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 (runs until the process is killed). Useful for integration tests that need a server on a random port.

run_with_config

Run the broker server with a specific config (runs until the process is killed).

run_with_shutdown

Run the broker server with graceful shutdown.