cli: config: add support for --show-origin (iterative#5126)

* cli: config: add support for --show-origin

Support the --show-origin option for config, which, similar to git,
prefixes each config option with the source file it originated from.

Fixes iterative#5119

* Reformat with black.

* Simplify logic for local config files.

* Add test for --show-config output.

* Update tests/func/test_config.py

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

dvc/command/config.py

@@ -1,8 +1,10 @@
 import argparse
 import logging
+import os
 
 from dvc.command.base import CmdBaseNoRepo, append_doc_link
 from dvc.config import Config, ConfigError
+from dvc.repo import Repo
 from dvc.utils.flatten import flatten
 
 logger = logging.getLogger(__name__)
@@ -34,6 +36,14 @@ def __init__(self, args):
         self.config = Config(validate=False)
 
     def run(self):
+        if self.args.show_origin:
+            if any((self.args.value, self.args.unset)):
+                logger.error(
+                    "--show-origin can't be used together with any of these "
+                    "options: -u/--unset, value"
+                )
+                return 1
+
         if self.args.list:
             if any((self.args.name, self.args.value, self.args.unset)):
                 logger.error(
@@ -43,7 +53,11 @@ def run(self):
                 return 1
 
             conf = self.config.load_one(self.args.level)
-            logger.info("\n".join(self._format_config(conf)))
+            prefix = self._config_file_prefix(
+                self.args.show_origin, self.config, self.args.level
+            )
+
+            logger.info("\n".join(self._format_config(conf, prefix)))
             return 0
 
         if self.args.name is None:
@@ -54,10 +68,14 @@ def run(self):
 
         if self.args.value is None and not self.args.unset:
             conf = self.config.load_one(self.args.level)
+            prefix = self._config_file_prefix(
+                self.args.show_origin, self.config, self.args.level
+            )
+
             if remote:
                 conf = conf["remote"]
             self._check(conf, remote, section, opt)
-            logger.info(conf[section][opt])
+            logger.info("{}{}".format(prefix, conf[section][opt]))
             return 0
 
         with self.config.edit(self.args.level) as conf:
@@ -90,9 +108,21 @@ def _check(self, conf, remote, section, opt=None):
             )
 
     @staticmethod
-    def _format_config(config):
+    def _format_config(config, prefix=""):
         for key, value in flatten(config).items():
-            yield f"{key}={value}"
+            yield f"{prefix}{key}={value}"
+
+    @staticmethod
+    def _config_file_prefix(show_origin, config, level):
+        if not show_origin:
+            return ""
+
+        fname = config.files[level]
+
+        if level in ["local", "repo"]:
+            fname = os.path.relpath(fname, start=Repo.find_root())
+
+        return fname + "\t"
 
 
 parent_config_parser = argparse.ArgumentParser(add_help=False)
@@ -152,4 +182,10 @@ def add_parser(subparsers, parent_parser):
         action="store_true",
         help="List all defined config values.",
     )
+    config_parser.add_argument(
+        "--show-origin",
+        default=False,
+        action="store_true",
+        help="Show the source file containing each config value.",
+    )
     config_parser.set_defaults(func=CmdConfig)

tests/func/test_config.py

@@ -48,9 +48,15 @@ def _do_test(self, local=False):
         self.assertEqual(ret, 0)
         self.assertTrue(self._contains(section, field, value, local))
 
+        ret = main(base + [section_field, value, "--show-origin"])
+        self.assertEqual(ret, 1)
+
         ret = main(base + [section_field])
         self.assertEqual(ret, 0)
 
+        ret = main(base + ["--show-origin", section_field])
+        self.assertEqual(ret, 0)
+
         ret = main(base + [section_field, newvalue])
         self.assertEqual(ret, 0)
         self.assertTrue(self._contains(section, field, newvalue, local))
@@ -60,9 +66,15 @@ def _do_test(self, local=False):
         self.assertEqual(ret, 0)
         self.assertFalse(self._contains(section, field, value, local))
 
+        ret = main(base + [section_field, "--unset", "--show-origin"])
+        self.assertEqual(ret, 1)
+
         ret = main(base + ["--list"])
         self.assertEqual(ret, 0)
 
+        ret = main(base + ["--list", "--show-origin"])
+        self.assertEqual(ret, 0)
+
     def test(self):
         self._do_test(False)
 
@@ -174,3 +186,28 @@ def test_config_remote(tmp_dir, dvc, caplog):
     caplog.clear()
     assert main(["config", "remote.myremote.region"]) == 0
     assert "myregion" in caplog.text
+
+
+def test_config_show_origin(tmp_dir, dvc, caplog):
+    (tmp_dir / ".dvc" / "config").write_text(
+        "['remote \"myremote\"']\n"
+        "  url = s3://bucket/path\n"
+        "  region = myregion\n"
+    )
+
+    caplog.clear()
+    assert main(["config", "--show-origin", "remote.myremote.url"]) == 0
+    assert (
+        "{}\t{}\n".format(os.path.join(".dvc", "config"), "s3://bucket/path")
+        in caplog.text
+    )
+
+    caplog.clear()
+    assert main(["config", "--list", "--show-origin"]) == 0
+    assert (
+        "{}\t{}\n".format(
+            os.path.join(".dvc", "config"),
+            "remote.myremote.url=s3://bucket/path",
+        )
+        in caplog.text
+    )