82 lines
1.9 KiB
Elixir
82 lines
1.9 KiB
Elixir
defmodule OpentelemetryFinch do
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@moduledoc """
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OpentelemetryFinch uses [telemetry](https://hexdocs.pm/telemetry/) handlers to
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create `OpenTelemetry` spans.
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## Usage
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In your application start:
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def start(_type, _args) do
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OpentelemetryFinch.setup()
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# ...
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end
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"""
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require OpenTelemetry.Tracer
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@typedoc "Setup options"
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@type opts :: []
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@doc """
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Initializes and configures the telemetry handlers.
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"""
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@spec setup(opts()) :: :ok
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def setup(_opts \\ []) do
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:telemetry.attach(
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{__MODULE__, :request_stop},
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[:finch, :request, :stop],
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&__MODULE__.handle_request_stop/4,
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%{}
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)
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end
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@doc false
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def handle_request_stop(_event, measurements, meta, _config) do
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duration = measurements.duration
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end_time = :opentelemetry.timestamp()
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start_time = end_time - duration
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status =
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case meta.result do
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{:ok, response} -> response.status
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_ -> 0
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end
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url = build_url(meta.request.scheme, meta.request.host, meta.request.port, meta.request.path)
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attributes = %{
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"http.url": url,
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"http.scheme": meta.request.scheme,
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"net.peer.name": meta.request.host,
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"net.peer.port": meta.request.port,
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"http.target": meta.request.path,
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"http.method": meta.request.method,
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"http.status_code": status
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}
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s =
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OpenTelemetry.Tracer.start_span("HTTP #{meta.request.method}", %{
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start_time: start_time,
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attributes: attributes,
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kind: :client
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})
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if meta.result |> elem(0) == :error do
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OpenTelemetry.Span.set_status(
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s,
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OpenTelemetry.status(:error, format_error(meta.result |> elem(1)))
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)
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end
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OpenTelemetry.Span.end_span(s)
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end
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defp build_url(scheme, host, port, path), do: "#{scheme}://#{host}:#{port}#{path}"
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defp format_error(%{__exception__: true} = exception), do: Exception.message(exception)
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defp format_error(reason), do: inspect(reason)
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end
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