Implementation:ArroyoSystems Arroyo Impulse Connector

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

Overview

ImpulseConnector is a built-in source-only connector that generates periodic events at a configurable rate, producing a fixed schema of counter and subtask_index fields for testing and development.

Description

The Impulse connector generates synthetic events with a two-column schema: counter (Int64, monotonically increasing) and subtask_index (Int64, the parallel task ID). It supports configurable event_rate (events per second), optional event_time_interval (in nanoseconds, to control how event timestamps advance), and optional message_count (to bound the total number of events). When message_count is specified, the description is prefixed with "Bounded". The connector does not support custom schemas; if a schema is provided, it must match the impulse schema exactly. The make_operator method constructs an ImpulseSourceFunc with ImpulseSpec::EventsPerSecond and the configured limit.

Usage

Use ImpulseConnector for generating synthetic test data streams when developing or benchmarking Arroyo pipelines without requiring external data sources.

Code Reference

Source Location

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

Signature

pub struct ImpulseConnector {}

pub fn impulse_schema() -> ConnectionSchema;

impl Connector for ImpulseConnector {
    type ProfileT = EmptyConfig;
    type TableT = ImpulseTable;

    fn name(&self) -> &'static str; // returns "impulse"
    fn table_type(&self, _: EmptyConfig, _: ImpulseTable) -> ConnectionType; // always Source
    fn get_schema(&self, _: EmptyConfig, _: ImpulseTable,
        _: Option<&ConnectionSchema>) -> Option<ConnectionSchema>;
    fn from_config(&self, id: Option<i64>, name: &str, config: EmptyConfig,
        table: ImpulseTable, _: Option<&ConnectionSchema>) -> anyhow::Result<Connection>;
    fn make_operator(&self, _: EmptyConfig, table: ImpulseTable,
        _: OperatorConfig) -> anyhow::Result<ConstructedOperator>;
}

Import

use arroyo_connectors::impulse::ImpulseConnector;
use arroyo_connectors::impulse::impulse_schema;

I/O Contract

Inputs

Name	Type	Required	Description
event_rate	f64	Yes	Target events per second
event_time_interval	Option<i64>	No	Nanosecond interval between event timestamps
message_count	Option<i64>	No	Total number of events to generate (unbounded if None)

Outputs

Name	Type	Description
counter	Int64	Monotonically increasing event counter
subtask_index	Int64	Parallel task index generating the event

Usage Examples

CREATE TABLE impulse_source (
    counter BIGINT,
    subtask_index BIGINT
) WITH (
    connector = 'impulse',
    event_rate = '1000',
    message_count = '10000'
);

Related Pages

• Environment:ArroyoSystems_Arroyo_Rust_Runtime