scanner.start() results in `_bluetooth.error: (1, 'Operation not permitted')`

First: I know this is a permissions issue - and I also see the step in the setup instructions to mitigate it.

System:

Ubuntu 17.10 x64 Pycharm 2018.1.3 (developing here) Python 3.6 in a virtualenv

Steps to Replicate:

pip install beacontools
# install libbluetooth headers and libpcap2
sudo apt-get install python-dev libbluetooth-dev libcap2-bin
# grant the python executable permission to access raw socket data
sudo setcap 'cap_net_raw,cap_net_admin+eip' $(readlink -f $(which python))
# install beacontools with scanning support
pip install beacontools[scan]

Then copy-paste example code from Scanner subsection (scanner = BeaconScanner...)

Traceback

Exception in thread Thread-5:
Traceback (most recent call last):
  File "/usr/lib/python3.6/threading.py", line 916, in _bootstrap_inner
    self.run()
  File "/home/william/PycharmProjects/bt-beacon/venv/lib/python3.6/site-packages/beacontools/scanner.py", line 94, in run
    self.toggle_scan(True)
  File "/home/william/PycharmProjects/bt-beacon/venv/lib/python3.6/site-packages/beacontools/scanner.py", line 110, in toggle_scan
    self.bluez.hci_send_cmd(self.socket, OGF_LE_CTL, OCF_LE_SET_SCAN_ENABLE, command)
_bluetooth.error: (1, 'Operation not permitted')

Things I Tried

Various forms of sudo setcap... including sudo setcap 'cap_net_raw,cap_net_admin+eip' $(which hcitool)'.

Has anyone else experienced and solved this issue?

[citruz]

Try executing sudo setcap 'cap_net_raw,cap_net_admin+eip' $(readlink -f $(which python))inside your venv.

[williamflynt]

Problem solved. From the above StackOverflow post by Graham King:

This might be because your home directory is mounted with nosuid, which seems to prevent capabilities working. Ubuntu encrypts the home directory, and mounts that with ecryptfs as nosuid.

This is critical, because capabilities (ie: setcap) is what allows this script to function without using sudo python. I cloned the project into my /tmp directory and there are no issues with running the scan.

I hope this helps others!