proxy: Improve logging (#7405)

## Problem

It's unclear from logs what's going on with the regional redis.

## Summary of changes

Make logs better.

proxy/src/cache/endpoints.rs

@@ -13,6 +13,7 @@ use redis::{
 };
 use serde::Deserialize;
 use tokio::sync::Mutex;
+use tracing::info;
 
 use crate::{
     config::EndpointCacheConfig,
@@ -71,7 +72,9 @@ impl EndpointsCache {
         }
         // If cache is disabled, just collect the metrics and return.
         if self.config.disable_cache {
-            ctx.set_rejected(self.should_reject(endpoint));
+            let rejected = self.should_reject(endpoint);
+            ctx.set_rejected(rejected);
+            info!(?rejected, "check endpoint is valid, disabled cache");
             return true;
         }
         // If the limiter allows, we don't need to check the cache.
@@ -79,6 +82,7 @@ impl EndpointsCache {
             return true;
         }
         let rejected = self.should_reject(endpoint);
+        info!(?rejected, "check endpoint is valid, enabled cache");
         ctx.set_rejected(rejected);
         !rejected
     }
@@ -171,6 +175,9 @@ impl EndpointsCache {
 
             if res.keys.is_empty() {
                 if return_when_finish {
+                    if total != 0 {
+                        break;
+                    }
                     anyhow::bail!(
                         "Redis stream {} is empty, cannot be used to filter endpoints",
                         self.config.stream_name