Add langserve version (#11195)

Add langserve version

libs/langserve/langserve/__init__.py

@@ -1,4 +1,15 @@
+"""Main entrypoint into package."""
+from importlib import metadata
+
 from langserve.client import RemoteRunnable
 from langserve.server import add_routes
 
 __all__ = ["RemoteRunnable", "add_routes"]
+
+
+try:
+    __version__ = metadata.version(__package__)
+except metadata.PackageNotFoundError:
+    # Case where package metadata is not available.
+    __version__ = ""
+del metadata  # optional, avoids polluting the results of dir(__package__)

libs/langserve/tests/unit_tests/test_version.py

@@ -0,0 +1,3 @@
+def test_version_available() -> None:
+    """Test that a version is available."""
+    from langserve import __version__  # noqa: F401