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

Stefan Blumentrath Stefan.Blumentrath at nina.no
Tue Aug 24 02:04:44 PDT 2021


What version of grass_sessions do you use?
I run grass_session 0.4 on Ubuntu 18.04 with GRASS 7.8 and your script works fine...

From: grass-user <grass-user-bounces at lists.osgeo.org> On Behalf Of Manuele Pesenti
Sent: tirsdag 24. august 2021 10:53
To: Grass User <grass-user at lists.osgeo.org>
Subject: Re: [GRASS-user] Error import from grass.pygrass.vector library




---- Attivato mar, 24 ago 2021 10:10:10 +0200 Stefan Blumentrath <Stefan.Blumentrath at nina.no<mailto:Stefan.Blumentrath at nina.no>> ha scritto ----

Hm...

Did you initialize the session, e.g. like:

with Session(gisdb="/tmp", location="location", create_opts="EPSG:4326"):
    from grass.pygrass.vector import Vector

Yes it's exactly what I do, the strange fact is that I can by-pass the exception assigning the LD_LIBRARY_PATH value before running the script even if even now before importing vector lib this env variable has the correct value exactly thanks to the grass_session lib import...

so the script modified as you suggested reported here under still raise the exception

# -*- 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']}")

with Session(gisdb="/tmp", location="location", create_opts="EPSG:4326"):

    from grass.pygrass.vector import Vector

print('DONE!')


while the old script (for convenience reported here under) runned as

$ LD_LIBRARY_PATH=$(grass78 --config path)/lib python import_test.py
LD_LIBRARY_PATH: /usr/lib/grass78/lib
GRASSBIN: /usr/bin/grass78
DONE!

returns just what printed in the script without raising the exception.

# -*- 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']}")

# with Session(gisdb="/tmp", location="location", create_opts="EPSG:4326"):

from grass.pygrass.vector import Vector

print('DONE!')

Cheers

    Manuele



Cheers
Stefan

From: grass-user <grass-user-bounces at lists.osgeo.org<mailto:grass-user-bounces at lists.osgeo.org>> On Behalf Of Manuele Pesenti
Sent: tirsdag 24. august 2021 09:38
To: Grass User <grass-user at lists.osgeo.org<mailto:grass-user at lists.osgeo.org>>
Subject: Re: [GRASS-user] Error import from grass.pygrass.vector library


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 <Stefan.Blumentrath at nina.no<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<https://eur01.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fzarch%2Fgrass-session%2Fblob%2F6097f834be20ee0d703deb2af90f22d6dc66f368%2Fgrass_session%2Fsession.py%23L332&data=04%7C01%7C%7C787f11b2fc5246a7da6d08d966dc9ee5%7C6cef373021314901831055b3abf02c73%7C0%7C0%7C637653920686707703%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C2000&sdata=XA2vZhGMasSyLFE3KRrBPaXUjewtp2MNBzA4Dwfre9g%3D&reserved=0>
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 <grass-user-bounces at lists.osgeo.org<mailto:grass-user-bounces at lists.osgeo.org>> On Behalf Of Manuele Pesenti
Sent: fredag 20. august 2021 16:40
To: grass-user <grass-user at lists.osgeo.org<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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