Trait StreamingBackend 

pub trait StreamingBackend: Send + Sync {
    // Required methods
    fn stream_add<'a>(
        &'a self,
        stream_key: &'a str,
        fields: Vec<(String, String)>,
        maxlen: Option<usize>,
    ) -> BoxFuture<'a, Result<String>>;
    fn stream_read_latest<'a>(
        &'a self,
        stream_key: &'a str,
        count: usize,
    ) -> BoxFuture<'a, Result<Vec<StreamEntry>>>;
    fn stream_read<'a>(
        &'a self,
        stream_key: &'a str,
        last_id: &'a str,
        count: usize,
        block_ms: Option<usize>,
    ) -> BoxFuture<'a, Result<Vec<StreamEntry>>>;
}

Optional trait for cache backends that support event streaming

This trait defines operations for event-driven architectures using streaming data structures like Redis Streams.

Capabilities

• Publish events to streams with automatic trimming
• Read latest entries (newest first)
• Read entries with blocking support

Backend Requirements

Not all cache backends support streaming. This trait is optional and should only be implemented by backends with native streaming support (e.g., Redis Streams, Kafka, Pulsar).

Example

use multi_tier_cache::StreamingBackend;
use anyhow::Result;
use futures_util::future::BoxFuture;

struct MyStreamingCache;

impl StreamingBackend for MyStreamingCache {
    fn stream_add<'a>(
        &'a self,
        _stream_key: &'a str,
        _fields: Vec<(String, String)>,
        _maxlen: Option<usize>,
    ) -> BoxFuture<'a, Result<String>> {
        Box::pin(async move { Ok("entry-id".to_string()) })
    }

    fn stream_read_latest<'a>(
        &'a self,
        _stream_key: &'a str,
        _count: usize,
    ) -> BoxFuture<'a, Result<Vec<(String, Vec<(String, String)>)>>> {
        Box::pin(async move { Ok(vec![]) })
    }

    fn stream_read<'a>(
        &'a self,
        _stream_key: &'a str,
        _last_id: &'a str,
        _count: usize,
        _block_ms: Option<usize>,
    ) -> BoxFuture<'a, Result<Vec<(String, Vec<(String, String)>)>>> {
        Box::pin(async move { Ok(vec![]) })
    }
}

Required Methods

fn stream_add<'a>( &'a self, stream_key: &'a str, fields: Vec<(String, String)>, maxlen: Option<usize>, ) -> BoxFuture<'a, Result<String>>

Add an entry to a stream

fn stream_read_latest<'a>( &'a self, stream_key: &'a str, count: usize, ) -> BoxFuture<'a, Result<Vec<StreamEntry>>>

Read the latest N entries from a stream (newest first)

fn stream_read<'a>( &'a self, stream_key: &'a str, last_id: &'a str, count: usize, block_ms: Option<usize>, ) -> BoxFuture<'a, Result<Vec<StreamEntry>>>

Read entries from a stream with optional blocking

Implementors

impl StreamingBackend for RedisStreams

Implement StreamingBackend trait for RedisStreams