Behaviour for pipeline stages.

Stages transform samples as they flow through a pipeline. Each stage processes one sample at a time and can:

• Transform the sample data
• Filter out samples (skip)
• Change the sample status
• Add metadata or measurements
• Fail with an error

Return Values

• {:ok, sample} - Continue with the transformed sample
• {:skip, reason} - Remove this sample from the pipeline
• {:error, reason} - Stage failed, error handling depends on runner config

Examples

defmodule NormalizeStage do
  @behaviour Forge.Stage

  def process(sample) do
    normalized = sample.data.value / 100.0
    data = Map.put(sample.data, :normalized, normalized)
    {:ok, %{sample | data: data}}
  end
end

defmodule FilterStage do
  @behaviour Forge.Stage

  def process(sample) do
    if sample.data.value > 0 do
      {:ok, sample}
    else
      {:skip, :negative_value}
    end
  end
end