feat(PROTO-945): implement Redis-based rate limiting and update dependencies

- Added RedisRateLimit for distributed rate limiting, allowing connection tracking across multiple instances.
- Updated Cargo.toml to include new dependencies for Redis and related packages.
- Enhanced README with Redis integration instructions and usage examples.
- Modified main.rs to support Redis configuration via command-line arguments.
- Updated Cargo.lock with new package versions and dependencies.

Author: jowparks

Cargo.lock

@@ -23,6 +23,9 @@ metrics-derive = "0.1"
 thiserror = "2.0.11"
 serde_json = "1.0.138"
 hostname = "0.4.0"
+redis = "0.24.0"
+redis-test = "0.9.0"
+
 
 [features]
 integration = []

Cargo.toml

@@ -22,7 +22,7 @@ You can build and test the project using [Cargo](https://doc.rust-lang.org/cargo
 # Build the project
 cargo build
 
-# Run all the tests
+# Run all the tests (requires local version of redis to be installed)
 cargo test --all-features
 ```
 
@@ -35,3 +35,30 @@ You can see a full list of parameters by running:
 
 `docker run ghcr.io/base/flashblocks-websocket-proxy:master --help`
 
+### Redis Integration
+
+The proxy supports distributed rate limiting with Redis. This is useful when running multiple instances of the proxy behind a load balancer, as it allows rate limits to be enforced across all instances.
+
+To enable Redis integration, use the following parameters:
+
+- `--redis-url` - Redis connection URL (e.g., `redis://localhost:6379`)
+- `--redis-key-prefix` - Prefix for Redis keys (default: `flashblocks`)
+
+Example:
+
+```bash
+docker run ghcr.io/base/flashblocks-websocket-proxy:master \
+  --upstream-ws wss://your-sequencer-endpoint \
+  --redis-url redis://redis:6379 \
+  --global-connections-limit 1000 \
+  --per-ip-connections-limit 10
+```
+
+When Redis is enabled, the following features are available:
+
+- Distributed rate limiting across multiple proxy instances
+- Connection tracking persists even if the proxy instance restarts
+- More accurate global connection limiting in multi-instance deployments
+
+If the Redis connection fails, the proxy will automatically fall back to in-memory rate limiting.
+

README.md

@@ -8,14 +8,15 @@ mod server;
 mod subscriber;
 
 use crate::metrics::Metrics;
-use crate::rate_limit::InMemoryRateLimit;
+use crate::rate_limit::{InMemoryRateLimit, RateLimit};
 use crate::registry::Registry;
 use crate::server::Server;
 use crate::subscriber::WebsocketSubscriber;
 use axum::http::Uri;
 use clap::Parser;
 use dotenv::dotenv;
 use metrics_exporter_prometheus::PrometheusBuilder;
+use rate_limit::RedisRateLimit;
 use std::net::SocketAddr;
 use std::sync::Arc;
 use tokio::signal::unix::{signal, SignalKind};
@@ -96,6 +97,21 @@ struct Args {
     /// Maximum backoff allowed for upstream connections
     #[arg(long, env, default_value = "20")]
     subscriber_max_interval: u64,
+
+    #[arg(
+        long,
+        env,
+        help = "Redis URL for distributed rate limiting (e.g., redis://localhost:6379). If not provided, in-memory rate limiting will be used."
+    )]
+    redis_url: Option<String>,
+
+    #[arg(
+        long,
+        env,
+        default_value = "flashblocks",
+        help = "Prefix for Redis keys"
+    )]
+    redis_key_prefix: String,
 }
 
 #[tokio::main]
@@ -176,10 +192,40 @@ async fn main() {
 
     let registry = Registry::new(sender, metrics.clone());
 
-    let rate_limiter = Arc::new(InMemoryRateLimit::new(
-        args.global_connections_limit,
-        args.per_ip_connections_limit,
-    ));
+    let rate_limiter = match &args.redis_url {
+        Some(redis_url) => {
+            info!(message = "Using Redis rate limiter", redis_url = redis_url);
+            match RedisRateLimit::new(
+                redis_url,
+                args.global_connections_limit,
+                args.per_ip_connections_limit,
+                &args.redis_key_prefix,
+            ) {
+                Ok(limiter) => {
+                    info!(message = "Connected to Redis successfully");
+                    Arc::new(limiter) as Arc<dyn RateLimit>
+                }
+                Err(e) => {
+                    error!(
+                        message =
+                            "Failed to connect to Redis, falling back to in-memory rate limiting",
+                        error = e.to_string()
+                    );
+                    Arc::new(InMemoryRateLimit::new(
+                        args.global_connections_limit,
+                        args.per_ip_connections_limit,
+                    )) as Arc<dyn RateLimit>
+                }
+            }
+        }
+        None => {
+            info!(message = "Using in-memory rate limiter");
+            Arc::new(InMemoryRateLimit::new(
+                args.global_connections_limit,
+                args.per_ip_connections_limit,
+            )) as Arc<dyn RateLimit>
+        }
+    };
 
     let server = Server::new(
         args.listen_addr,