[GRASS-dev] Working with TGIS without starting GRASS explicitly

Sat Sep 24 02:35:48 PDT 2016

Hi Laurent,
i have attached a Python script that shows the handling of tgis.init() in a
subprocess in case location and mapsets change using grass72.
The following output was generated with this script, it seems to work on my
system:

soeren at knecht:~$ python test_tgis.py
New envrionment: {u'MAPSET': u'PERMANENT', u'GISDBASE':
u'/home/soeren/grassdata', u'LOCATION_NAME': u'nc_spm_08_grass7'}
TGIS init:
    database: /home/soeren/grassdata
    location: nc_spm_08_grass7
    mapset: PERMANENT
New envrionment: {u'MAPSET': u'user1', u'GISDBASE':
u'/home/soeren/grassdata', u'LOCATION_NAME': u'nc_spm_08_grass7'}
TGIS init:
    database: /home/soeren/grassdata
    location: nc_spm_08_grass7
    mapset: user1
New envrionment: {u'MAPSET': u'PERMANENT', u'GISDBASE':
u'/home/soeren/grassdata', u'LOCATION_NAME': u'nc_spm_08'}
TGIS init:
    database: /home/soeren/grassdata
    location: nc_spm_08
    mapset: PERMANENT
New envrionment: {u'MAPSET': u'user1', u'GISDBASE':
u'/home/soeren/grassdata', u'LOCATION_NAME': u'nc_spm_08'}
TGIS init:
    database: /home/soeren/grassdata
    location: nc_spm_08
    mapset: user1

Best regards
Soeren

2016-09-24 5:32 GMT+02:00 Laurent C. <lrntct at gmail.com>:

> Hi Sören,
>
> I followed you suggestion and now each simulation run in its own process
> using the multiprocessing library. It works well, thanks.
> However, there was indeed something strange going on:
> The new mapset, location and accessible mapsets were set properly, as seen
> by the output of g.mapset and g.mapsets
> However, the output of ciface.available_mapsets() and therefore
> core.get_available_temporal_mapsets() were not updated after the first
> simulation, so tgis.init() were failing, not seeing the new current mapset
> in its own list of available mapsets.
>
> Below was the output of the software:
>
> g.mapset -p
> swashes_1d_1000m
> g.mapsets -p
> Accessible mapsets:
> swashes_1d_1000m PERMANENT
> ciface.available_mapsets()
> ['swashes_1d_1000m', 'PERMANENT']
> get_available_temporal_mapsets()
> {'swashes_1d_1000m': ('sqlite', '/home/laurent/grassdata/
> flood_test/swashes_1d_1000m/tgis/sqlite.db')}
> Starting simulation for configuration file macdo1000.ini...
> [...]
> g.mapset -p
> hull
> g.mapsets -p
> Accessible mapsets:
> hull PERMANENT hull_rain
> ciface.available_mapsets()
> ['swashes_1d_1000m', 'PERMANENT']
> get_available_temporal_mapsets()
> {'swashes_1d_1000m': ('sqlite', '/home/laurent/grassdata/
> flood_test/swashes_1d_1000m/tgis/sqlite.db')}
> ERROR: Unable to execute sql statement. There is no temporal database
> connection defined for mapset <hull>
>
> It seems that tgis.init() is not doing what it is supposed to, according
> to the documentation:
>
> "Re-run this function in case the following GRASS variables change while
> the process runs:
> - MAPSET
> - LOCATION_NAME
> - GISDBASE
> - TGIS_DISABLE_MAPSET_CHECK
> - TGIS_DISABLE_TIMESTAMP_WRITE
> "
>
> Thanks again.
>
> Regards,
> Laurent
>
> 2016-09-22 13:52 GMT-05:00 Sören Gebbert <soerengebbert at googlemail.com>:
> > Hi Laurent,
> > the temporal framework was neither tested nor designed to work in a
> script
> > that changes the location while running. I would suggest to run the
> temporal
> > framework related code in a subprocess that is created each time the
> > location or mapset changes. Unfortunately i have no other suggestion.
> >
> > However, have you tested your code with grass 7.2 or 7.3? Many
> improvements
> > have been implement in the recent version that would be beneficial to
> use.
> >
> > Best regards
> > Soeren
> >
> > 2016-09-22 2:47 GMT+02:00 Laurent C. <lrntct at gmail.com>:
> >>
> >> Hello all,
> >>
> >> I've ran into another related issue.
> >> One of the goal of running the software outside of GRASS shell is to
> >> batch process simulations in various Locations/mapsets.
> >>
> >> I set the GRASS session for each case. The simulation works well for
> >> the first case.
> >> However when starting the second case, tgis.init() fails with the
> >> following error:
> >>
> >> ERROR: Unable to execute sql statement. There is no temporal database
> >> connection defined for mapset <hull>
> >>
> >> The mapset and location are properly set.
> >> If this case is run first, it works well and it's the second one that
> >> fail.
> >> Running t.connect -c between two cases does not solve the problem.
> >> Actually, t.connect -p shows the correct connection parameters, but
> >> tgis.init() still fails.
> >>
> >> Regards,
> >> Laurent
> >>
> >>
> >> 2016-09-21 18:27 GMT-05:00 Laurent C. <lrntct at gmail.com>:
> >> > Hi Sören,
> >> >
> >> > Setting LD_LIBRARY_PATH is working, thanks. But it cannot be set at
> >> > run-time, which is not very user-friendly.
> >> > I guess this issue is related to the ticket 2424 [1].
> >> >
> >> > I managed to get it work at run-time by restarting the program with
> >> > sys.execv() after setting the path [2], but I find it a bit ugly and
> >> > quite verbose to be multi-platform.
> >> >
> >> > It would be great if an easier option was possible.
> >> >
> >> > Regards,
> >> > Laurent
> >> >
> >> > [1] https://trac.osgeo.org/grass/ticket/2424
> >> > [2]
> >> > http://stackoverflow.com/questions/6543847/setting-ld-
> library-path-from-inside-python
> >> >
> >> >
> >> > 2016-09-21 15:40 GMT-05:00 Sören Gebbert <
> soerengebbert at googlemail.com>:
> >> >> Hi,
> >> >> i think you have to put the GRASS libraries into your LD_LIBRARY_PATH
> >> >> so
> >> >> that the python wrapper can access them.
> >> >>
> >> >> Best regards
> >> >> Soeren
> >> >>
> >> >> 2016-09-21 20:37 GMT+02:00 Laurent C. <lrntct at gmail.com>:
> >> >>>
> >> >>> Hello all,
> >> >>>
> >> >>> I'm trying to adapt a python module in order for it to be run
> outside
> >> >>> of
> >> >>> GRASS.
> >> >>> I followed the instructions from the wiki and
> >> >>> lib/python/script/setup.py
> >> >>>
> >> >>> gsetup.init() run without error and I can list maps like in the
> >> >>> example.
> >> >>>
> >> >>> However, when I try to import the temporal module, I receive this
> >> >>> error:
> >> >>>
> >> >>> import grass.temporal as tgis
> >> >>> File "/usr/lib/grass70/etc/python/grass/temporal/__init__.py", line
> >> >>> 1, in <module>
> >> >>> from core import *
> >> >>> File "/usr/lib/grass70/etc/python/grass/temporal/core.py", line 38,
> >> >>> in <module>
> >> >>> from c_libraries_interface import *
> >> >>> File
> >> >>> "/usr/lib/grass70/etc/python/grass/temporal/c_libraries_
> interface.py",
> >> >>> line 19, in <module>
> >> >>> import grass.lib.gis as libgis
> >> >>> File "/usr/lib/grass70/etc/python/grass/lib/gis.py", line 23, in
> >> >>> <module>
> >> >>> _libs["grass_gis.7.0.4"] = load_library("grass_gis.7.0.4")
> >> >>> File "/usr/lib/grass70/etc/python/grass/lib/ctypes_loader.py", line
> >> >>> 55, in load_library
> >> >>> return self.load(path)
> >> >>> File "/usr/lib/grass70/etc/python/grass/lib/ctypes_loader.py", line
> >> >>> 71, in load
> >> >>> raise ImportError,e
> >> >>> ImportError: libgrass_datetime.7.0.4.so: cannot open shared object
> >> >>> file: No such file or directory
> >> >>>
> >> >>>
> >> >>> Did I forgot to set-up something or this is a bug?
> >> >>>
> >> >>> Cheers,
> >> >>> Laurent
> >> >>> _______________________________________________
> >> >>> grass-dev mailing list
> >> >>> grass-dev at lists.osgeo.org
> >> >>> http://lists.osgeo.org/mailman/listinfo/grass-dev
> >> >>
> >> >>
> >
> >
>
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