Implementation:ArroyoSystems Arroyo Preview Connector

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

Overview

PreviewConnector is a hidden sink-only connector that sends pipeline output to the Arroyo web console for real-time query result preview.

Description

The Preview connector is a special internal connector (hidden: true) that cannot be created directly in SQL (from_options returns an error). It is constructed programmatically via from_config and is used by the Arroyo web UI to display live query results in the console preview pane. The connector has EmptyConfig for both profile and table types, and the make_operator method constructs a default PreviewSink operator. It requires a schema to be provided (no custom schemas supported) and propagates bad_data, framing, and metadata_fields from the schema configuration.

Usage

PreviewConnector is used internally by the Arroyo web console for live query result preview and cannot be instantiated directly from SQL queries.

Code Reference

Source Location

• Repository: ArroyoSystems_Arroyo
• File: crates/arroyo-connectors/src/preview/mod.rs

Signature

pub struct PreviewConnector {}

impl Connector for PreviewConnector {
    type ProfileT = EmptyConfig;
    type TableT = EmptyConfig;

    fn name(&self) -> &'static str; // returns "preview"
    fn table_type(&self, _: EmptyConfig, _: EmptyConfig) -> ConnectionType; // always Sink
    fn from_options(&self, ...) -> anyhow::Result<Connection>; // always errors
    fn from_config(&self, id: Option<i64>, name: &str, config: EmptyConfig,
        table: EmptyConfig, schema: Option<&ConnectionSchema>) -> anyhow::Result<Connection>;
    fn make_operator(&self, _: EmptyConfig, _: EmptyConfig,
        _: OperatorConfig) -> anyhow::Result<ConstructedOperator>;
}

Import

use arroyo_connectors::preview::PreviewConnector;

I/O Contract

Inputs

Name	Type	Required	Description
schema	ConnectionSchema	Yes	Schema for the data to preview

Outputs

Name	Type	Description
preview data	Console output	Data displayed in the Arroyo web console preview pane

Usage Examples

// PreviewConnector is used internally by the Arroyo web UI
// It cannot be created via SQL - from_options always returns an error
let connector = PreviewConnector {};
let connection = connector.from_config(
    None,
    "preview_sink",
    EmptyConfig {},
    EmptyConfig {},
    Some(&schema),
)?;

Related Pages

• Environment:ArroyoSystems_Arroyo_Rust_Runtime