()

Observe current value for histogram or summary.

observe_duration(name, start_time)

@spec observe_duration(name(), :erlang.timestamp()) :: :ok | error()

Observe time difference in ms between starting time and current time.

observe_duration(name, labels, start_time)

@spec observe_duration(name(), labels(), :erlang.timestamp()) :: :ok | error()

set(name, value)

@spec set(name(), float()) :: :ok

set(name, labels, value)

@spec set(list(), labels(), float()) :: :ok

Set gauge to specified value.

Returns :ok.

Examples

iex> PrometheusExometer.Metrics.set([:records], 1000)
:ok

set_duration(name, start_time)

@spec set_duration(name(), :erlang.timestamp()) :: :ok

Set metric to the difference between the specified timestamp and the current time in ms.

Returns :ok.

Examples

start_time = :os.timestamp()
do_some_work()
PrometheusExometer.Metrics.set_duration([:duration], start_time)

set_duration(name, labels, start_time)

@spec set_duration(name(), labels(), :erlang.timestamp()) :: :ok

set_to_current_time(name)

@spec set_to_current_time(name()) :: :ok

set_to_current_time(name, labels)

@spec set_to_current_time(name(), labels()) :: :ok

Set metric to the current Unix time in seconds.

tc(name, mod, fun, args)

@spec tc(name(), module(), atom(), list()) :: any()

Record duration in ms of a function call, like Erlang :timer.tc/3

tc(name, labels, mod, fun, args)

@spec tc(name(), labels(), module(), atom(), list()) :: any()

update(name, tuple_value)

@spec update(name(), value()) :: :ok | error()

update(name, labels, value)

@spec update(name(), labels(), value()) :: :ok | error()

Update Exometer metric with labels