Add ButlerURI support to config file override paths.

Author: TallJimbo

python/lsst/pipe/base/configOverrides.py

@@ -29,6 +29,7 @@
 from enum import Enum
 from operator import attrgetter
 
+from lsst.daf.butler import ButlerURI
 from lsst.utils import doImport
 
 OverrideTypes = Enum("OverrideTypes", "Value File Python Instrument")
@@ -147,10 +148,11 @@ def addFileOverride(self, filename):
 
         Parameters
         ----------
-        filename : str
-            Path to the override file.
+        filename : `str` or `ButlerURI`
+            Path or URI to the override file.  All URI schemes supported by
+            `ButlerURI` are supported.
         """
-        self._overrides.append((OverrideTypes.File, filename))
+        self._overrides.append((OverrideTypes.File, ButlerURI(filename)))
 
     def addValueOverride(self, field, value):
         """Add override for a specific field.
@@ -234,7 +236,8 @@ def applyTo(self, config):
 
         for otype, override in self._overrides:
             if otype is OverrideTypes.File:
-                config.load(override)
+                with override.open("r") as buffer:
+                    config.loadFromStream(buffer, filename=str(override))
             elif otype is OverrideTypes.Value:
                 field, value = override
                 if isinstance(value, str):