commit 6dd22610ea3a6f7e86d9c0d45a5b1d56c5203c6b · comet.sh/drinkup

+58

lib/consumer.ex

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       defmodule Drinkup.Consumer do

     

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         @moduledoc """

     

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         An unopinionated consumer of the Firehose. Will receive all events, not just commits.

     

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         """

     

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         alias Drinkup.{ConsumerGroup, Event}

     

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         @callback handle_event(Event.t()) :: any()

     

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         defmacro __using__(_opts) do

     

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           quote location: :keep do

     

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             use GenServer

     

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             require Logger

     

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             @behaviour Drinkup.Consumer

     

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             def child_spec(opts) do

     

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               %{

     

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                 id: __MODULE__,

     

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                 start: {__MODULE__, :start_link, [opts]},

     

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                 type: :worker,

     

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                 restart: :permanent,

     

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                 max_restarts: 0,

     

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                 shutdown: 500

     

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               }

     

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             end

     

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             def start_link(opts) do

     

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               GenServer.start_link(__MODULE__, [], opts)

     

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             end

     

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             @impl GenServer

     

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             def init(_) do

     

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               ConsumerGroup.join()

     

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               {:ok, nil}

     

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             end

     

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             @impl GenServer

     

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             def handle_info({:event, event}, state) do

     

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               {:ok, _pid} =

     

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                 Task.start(fn ->

     

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                   try do

     

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                     __MODULE__.handle_event(event)

     

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                   rescue

     

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                     e ->

     

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                       Logger.error(

     

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                         "Error in event handler: #{Exception.format(:error, e, __STACKTRACE__)}"

     

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                       )

     

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                   end

     

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                 end)

     

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               {:noreply, state}

     

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             end

     

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             defoverridable GenServer

     

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           end

     

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         end

     

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       end

+39

lib/consumer_group.ex

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       defmodule Drinkup.ConsumerGroup do

     

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         @moduledoc """

     

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         Register consumers and dispatch events to them.

     

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         """

     

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         alias Drinkup.Event

     

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         @scope __MODULE__

     

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         @group :consumers

     

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         def start_link(_) do

     

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           :pg.start_link(@scope)

     

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         end

     

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         def child_spec(opts) do

     

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           %{

     

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             id: __MODULE__,

     

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             start: {__MODULE__, :start_link, [opts]},

     

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             type: :worker,

     

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             restart: :permanent,

     

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             shutdown: 500

     

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           }

     

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         end

     

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         @spec join() :: :ok

     

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         def join(), do: join(self())

     

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         @spec join(pid()) :: :ok

     

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         def join(pid), do: :pg.join(@scope, @group, pid)

     

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         @spec dispatch(Event.t()) :: :ok

     

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         def dispatch(event) do

     

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           @scope

     

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           |> :pg.get_members(@group)

     

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           |> Enum.each(&send(&1, {:event, event}))

     

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         end

     

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         # TODO: read `:pg` docs on what `monitor` is used fo

     

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       end

+14

lib/drinkup.ex

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       defmodule Drinkup do

     

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         use Supervisor

     

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         def start_link(arg \\ []) do

     

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           Supervisor.start_link(__MODULE__, arg, name: __MODULE__)

     

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         end

     

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         def init(_) do

     

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           children = [

     

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             Drinkup.ConsumerGroup,

     

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             Drinkup.Socket

     

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           ]

     

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           Supervisor.init(children, strategy: :one_for_one)

     

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         end

     

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       end

+4 -2

lib/event.ex

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       defmodule Drinkup.Event do

     

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         alias Drinkup.Event

     

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         @spec from(String.t(), map()) ::

     

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         @type t() ::

     

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                 Event.Commit.t()

     

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                 | Event.Sync.t()

     

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                 | Event.Identity.t()

     

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                 | Event.Account.t()

     

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                 | Event.Info.t()

     

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                 | nil

     

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         @spec from(String.t(), map()) :: t() | nil

     

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         def from("#commit", payload), do: Event.Commit.from(payload)

     

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         def from("#sync", payload), do: Event.Sync.from(payload)

     

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         def from("#identity", payload), do: Event.Identity.from(payload)

     
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         @spec valid_seq?(integer() | nil, any()) :: boolean()

     

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         def valid_seq?(nil, seq) when is_integer(seq), do: true

     

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         def valid_seq?(last_seq, nil) when is_integer(last_seq), do: true

     

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         def valid_seq?(last_seq, seq) when is_integer(last_seq) and is_integer(seq), do: seq > last_seq

     

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         def valid_seq?(_last_seq, _seq), do: false

     

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       end

+20 -11

lib/socket.ex

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         """

     

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         require Logger

     

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         alias Drinkup.Event

     

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         alias Drinkup.{ConsumerGroup, Event}

     

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         @behaviour :gen_statem

     

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         @default_host "https://bsky.network"

     
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         @impl true

     

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         def callback_mode, do: [:state_functions, :state_enter]

     

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         def start_link(opts \\ []) do

     

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         def child_spec(opts) do

     

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           %{

     

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             id: __MODULE__,

     

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             start: {__MODULE__, :start_link, [opts, []]},

     

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             type: :worker,

     

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             restart: :permanent,

     

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             shutdown: 500

     

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           }

     

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         end

     

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         def start_link(opts \\ [], statem_opts) do

     

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           opts = Keyword.validate!(opts, host: @default_host)

     

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           host = Keyword.get(opts, :host)

     

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           cursor = Keyword.get(opts, :cursor)

     

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           :gen_statem.start_link(__MODULE__, {host, cursor}, [])

     

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           :gen_statem.start_link(__MODULE__, {host, cursor}, statem_opts)

     

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         end

     

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         @impl true

     
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           with {:ok, header, next} <- CAR.DagCbor.decode(frame),

     

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                {:ok, payload, _} <- CAR.DagCbor.decode(next),

     

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                {%{"op" => @op_regular, "t" => type}, _} <- {header, payload},

     

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                true <- type == "#info" || Event.valid_seq?(data.seq, payload["seq"]),

     

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                data <- %{data | seq: payload["seq"] || data.seq},

     

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                message <-

     

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                  Event.from(type, payload) do

     

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                true <- Event.valid_seq?(data.seq, payload["seq"]) do

     

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             data = %{data | seq: payload["seq"] || data.seq}

     

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             message = Event.from(type, payload)

     

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             :ok = :gun.update_flow(conn, stream, @flow)

     

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             case message do

     

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               %Event.Commit{} = commit ->

     

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                 IO.inspect(commit.ops, label: commit.repo)

     

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               nil ->

     

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                 Logger.warning("Received unrecognised event from firehose: #{inspect({type, payload})}")

     

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               msg ->

     

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                 IO.inspect(msg)

     

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               message ->

     

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                 ConsumerGroup.dispatch(message)

     

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             end

     

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             {:keep_state, data}