Is PythonDatasource supported in Mapnik 3?

[Matt Terry]

Hi,

I'm in the process of upgrading from Mapnik 2.2 to 3.  I use Mapnik through the Python bindings, primarily through PythonDatasource.  Is PythonDatasources still supported in Mapnik 3?

Mapnik 2.1 introduced a Python plugin ([1], [2]) that enabled python data sources.  That is, libmapnik would call back into Python to get the features for a given bounding box.  One would use this via `mapnik.Python` [3] and `mapnik.PythonDatasource` [4].  This function/class is still defined in the Python bindings, but the supporting code in mapnik appears to have been removed when the Python bindings were split into their own repo.

When I run the following code (simplified from an example on the wiki [5])

import mapnik                                                                   

                                                                                

class TestDatasource(mapnik.PythonDatasource):                                  

    def features(self, query):                                                  

        return []                                                               

                                                                                

ds = mapnik.Python(factory='TestDatasource')

I get the following error:

RuntimeError: Could not create datasource for type: 'python' (searched for datasource plugins in '/var/lib/conda/envs/nextdoor/lib/mapnik/input') 

I'm building libmapnik & python-mapnik from source, so it is possible that I've built them incorrectly.  That said, this looks like PythonDatasource is no long supported and `mapnik.Python` and `mapnik.PythonDatasource` are vestigial.  Can someone more familiar with the guts of Mapnik confirm that this is indeed the case?

-matt

PS I have conda builds for libmapnik and python-mapnik if anyone is interested in reproducing my error. [6]

[1] https://github.com/mapnik/mapnik/blob/2.2.x/SConstruct#L112

[2] https://github.com/mapnik/mapnik/tree/2.2.x/plugins/input/python

[3] https://github.com/mapnik/python-mapnik/blob/master/mapnik/__init__.py#L691

[4] https://github.com/mapnik/python-mapnik/blob/master/mapnik/__init__.py#L714

[5] https://github.com/mapnik/mapnik/wiki/Python-Plugin

[6] conda install -c mrterry python-mapnik

[Matt Terry]

The Python input plugin has been moved to a separate repo.  Quoting talaj from github:

Some plugins have been moved from Mapnik repo to https://github.com/mapnik/non-core-plugins. See mapnik/mapnik#2773.