command: print the current cache directory when no cmd flags are provided (#4613)

* command: print the current cache directory when no cmd flags are provided
tests: corrected the test for cache dir cmomand

comamnd 'dvc cache dir' now prints the current cache dir
when no cmd flags are provided and modified existing test for
the same.

Fixes #1998

Signed-off-by: Girish Joshi <[email protected]>

* command: updated validation for args.value and args.unset flag
according to current convention in dvc/command/cache.py

Signed-off-by: Girish Joshi <[email protected]>

* Update dvc/command/cache.py

* dont forget logger

Co-authored-by: Ruslan Kuprieiev <[email protected]>
Co-authored-by: Ruslan Kuprieiev <[email protected]>

dvc/command/cache.py

@@ -1,12 +1,18 @@
 import argparse
+import logging
 
 from dvc.command import completion
 from dvc.command.base import append_doc_link, fix_subparsers
 from dvc.command.config import CmdConfig
 
+logger = logging.getLogger(__name__)
+
 
 class CmdCacheDir(CmdConfig):
     def run(self):
+        if self.args.value is None and not self.args.unset:
+            logger.info(self.config["cache"]["dir"])
+            return 0
         with self.config.edit(level=self.args.level) as edit:
             edit["cache"]["dir"] = self.args.value
         return 0
@@ -55,6 +61,8 @@ def add_parser(subparsers, parent_parser):
         "value",
         help="Path to cache directory. Relative paths are resolved relative "
         "to the current directory and saved to config relative to the "
-        "config file location.",
+        "config file location. If no path is provided, it returns the "
+        "current cache directory.",
+        nargs="?",
     ).complete = completion.DIR
     cache_dir_parser.set_defaults(func=CmdCacheDir)

tests/func/test_cache.py

@@ -154,7 +154,7 @@ class TestCacheLinkType(TestDvc):
 class TestCmdCacheDir(TestDvc):
     def test(self):
         ret = main(["cache", "dir"])
-        self.assertEqual(ret, 254)
+        self.assertEqual(ret, 0)
 
     def test_abs_path(self):
         dname = os.path.join(os.path.dirname(self._root_dir), "dir")