cache: share ingress rate limits across instances

apps/mcp-server/src/main.rs

@@ -8,7 +8,8 @@ use std::{env, net::SocketAddr, time::Duration};
 
 use crank_registry::{PostgresPoolConfig, PostgresRegistry};
 use crank_runtime::{
-    RequestRateLimitConfig, RequestRateLimiter, RuntimeExecutor, RuntimeLimits, SecretCrypto,
+    RequestRateLimitConfig, RequestRateLimiter, RuntimeCacheConfig, RuntimeCacheStores,
+    RuntimeExecutor, RuntimeLimits, SecretCrypto,
 };
 use sqlx::postgres::PgConnectOptions;
 use tokio::net::TcpListener;
@@ -38,6 +39,8 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
     let socket_addr: SocketAddr = bind_addr.parse()?;
     let pool_config = PostgresPoolConfig::from_env()?;
     let runtime_limits = RuntimeLimits::from_env()?;
+    let cache_config = RuntimeCacheConfig::from_env()?;
+    let cache_stores = RuntimeCacheStores::from_config(&cache_config).await?;
     let api_rate_limit = mcp_api_rate_limit_config_from_env()?;
     let database_options = database_options_from_env()?;
     let registry = PostgresRegistry::connect_with_options_and_pool_config(
@@ -58,7 +61,11 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         base_url,
         secret_crypto,
         runtime,
-        RequestRateLimiter::new(api_rate_limit),
+        if cache_config.backend.is_external() {
+            RequestRateLimiter::new_shared(api_rate_limit, cache_stores.rate_limit.clone())
+        } else {
+            RequestRateLimiter::new(api_rate_limit)
+        },
         std::sync::Arc::new(session_store),
         std::sync::Arc::new(CommunityMachineCredentialVerifier),
     );
@@ -71,6 +78,7 @@ async fn main() -> Result<(), Box<dyn std::error::Error>> {
         runtime_max_concurrent_jobs = runtime_limits.max_concurrent_jobs,
         mcp_rate_limit_rps = api_rate_limit.requests_per_second,
         mcp_rate_limit_burst = api_rate_limit.burst,
+        cache_backend = %cache_config.backend,
         max_connections = pool_config.max_connections,
         min_connections = pool_config.min_connections,
         acquire_timeout_ms = pool_config.acquire_timeout_ms,