prometheus_exometer

v0.2.0

prometheus_exometer v0.2.0 PrometheusExometer.Metrics View Source

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.

Link to this section 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

Link to this section Types

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error() View Source 
error() :: {:error, any()}

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labels() View Source 
labels() :: Keyword.t()

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name() View Source 
name() :: :exometer.name()

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value() View Source 
value() :: any()

Link to this section Functions

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combine_name_labels(name, labels) View Source 
combine_name_labels(name(), labels()) :: name()

Combine base metric name with labels.

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dec(name) View Source 
dec(name()) :: :ok

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dec(name, labels) View Source 
dec(name(), labels() | value()) :: :ok

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dec(name, labels, value) View Source 
dec(name(), labels(), value()) :: :ok

Decrement counter or gauge metric.

Returns :ok.

Examples 

iex> PrometheusExometer.Metrics.dec([:active_requests])
:ok
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ensure_child(name, labels) View Source 
ensure_child(name(), labels()) :: :ok | error()

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

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get_value(name) View Source 
get_value(name()) :: {:ok, any()} | {:error, :not_found}

Get Exometer metric value

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get_value(name, labels) View Source 
get_value(name(), labels()) :: {:ok, any()} | {:error, :not_found}

Get Exometer metric value with labels

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inc(name) View Source 
inc(name()) :: :ok

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inc(name, labels) View Source 
inc(name(), labels() | value()) :: :ok

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inc(name, labels, value) View Source 
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
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observe(name, value) View Source 
observe(name(), value()) :: :ok | error()

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observe(name, labels, value) View Source 
observe(name(), labels(), float() | integer()) :: :ok | error()

Observe current value for histogram or summary.

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observe_duration(name, start_time) View Source 
observe_duration(name(), :erlang.timestamp()) :: :ok | error()

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

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observe_duration(name, labels, start_time) View Source 
observe_duration(name(), labels(), :erlang.timestamp()) :: :ok | error()

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set(name, value) View Source 
set(name(), float()) :: :ok

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set(name, labels, value) View Source 
set(list(), labels(), float()) :: :ok

Set gauge to specified value.

Returns :ok.

Examples 

iex> PrometheusExometer.Metrics.set([:records], 1000)
:ok
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set_duration(name, start_time) View Source 
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)
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set_duration(name, labels, start_time) View Source 
set_duration(name(), labels(), :erlang.timestamp()) :: :ok

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set_to_current_time(name) View Source 
set_to_current_time(name()) :: :ok

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set_to_current_time(name, labels) View Source 
set_to_current_time(name(), labels()) :: :ok

Set metric to the current Unix time in seconds.

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tc(name, mod, fun, args) View Source 
tc(name(), module(), atom(), list()) :: any()

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

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tc(name, labels, mod, fun, args) View Source 
tc(name(), labels(), module(), atom(), list()) :: any()

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update(name, tuple_value) View Source 
update(name(), value()) :: :ok | error()

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update(name, labels, value) View Source 
update(name(), labels(), value()) :: :ok | error()

Update Exometer metric with labels