Crate hermes_server 

hermes-server is the server-side crate for the Hermes gRPC event broker.

It provides:

• a broker engine with fanout and queue-group delivery
• a gRPC service implementation (via tonic)
• optional durable delivery with redelivery + garbage-collection loops

Quick start

Run a server from a bound TcpListener:

use tokio::net::TcpListener;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let listener = TcpListener::bind("127.0.0.1:4222").await?;
    hermes_server::run(listener).await?;
    Ok(())
}

Run with explicit configuration:

use tokio::net::TcpListener;
use hermes_server::config::ServerConfig;

#[tokio::main]
async fn main() -> Result<(), Box<dyn std::error::Error>> {
    let listener = TcpListener::bind("127.0.0.1:4222").await?;
    let mut cfg = ServerConfig::default();
    cfg.subscriber_channel_capacity = 16_384;
    cfg.store_path = Some("hermes.redb".into());
    hermes_server::run_with_config(listener, cfg).await?;
    Ok(())
}

Configuration

The server can be configured programmatically with config::ServerConfig and can also be initialized from environment variables through ServerConfig::from_env().

Useful env vars include:

• HERMES_LISTEN_ADDR
• HERMES_CHANNEL_CAPACITY
• HERMES_GRPC_OUTPUT_BUFFER
• HERMES_STORE_PATH
• HERMES_REDELIVERY_INTERVAL
• HERMES_MAX_DELIVERY_ATTEMPTS
• HERMES_RETENTION_SECS
• HERMES_ACK_TIMEOUT
• HERMES_MAX_IN_FLIGHT
• HERMES_GC_INTERVAL
• HERMES_REDELIVERY_BATCH_SIZE

Notes

• If store_path is None, the server runs in fire-and-forget mode (no durable redelivery persistence).
• If store_path is set, durable store-backed redelivery and GC loops are spawned.

Modules

broker

config

grpc

redelivery

subscription

Functions

run

Run the broker server on the given listener. Useful for integration tests that need a server on a random port.

run_with_config

Run the broker server with a specific config.