Add task for listing connected users

alexmuller · alexmuller · commit fa7e347baebd · 2015-08-24T16:52:58.000+01:00
This task can be used like this:

```
fab production all vm.connected_users
```

If there are users connected:

```
There are users connected to machine-1.vdc:
  - a_user
  - another_user
```

This is useful if you want to switch off a machine like the jumpbox
that everyone is connected through.
diff --git a/vm.py b/vm.py
@@ -122,3 +122,20 @@ def host_key(hostname):
   else:
     with hide('running'):
       run("ssh-keygen -l -f /dev/stdin <<< '{0}'".format(ssh_key))
+
+@task
+@parallel(pool_size=5)
+def connected_users():
+  """
+  Output a list of users who are logged in to a machine
+  """
+
+  with hide('running', 'stdout'):
+    username = run('whoami')
+    users = run('who | grep -v {0} || true'.format(username))
+
+  if users:
+    print 'There are users connected to {0}:'.format(env.host_string)
+    for user in users.split("\n"):
+      print '  - {0}'.format(user.split(' ')[0])
+    print "\n"
