Ogle

Telemetry.Metrics reporter for Prometheus and StatsD (including Datadog).

Ogle has some important differences from libraries like TelemetryMetricsPrometheus.Core and TelemetryMetricsStatsd:

• Instead of sampling or on-demand aggregation of samples, Ogle estimates distributions using histograms.
• Instead of sending one datagram per telemetry event, Ogle's StatsD reporting runs periodically, batching all lines into the smallest number of datagram packets possible while still obeying the configured :mtu setting.

To use it, start a reporter with start_link/1, providing a keyword list of options (see Ogle.Options for the schema against which options are validated).

import Telemetry.Metrics

Ogle.start_link(
  name: MyOgle,
  metrics: [
    counter("http.request.count"),
    sum("http.request.payload_size"),
    last_value("vm.memory.total")
  ]
)

or put it under a supervisor:

import Telemetry.Metrics

children = [
  {Ogle, [
    name: MyOgle,
    metrics: [
      counter("http.request.count"),
      sum("http.request.payload_size"),
      last_value("vm.memory.total")
    ]
  ]}
]

Supervisor.start_link(children, ...)

By default, Ogle does not emit StatsD data. It can be enabled by passing in configuration with the statsd keyword. Ogle's StatsD reporting supports Unix Domain Sockets.

What's Missing

Currently, there's no implementation of 'summary' metrics. Since histograms are relatively inexpensive in Ogle, we suggest you use 'distribution' metrics instead.

Installation

Ogle package can be installed by adding ogle to your list of dependencies in mix.exs:

def deps do
  [
    {:ogle, "~> 3.3"}
  ]
end

Documentation can be generated with ExDoc and published on HexDocs. Once published, the docs can be found at https://hexdocs.pm/ogle.