[GRASS-user] Error import from grass.pygrass.vector library

[Manuele Pesenti]

Drear Stefan,
thanks for your quick reply but the solution is not so clear, I already use grass_session library even if not reported in the attached example, how can it helps with the issue? Just import the vector library after the session is loaded does not solve as far as I've tested.

Cheers

    Manuele

---- Attivato ven, 20 ago 2021 21:26:22 +0200 Stefan Blumentrath <mailto:Stefan.Blumentrath at nina.no> ha scritto ----



Dear Manuele,

 

For ctypes in pygrass, the C-libraries need to be loaded explicitly.

 

You could have a look here:

https://github.com/zarch/grass-session/blob/6097f834be20ee0d703deb2af90f22d6dc66f368/grass_session/session.py#L332

to see how it can be done, or just use the grass_session python library (pip install grass-session) for convenience…

 

Cheers

Stefan

 

From: grass-user <mailto:grass-user-bounces at lists.osgeo.org> On Behalf Of Manuele Pesenti
 Sent: fredag 20. august 2021 16:40
 To: grass-user <mailto:grass-user at lists.osgeo.org>
 Subject: [GRASS-user] Error import from grass.pygrass.vector library


 

Dear All,


 


I'm moving my first steps on the development of a python script that uses Grass, but I cannot import from the grass.pygrass.vector library.


I work on a Ubuntu/Linux environment and I've installed grass using apt, this is the test script I'm currently running:


 


# -*- coding: utf-8 -*-


 


import os, sys


 


GISBASE = '/usr/lib/grass78'


GRASSBIN = '/usr/bin/grass78'


 


# Define GRASS-Python environment


os.environ['GISBASE'] = GISBASE


 


os.environ['GRASSBIN'] = GRASSBIN


 


sys.path.append(os.path.join(GISBASE, "etc", "python"))


 


from grass_session import Session


import grass.script as gs


 


print(f"LD_LIBRARY_PATH: {os.environ['LD_LIBRARY_PATH']}")


print(f"GRASSBIN: {os.environ['GRASSBIN']}")


 


from grass.pygrass.vector import Vector


 


print('DONE!')


 


and this is the output:


 


$ python import_test.py 


LD_LIBRARY_PATH: /usr/lib/grass78/lib


GRASSBIN: /usr/bin/grass78


Traceback (most recent call last):


  File "/usr/lib/grass78/etc/python/grass/lib/ctypes_loader.py", line 76, in load


    return ctypes.cdll.LoadLibrary(path)


  File "/usr/lib/python3.9/ctypes/__init__.py", line 452, in LoadLibrary


    return self._dlltype(name)


  File "/usr/lib/python3.9/ctypes/__init__.py", line 374, in __init__


    self._handle = _dlopen(self._name, mode)


OSError: libgrass_datetime.7.8.so: cannot open shared object file: No such file or directory


 


During handling of the above exception, another exception occurred:


 


Traceback (most recent call last):


  File "/home/manuele/Lavoro/ETS/ETSCore/scripts/import_test.py", line 21, in <module>


    from grass.pygrass.vector import Vector


  File "/usr/lib/grass78/etc/python/grass/pygrass/vector/__init__.py", line 5, in <module>


    import grass.lib.gis as libgis


  File "/usr/lib/grass78/etc/python/grass/lib/gis.py", line 23, in <module>


    _libs["grass_gis.7.8"] = load_library("grass_gis.7.8")


  File "/usr/lib/grass78/etc/python/grass/lib/ctypes_loader.py", line 62, in load_library


    return self.load(path)


  File "/usr/lib/grass78/etc/python/grass/lib/ctypes_loader.py", line 78, in load


    raise ImportError(e)


ImportError: libgrass_datetime.7.8.so: cannot open shared object file: No such file or directory



 


Thank you very mutch for any help


 


Cheers


 


      Manuele


 


 


 



 
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