defmodule Kraken.Define.Decomposer do
alias Kraken.Utils
def define(definition, decomposer_module, pipeline_helpers \\ []) do
prepare = Map.get(definition, "prepare", false)
service_name = get_in(definition, ["service", "name"]) || raise "Missing service name!"
service_function =
get_in(definition, ["service", "function"]) || raise "Missing service function!"
get_in(definition, ["decompose", "events"]) || get_in(definition, ["decompose", "events"]) ||
raise "Missing decompose events or event!"
decompose = Map.get(definition, "decompose")
helpers = Utils.helper_modules(definition) ++ pipeline_helpers
template()
|> EEx.eval_string(
decomposer_module: decomposer_module,
service_name: service_name,
service_function: service_function,
prepare: prepare,
decompose: decompose,
helpers: helpers
)
|> Utils.eval_code()
|> case do
{:ok, _code} ->
{:ok, decomposer_module}
end
end
defp template() do
"""
defmodule <%= decomposer_module %> do
@prepare "<%= Base.encode64(:erlang.term_to_binary(prepare)) %>"
|> Base.decode64!()
|> :erlang.binary_to_term()
@decompose "<%= Base.encode64(:erlang.term_to_binary(decompose)) %>"
|> Base.decode64!()
|> :erlang.binary_to_term()
@helpers "<%= Base.encode64(:erlang.term_to_binary(helpers)) %>"
|> Base.decode64!()
|> :erlang.binary_to_term()
def call(event, _opts) when is_map(event) do
%Kraken.Define.Decomposer.Call{
event: event,
service_name: "<%= service_name %>",
service_function: "<%= service_function %>",
prepare: @prepare,
decompose: @decompose,
helpers: @helpers
}
|> Kraken.Define.Decomposer.Call.call()
end
def call(_event, _opts) do
raise "Event must be a map"
end
end
"""
end
defmodule Call do
@moduledoc false
defstruct event: nil,
service_name: nil,
service_function: nil,
prepare: false,
decompose: false,
helpers: []
alias Octopus.Transform
@spec call(%__MODULE__{}) :: {:ok, map()} | {:error, any()}
def call(%__MODULE__{
event: event,
service_name: service_name,
service_function: service_function,
prepare: prepare,
decompose: decompose,
helpers: helpers
}) do
with {:ok, args} <-
Transform.transform(event, prepare, helpers),
{:ok, args} <-
Octopus.call(service_name, service_function, args),
{:ok, args} <-
Transform.transform(args, decompose, helpers) do
event = Map.get(args, "event")
events = Map.get(args, "events")
cond do
events && event ->
{events, event}
events ->
events
true ->
raise "Events or events with event must be present!"
end
else
{:error, error} -> {:error, error}
end
end
end
end