Claudio Ortolina
65 lines
2.0 KiB
Elixir
65 lines
2.0 KiB
Elixir
defmodule MusicBrainz.API.ErrorResponse do
|
|
@moduledoc """
|
|
Structured error response for MusicBrainz API calls.
|
|
|
|
MusicBrainz uses classic HTTP status codes as the error channel. The body is a
|
|
flat JSON `{"error": "message"}` with no numeric application codes.
|
|
|
|
## Rate limiting
|
|
|
|
MusicBrainz signals rate limiting with **HTTP 503**, not 429. The service does
|
|
not use 429 at all — a 503 response with a `Retry-After` header is the rate
|
|
limit signal. `from_response/1` therefore maps 503 to `:rate_limit` (not the
|
|
generic `:server_error` classification from `MusicLibrary.HttpError`).
|
|
"""
|
|
|
|
@behaviour MusicLibrary.ErrorResponse
|
|
|
|
alias MusicLibrary.HttpError
|
|
|
|
@type t :: %__MODULE__{
|
|
status: integer() | nil,
|
|
message: String.t() | nil,
|
|
kind: HttpError.kind(),
|
|
body: term()
|
|
}
|
|
|
|
defstruct [:status, :message, :kind, :body]
|
|
|
|
@spec from_response(Req.Response.t() | map()) :: t()
|
|
def from_response(%{status: 503, body: body} = _response) do
|
|
%__MODULE__{
|
|
status: 503,
|
|
message: extract_message(body),
|
|
kind: :rate_limit,
|
|
body: body
|
|
}
|
|
end
|
|
|
|
def from_response(%{status: status, body: body} = _response) do
|
|
%__MODULE__{
|
|
status: status,
|
|
message: extract_message(body),
|
|
kind: HttpError.default_kind(status),
|
|
body: body
|
|
}
|
|
end
|
|
|
|
@impl MusicLibrary.ErrorResponse
|
|
@spec retryable?(t()) :: boolean()
|
|
def retryable?(%__MODULE__{kind: kind}) when kind in [:rate_limit, :server_error, :timeout],
|
|
do: true
|
|
|
|
def retryable?(%__MODULE__{}), do: false
|
|
|
|
@impl MusicLibrary.ErrorResponse
|
|
@spec retry_delay_seconds(t()) :: pos_integer()
|
|
def retry_delay_seconds(%__MODULE__{kind: :rate_limit}), do: 60
|
|
def retry_delay_seconds(%__MODULE__{kind: :server_error}), do: 30
|
|
def retry_delay_seconds(%__MODULE__{kind: :timeout}), do: 10
|
|
def retry_delay_seconds(%__MODULE__{}), do: 30
|
|
|
|
defp extract_message(%{"error" => message}) when is_binary(message), do: message
|
|
defp extract_message(_), do: nil
|
|
end
|