Change Map value to be a Future itself, use System.nanoTime

polaris-service/src/main/java/org/apache/polaris/service/ratelimiter/ClockImpl.java

@@ -20,14 +20,11 @@
 
 /** An implementation of our Clock interface using opentelemetry's Clock implementation */
 public class ClockImpl implements Clock {
-  private final io.opentelemetry.sdk.common.Clock openTelemetryClock;
-
   public ClockImpl() {
-    openTelemetryClock = io.opentelemetry.sdk.common.Clock.getDefault();
   }
 
   @Override
   public long nanoTime() {
-    return openTelemetryClock.nanoTime();
+    return System.nanoTime();
   }
 }

polaris-service/src/main/java/org/apache/polaris/service/ratelimiter/DefaultRateLimiterFactory.java

@@ -36,10 +36,10 @@ public class DefaultRateLimiterFactory implements RateLimiterFactory {
   private double windowSeconds;
 
   @Override
-  public Future<RateLimiter> createRateLimiter(String key, Clock clock) {
+  public Future<RateLimiter> createRateLimiter(String key) {
     return CompletableFuture.supplyAsync(
         () ->
             new OpenTelemetryRateLimiter(
-                requestsPerSecond, requestsPerSecond * windowSeconds, clock));
+                requestsPerSecond, requestsPerSecond * windowSeconds, new ClockImpl()));
   }
 }

polaris-service/src/main/java/org/apache/polaris/service/ratelimiter/NoOpRateLimiterFactory.java

@@ -26,7 +26,7 @@
 @JsonTypeName("no-op")
 public class NoOpRateLimiterFactory implements RateLimiterFactory {
   @Override
-  public Future<RateLimiter> createRateLimiter(String key, Clock clock) {
+  public Future<RateLimiter> createRateLimiter(String key) {
     return CompletableFuture.supplyAsync(NoOpRateLimiter::new);
   }
 }

polaris-service/src/main/java/org/apache/polaris/service/ratelimiter/RateLimiterFactory.java

@@ -35,8 +35,7 @@ public interface RateLimiterFactory extends Discoverable {
    *
    * @param key The rate limiting key. Rate limiters may optionally choose to discriminate their
    *     behavior by the key.
-   * @param clock The clock which tells you the current time
    * @return a Future with the constructed RateLimiter
    */
-  Future<RateLimiter> createRateLimiter(String key, Clock clock);
+  Future<RateLimiter> createRateLimiter(String key);
 }

polaris-service/src/main/java/org/apache/polaris/service/ratelimiter/RateLimiterFilter.java

@@ -31,6 +31,7 @@
 import java.util.Map;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.concurrent.ExecutionException;
+import java.util.concurrent.Future;
 import java.util.concurrent.TimeUnit;
 import java.util.concurrent.TimeoutException;
 import org.apache.polaris.core.context.CallContext;
@@ -47,7 +48,7 @@ public class RateLimiterFilter implements Filter {
   private static final Clock CLOCK = new ClockImpl();
 
   private final RateLimiterConfig config;
-  private final Map<String, RateLimiter> perRealmLimiters = new ConcurrentHashMap<>();
+  private final Map<String, Future<RateLimiter>> perRealmLimiters = new ConcurrentHashMap<>();
 
   public RateLimiterFilter(RateLimiterConfig config) {
     this.config = config;
@@ -67,16 +68,10 @@ public void doFilter(ServletRequest request, ServletResponse response, FilterCha
   }
 
   private RateLimiter maybeBlockToGetRateLimiter(String realm) {
-    return perRealmLimiters.computeIfAbsent(realm, this::createRateLimiterBlocking);
-  }
-
-  /** Creates a rate limiter, enforcing a timeout on how long creation can take. */
-  private RateLimiter createRateLimiterBlocking(String key) {
     try {
-      return config
-          .getRateLimiterFactory()
-          .createRateLimiter(key, CLOCK)
-          .get(config.getConstructionTimeoutMillis(), TimeUnit.MILLISECONDS);
+      return perRealmLimiters.computeIfAbsent(realm, (key) -> config
+              .getRateLimiterFactory()
+              .createRateLimiter(key)).get(config.getConstructionTimeoutMillis(), TimeUnit.MILLISECONDS);
     } catch (InterruptedException | ExecutionException | TimeoutException e) {
       return getDefaultRateLimiterOnConstructionFailed(e);
     }

polaris-service/src/main/resources/META-INF/services/org.apache.polaris.service.ratelimiter.RateLimiterFactory

@@ -18,3 +18,4 @@
 #
 
 org.apache.polaris.service.ratelimiter.DefaultRateLimiterFactory
+org.apache.polaris.service.ratelimiter.NoOpRateLimiterFactory

polaris-service/src/test/java/org/apache/polaris/service/ratelimiter/MockRateLimiterFactory.java

@@ -41,7 +41,7 @@ public class MockRateLimiterFactory implements RateLimiterFactory {
   public boolean neverFinishConstruction;
 
   @Override
-  public Future<RateLimiter> createRateLimiter(String key, Clock clock) {
+  public Future<RateLimiter> createRateLimiter(String key) {
     if (neverFinishConstruction) {
       // This future will never finish
       return new CompletableFuture<>();