对于其他陷入这种事情的人：因为我在 :python 实例周围有一个 GenServer，所以我刚刚利用了 handle_info：
def handle_info({:python, message}, session) do
message |> String.split("\n", trim: true)
SomeWeb.Endpoint.broadcast("log", "update", %{body: message})
{:stop, :normal, session}
end
详情
为了按照@7stud 的建议更全面地概述我的解决方案，我将包括基于erlport 和this great post 的更广泛的方法。因此，我有一个看起来像这样的Python 模块：
defmodule App.Python do
@doc """
Python instance pointing to priv/python.
"""
def start() do
path = [
:code.priv_dir(:prefect),
"python"
]|> Path.join()
{:ok, pid} = :python.start([
{:python_path, to_charlist(path)}
])
pid
end
def call(pid, module, function, args \\ []) do
:python.call(pid, module, function, args)
end
def cast(pid, message) do
:python.cast(pid, message)
end
def stop(pid) do
:python.stop(pid)
end
end
它是从处理其生成和终止的 GenServer 调用的：
defmodule App.PythonServer do
@doc """
Receives async. messages from Python instance.
"""
use GenServer
alias App.Python
def start_link() do
GenServer.start_link(__MODULE__, [])
end
def init(_args) do
pid = Python.start()
Python.call(pid, :bridge, :register_handler, [self()])
App.Application.broadcast_change
{:ok, pid}
end
def cast_draw(id) do
{:ok, pid} = start_link()
GenServer.cast(pid, {:id, id})
end
def call_draw(id) do
{:ok, pid} = start_link()
GenServer.call(pid, {:id, id}, 10_000)
end
def handle_call({:id, id}, _from, session) do
result = Python.call(session, :bridge, :draw, [id])
{:reply, result, session}
end
def handle_cast({:id, id}, session) do
Python.cast(session, id)
{:noreply, session}
end
def handle_info({:python, message}, session) do
msg = message |> format_response
{:ok, time} = Timex.now |> Timex.format("{h12}:{m}{am} {D}/{M}/{YYYY}")
AppWeb.Endpoint.broadcast("log", "update", %{time: time, body: msg, process: message})
{:stop, :normal, session}
end
def terminate(_reason, session) do
Python.stop(session)
App.Application.broadcast_change
:ok
end
defp format_response(message) do
if String.contains? message, "[result] Sent" do
message |> String.split("\n", trim: true) |> Enum.at(-2)
else
message |> String.split("\n", trim: true) |> Enum.take(-12) |> Enum.join("\n")
end
end
end
如果 STDOUT 没有从bridge.py（或任何其他 Python 模块）返回某个字符串，你可以在最后看到它会返回一个堆栈跟踪。说起来，bridge.py 看起来像这样：
import os
import sys
import subprocess
from erlport.erlang import set_message_handler, cast
from erlport.erlterms import Atom
message_handler = None # reference to the elixir process to send
cmd = "xvfb-run -a python"
py = os.path.join("/home/ubuntu/app/priv/python/export.py")
def cast_message(pid, message):
cast(pid, message)
def register_handler(pid):
global message_handler
message_handler = pid
def handle_message(id):
try:
result = draw(id)
print result
if message_handler:
cast_message(message_handler, (Atom('python'), result))
except Exception, error:
print error
if message_handler:
cast_message(message_handler, (Atom('python'), error))
pass
def draw(id):
proc = subprocess.check_output(
"{0} {1} {2}".format(cmd, py, id), stderr = subprocess.STDOUT, shell = True
)
return proc
set_message_handler(handle_message)