Lastpass lookup plugin (#16285)

This plugin can be used with the lpass cli interface for lastpass.
[lastpass-cli](https://github.com/lastpass/lastpass-cli)

Example:
Add a lookup to your playbooks/variables somewhere:
```
some_variable: "{{ lookup('lastpass','Some Lastpass entry name or ID', field='username') }}"
```
Usage:
* start a lpass session prior to using ansible
* run ansible
* logout when finished

```
lpass login user@domain.com
ansible-playbook foo.yml
lpass logout
```

lib/ansible/plugins/lookup/lastpass.py

@@ -0,0 +1,79 @@
+# (c) 2016, Andrew Zenk <azenk@umn.edu>
+#
+# This file is part of Ansible
+#
+# Ansible is free software: you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation, either version 3 of the License, or
+# (at your option) any later version.
+#
+# Ansible is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+#
+# You should have received a copy of the GNU General Public License
+# along with Ansible.  If not, see <http://www.gnu.org/licenses/>.
+from __future__ import (absolute_import, division, print_function)
+__metaclass__ = type
+
+from subprocess import Popen, PIPE
+
+from ansible.errors import AnsibleError
+from ansible.plugins.lookup import LookupBase
+
+
+class LPassException(AnsibleError):
+    pass
+
+
+class LPass(object):
+
+    def __init__(self, path='lpass'):
+        self._cli_path = path
+
+    @property
+    def cli_path(self):
+        return self._cli_path
+
+    @property
+    def logged_in(self):
+        out, err = self._run(self._build_args("logout"), stdin="n\n", expected_rc=1)
+        return err.startswith("Are you sure you would like to log out?")
+
+    def _run(self, args, stdin=None, expected_rc=0):
+        p = Popen([self.cli_path] + args, stdout=PIPE, stderr=PIPE, stdin=PIPE)
+        out, err = p.communicate(stdin)
+        rc = p.wait()
+        if rc != expected_rc:
+            raise LPassException(err)
+        return out, err
+
+    def _build_args(self, command, args=None):
+        if args is None:
+            args = []
+        args = [command] + args
+        args += ["--color=never"]
+        return args
+
+    def get_field(self, key, field):
+        if field in ['username', 'password', 'url', 'notes', 'id', 'name']:
+            out, err = self._run(self._build_args("show", ["--{0}".format(field), key]))
+        else:
+            out, err = self._run(self._build_args("show", ["--field={0}".format(field), key]))
+        return out.strip()
+
+
+class LookupModule(LookupBase):
+
+    def run(self, terms, variables=None, **kwargs):
+        lp = LPass()
+
+        if not lp.logged_in:
+            raise AnsibleError("Not logged into lastpass: please run 'lpass login' first")
+
+        field = kwargs.get('field', 'password')
+        values = []
+        for term in terms:
+            values.append(lp.get_field(term, field))
+        return values