Add cache_root context manager

Author: acampove

README.md

@@ -170,13 +170,9 @@ class Tester(Wcache):
 
         return res
 
-# This will set the root directory where cached data goes
-# The data will go to `/some/directory/Tester`
-# This has to be done ONCE and only ONCE.
-Wcache.set_cache_root(root='/some/directory')
-
-obj = Tester(nval=3)
-...
+with Cache.cache_path(path='/some/directory')
+    obj = Tester(nval=3)
+    ...
 ```
 
 where the tester class has access to extra functionalities to:

src/dmu/workflow/cache.py

@@ -256,6 +256,26 @@ def _context():
         return _context()
     # ---------------------------
     @classmethod
+    def cache_root(cls, path : Path):
+        '''
+        Context manager used to set caching directory
+
+        Parameters
+        ----------------
+        path: Path to directory where outputs will be cached
+        '''
+        old_val = cls._cache_root
+        @contextmanager
+        def _context():
+            cls._cache_root = str(path)
+            try:
+                yield
+            finally:
+                cls._cache_root = old_val
+
+        return _context()
+    # ---------------------------
+    @classmethod
     def set_cache_root(cls, root : str | Path) -> None:
         '''
         Sets the path to the directory WRT which the _out_path_

tests/worflow/test_cache.py

@@ -4,6 +4,7 @@
 import os
 import pytest
 
+from pathlib               import Path
 from dmu.generic           import utilities as gut
 from dmu.workflow.cache    import Cache     as Wcache
 from dmu.logging.log_store import LogStore
@@ -145,3 +146,15 @@ def test_cache_with_dir():
 
         assert res == out
 # -----------------------------------
+def test_cache_context(tmp_path : Path):
+    '''
+    Tests setting caching directory through context manager
+    '''
+    log.info('')
+    res = 4 * [1]
+
+    with Wcache.cache_root(path=tmp_path):
+        obj = Tester(nval=4, name='cache_context')
+        out = obj.run()
+
+    assert res == out