Mysql.sock disappeared.

 mysql: stable 5.7.20 (bottled), develop 8.0.3-rc
Open source relational database management system
https://dev.mysql.com/doc/refman/5.7/en/
Conflicts with:
  mariadb (because mysql, mariadb, and percona install the same binaries.)
  mariadb-connector-c (because both install plugins)
  mysql-cluster (because mysql, mariadb, and percona install the same binaries.)
  mysql-connector-c (because both install MySQL client libraries)
  percona-server (because mysql, mariadb, and percona install the same binaries.)
/usr/local/Cellar/mysql/5.7.20 (324 files, 233.7MB)*
  Pouled from bottle on 2017-11-25 at 09:34:57
From: https://github.com/Homebrew/homebrew-core/blob/master/Formula/mysql.rb
== > Dependencies
Build: cmake✘
Required: openssl✔
==>Requirements
Required: macOS>=10.7✔
== > Options
--with-archive-storage-engine
    Compile with the ARCHIVE storage engine enabled
--with-blackhole-storage-engine
    Compile with the BLACKHOLE storage engine enabled
--with-debug
    Build with debug support
--with-embedded
    Build the embedded server
--with-local-infile
    Build with local info loading support
--with-test
    Build with unit tests
--develop
    Install development version 8.0.3-rc
==>Caveats
We've installed your MySQL database without a root password.To secure it run:
    mysql_secure_installation

MySQL is configured to only allow connections from localhost by default

To connect run:
    mysql-uroot

To have launchd start mysql now and restart at login:
  brew services start mysql
Or, if you don't want / need a background service you can just run:
  mysql.server start