NatureWhistle.Notifier.Behaviour behaviour (nature_whistle v0.2.0)

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Behaviour for implementing custom notifiers.

A notifier is responsible for delivering an alert message to an external service.

Implementing a custom notifier

To create your own notifier, define a module that adopts this behaviour and implements deliver/3.

Example

defmodule MyApp.Notifiers.Discord do
  @behaviour NatureWhistle.Notifier.Behaviour

  @impl true
  def deliver(message, _metadata, config) do
    url = Keyword.fetch!(config, :webhook_url)
    # send HTTP request...
    {:ok, :sent}
  end
end

Then use the module name as the :notifier in your alert configuration:

%{
  id: :some_alert,
  notifier: MyApp.Notifiers.Discord,
  notifier_config: [webhook_url: "https://discord.com/..."]
}

Supported

Starting from v0.2.0, any module that implements this behaviour can be used as a notifier. The optional :notifier_config field is passed as the third argument to deliver/3.

Summary

Callbacks

deliver(message, metadata, config)

Delivers an alert message to the external service.

Callbacks

deliver(message, metadata, config)

@callback deliver(message :: String.t(), metadata :: map(), config :: keyword()) ::
  {:ok, term()} | {:error, term()}

Delivers an alert message to the external service.

Called by nature_whistle when an alert or calm message needs to be sent.

Parameters

  • message – The fully formatted message string (placeholders already replaced).
  • metadata – A map of additional telemetry metadata (may be empty).
  • config – A keyword list of configuration options for this notifier, as defined in the host’s config.exs under :notifiers for the corresponding atom name. For custom module notifiers, config will be an empty list unless extended in the future.

Return value

Must return one of:

  • {:ok, term()} – on success (the term can be anything, e.g., :sent).
  • {:error, reason} – on failure (reason should be a string or an error term).