make execute() not require explicit '**kwargs'

CHANGELOG.rst

@@ -8,6 +8,7 @@ Changelog
 * use ``concurrent.futures`` instead of ``multiprocessing``
 * make some dependencies optional (Flask, boto3, etc.)
 * speed up ``count_tiles()``
+* ``execute()`` function does not require explicit ``**kwargs`` anymore
 
 
 ----

README.rst

@@ -75,7 +75,7 @@ and a ``.py`` file or a Python module path where you specify the process itself
 
 .. code-block:: python
 
-    def execute(mp, resampling="nearest", **kwargs):
+    def execute(mp, resampling="nearest"):
         # Open elevation model.
         with mp.open("dem", resampling=resampling) as src:
             # Skip tile if there is no data available.

mapchete/_core.py

@@ -498,19 +498,14 @@ def _execute(self, process_tile, raise_nodata=False):
         try:
             with Timer() as t:
                 # Actually run process.
-                if len(inspect.getargspec(self.config.process_func).args) == 1:
-                    process_data = self.config.process_func(tile_process)
-                else:
-                    process_data = self.config.process_func(
-                        tile_process,
-                        **{
-                            k: v for k, v in six.iteritems(params)
-                            if k not in [
-                                "input", "output", "pyramid", "zoom_levels",
-                                "mapchete_file", "init_bounds", "init_zoom_levels"
-                            ]
-                        }
-                    )
+                process_data = self.config.process_func(
+                    tile_process,
+                    # only pass on kwargs which are defined in execute()
+                    **{
+                        k: v for k, v in params.items()
+                        if k in inspect.signature(self.config.process_func).parameters
+                    }
+                )
         except Exception as e:
             # Log process time
             logger.exception(

mapchete/config.py

@@ -14,7 +14,6 @@
 from copy import deepcopy
 import imp
 import importlib
-import inspect
 import logging
 import operator
 import os
@@ -51,7 +50,7 @@
 _RESERVED_PARAMETERS = [
     "baselevels",       # enable interpolation from other zoom levels
     "bounds",           # process bounds
-    "process",     # path to .py file or module path
+    "process",          # path to .py file or module path
     "config_dir",       # configuration base directory
     "process_minzoom",  # minimum zoom where process is valid (deprecated)
     "process_maxzoom",  # maximum zoom where process is valid (deprecated)
@@ -422,12 +421,7 @@ def process_func(self):
                     """instanciating MapcheteProcess is deprecated, """
                     """provide execute() function instead""")
             if hasattr(process_module, "execute"):
-                user_execute = process_module.execute
-                if len(inspect.signature(user_execute).parameters) == 0:
-                    raise ImportError(
-                        "execute() function has to accept at least one argument"
-                    )
-                return user_execute
+                return process_module.execute
             else:
                 raise ImportError(
                     "No execute() function found in %s" % self._raw["process"]

test/example_process.py

@@ -1,7 +1,7 @@
 """Example process file."""
 
 
-def execute(mp, **kwargs):
+def execute(mp):
     """User defined process."""
     # Reading and writing data works like this:
     with mp.open("file1", resampling="bilinear") as raster_file:

test/test_errors.py

@@ -230,14 +230,6 @@ def test_malformed_process(cleantopo_br, malformed_py):
         mapchete.open(config)
 
 
-def test_execute_params(cleantopo_br, execute_params_error_py):
-    """Assert import error is raised."""
-    config = cleantopo_br.dict
-    config.update(process=execute_params_error_py)
-    with pytest.raises(errors.MapcheteProcessImportError):
-        mapchete.open(config)
-
-
 def test_syntax_error(mp_tmpdir, cleantopo_br, syntax_error_py):
     """Assert syntax error is raised."""
     config = cleantopo_br.dict

test/test_mapchete.py

@@ -415,3 +415,10 @@ def test_snap_bounds_errors():
         mapchete.config.snap_bounds(bounds=(0, 1, ))
     with pytest.raises(TypeError):
         mapchete.config.snap_bounds(bounds=bounds, pyramid="invalid")
+
+
+def test_execute_params(cleantopo_br, execute_params_error_py):
+    """Assert execute() without parameters passes."""
+    config = cleantopo_br.dict
+    config.update(process=execute_params_error_py)
+    mapchete.open(config)