api: Add exp_save.

dvc/api/__init__.py

@@ -2,10 +2,11 @@ from dvc.fs.dvc import _DVCFileSystem as DVCFileSystem
 
 from .data import open  # pylint: disable=redefined-builtin
 from .data import get_url, read
-from .experiments import make_checkpoint
+from .experiments import exp_save, make_checkpoint
 from .show import metrics_show, params_show
 
 __all__ = [
+    "exp_save",
     "get_url",
     "make_checkpoint",
     "open",

dvc/api/experiments.py

@@ -1,6 +1,7 @@
 import builtins
 import os
 from time import sleep
+from typing import List, Optional
 
 from dvc.env import DVC_CHECKPOINT, DVC_ROOT
 from dvc.repo import Repo
@@ -31,3 +32,40 @@ def make_checkpoint():
         os.fsync(fobj.fileno())
     while os.path.exists(signal_file):
         sleep(0.1)
+
+
+def exp_save(
+    name: Optional[str] = None,
+    force: bool = False,
+    include_untracked: Optional[List[str]] = None,
+):
+    """
+    Create a new DVC experiment using `exp save`.
+
+    See https://dvc.org/doc/command-reference/exp/save.
+
+    Args:
+        name (str, optional): specify a name for this experiment.
+            If `None`, a default one will be generated, such as `urban-sign`.
+            Defaults to `None`.
+        force (bool):  overwrite the experiment if an experiment with the same
+            name already exists.
+            Defaults to `False`.
+        include_untracked (List[str], optional): specify untracked file(s) to
+            be included in the saved experiment.
+            Defaults to `None`.
+
+    Returns:
+        str: The `Git revision`_ of the created experiment.
+
+    Raises:
+        ExperimentExistsError: If an experiment with `name` already exists and
+            `force=False`.
+
+    .. _Git revision:
+        https://git-scm.com/docs/revisions
+    """
+    with Repo() as repo:
+        return repo.experiments.save(
+            name=name, force=force, include_untracked=include_untracked
+        )

tests/func/api/test_experiments.py

@@ -0,0 +1,18 @@
+import pytest
+
+from dvc import api
+from dvc.repo.experiments.exceptions import ExperimentExistsError
+
+
+def test_exp_save(tmp_dir, dvc, scm, mocker):
+    tmp_dir.scm_gen({"foo": "foo"}, commit="initial")
+
+    api.exp_save()
+
+    api.exp_save("foo")
+    with pytest.raises(
+        ExperimentExistsError,
+        match="Experiment conflicts with existing experiment 'foo'.",
+    ):
+        api.exp_save("foo")
+    api.exp_save("foo", force=True)