Merge pull request #408 from compas-dev/raise-bfnserror

Raise specific exceptions if backend feature is not supported

Author: gonzalocasas

CHANGELOG.md

@@ -11,6 +11,8 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Changed
 
+* Raise `BackendFeatureNotSupportedError` exceptions when a features is not supported by the planner, instead of generic `Exception`.
+
 ### Removed
 
 

src/compas_fab/backends/__init__.py

@@ -91,9 +91,10 @@
     :nosignatures:
 
     BackendError
+    BackendFeatureNotSupportedError
     CartesianMotionError
-    KinematicsError
     InverseKinematicsError
+    KinematicsError
 
 Interfaces
 ==========
@@ -108,8 +109,9 @@
 # Base imports
 from .exceptions import (
     BackendError,
-    KinematicsError,
+    BackendFeatureNotSupportedError,
     InverseKinematicsError,
+    KinematicsError,
 )
 from .tasks import (
     FutureResult,
@@ -158,8 +160,9 @@
 __all__ = [
     # Base
     "BackendError",
-    "KinematicsError",
+    "BackendFeatureNotSupportedError",
     "InverseKinematicsError",
+    "KinematicsError",
     "FutureResult",
     "CancellableFutureResult",
     # ROS

src/compas_fab/backends/exceptions.py

@@ -4,8 +4,9 @@
 
 __all__ = [
     "BackendError",
-    "KinematicsError",
+    "BackendFeatureNotSupportedError",
     "InverseKinematicsError",
+    "KinematicsError",
 ]
 
 
@@ -17,6 +18,12 @@ def __init__(self, message):
         super(BackendError, self).__init__(message)
 
 
+class BackendFeatureNotSupportedError(Exception):
+    """Indicates that the selected backend does not support the selected feature."""
+
+    pass
+
+
 class KinematicsError(BackendError):
     """Indicates a kinematic solver exception."""
 

src/compas_fab/backends/interfaces/client.py

@@ -1,6 +1,7 @@
 from __future__ import absolute_import
 from __future__ import division
 from __future__ import print_function
+from compas_fab.backends.exceptions import BackendFeatureNotSupportedError
 
 
 def forward_docstring(backend_feature):
@@ -117,40 +118,40 @@ def inverse_kinematics(self, *args, **kwargs):
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def forward_kinematics(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def plan_motion(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def plan_cartesian_motion(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     # ==========================================================================
     # collision objects and planning scene
@@ -161,67 +162,67 @@ def get_planning_scene(self, *args, **kwargs):
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def reset_planning_scene(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def add_collision_mesh(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def remove_collision_mesh(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def append_collision_mesh(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def add_attached_collision_mesh(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")
 
     def remove_attached_collision_mesh(self, *args, **kwargs):
         """Default method for planner.
 
         Raises
         ------
-        Exception
+        BackendFeatureNotSupportedError
             Planner does not have this feature.
         """
-        raise Exception("Assigned planner does not have this feature.")
+        raise BackendFeatureNotSupportedError("Assigned planner does not have this feature.")

src/compas_fab/ghpython/components/Cf_VisualizeRobot/code.py

@@ -14,6 +14,7 @@
 from ghpythonlib.componentbase import executingcomponent as component
 from scriptcontext import sticky as st
 
+from compas_fab.backends import BackendFeatureNotSupportedError
 from compas_fab.robots import PlanningScene
 
 
@@ -89,7 +90,15 @@ def RunScript(
 
                 if update_scene:
                     scene = PlanningScene(robot)
-                    scene = robot.client.get_planning_scene()
+                    try:
+                        scene = robot.client.get_planning_scene()
+                    except BackendFeatureNotSupportedError:
+                        print(
+                            "The selected backend does not support collision meshes. If you need collision mesh support, use a different backend."
+                        )
+                        scene = None
+                        show_cm = False
+                        show_acm = False
 
                 if update_scene and show_cm:
                     collision_meshes = []