Problem upgrading to newest python API

aribes

Hi,

I have been using the API through the pymetawear package (version 0.8.0). I would like to upgrade my code to the official Python SDK, but I fail to run even the led.py example.

I created a new pip virtual environment, installed mbientlab version of pygattlib and metawear packages.

When trying to run the examples in the examples folder, e.g. python led.py MAC_ADDRESS, I get one of the two following errors:

-----------------------------------------

Traceback (most recent call last):

  File "led.py", line 10, in <module>

    device.connect()

  File "/home/aribes/Environments/metawear/local/lib/python2.7/site-packages/mbientlab/metawear/__init__.py", line 155, in connect

    self.gatt.connect(True, channel_type='random')

RuntimeError: Channel or attrib not ready

-------------------------------------------

Traceback (most recent call last):

  File "_ctypes/callbacks.c", line 315, in 'calling callback function'

  File "/home/aribes/Environments/metawear/local/lib/python2.7/site-packages/mbientlab/metawear/__init__.py", line 198, in _read_gatt_char

    raw = self.gatt.read_by_uuid(uuid)[0]

RuntimeError: Device is not responding!

Traceback (most recent call last):

  File "led.py", line 10, in <module>

    device.connect()

  File "/home/aribes/Environments/metawear/local/lib/python2.7/site-packages/mbientlab/metawear/__init__.py", line 189, in connect

    raise RuntimeError("Error initializing the API (%d)" % (self.init_status))

RuntimeError: Error initializing the API (16)

-------------------------------------------------------

But if I then switch to version 0.8.0 of pymetawear (which wraps Cpp API), it works well. 

Also I noted that pymetawear develop version (0.9.x) is a wrapper around official python wrapper. I am also not able to use it (obviously, if official python sdk does not work, that pymetawear version should not as well).

Eric

Which Linux distro are you running?  The latest Python SDK works fine on my Ubuntu 16.04 and openSUSE tumbleweed VMs

aribes

Ubuntu 16.04 and python 2.7

Eric

Are you running as superuser?

aribes

No, but that never has caused a problem, thanks to this post on SO https://unix.stackexchange.com/questions/96106/bluetooth-le-scan-as-non-root

I run this command, so python gets capabilities to scan. That was enough for previous versions.

sudo setcap 'cap_net_raw,cap_net_admin+eip' /home/aribes/Environments/metawear/bin/python

Eric

Hrm, well the only difference with older pymetawear versions and the current Python SDKs is the underlying Python ble library.  We use a custom fork of pygattlib, which you can find here

https://github.com/mbientlab/pygattlib

Are these connection issues frequently occurring?  Have you tried resetting the BT adapter?

aribes

I am using your pygattlib fork, as recommended in the docs.

I also realized that if I use pygatt==3.2.0, with the pymetawear==0.8.0, I get the following error:

Traceback (most recent call last):

  File "_ctypes/callbacks.c", line 315, in 'calling callback function'

  File "/home/aribes/Projects/wear/sensor_manager/venv/local/lib/python2.7/site-packages/pymetawear-0.8.0-py2.7.egg/pymetawear/backends/__init__.py", line 154, in mbl_mw_write_gatt_char

    self.write_gatt_char_by_uuid(characteristic, command, length)

  File "/home/aribes/Projects/wear/sensor_manager/venv/local/lib/python2.7/site-packages/pymetawear-0.8.0-py2.7.egg/pymetawear/backends/pygatt.py", line 134, in write_gatt_char_by_uuid

    self.requester.char_write(str(self.get_uuid(characteristic)), data_to_send)

  File "/home/aribes/Projects/wear/sensor_manager/venv/local/lib/python2.7/site-packages/pygatt/device.py", line 92, in char_write

    return self.char_write_handle(self.get_handle(uuid), value,

  File "/home/aribes/Projects/wear/sensor_manager/venv/local/lib/python2.7/site-packages/pygatt/device.py", line 208, in get_handle

    raise exceptions.BLEError(message)

pygatt.exceptions.BLEError: No characteristic found matching 326a9001-85cb-9195-d9dd-464cfbbae75a

So I have to use version 3.1.0. 

I have tried resetting the BT adapter, and rebooting the machine. These errors occur always when using the latest version of the python sdk, so right now I am stuck with pymetawear==0.8.0 which is the only that works.

aribes

Starting a new virtualenv to run some more tests in the Raspberry Pi 3, with python 2.7, I get the following errors:

First one because of permissions:

Traceback (most recent call last):

  File "multi_device.py", line 26, in <module>

    d.connect()

  File "/home/pi/Libraries/metawear/local/lib/python2.7/site-packages/mbientlab/metawear/__init__.py", line 155, in connect

    self.gatt.connect(True, channel_type='random')

RuntimeError: Could not update HCI connection: Operation not permitted

Then I use this command to solve it:

sudo setcap 'cap_net_raw,cap_net_admin+eip' /home/pi/Libraries/metawear/bin/python

Then if I run the following MetaWear-SDK-python example:

$ python multi_device.py EC:44:5E:DD:E1:74

I get one of the following two errors:

Traceback (most recent call last):

  File "_ctypes/callbacks.c", line 315, in 'calling callback function'

  File "/home/pi/Libraries/metawear/local/lib/python2.7/site-packages/mbientlab/metawear/__init__.py", line 198, in _read_gatt_char

    raw = self.gatt.read_by_uuid(uuid)[0]

RuntimeError: Device is not responding!

Violación de segmento (means segment violation)

Or this other one

*** Error in `python': double free or corruption (fasttop): 0x75b02a68 ***

Abortado

My pip freeze command outputs the following (note that I installed ipython, so it has more stuff than minimum needed)

backports.shutil-get-terminal-size==1.0.0

certifi==2018.1.18

chardet==3.0.4

decorator==4.2.1

enum34==1.1.6

gattlib==0.20171002

idna==2.6

ipython==5.5.0

ipython-genutils==0.2.0

metawear==0.3.1

pathlib2==2.3.0

pexpect==4.3.1

pickleshare==0.7.4

prompt-toolkit==1.0.15

ptyprocess==0.5.2

Pygments==2.2.0

requests==2.18.4

scandir==1.6

simplegeneric==0.8.1

six==1.11.0

traitlets==4.3.2

urllib3==1.22

wcwidth==0.1.7

What else could I test? Can you provide me with some environment that you know works for you with raspberry pi 3 that I can test?

Eric

Can you try running your scripts outside of virtualenv?
What bluez version are using?

aribes

Ok, I will try without virtualenv. I am not using bluez but pygatt. With bluez backend (pymetawear 0.8.0) I remember I was getting some error.

Eric

Bluez is the official Linux Bluetooth protocol stack.  All linux ble libraries use it.

aribes

apt-cache show bluez gives this output

Package: bluez

Version: 5.43-2+deb9u1

Architecture: armhf

Maintainer: Debian Bluetooth Maintainers <pkg-bluetooth-maintainers@lists.alioth.debian.org>

Installed-Size: 3364

Depends: libc6 (>= 2.15), libdbus-1-3 (>= 1.9.14), libglib2.0-0 (>= 2.31.8), libreadline7 (>= 6.0), libudev1 (>= 196), init-system-helpers (>= 1.18~), kmod, udev (>= 170-1), lsb-base, dbus

Suggests: pulseaudio-module-bluetooth

Conflicts: bluez-audio (<= 3.36-3), bluez-utils (<= 3.36-3)

Breaks: udev (<< 170-1)

Replaces: bluez-audio (<= 3.36-3), bluez-input, bluez-network, bluez-serial, bluez-utils (<= 3.36-3), udev (<< 170-1)

aribes

By the way, could you provide me with info of what versions of what packages are shipped in the SensorHub? Could I get a downloadable image of it? 

Eric

I'll check once I have access to our Pi.  

MetaHub images are only provided to hub owners.

aribes

Ok, then even though I cannot get an image, could you provide me with the versions of the critical packages? I guess kernel and bluez versions should suffice, but maybe there are other packages that play a role into the problems I am experiencing.

Eric

kernel: Linux raspberrypi 4.9.59-v7+

bluez: 5.43-2+deb9u1

python: 2.7.13-2

python3: 3.5.3-1

nodejs: 8.9.3