Module state 

State Management for Stream Processing

Provides stateful operators with persistence, checkpointing, and recovery capabilities. Essential for production streaming applications that need fault tolerance.

Features

• Stateful Operators: Maintain state across events (counters, aggregations, etc.)
• Checkpointing: Periodic state snapshots for fault tolerance
• Recovery: Restore state after failures
• Multiple Backends: Memory, File, and extensible to RocksDB/Redis
• TTL Support: Automatic state expiration

Example

use rust_rule_engine::streaming::state::*;

// Create state store
let mut state = StateStore::new(StateBackend::Memory);

// Store and retrieve state
state.put("user_count", Value::Integer(42))?;
let count = state.get("user_count")?;

// Checkpoint for fault tolerance
state.checkpoint("checkpoint_1")?;

Structs

CheckpointMetadata

Metadata about a checkpoint

StateConfig

Configuration for state management

StateStatistics

Statistics about state store

StateStore

Main state store for managing stateful operations

StatefulOperator

Stateful operator that maintains state across events

Enums

StateBackend

Backend type for state storage

Type Aliases

StateResult

Result type for state operations