Data Daemon

An Elixir StatsD client made for DataDog.

Quick Setup

# In your config/config.exs file
config :my_app, Sample.DataDog,
  url: "statsd+udp://localhost:8125"

# In your application code
defmodule Sample.DataDog do
  @moduledoc ~S"My DataDog reporter."
  use DataDaemon,
    otp_app: :my_app,
    extensions: [:datadog, :erlang_vm]
end

defmodule Sample.App do
  alias Sample.DataDog

  def send_metrics do
    tags = [zone: "us-east-1a"]

    DataDog.gauge("request.queue_depth", 12, tags: tags)

    DataDog.distribution("connections", 123, tags: tags)
    DataDog.histogram("request.file_size", 1034, tags: tags)

    DataDog.timing("request.duration", 34, tags: tags)

    DataDog.increment("request.count_total", tags: tags)
    DataDog.decrement("request.count_total", tags: tags)
    DataDog.count("request.count_total", 2, tags: tags)
  end
end

Installation

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

def deps do
  [
    {:data_daemon, "~> 0.3"}
  ]
end

The docs can be found at https://hexdocs.pm/data_daemon.

Extensions

DataDog

A DataDog extension is available offering the following functionality:

• distribution/3 metric.
• event/3 event sending over UDP.
• error_handler is available as option and can be used to send errors as events.

Events

Create an event for the DataDog event stream by passing a title and message to event/3.

The following options are also supported:

Example

defmodule Sample.DataDog do
  @moduledoc ~S"My DataDog reporter."
  use DataDaemon,
    otp_app: :my_app,
    extensions: [:datadog],
    error_handler: true
end

defmodule Sample.App do
  alias Sample.DataDog

  def send_events do
    tags = [zone: "us-east-1a"]

    DataDog.event("Event Title", "Event body.\nMore details", tags: tags)
  end
end

All event options are support, for more details see: []

Erlang VM

An Erlang VM extension is available logging Erlang VM stats/metrics every minute.

The reporting interval can be configured with the :rate (in millisecond) inside the :erlang_vm config.

Example: config :my_app, MyDaemon, erlang_vm: [rate: 1_000] for updates every second.

The following metrics are tracked:

• vm.process.count, the current process count.
• vm.process.limit, the current process limit.
• vm.process.queue, the current amount of processes queued for running.
• vm.port.count, the current port count.
• vm.port.limit, the current port limit.
• vm.atom.count, the current atom count.
• vm.atom.limit, the current atom limit.
• vm.error.queue, the amount of process messages queued for the error logger.
• vm.uptime, erlang uptime.
• vm.refresh, the amount of time (ms) since last stat check.
• vm.reductions, amount of reductions.
• vm.message.queue, total queued messages over all processes.
• vm.modules, current amount of loaded modules.
• vm.memory.total, total memory use in Kb.
• vm.memory.processes, total process memory chunk use in Kb.
• vm.memory.processes_used, total process memory use in Kb.
• vm.memory.system, total system memory use in Kb.
• vm.memory.atom, total atom memory chunk use in Kb.
• vm.memory.atom_used, total atom memory use in Kb.
• vm.memory.binary, total binary memory use in Kb.
• vm.memory.code, total code memory use in Kb.
• vm.memory.ets, total ets memory use in Kb.
• vm.io.in, total IO input in Kb.
• vm.io.out, total IO output in Kb.
• vm.garbage_collection.count, number of garbage collections.
• vm.garbage_collection.words, number of words garbage.

Changelog

0.3.0 (2020-01-30)

Changes:

• New socket logic for Erlang OTP 22 and up.

Bug fixes:

• Hound spec. (Dialyzer)
• DataDaemon spec. (Dialyzer)

0.2.4 (2020-01-29)

Bug fixes:

• Make hound resolve and open a new socket on some errors.

0.2.3 (2019-04-30)

Bug fixes:

• Make hound update async to prevent pool-resolver deadlock.

0.2.2 (2019-04-29)

New features:

• vm.refresh erlang vm metric that tracks time (ms) since last stat check.

Bug fixes:

• Fixes issue where the vm.uptime metric wouldn’t actually track uptime, but time since last vm check.

0.2.1 (2019-04-27)

New features:

• :minimum_ttl option to set a minimum TTL to prevent excessive refreshing. (Default: 1_000)

Optimizations:

• :erlang_vm extension runs as additional child to restart during crashes.
• Perform actual resolve in async process to prevent deadlock during excessive DNS refresh.
• DNS resolves in separate process removing use of :timer and only sending an update to workers if IP changes.

Bug fixes:

• Fixes issue where the :erlang_vm would link its process not to the DataDaemon, but the calling process.

0.2.0 (2019-04-17)

New features:

• :erlang_vm extension. Logs Erlang VM stats/metrics every minute. (Can be configured)

Optimizations:

• Make config more dynamic.
• DNS resolves in separate process removing use of :timer and only sending an update to workers if IP changes.

0.1.4 (2019-03-25)

New features:

• Allow config overwrite by passing keyword settings to the child spec or start link.

Optimizations:

• Keep using old IP in case DNS refresh fails.
• Added extra logging around DNS failures.

0.1.3 (2018-11-03)

New features:

• The :hound setting now allows you to set the pool settings.

Optimizations:

• DNS lookup only updates header on change.

Fixes:

• Functions with default arguments are now properly overwritten.

0.1.2 (2018-10-09)

New features:

• Test mode now supported as configuration.
• The :error_handler setting now allows you to set a minimum level. (Default: :info, possible: :debug, :info, :warn, and :error)
• Add :dsn_refresh config for refreshing the host name. (Default: :ttl, possible: :ttl and <integer>. (seconds))

Optimizations:

• DNS lookup only updates header on change.

Fixes:

• Functions with default arguments are now properly overwritten.

0.1.0 (2018-10-07)

New features:

• Extension system to allow for different StatsD extensions.
• Add new tag and value formats:
  • iodata now supported for tags and values.
  • {:config, app, key} now supported for tags.
• DataDog Events are now supported with event/3.
• DataDog can now be used as error handler by setting error_handler: true in module.

Optimizations:

• Plug reported optimized for detached user response and compile time optimizations.