如何找到使用自制软件启动的mongo服务器端口？

Question

我通过以下方式启动了mongo服务器

   brew services restart mongodb@3.4
Stopping `mongodb@3.4`... (might take a while)
==> Successfully stopped `mongodb@3.4` (label: homebrew.mxcl.mongodb@3.4)
==> Successfully started `mongodb@3.4` (label: homebrew.mxcl.mongodb@3.4)

我可以检查它是否确实在运行

   brew services list
Name        Status  User     Plist
mongodb@3.4 started root     /Library/LaunchDaemons/homebrew.mxcl.mongodb@3.4.plist

但是当我尝试通过标准端口连接它时，它失败了：

   lsof -i:27017
COMMAND     PID     USER   FD   TYPE             DEVICE SIZE/OFF NODE NAME

GUI：

通过cat结果中列出的plist文件brew services list，我得到了mongodb配置文件路径：

cat /Library/LaunchDaemons/homebrew.mxcl.mongodb@3.4.plist
<?xml version="1.0" encoding="UTF-8"?>
...
    <string>/usr/local/etc/mongod.conf</string>
...

所以我cat conf文件：

cat /usr/local/etc/mongod.conf 
systemLog:
  destination: file
  path: /usr/local/var/log/mongodb/mongo.log
  logAppend: true
storage:
  dbPath: /usr/local/var/mongodb
net:
  bindIp: 127.0.0.1

因此，我再次选择系统日志：

cat /usr/local/var/log/mongodb/mongo.log
2018-10-10T11:02:19.071+0800 I NETWORK  [initandlisten] shutdown: going to close listening sockets...
2018-10-10T11:02:19.071+0800 I NETWORK  [initandlisten] removing socket file: /tmp/mongodb-27017.sock
2018-10-10T11:02:19.071+0800 I NETWORK  [initandlisten] shutdown: going to flush diaglog...
2018-10-10T11:02:19.071+0800 I CONTROL  [initandlisten] now exiting
2018-10-10T11:02:19.071+0800 I CONTROL  [initandlisten] shutting down with code:100

因此lsof -i:27017未给出任何结果的原因是mongo服务器遇到了一些错误并存在。伤心...

问题就变成了：如何找到导致mongo服务器退出的错误的根源？以及如何解决？谢谢！