Ev3dev: pybluez missing gattlib (required for BLE)

[JorgePe]

Hi.
I'm using yesterday snapshot, 07Nov2016, ev3dev 4.4.24-16-ev3dev-ev3, no updates and nothing else installed.
I'm trying pybluez since it is now included with ev3dev. I'm interested in BT 4.0 BLE communication.

pybluez README has a few examples for BLE but they only work if we have also gattlib (pygattlib)

I tried to install gattlib according to the README instructions but failed:
Directory '.' is not installable. File 'setup.py' not found.

In the past I've managed to install gattlib compiling from source but it takes a lot of time and requires a huge swapfile (process is described here: http://www.ev3dev.org/docs/tutorials/controlling-wedo2-motor/)

Is it possible to include gattlib with pybluez in future snapshots?

[JorgePe]

Just a quick note: the reason for installation faillure seems the same, out of memory.
So I added a ~900 MB swap again, but installation keeps failling. But direct installation of gattlib works:
sudo pip3 install gattlib
(pip also works, for python 2.x version)

900 MB seems overkill but just one of the components, "bindings", makes cc1plus to allocate more than 580 MB!

After successful installation, I can now use bluetooth.ble:

from bluetooth.ble import DiscoveryService

(and of course also import gattlib directly).

Since I'm planning a few other tutorials on BLE devices (LEGO WeDo 2.0, TI SensorTag, Vengit SBrick/SBrick+ and probably BBC micro:bit) I'm considering to split the WeDo 2.0 tutorial I already made in two, so the mess of pyhton + BLE can be in a separate tutorial that all others can link to.
(sorry for my english).

[dlech]

I have uploaded a new python3-gattlib package to the ev3dev repositories. Please test.

It turns out the pygattlib project already had a debian package we could borrow.
https://github.com/ev3dev/gattlib

[JorgePe]

@dlech Great work!!!

Snapshot image from 17 Jan 2017, no updates whatsoever
Just enabled Bluetooth in the Brickman and checked with hciconfig -a that my USB BT4-BLE dongle is hci0
First example from the README.md works at first attempt (just added shebang):

#!/usr/bin/env python3
from gattlib import DiscoveryService
service = DiscoveryService("hci0")
devices = service.discover(2)
for address, name in devices.items():
    print("name: {}, address: {}".format(name, address))

chmod +x test01.py
sudo ./test01.py

name: LPF2 Smart Hub 2 I/O, address: A0:E6:F8:1E:37:B5

Now I just need some time to rewrite and retest my scripts and the update the tutorials.

[JorgePe]

@dlech sorry, spoke to soon

python-gattlib version seems to be to old - it can discover BLE devices but cannot connect to them (at least I cannot).

I tried to use my basic WeDo 2.0 motor script but it complains about arguments - compiled version accepts choosing the hci device but ev3dev packaged doesn't (it was merged to the code 6 months later).
If I ignore the hci device the script works (as long as my BLE dongle stays hci0) but I never get a connection and the WeDo 2.0 SmartHub powers off.
Tried low level example from source (from ev3dev source) and it fails with:

RuntimeError: Channel or attrib not ready

Maybe I can create a .deb package from present source code but I don't know how to integrate it on ev3dev ecosystem so it will probably break next time bluez or any other library is updated.

[dlech]

I was wondering about that. It looks like the PyPi version is the same old version, so I hoped that it would be good enough.

I created the package from https://github.com/ev3dev/gattlib, so if you want to update that to a newer version of gattlib, be my guest. You can read more about packaging here. If there is a tarball of a newer version of pygattlib, I would suggest using gbp import-orig.

[JorgePe]

Thanks, have to find some time alone to read it.
Pypi seems 0.20150805 while deb seems 0.20150131
Funny how just half an year can make quite a difference.

[dlech]

It was easy for me, so I've gone ahead and started building a package based on the 0.20150805 version.

[dlech]

python3-gattlib_0.20150805-1ev3dev1 is now pushed. Please test.

[JorgePe]

@dlech Very nice, motor running!