Adapt pysteps to allow for nowcast plugins.

pysteps/__init__.py

@@ -218,3 +218,4 @@ def load_config_file(params_file=None, verbose=False, dryrun=False):
 
 # After the sub-modules are loaded, register the discovered importers plugin.
 io.interface.discover_importers()
+nowcasts.interface.discover_nowcasts()

pysteps/nowcasts/__init__.py

@@ -1,3 +1,3 @@
 """Implementations of deterministic and ensemble nowcasting methods."""
 
-from pysteps.nowcasts.interface import get_method
+from pysteps.nowcasts.interface import discover_nowcasts, nowcasts_info, get_method

pysteps/nowcasts/interface.py

@@ -30,6 +30,9 @@
     get_method
 """
 
+from pprint import pprint
+from pysteps import nowcasts
+import importlib
 from pysteps.extrapolation.interface import eulerian_persistence
 from pysteps.nowcasts import (
     anvil,
@@ -39,7 +42,10 @@
     steps,
     sseps,
 )
+
 from pysteps.nowcasts import lagrangian_probability
+import os
+
 
 _nowcast_methods = dict()
 _nowcast_methods["anvil"] = anvil.forecast
@@ -54,6 +60,91 @@
 _nowcast_methods["steps"] = steps.forecast
 
 
+def discover_nowcasts():
+    """
+    Search for installed nowcasts plugins in the entrypoint 'pysteps.plugin.nowcasts'
+
+    The nowcasts method found are added to the `pysteps.nowcasts.interface_nowcasts_methods`
+    dictionary containing the available nowcasts_methods.
+    """
+
+    # The pkg resources needs to be reload to detect new packages installed during
+    # the execution of the python application. For example, when the plugins are
+    # installed during the tests
+    import pkg_resources
+
+    importlib.reload(pkg_resources)
+
+    for entry_point in pkg_resources.iter_entry_points(
+        group="pysteps.plugins.nowcasts", name=None
+    ):
+        _module = entry_point.load()
+        nowcast_module_name = entry_point.name
+
+        if nowcast_module_name not in _nowcast_methods:
+            _nowcast_methods[nowcast_module_name] = _module
+
+        else:
+            RuntimeWarning(
+                f"The Nowcasts methode '{nowcast_module_name}' is already available in"
+                "'pysteps.nowcasts._nowcasts_methods'.\n"
+                f"Skipping {entry_point.module_name}:{'.'.join(entry_point.attrs)}"
+            )
+        if hasattr(nowcasts, nowcast_module_name):
+            RuntimeWarning(
+                f"The nowcasts method '{nowcast_module_name}' is already an attribute"
+                "of 'pysteps.nowcasts'.\n"
+                f"Skipping {entry_point.module_name}:{'.'.join(entry_point.attrs)}"
+            )
+        else:
+            setattr(nowcasts, nowcast_module_name, _module)
+
+
+def nowcasts_info():
+    """Print all the available nowcast methods."""
+
+    # nowcasts methods available in the `nowcasts` package
+    available_nowcasts = [
+        attr.split(".")[0]
+        for attr in os.listdir(" ".join(nowcasts.__path__))
+        if not attr.startswith("__") and attr != "interface.py"
+    ]
+    print("\nMethods available in the pysteps.nowcasts")
+    pprint(available_nowcasts)
+    # nowcasts declared in the pysteps.nowcast interface
+
+    nowcasts_in_the_interface = [f for f in _nowcast_methods.keys()]
+
+    print("\nMethods available in the pysteps.nowcasts.get_method interface")
+    pprint([(short_name, f.__name__) for short_name, f in _nowcast_methods.items()])
+
+    # Let's use sets to find out if there are importers present in the importer module
+    # but not declared in the interface, and viceversa.
+    available_nowcasts = set(available_nowcasts)
+    nowcasts_in_the_interface = set(nowcasts_in_the_interface)
+
+    difference = available_nowcasts ^ nowcasts_in_the_interface
+    if len(difference) > 0:
+        print("\nIMPORTANT:")
+        _diff = available_nowcasts - nowcasts_in_the_interface
+        if len(_diff) > 0:
+            print(
+                "\nIMPORTANT:\nThe following importers are available in pysteps.nowcasts module "
+                "but not in the pysteps.nowcasts.get_method interface"
+            )
+            pprint(_diff)
+        _diff = nowcasts_in_the_interface - available_nowcasts
+        if len(_diff) > 0:
+            print(
+                "\nWARNING:\n"
+                "The following importers are available in the pysteps.nowcasts.get_method "
+                "interface but not in the pysteps.nowcasts module"
+            )
+            pprint(_diff)
+
+    return available_nowcasts, nowcasts_in_the_interface
+
+
 def get_method(name):
     """
     Return a callable function for computing nowcasts.
@@ -90,6 +181,7 @@
     |  sseps          | short-space ensemble prediction system (SSEPS).       |
     |                 | Essentially, this is a localization of STEPS          |
     +-----------------+-------------------------------------------------------+
+
     """
     if isinstance(name, str):
         name = name.lower()

pysteps/tests/test_interfaces.py

@@ -260,6 +260,20 @@ def test_nowcasts_interface():
         for i in range(num_timesteps):
             assert numpy.all(forecast[i] == precip)
 
+    # Test for invalid method types
+    with pytest.raises(ValueError):
+        pysteps.nowcasts.interface.get_method("linear")
+
+    assert isinstance(
+        pysteps.nowcasts.interface.nowcasts_info()[0],
+        set,
+    )
+
+    assert isinstance(
+        pysteps.nowcasts.interface.nowcasts_info()[1],
+        set,
+    )
+
 
 def test_utils_interface():
     """Test utils module interface."""

pysteps/tests/test_plugins_support.py

@@ -10,7 +10,6 @@
 import sys
 import tempfile
 
-
 __ = pytest.importorskip("cookiecutter")
 from cookiecutter.main import cookiecutter