Files
lancedb/python/python/tests/test_function_packaging.py
T
Xuanwo 0b18dcdaec fix(python): warn instead of failing on local imports in @udf source (#4318)
Since 0.40.0b8 (#4254), `@udf` raises when the packaged source imports a
module from a local source tree that is neither shipped with `code=` nor
named by a declared pip/conda package. That turned registrations that
used to succeed into errors:

- Callers that rewrite the packaged source before registering it now
fail at decoration. Sophon's datagen integration suite inlines its
test-module helpers this way, and
`test_registered_udf_source_stands_alone_on_a_worker` fails on 0.40.0b8.
- The check cannot know which modules a distribution installs. A
declared package whose distribution name differs from its module (for
example an internal library installed editable) is reported as local,
and there was no way to proceed.

This keeps the diagnosis but makes it a `UserWarning`, so registration
behaves as it did before #4254 and still tells the author, at
registration time, why the worker is likely to fail.
2026-09-24 18:02:25 +08:00

528 lines
16 KiB
Python

# SPDX-License-Identifier: Apache-2.0
# SPDX-FileCopyrightText: Copyright The LanceDB Authors
"""Class Functions, initialization, and the source that travels with a Function."""
from __future__ import annotations
import base64
import importlib
import json
import subprocess
import sys
import textwrap
import warnings
from pathlib import Path
from typing import Annotated, Optional
import pyarrow as pa
import pytest
from lancedb import col
from lancedb.functions import FunctionVersion, udf
FIXTURES = (
Path(__file__).parents[3]
/ "rust"
/ "lancedb"
/ "tests"
/ "fixtures"
/ "first_class_functions"
/ "v1"
)
def artifact(definition) -> bytes:
return base64.b64decode(definition.registration_request.artifact.content.data)
def bundle_files(definition) -> dict[str, str]:
assert definition.registration_request.artifact.kind == "python_bundle"
return json.loads(artifact(definition))["files"]
@pytest.fixture
def helper_package(tmp_path, monkeypatch):
"""A local package on sys.path, the way a project's own helpers are."""
def write(name: str, files: dict[str, str]):
root = tmp_path / name
for path, source in files.items():
target = root / path
target.parent.mkdir(parents=True, exist_ok=True)
target.write_text(textwrap.dedent(source))
monkeypatch.syspath_prepend(str(tmp_path))
for module in [
module for module in sys.modules if module.split(".")[0] == name
]:
del sys.modules[module]
importlib.invalidate_caches()
return importlib.import_module(name)
return write
@udf
class scale:
def __init__(
self,
factor: float,
label: str,
offset: float = 0.0,
tags: Optional[list[str]] = None,
retry: Annotated[dict, pa.struct([("attempts", pa.int32())])] = None,
):
self.factor, self.offset = factor, offset
def __call__(self, value: float) -> float:
return value * self.factor + self.offset
class NoCall:
pass
class BadClose:
def __call__(self, value: int) -> int:
return value
def close(self, force):
pass
def test_class_function_declares_inputs_output_and_initialization():
signature = scale.registration_request.signature
assert [(p.name, p.arrow_type) for p in signature.inputs] == [("value", "float64")]
assert [
(field.name, field.arrow_type, field.nullable)
for field in signature.initialization
] == [
("factor", "float64", False),
("label", "utf8", False),
("offset", "float64", True),
("tags", "list<utf8>", True),
(
"retry",
'{"fields":[{"name":"attempts","nullable":true,"type":{"type":"int32"}}],'
'"type":"struct"}',
True,
),
]
# Calling the definition constructs the class, so local tests are ordinary.
assert scale(factor=2.0, label="x")(1.5) == 3.0
assert scale.registration_request.artifact.entrypoint == "scale"
source = artifact(scale).decode()
assert source.startswith("from __future__ import annotations\n")
assert "class scale:" in source and "@udf" not in source
def test_function_without_initialization_keeps_its_wire_form():
@udf
def double(value: int) -> int:
return value * 2
request = json.loads(double.registration_request.to_canonical_json())
assert "initialization" not in request["signature"]
assert request["artifact"]["kind"] == "python_callable"
@pytest.mark.parametrize(
("init", "message"),
[
("def __init__(self, blob: bytes): pass", "initialization takes booleans"),
("def __init__(self, *args: int): pass", "named and non-variadic"),
("def __init__(self, factor): pass", "missing Function initialization"),
("def __init__(self, value: int): pass", "share names \\['value'\\]"),
],
)
def test_class_function_rejects_unsupported_initialization(init, message):
namespace = {}
exec(
textwrap.dedent(
f"""
class bad:
{init}
def __call__(self, value: int) -> int:
return value
"""
),
namespace,
)
with pytest.raises((TypeError, ValueError), match=message):
udf(namespace["bad"])
def test_class_function_requires_call_and_a_plain_close():
with pytest.raises(TypeError, match="synchronous __call__"):
udf(NoCall)
with pytest.raises(TypeError, match="close must be a method taking no"):
udf(BadClose)
def test_nested_class_and_closure_are_rejected_with_the_reason():
def build():
class nested:
def __call__(self, value: int) -> int:
return value
return nested
with pytest.raises(ValueError, match="defined at module level"):
udf(build())
factor = 3
with pytest.raises(ValueError, match="capture closure values"):
@udf
def closes_over(value: int) -> int:
return value * factor
def test_binding_passes_initialization_as_constants():
version = FunctionVersion.from_json(
json.dumps(
{
**json.loads(
(FIXTURES / "remote_function_version.canonical.json").read_text()
),
"signature": {
"inputs": [
{"name": "text", "arrow_type": "utf8", "nullable": True}
],
"output": {
"kind": "scalar",
"arrow_type": "list<float32>",
"nullable": False,
},
"initialization": [
{"name": "model", "arrow_type": "utf8", "nullable": False},
{"name": "dimensions", "arrow_type": "int32", "nullable": True},
],
},
}
)
)
application = version(text=col("body"), model="small", dimensions=(512))
assert dict(application.initialization) == {"model": "small", "dimensions": 512}
assert json.loads(application.to_canonical_json())["initialization"] == {
"dimensions": 512,
"model": "small",
}
assert version(text=col("body"), model="small").initialization == {"model": "small"}
with pytest.raises(TypeError, match=r"missing initialization: \['model'\]"):
version(text=col("body"))
with pytest.raises(TypeError, match="takes a constant"):
version(text=col("body"), model=col("model"))
with pytest.raises(ValueError, match="must be finite"):
version(text=col("body"), model="small", dimensions=float("nan"))
with pytest.raises(TypeError, match="takes booleans"):
version(text=col("body"), model=object())
def test_code_packages_ship_as_a_bundle_and_version_with_their_source(
tmp_path, helper_package
):
files = {
"__init__.py": "",
"rate.py": """
class TokenBucket:
def __init__(self, tokens_per_minute):
self.tokens_per_minute = tokens_per_minute
""",
"__pycache__/rate.cpython-312.pyc": "",
"fixtures/data.json": "{}",
"not-a-module.py": "",
}
helper_package("fx_helpers", files)
(tmp_path / "fx_helpers_functions.py").write_text(
textwrap.dedent(
"""
import fx_helpers
from fx_helpers.rate import TokenBucket
from lancedb import udf
@udf(code=[fx_helpers])
class limited:
def __init__(self, tpm: int):
self.limiter = TokenBucket(tpm)
def __call__(self, value: int) -> int:
return value
"""
)
)
def define():
sys.modules.pop("fx_helpers_functions", None)
return importlib.import_module("fx_helpers_functions").limited
first = define()
shipped = bundle_files(first)
assert sorted(shipped) == [
"fx_helpers/__init__.py",
"fx_helpers/rate.py",
"user_function.py",
]
assert (
"from fx_helpers.rate import TokenBucket as TokenBucket"
in (shipped["user_function.py"])
)
# Only the helper changes: a new artifact digest, the same environment.
helper_package(
"fx_helpers", {**files, "rate.py": textwrap.dedent(files["rate.py"]) + "# v2\n"}
)
second = define()
assert (
first.registration_request.artifact.digest
!= second.registration_request.artifact.digest
)
assert first.registration_request.runtime == second.registration_request.runtime
def test_code_rejects_submodules_duplicates_and_non_modules(helper_package):
helpers = helper_package("fx_rejects", {"__init__.py": "", "sub.py": ""})
import fx_rejects.sub
for code, message in [
([fx_rejects.sub], "top-level modules"),
([helpers, helpers], "more than once"),
(["fx_rejects"], "imported modules"),
([json], "cannot ship module 'json'"),
]:
with pytest.raises((TypeError, ValueError), match=message):
@udf(code=code)
def f(value: int) -> int:
return value
def test_local_module_outside_code_warns_at_registration(tmp_path, helper_package):
"""The worker most likely cannot import a local module that is neither
shipped nor declared, but registration still succeeds: a declared
distribution may install it under another name, and callers may rewrite
the packaged source before registering it."""
helper_package(
"fx_local", {"__init__.py": "def normalize(value):\n return value\n"}
)
def define(name, options):
(tmp_path / f"{name}.py").write_text(
textwrap.dedent(
f"""
from fx_local import normalize
from lancedb import udf
@udf({options})
def {name}(value: int) -> int:
return normalize(value)
"""
)
)
return getattr(importlib.import_module(name), name)
with pytest.warns(UserWarning, match=r"local module.*code=\[fx_local\]"):
local = define("fx_uses_local", "")
assert "from fx_local import normalize" in artifact(local).decode()
# A declared package that provides the module is trusted to install it.
with warnings.catch_warnings():
warnings.simplefilter("error")
installed = define("fx_uses_installed", "pip=['fx-local==1.0']")
assert "from fx_local import normalize" in artifact(installed).decode()
MMLB_HELPERS = {
"__init__.py": "",
"rate.py": """
class TokenBucket:
constructed = 0
def __init__(self, tokens_per_minute):
TokenBucket.constructed += 1
self.tokens_per_minute = tokens_per_minute
self.acquired = 0
def acquire(self, tokens):
self.acquired += tokens
""",
"embedding.py": """
from fx_mmlb.rate import TokenBucket
class OpenAIEmbedder:
def __init__(self, model: str, tpm_limit: int, max_attempts: int = 6):
self.model = model
self.limiter = TokenBucket(tpm_limit)
self.max_attempts = max_attempts
def embed(self, texts):
self.limiter.acquire(sum(len(text) for text in texts))
return [[float(len(text))] for text in texts]
""",
}
MMLB_FUNCTIONS = """
import pyarrow as pa
import fx_mmlb
from fx_mmlb.embedding import OpenAIEmbedder
from lancedb import udf
TEXT = pa.schema([pa.field("text", pa.string())])
EMBEDDING = pa.list_(pa.field("item", pa.float64(), nullable=False))
@udf(code=[fx_mmlb], input_schema=TEXT, output_schema=EMBEDDING)
class openai_embedding_batch(OpenAIEmbedder):
def __call__(self, text: pa.Array) -> pa.Array:
item = pa.field("item", pa.float64(), nullable=False)
return pa.array(self.embed(text.to_pylist()), pa.list_(item))
@udf(code=[fx_mmlb])
class openai_embedding(OpenAIEmbedder):
def __call__(self, text: str) -> list[float]:
return self.embed([text])[0]
"""
def test_shared_helpers_construct_state_on_every_path(tmp_path, helper_package):
"""The MMLB rate limiter, shared by a row and a batch Function: both are
initialized through the same helper, so neither path can skip it."""
helper_package("fx_mmlb", MMLB_HELPERS)
(tmp_path / "fx_mmlb_functions.py").write_text(MMLB_FUNCTIONS)
functions = importlib.import_module("fx_mmlb_functions")
signatures = [
functions.openai_embedding_batch.registration_request.signature,
functions.openai_embedding.registration_request.signature,
]
for signature in signatures:
assert [field.name for field in signature.initialization] == [
"model",
"tpm_limit",
"max_attempts",
]
# Each bundle imports on its own, in a process that has never seen the
# client's modules, the way the worker's image code layer does.
for definition, call in [
(
functions.openai_embedding_batch,
"instance(pa.array(['ab', 'abc'])).to_pylist()",
),
(functions.openai_embedding, "[instance('ab'), instance('abc')]"),
]:
worker = tmp_path / definition.__name__
for path, source in bundle_files(definition).items():
(worker / path).parent.mkdir(parents=True, exist_ok=True)
(worker / path).write_text(source)
probe = textwrap.dedent(
f"""
import sys
sys.path.insert(0, {str(worker)!r})
import pyarrow as pa
import user_function
from fx_mmlb.rate import TokenBucket
cls = getattr(user_function, {definition.__name__!r})
instance = cls(model="small", tpm_limit=1000)
print(repr(({call}, TokenBucket.constructed, instance.limiter.acquired)))
"""
)
result = subprocess.run(
[sys.executable, "-I", "-c", probe],
capture_output=True,
text=True,
cwd=worker,
)
assert result.returncode == 0, result.stderr
assert result.stdout.strip() == "([[2.0], [3.0]], 1, 5)"
def test_main_definitions_travel_by_source(tmp_path):
"""Notebook cells and scripts define helpers in __main__, which a worker
cannot import; they are packaged by source, dependencies first."""
script = tmp_path / "notebook.py"
script.write_text(
textwrap.dedent(
"""
import json
import math
from dataclasses import dataclass
from lancedb import udf
SCALE = 2
@dataclass
class Settings:
factor: int
def helper(value):
return math.floor(value) * SCALE
class Base:
def run(self, value):
return helper(value) * self.settings.factor
@udf
class scaled(Base):
def __init__(self, factor: int):
self.settings = Settings(factor)
def __call__(self, value: float) -> int:
return self.run(value)
print(json.dumps(scaled.registration_request.to_canonical_json()))
"""
)
)
result = subprocess.run(
[sys.executable, str(script)], capture_output=True, text=True
)
assert result.returncode == 0, result.stderr
request = json.loads(json.loads(result.stdout))
assert request["artifact"]["kind"] == "python_callable"
source = base64.b64decode(request["artifact"]["content"]["data"]).decode()
assert source.index("def helper") < source.index("class Base")
assert source.index("class Base") < source.index("class scaled")
assert source.index("class Settings") < source.index("class scaled")
assert "@dataclass" in source
assert "SCALE = 2" in source
namespace = {}
exec(compile(source, "user_function.py", "exec"), namespace)
assert namespace["scaled"](factor=3)(2.7) == 12
def test_main_lambdas_are_rejected(tmp_path):
script = tmp_path / "lambda.py"
script.write_text(
textwrap.dedent(
"""
from lancedb import udf
double = lambda value: value * 2
@udf
def uses_lambda(value: int) -> int:
return double(value)
"""
)
)
result = subprocess.run(
[sys.executable, str(script)], capture_output=True, text=True
)
assert result.returncode != 0
assert "not lambdas, closures, or nested definitions" in result.stderr