cgconfig.conf

group gotools {
  perm {
    admin {
      uid = UID;
      gid = UID;
    }
    task {
      uid = UID;
      gid = UID;
    }
  }
  cpu {
    cpu.shares = 256;
  }
  memory {
# limit to 6GB
    memory.limit_in_bytes = 6442450944;
  }
}
~

gopls.bash

#!/bin/bash

cgexec \
  -g memory,cpu:gotools \
  $GOPATH/bin/gopls.real "$@"

setup.example

$ sudo apt install cgroup-tools
$ mv cgconfig.conf /etc/cgconfig.conf
$ sed -i -e 's|UID|$(id -u)|' /etc/cgconfig.conf
$ sudo cgconfigparser -l /etc/cgconfig.conf
$ mv $GOPATH/bin/gopls $GOPATH/bin/gopls.real
$ ln -sf /path/to/gopls.bash $GOPATH/bin/gopls

Not totally clear to me if /etc/cgconfig.conf is automatically parsed at boot. Also, obviously, if you are running a different distribution you will have to change the install step.

Also worth noting, to get the most mileage out of this you will probably have to configure your editor to pass the --remote=auto option to gopls.