Xuanwo b944055b63 feat(python): class Functions with initialization and shipped helper code (#4254)
Stacked on #4253.

Remote Python Functions could not share helper code, take typed
parameters, or keep per-process state: helpers became `from <module>
import ...` lines a worker cannot resolve, every parameter was an `env=`
string, and state had to be stashed on imported modules. MMLB's OpenAI
preset shows the cost — 24 env vars, a 302-line callable, and a rate
limiter duplicated between the scalar and batch variants, one of which
never constructed it (ENT-2516).

**Class Functions.** `@udf` accepts a class. Each remote instance runs
`__init__` once, calls `__call__` for every row or batch it processes
(row or batch mode is inferred from annotations as before), and calls
`close()` once if defined. Calling the definition locally constructs the
class, so unit tests stay ordinary.

**Initialization.** The annotated `__init__` parameters become the
Function's initialization fields. A binding passes their values beside
its column inputs: `fn(text=col("body"), model="small",
dimensions=512)`. Values are constants of that binding; another column
can bind the same Function version with other values. Types are limited
to booleans, integers, floats, strings, and lists or structs of them,
which have one unambiguous JSON and SQL spelling. A parameter with a
default may be omitted; a null value then takes the default.
Initialization and input names must be disjoint because both are keyword
arguments of one call. Secrets stay on `EnvVarSecret`.

**Helper code.** `code=[package, ...]` ships top-level modules or
packages as Python source in a `python_bundle` artifact (a canonical
JSON object of path → source), imported normally on the worker. Changing
a helper changes the artifact digest and so the Function version; the
environment from `pip`/`conda` is reused. Functions and classes defined
in `__main__` (notebook cells, scripts) are packaged by source,
recursively and dependencies first. An import of a module that lives in
a local source tree, is not shipped with `code=`, and names no declared
package is now rejected at registration instead of failing on the
worker. Closures, lambdas, and nested definitions are still rejected,
with the reason.

A Function without these features packages byte-identically to before
(`python_callable`, same digest, no `initialization` on the wire). Class
sources are located through a method's code object, because
`inspect.getsource` cannot find a class defined in a notebook cell or
doctest.

The packaging contract is documented on `udf`. Sophon changes that build
and execute these artifacts are in lancedb/sophon; they were verified
end to end on a Linux local server (registration → REST, SQL, and
materialized-view bindings with different initialization → refresh →
query, one construction per instance).
2026-09-24 00:56:52 +08:00
2026-09-09 15:33:04 +08:00
2023-03-17 18:15:19 -07:00
2025-03-10 09:01:23 -07:00

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LanceDB

The Multimodal AI Lakehouse

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The ultimate multimodal data platform for AI/ML applications.

LanceDB is designed for fast, scalable, and production-ready vector search. It is built on top of the Lance columnar format. You can store, index, and search over petabytes of multimodal data and vectors with ease. LanceDB is a central location where developers can build, train and analyze their AI workloads.


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Key Features:

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Follow the Quickstart doc to set up LanceDB locally.

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Interface Documentation
Python SDK https://lancedb.github.io/lancedb/python/python/
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Developer-friendly OSS embedded retrieval library for multimodal AI. Search More; Manage Less.
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