python datasource input plugin missing

[dolfandringa]

I am trying to make my own python datasource (and add docs for it). All code seems to be present in the python-mapnik repository, except for the python input plugin. But it's also not present in the mapnik repository afaiks.

I made a class in geopandas_datasource.py named GeopandasDatasource and then thought I needed to register it like this:

mapnik.register_plugins(str(Path('.').resolve()))
l.datasource = mapnik.Python(factory='geopandas_datasource:GeoPandasDataSource', gdf=frame)

but I get an error:

RuntimeError: Could not create datasource for type: 'python' (searched for datasource plugins in '/home/dolfandringa/Documents/GPS tracks, /usr/local/lib/mapnik/input')

And now that I dig deeper, in /usr/local/lib/mapnik/input I only see the following:

csv.input
geojson.input
pgraster.input
raster.input
sqlite.input
gdal.input
ogr.input
postgis.input
shape.input
topojson.input

no python.input. And in the mapnik code there is also no code for one. But I can't find any code for it either in the python-mapnik. What am I missing here?

[mathisloge]

actually you would need to create a c++ plugin that wraps those. I don't know of any python plugin. All those other plugins are c++ libraries.

So you might be able to do this, but it would be a bit more complicated.

I would think of something like this:

1. create a c++ mapnik plugin like the others
2. the plugin loading of mapnik is as followed: load .input file and look for a symbol datasource_name and call it. This gets the name for the plugin under which it will be registered. Now, here it gets tricky: You would need to register e.g. a plugin called python which in turn have own bindings to load data from python calls (e.g. geopandas)

The symbols for plugins might change with upcoming mapnik v4