hydra: support plugins (iterative#10240)

* hydra: support plugins

* Update dvc/utils/hydra.py

* fix tests

* load plugins after some checks run

---------

Co-authored-by: Ruslan Kuprieiev <kupruser@gmail.com>
Co-authored-by: Saugat Pachhai (सौगात) <suagatchhetri@outlook.com>
Co-authored-by: skshetry <18718008+skshetry@users.noreply.github.com>

dvc/config_schema.py

@@ -346,6 +346,7 @@ def __call__(self, data):
         Exclusive("config_dir", "config_source"): str,
         Exclusive("config_module", "config_source"): str,
         "config_name": str,
+        "plugins_path": str,
     },
     "studio": {
         "token": str,

dvc/repo/experiments/queue/base.py

@@ -486,11 +486,15 @@ def _update_params(self, params: Dict[str, List[str]]):
                 else:
                     config_dir = None
                 config_name = hydra_config.get("config_name", "config")
+                plugins_path = os.path.join(
+                    self.repo.root_dir, hydra_config.get("plugins_path", "")
+                )
                 compose_and_dump(
                     path,
                     config_dir,
                     config_module,
                     config_name,
+                    plugins_path,
                     overrides,
                 )
             else:

dvc/utils/hydra.py

@@ -13,11 +13,24 @@
 logger = logger.getChild(__name__)
 
 
+def load_hydra_plugins(plugins_path: str):
+    import sys
+
+    from hydra.core.plugins import Plugins
+
+    sys.path.append(plugins_path)
+    try:
+        Plugins.instance()
+    finally:
+        sys.path.remove(plugins_path)
+
+
 def compose_and_dump(
     output_file: "StrPath",
     config_dir: Optional[str],
     config_module: Optional[str],
     config_name: str,
+    plugins_path: str,
     overrides: List[str],
 ) -> None:
     """Compose Hydra config and dumpt it to `output_file`.
@@ -30,6 +43,7 @@ def compose_and_dump(
             Ignored if `config_dir` is not `None`.
         config_name: Name of the config file containing defaults,
             without the .yaml extension.
+        plugins_path: Path to auto discover Hydra plugins.
         overrides: List of `Hydra Override`_ patterns.
 
     .. _Hydra Override:
@@ -47,6 +61,7 @@ def compose_and_dump(
         initialize_config_dir if config_dir else initialize_config_module
     )
 
+    load_hydra_plugins(plugins_path)
     with initialize_config(  # type: ignore[attr-defined]
         config_source, version_base=None
     ):

tests/func/utils/test_hydra.py

@@ -176,7 +176,9 @@ def test_compose_and_dump_overrides(tmp_dir, suffix, overrides, expected):
     output_file = tmp_dir / f"params.{suffix}"
     config_dir = hydra_setup(tmp_dir, "conf", "config")
     config_module = None
-    compose_and_dump(output_file, config_dir, config_module, config_name, overrides)
+    compose_and_dump(
+        output_file, config_dir, config_module, config_name, str(tmp_dir), overrides
+    )
     assert output_file.parse() == expected
 
 
@@ -229,7 +231,9 @@ def test_compose_and_dump_dir_module(
     )
 
     with error_context:
-        compose_and_dump(output_file, config_dir, config_module, config_name, [])
+        compose_and_dump(
+            output_file, config_dir, config_module, config_name, str(tmp_dir), []
+        )
         assert output_file.parse() == config_content
 
 
@@ -241,7 +245,7 @@ def test_compose_and_dump_yaml_handles_string(tmp_dir):
     config.parent.mkdir()
     config.write_text("foo: 'no'\n")
     output_file = tmp_dir / "params.yaml"
-    compose_and_dump(output_file, str(config.parent), None, "config", [])
+    compose_and_dump(output_file, str(config.parent), None, "config", str(tmp_dir), [])
     assert output_file.read_text() == "foo: 'no'\n"
 
 
@@ -253,12 +257,38 @@ def test_compose_and_dump_resolves_interpolation(tmp_dir):
     config.parent.mkdir()
     config.dump({"data": {"root": "path/to/root", "raw": "${.root}/raw"}})
     output_file = tmp_dir / "params.yaml"
-    compose_and_dump(output_file, str(config.parent), None, "config", [])
+    compose_and_dump(output_file, str(config.parent), None, "config", str(tmp_dir), [])
     assert output_file.parse() == {
         "data": {"root": "path/to/root", "raw": "path/to/root/raw"}
     }
 
 
+def test_compose_and_dump_plugins(tmp_dir):
+    """Ensure Hydra plugins are loaded."""
+    from hydra.core.plugins import Plugins
+
+    from dvc.utils.hydra import compose_and_dump
+
+    # clear cached plugins
+    Plugins._instances.pop(Plugins, None)
+
+    config = tmp_dir / "conf" / "config.yaml"
+    config.parent.mkdir()
+    config.write_text("foo: '${plus_10:1}'\n")
+
+    plugins = tmp_dir / "hydra_plugins"
+    plugins.mkdir()
+    (plugins / "resolver.py").write_text(
+        """\
+from omegaconf import OmegaConf
+OmegaConf.register_new_resolver('plus_10', lambda x: x + 10)"""
+    )
+
+    output_file = tmp_dir / "params.yaml"
+    compose_and_dump(output_file, str(config.parent), None, "config", str(tmp_dir), [])
+    assert output_file.read_text() == "foo: 11\n"
+
+
 @pytest.mark.parametrize(
     "overrides, expected",
     [