Python Slack App无法监听响应消息事件问题排查

问题背景 #

• 参照Slack官方Python SDK教程开发Slack应用，推进至教程第4步中途时，应用无法对Slack工作区内发送的任何消息做出响应
• 已严格按照教程要求完成应用权限配置，所有权限配置与教程指引完全一致
• 本地启动应用时命令行提示Bolt app is running! (development server)，确认服务已在3000端口正常启动

应用完整代码 #

import logging
from slack_bolt import App
from slack_sdk.web import WebClient
from onboarding_tutorial import OnboardingTutorial

app = App(token="first secret token here", signing_secret="second secret token here")
onboarding_tutorials_sent = {}


def start_onboarding(user_id: str, channel: str, client: WebClient):
    # Create a new onboarding tutorial.
    onboarding_tutorial = OnboardingTutorial(channel)

    # Get the onboarding message payload
    message = onboarding_tutorial.get_message_payload()

    # Post the onboarding message in Slack
    response = client.chat_postMessage(**message)

    # Capture the timestamp of the message we've just posted so
    # we can use it to update the message after a user
    # has completed an onboarding task.
    onboarding_tutorial.timestamp = response["ts"]

    # Store the message sent in onboarding_tutorials_sent
    if channel not in onboarding_tutorials_sent:
        onboarding_tutorials_sent[channel] = {}
    onboarding_tutorials_sent[channel][user_id] = onboarding_tutorial


# ================ Team Join Event =============== #
# When the user first joins a team, the type of the event will be 'team_join'.
# Here we'll link the onboarding_message callback to the 'team_join' event.

# Note: Bolt provides a WebClient instance as an argument to the listener function
# we've defined here, which we then use to access Slack Web API methods like conversations_open.
# For more info, checkout: https://slack.dev/bolt-python/concepts#message-listening


@app.event("team_join")
def onboarding_message(event, client):
    """Create and send an onboarding welcome message to new users. Save the
    time stamp of this message so we can update this message in the future.
    """
    # Get the id of the Slack user associated with the incoming event
    user_id = event.get("user", {}).get("id")

    # Open a DM with the new user.
    response = client.conversations_open(users=user_id)
    channel = response["channel"]["id"]

    # Post the onboarding message.
    start_onboarding(user_id, channel, client)


# ============= Reaction Added Events ============= #
# When a users adds an emoji reaction to the onboarding message,
# the type of the event will be 'reaction_added'.
# Here we'll link the update_emoji callback to the 'reaction_added' event.


@app.event("reaction_added")
def update_emoji(event, client):
    """Update the onboarding welcome message after receiving a "reaction_added"
    event from Slack. Update timestamp for welcome message as well.
    """
    # Get the ids of the Slack user and channel associated with the incoming event
    channel_id = event.get("item", {}).get("channel")
    user_id = event.get("user")

    if channel_id not in onboarding_tutorials_sent:
        return

    # Get the original tutorial sent.
    onboarding_tutorial = onboarding_tutorials_sent[channel_id][user_id]

    # Mark the reaction task as completed.
    onboarding_tutorial.reaction_task_completed = True

    # Get the new message payload
    message = onboarding_tutorial.get_message_payload()

    # Post the updated message in Slack
    updated_message = client.chat_update(**message)


# =============== Pin Added Events ================ #
# When a users pins a message the type of the event will be 'pin_added'.
# Here we'll link the update_pin callback to the 'pin_added' event.


@app.event("pin_added")
def update_pin(event, client):
    """Update the onboarding welcome message after receiving a "pin_added"
    event from Slack. Update timestamp for welcome message as well.
    """
    # Get the ids of the Slack user and channel associated with the incoming event
    channel_id = event.get("channel_id")
    user_id = event.get("user")

    # Get the original tutorial sent.
    onboarding_tutorial = onboarding_tutorials_sent[channel_id][user_id]

    # Mark the pin task as completed.
    onboarding_tutorial.pin_task_completed = True

    # Get the new message payload
    message = onboarding_tutorial.get_message_payload()

    # Post the updated message in Slack
    updated_message = client.chat_update(**message)


# ============== Message Events ============= #
# When a user sends a DM, the event type will be 'message'.
# Here we'll link the message callback to the 'message' event.


@app.event("message")
def message(event, client):
    """Display the onboarding welcome message after receiving any message
    """
    channel_id = event.get("channel")
    user_id = event.get("user")
    text = event.get("text")

    return start_onboarding(user_id, channel_id, client)


if __name__ == "__main__":
    logger = logging.getLogger()
    logger.setLevel(logging.DEBUG)
    logger.addHandler(logging.StreamHandler())
    app.start(3000)

命令行运行记录 #

Microsoft Windows [Version 10.0.19041.388]
(c) 2020 Microsoft Corporation. All rights reserved.

C:\Users\sprogissd>cd pycharmprojects/pythonproject

C:\Users\sprogissd\PycharmProjects\pythonProject>python3 app.py
Bolt app is running! (development server)

故障原因与修复方案 #

本地3000端口服务启动正常但完全收不到Slack事件，核心原因是本地运行的服务处于内网，没有公网可访问的入口，Slack无法将工作区的事件推送到你的本地服务，大概率是跳过了教程第4步要求的内网穿透配置，或是配置后未正确填写回调地址。
按以下步骤逐一排查修复：

• 配置内网穿透隧道：启动ngrok工具，执行命令ngrok http 3000，拿到工具分配的https://<随机字符>.ngrok.io格式公网地址
• 配置Slack回调地址：进入Slack应用管理后台的Event Subscriptions页面，打开事件订阅开关，将Request URL填写为https://<你的ngrok公网地址>/slack/events，等待Slack自动完成地址校验，校验通过后会显示绿色对勾标识
• 确认事件订阅范围：在Event Subscriptions页面的Subscribe to bot events板块，确认已添加代码中用到的所有事件类型：team_join、message.channels、message.im、reaction_added、pin_added，保存配置后重新将应用安装到对应工作区
• 校验凭证正确性：确认代码中填写的token为应用的Bot User OAuth Token，signing_secret为应用Basic Information页面的Signing Secret，两类凭证填混会导致Slack请求签名校验失败，应用不会处理任何推送事件

注意事项：ngrok免费版每次重启都会更换分配的公网地址，每次重启ngrok后都需要到Slack后台更新Request URL配置。配置正确的前提下，Slack推送事件到本地服务时，运行app.py的命令行会打印DEBUG级别的请求接收日志，不会仅显示启动提示。

内容的提问来源于stack exchange，提问作者sprogissd