129 lines
3.0 KiB
Elixir
129 lines
3.0 KiB
Elixir
defmodule Phoenix.PubSub.PG2 do
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@moduledoc """
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Phoenix PubSub adapter based on `:pg`/`:pg2`.
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It runs on Distributed Erlang and is the default adapter.
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"""
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@behaviour Phoenix.PubSub.Adapter
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use Supervisor
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## Adapter callbacks
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@impl true
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def node_name(_), do: node()
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@impl true
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def broadcast(adapter_name, topic, message, dispatcher) do
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case pg_members(group(adapter_name)) do
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{:error, {:no_such_group, _}} ->
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{:error, :no_such_group}
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pids ->
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message = forward_to_local(topic, message, dispatcher)
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for pid <- pids, node(pid) != node() do
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send(pid, message)
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end
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:ok
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end
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end
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@impl true
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def direct_broadcast(adapter_name, node_name, topic, message, dispatcher) do
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send({group(adapter_name), node_name}, {:forward_to_local, topic, message, dispatcher})
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:ok
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end
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defp forward_to_local(topic, message, dispatcher) do
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{:forward_to_local, topic, message, dispatcher}
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end
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defp group(adapter_name) do
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groups = :persistent_term.get(adapter_name)
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elem(groups, :erlang.phash2(self(), tuple_size(groups)))
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end
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if Code.ensure_loaded?(:pg) do
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defp pg_members(group) do
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:pg.get_members(Phoenix.PubSub, group)
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end
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else
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defp pg_members(group) do
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:pg2.get_members({:phx, group})
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end
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end
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## Supervisor callbacks
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@doc false
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def start_link(opts) do
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name = Keyword.fetch!(opts, :name)
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pool_size = Keyword.get(opts, :pool_size, 1)
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adapter_name = Keyword.fetch!(opts, :adapter_name)
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Supervisor.start_link(__MODULE__, {name, adapter_name, pool_size}, name: :"#{adapter_name}_supervisor")
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end
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@impl true
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def init({name, adapter_name, pool_size}) do
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[_ | groups] =
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for number <- 1..pool_size do
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:"#{adapter_name}_#{number}"
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end
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# Use `adapter_name` for the first in the pool for backwards compatability
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# with v2.0 when the pool_size is 1.
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groups = [adapter_name | groups]
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:persistent_term.put(adapter_name, List.to_tuple(groups))
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children =
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for group <- groups do
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Supervisor.child_spec({Phoenix.PubSub.PG2Worker, {name, group}}, id: group)
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end
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Supervisor.init(children, strategy: :one_for_one)
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end
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end
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defmodule Phoenix.PubSub.PG2Worker do
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@moduledoc false
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use GenServer
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@doc false
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def start_link({name, group}) do
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GenServer.start_link(__MODULE__, {name, group}, name: group)
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end
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@impl true
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def init({name, group}) do
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:ok = pg_join(group)
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{:ok, name}
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end
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@impl true
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def handle_info({:forward_to_local, topic, message, dispatcher}, pubsub) do
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Phoenix.PubSub.local_broadcast(pubsub, topic, message, dispatcher)
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{:noreply, pubsub}
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end
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@impl true
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def handle_info(_, pubsub) do
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{:noreply, pubsub}
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end
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if Code.ensure_loaded?(:pg) do
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defp pg_join(group) do
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:ok = :pg.join(Phoenix.PubSub, group, self())
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end
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else
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defp pg_join(group) do
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namespace = {:phx, group}
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:ok = :pg2.create(namespace)
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:ok = :pg2.join(namespace, self())
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:ok
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end
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end
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end
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