mirror of
https://github.com/fly-apps/live_beats.git
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96 lines
2.8 KiB
Elixir
96 lines
2.8 KiB
Elixir
defmodule LiveBeats do
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@moduledoc """
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The main interface for shared functionality.
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"""
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require Logger
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@doc """
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Looks up `Application` config or raises if keyspace is not configured.
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## Examples
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config :live_beats, :files, [
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uploads_dir: Path.expand("../priv/uploads", __DIR__),
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host: [scheme: "http", host: "localhost", port: 4000],
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]
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iex> LiveBeats.config([:files, :uploads_dir])
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iex> LiveBeats.config([:files, :host, :port])
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"""
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def config([main_key | rest] = keyspace) when is_list(keyspace) do
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main = Application.fetch_env!(:live_beats, main_key)
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Enum.reduce(rest, main, fn next_key, current ->
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case Keyword.fetch(current, next_key) do
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{:ok, val} -> val
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:error -> raise ArgumentError, "no config found under #{inspect(keyspace)}"
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end
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end)
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end
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@doc """
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Attaches a modules to another for listening of events.
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Events are executed in the caller's process. Accepts
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the `:to` option which a tuple of the form: {ContextModule, StructModule}
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You attached to conctext modules on a struct-by-struct basis for granular
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events. The struct module passed must implement a valid struct or an error
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is raised.
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Events that executed are sent to a `handle_execute/2`, callback, which the
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source module and executed event as arguments.
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## Examples
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defmodule MyModule do
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def handle_execute({Accounts, %Accounts.Events.UpdateUpdated{user: user}}) do
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IO.inspect({:user_updated, user})
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end
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end
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iex> LiveBeats.attach(MyModule, to: {Accounts, Accounts.Events.UserUpdated})
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:ok
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iex> LiveBeats.execute(Accounts, %Accounts.Events.UserUpdated{user: new_user})
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"""
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def attach(target_mod, opts) when is_atom(target_mod) do
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{src_mod, struct_mod} = Keyword.fetch!(opts, :to)
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_ = struct_mod.__struct__
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:ok =
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:telemetry.attach(target_mod, [src_mod, struct_mod], &__MODULE__.handle_execute/4, %{
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target: target_mod
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})
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end
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@doc """
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Executes an event from the context module with an event struct.
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Events are exected *in the caller's process*, for every attached listener.
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## Examples
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iex> LiveBeats.attach(MyModule, to: {Accounts, Accounts.Events.UserUpdated})
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:ok
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iex> LiveBeats.execute(Accounts, %Accounts.Events.UserUpdated{user: new_user})
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"""
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def execute(src_mod, event_struct) when is_struct(event_struct) do
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:telemetry.execute([src_mod, event_struct.__struct__], event_struct, %{})
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end
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@doc false
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def handle_execute([src_mod, event_mod], %event_mod{} = event_struct, _meta, %{target: target}) do
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try do
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target.handle_execute({src_mod, event_struct})
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catch
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kind, err ->
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Logger.error("""
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executing {#{inspect(src_mod)}, #{inspect(event_mod)}} failed with #{inspect(kind)}
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#{inspect(err)}
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""")
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end
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end
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end
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