my mongodb server had stoped working on my mac:

ISSUE:
Failed to unlink socket file /tmp/mongodb-27017.sock Permission denied

check the log file and found the error:

view /usr/local/var/log/mongodb/mongod.log

Check the /tmp/mongodb-27017.sock permission, owner is root?

ls -ls /tmp/mongodb-27017.sock
output

"0 srwx------ 1 mongodb mongodb 0 Aug 24 04:01 /tmp/mongodb-27017.sock"

solution:

rm /tmp/mongodb-27017.sock

then

systemctl start mongod.service

start mongo, it appears:

$ mongo
MongoDB shell version v4.2.5
connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb
2020-04-08T20:05:01.381+0800 E QUERY [js] Error: couldn't connect to server 127.0.0.1:27017, connection attempt failed: SocketException: Error connecting to 127.0.0.1:27017 :: caused by :: Connection refused :
connect@src/mongo/shell/mongo.js:341:17
@(connect):2:6
2020-04-08T20:05:01.384+0800 F - [main] exception: connect failed
2020-04-08T20:05:01.384+0800 E - [main] exiting with code 1

try to repair, but failed!

$ mongod -–repair
Error parsing command line: unrecognised option '-–repair'
try 'mongod --help' for more information

check th mongod.conf file (/usr/local/etc/mongod.conf), but it's not in the path.

view /etc/mongod.conf

ok, reinstall ?

$ brew uninstall mongodb-community@4.2

$ brew install mongodb-community@4.2

$ brew services start mongodb-community@4.2

In addition to the binaries, the install creates:

the configuration file (/usr/local/etc/mongod.conf)
the log directory path (/usr/local/var/log/mongodb)
the data directory path (/usr/local/var/mongodb)
run mongodb community :

$ mongod --config /usr/local/etc/mongod.conf

about to fork child process, waiting until server is ready for connections.

forked process: 37247

ERROR: child process failed, exited with error number 1

To see additional information in this output, start without the "--fork" option.

192:etc jessea$ mongod --config /usr/local/etc/mongod.conf

2020-04-08T21:51:29.689+0800 F CONTROL [main] Failed global initialization: FileNotOpen: logpath "/usr/local/var/log/mongodb/mongo.log" should name a file, not a directory.

$ cd /usr/local/var/log/mongodb/

// if you want to remove file, use rm filename

$ rm -r mongo.log

$ touch mongo.log

// To run MongoDB manually as a background process

$ mongod --config /usr/local/etc/mongod.conf --fork

about to fork child process, waiting until server is ready for connections.

forked process: 37320

child process started successfully, parent exiting

$ brew services start mongodb-community@4.2

Service `mongodb-community` already started, use `brew services restart mongodb-community` to restart.

$ brew services list

Name Status User Plist

mongodb-community started /Users/jessea/Library/LaunchAgents/homebrew.mxcl.mongodb-community.plist

// connect a mongo shell to the running instance. ( or "mongo --port 27017")

$ mongo

MongoDB shell version v4.2.5

connecting to: mongodb://127.0.0.1:27017/?compressors=disabled&gssapiServiceName=mongodb

Implicit session: session { "id" : UUID("751dee53-9e1f-4c41-a361-95e2918f4426") }

MongoDB server version: 4.2.5

Server has startup warnings:

2020-04-08T22:05:15.048+0800 I CONTROL [initandlisten]

2020-04-08T22:05:15.049+0800 I CONTROL [initandlisten] ** WARNING: Access control is not enabled for the database.

2020-04-08T22:05:15.050+0800 I CONTROL [initandlisten] ** Read and write access to data and configuration is unrestricted.

2020-04-08T22:05:15.051+0800 I CONTROL [initandlisten]

---

Enable MongoDB's free cloud-based monitoring service, which will then receive and display

metrics about your deployment (disk utilization, CPU, operation statistics, etc).

The monitoring data will be available on a MongoDB website with a unique URL accessible to you

and anyone you share the URL with. MongoDB may use this information to make product

improvements and to suggest MongoDB products and deployment options to you.

To enable free monitoring, run the following command: db.enableFreeMonitoring()

To permanently disable this reminder, run the following command: db.disableFreeMonitoring()

---

> exit