Implementation:ArroyoSystems Arroyo Udf Api Types

Knowledge Sources	ArroyoSystems_Arroyo
Domains	Streaming, UDF, API
Last Updated	2026-02-08 08:00 GMT

Overview

Defines the API-level types for user-defined function (UDF) management, including creation, validation, and storage representations for both Rust and Python UDFs.

Description

This module provides the types for the UDF management API:

• Udf -- a lightweight UDF reference used within pipeline definitions, containing a definition string and language (Rust or Python).
• UdfLanguage -- an enum with variants Python and Rust (default). Derives Display and EnumString from strum for serialization and parsing.
• ValidateUdfPost -- request type for validating a UDF definition before registration.
• UdfValidationResult -- response type with the parsed udf_name and any validation errors.
• UdfPost -- request for creating/updating a global UDF with prefix, language, definition, and optional description.
• GlobalUdf -- the persisted representation of a registered UDF with id, prefix, name, language, timestamps, definition, description, and optional dylib_url pointing to the compiled shared library.

Usage

Use these types when implementing or consuming the UDF endpoints in the Arroyo REST API for registering, validating, and managing user-defined functions.

Code Reference

Source Location

• Repository: ArroyoSystems_Arroyo
• File: crates/arroyo-rpc/src/api_types/udfs.rs

Signature

pub struct Udf { pub definition: String, pub language: UdfLanguage }

pub enum UdfLanguage { Python, Rust }

pub struct ValidateUdfPost { pub definition: String, pub language: UdfLanguage }
pub struct UdfValidationResult { pub udf_name: Option<String>, pub errors: Vec<String> }

pub struct UdfPost {
    pub prefix: String,
    pub language: UdfLanguage,
    pub definition: String,
    pub description: Option<String>,
}

pub struct GlobalUdf {
    pub id: String,
    pub prefix: String,
    pub name: String,
    pub language: UdfLanguage,
    pub created_at: u64,
    pub updated_at: u64,
    pub definition: String,
    pub description: Option<String>,
    pub dylib_url: Option<String>,
}

Import

use arroyo_rpc::api_types::udfs::{Udf, UdfLanguage, UdfPost, GlobalUdf, ValidateUdfPost, UdfValidationResult};

I/O Contract

Inputs

Name	Type	Required	Description
definition	String	Yes	UDF source code (Rust or Python)
language	UdfLanguage	No (defaults to Rust)	Programming language of the UDF
prefix	String	Yes (for UdfPost)	Namespace prefix for the UDF

Outputs

Name	Type	Description
GlobalUdf	GlobalUdf	Persisted UDF with compilation artifacts
UdfValidationResult	UdfValidationResult	Parsed name and any validation errors

Usage Examples

use arroyo_rpc::api_types::udfs::{UdfPost, UdfLanguage};

let udf_request = UdfPost {
    prefix: "my_udfs".to_string(),
    language: UdfLanguage::Rust,
    definition: r#"
        fn my_transform(x: i64) -> i64 {
            x * 2
        }
    "#.to_string(),
    description: Some("Doubles the input value".to_string()),
};

Related Pages

• Environment:ArroyoSystems_Arroyo_Rust_Runtime