Implementation:ArroyoSystems Arroyo Checkpoint Api Types

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

Overview

Defines the API-level types for representing checkpoint metadata, checkpoint event spans, and checkpoint lifecycle phases used by the Arroyo REST API and controller.

Description

This module provides serializable types for checkpoint reporting in the Arroyo UI and API:

• Checkpoint -- top-level checkpoint info with epoch, backend name, start/finish times, and event spans.
• CheckpointEventSpan -- a time-bounded event within a checkpoint (start_time, finish_time, event name, description).
• SubtaskCheckpointGroup -- per-subtask checkpoint data including bytes written and event spans.
• OperatorCheckpointGroup -- per-operator checkpoint data aggregating subtask groups with metadata write timing.
• JobCheckpointEventType -- enum of checkpoint lifecycle phases: Checkpointing, CheckpointingOperators, WritingMetadata, Compacting, Committing.
• JobCheckpointSpan -- a timed span for a checkpoint phase with now() constructor and finish() method using SystemTime.

Usage

Use these types when building checkpoint detail views in the API, or when the controller needs to track and report checkpoint progress to the frontend.

Code Reference

Source Location

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

Signature

pub struct Checkpoint {
    pub epoch: u32,
    pub backend: String,
    pub start_time: u64,
    pub finish_time: Option<u64>,
    pub events: Vec<CheckpointEventSpan>,
}

pub struct CheckpointEventSpan {
    pub start_time: u64,
    pub finish_time: u64,
    pub event: String,
    pub description: String,
}

pub enum JobCheckpointEventType {
    Checkpointing, CheckpointingOperators, WritingMetadata, Compacting, Committing,
}

pub struct JobCheckpointSpan {
    pub event: JobCheckpointEventType,
    pub start_time: u64,
    pub finish_time: Option<u64>,
}

impl JobCheckpointSpan {
    pub fn now(event: JobCheckpointEventType) -> Self;
    pub fn finish(&mut self);
}

Import

use arroyo_rpc::api_types::checkpoints::{
    Checkpoint, CheckpointEventSpan, OperatorCheckpointGroup,
    JobCheckpointEventType, JobCheckpointSpan,
};

I/O Contract

Inputs

Name	Type	Required	Description
epoch	u32	Yes	Checkpoint epoch number
event	JobCheckpointEventType	Yes	The phase of the checkpoint lifecycle

Outputs

Name	Type	Description
JobCheckpointSpan	JobCheckpointSpan	A timed span recording when a checkpoint phase started and finished
CheckpointEventSpan	CheckpointEventSpan	API-level representation with event name and description

Usage Examples

use arroyo_rpc::api_types::checkpoints::{JobCheckpointEventType, JobCheckpointSpan};

// Start tracking a checkpoint phase
let mut span = JobCheckpointSpan::now(JobCheckpointEventType::CheckpointingOperators);

// ... perform checkpointing work ...

// Mark the phase as complete
span.finish();

// Convert to API representation
let api_span: CheckpointEventSpan = span.into();

Related Pages

• Environment:ArroyoSystems_Arroyo_Rust_Runtime