Use Optional for getConfig/resolveConfig calls

Some minor changes to log output as well

11 files changed, 72 insertions, 76 deletions

diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigProxyRpcServer.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigProxyRpcServer.java
index 158df654439..7b8deb19831 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigProxyRpcServer.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigProxyRpcServer.java
@@ -19,12 +19,15 @@ import com.yahoo.vespa.config.protocol.JRTServerConfigRequestV3;
 
 import java.util.Arrays;
 import java.util.Iterator;
+import java.util.Optional;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
+import static com.yahoo.vespa.config.ErrorCode.INTERNAL_ERROR;
+
 /**
  * An RPC server that handles config and file distribution requests.
  *
@@ -247,25 +250,26 @@ public class ConfigProxyRpcServer implements Runnable, TargetWatcher {
     private void getConfigImpl(JRTServerConfigRequest request) {
         ResponseHandler responseHandler = new ResponseHandler();
         request.getRequestTrace().trace(TRACELEVEL, "Config proxy getConfig()");
-        log.log(Level.FINE, () ->"getConfig: " + request.getShortDescription() + ",config checksums=" + request.getRequestConfigChecksums());
+        log.log(Level.FINE, () ->"getConfig: " + request);
         if (!request.validateParameters()) {
-            // Error code is set in verifyParameters if parameters are not OK.
-            log.log(Level.WARNING, "Parameters for request " + request + " did not validate: " + request.errorCode() + " : " + request.errorMessage());
-            responseHandler.returnErrorResponse(request, request.errorCode(), "Parameters for request " + request.getShortDescription() + " did not validate: " + request.errorMessage());
+            // Error code is set in validateParameters if parameters are not OK.
+            log.log(Level.WARNING, "Invalid parameters for request " + request + ": " + request.errorCode() + " : " + request.errorMessage());
+            responseHandler.returnErrorResponse(request, request.errorCode(), "Invalid parameters for request " + request +
+                    ": " + request.errorMessage());
             return;
         }
+
         try {
-            RawConfig config = proxyServer.resolveConfig(request);
-            if (config == null) {
-                log.log(Level.FINEST, () -> "No config received yet for " + request.getShortDescription() + ", not sending response");
-            } else if (ProxyServer.configOrGenerationHasChanged(config, request)) {
-                responseHandler.returnOkResponse(request, config);
-            } else {
-                log.log(Level.FINEST, () -> "No new config for " + request.getShortDescription() + ", not sending response");
-            }
+            Optional<RawConfig> config = proxyServer.resolveConfig(request);
+            if (config.isEmpty())
+                log.log(Level.FINEST, () -> "No config received yet for " + request + ", not sending response");
+            else if (ProxyServer.configOrGenerationHasChanged(config.get(), request))
+                responseHandler.returnOkResponse(request, config.get());
+            else
+                log.log(Level.FINEST, () -> "No new config for " + request + ", not sending response");
         } catch (Exception e) {
-            e.printStackTrace();
-            responseHandler.returnErrorResponse(request, com.yahoo.vespa.config.ErrorCode.INTERNAL_ERROR, e.getMessage());
+            log.log(Level.WARNING, "Resolving config " + request + " failed", e);
+            responseHandler.returnErrorResponse(request, INTERNAL_ERROR, e.getMessage());
         }
     }
 
diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigSourceClient.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigSourceClient.java
index dae732e56ec..d771d440078 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigSourceClient.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ConfigSourceClient.java
@@ -5,6 +5,7 @@ import com.yahoo.vespa.config.RawConfig;
 import com.yahoo.vespa.config.protocol.JRTServerConfigRequest;
 
 import java.util.List;
+import java.util.Optional;
 
 /**
  * A client to a config source, which could be an RPC config server or some other backing for
@@ -14,7 +15,7 @@ import java.util.List;
  */
 interface ConfigSourceClient {
 
-    RawConfig getConfig(RawConfig input, JRTServerConfigRequest request);
+    Optional<RawConfig> getConfig(RawConfig input, JRTServerConfigRequest request);
 
     void shutdown();
 
diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/DelayedResponseHandler.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/DelayedResponseHandler.java
index 0e8ebe0d9c9..cae70b41c8c 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/DelayedResponseHandler.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/DelayedResponseHandler.java
@@ -6,6 +6,7 @@ import com.yahoo.vespa.config.RawConfig;
 import com.yahoo.vespa.config.protocol.JRTServerConfigRequest;
 import com.yahoo.yolean.Exceptions;
 
+import java.util.Optional;
 import java.util.concurrent.atomic.AtomicLong;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -47,9 +48,9 @@ public class DelayedResponseHandler implements Runnable {
             while ((response = delayedResponses.responses().poll()) != null) {
                 JRTServerConfigRequest request = response.getRequest();
                 ConfigCacheKey cacheKey = new ConfigCacheKey(request.getConfigKey(), request.getRequestDefMd5());
-                RawConfig config = memoryCache.get(cacheKey);
-                if (config != null) {
-                    responseHandler.returnOkResponse(request, config);
+                Optional<RawConfig> config = memoryCache.get(cacheKey);
+                if (config.isPresent()) {
+                    responseHandler.returnOkResponse(request, config.get());
                     sentResponses.incrementAndGet();
                 } else {
                     log.log(Level.WARNING, "Timed out (timeout " + request.getTimeout() + ") getting config " +
diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCache.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCache.java
index e2ab5de40e9..ff10adf88e9 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCache.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCache.java
@@ -14,6 +14,7 @@ import java.io.IOException;
 import java.io.Writer;
 import java.nio.file.Files;
 import java.util.Collection;
+import java.util.Optional;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.logging.Level;
 import java.util.logging.Logger;
@@ -31,8 +32,8 @@ public class MemoryCache {
 
     private final ConcurrentHashMap<ConfigCacheKey, RawConfig> cache = new ConcurrentHashMap<>(500, 0.75f);
 
-    public RawConfig get(ConfigCacheKey key) {
-        return cache.get(key);
+    public Optional<RawConfig> get(ConfigCacheKey key) {
+        return Optional.ofNullable(cache.get(key));
     }
 
     /**
diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClient.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClient.java
index f1be03f07d4..d207fcce639 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClient.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClient.java
@@ -8,6 +8,7 @@ import com.yahoo.vespa.config.protocol.JRTServerConfigRequest;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 import java.util.logging.Level;
 import java.util.logging.Logger;
 
@@ -33,16 +34,13 @@ class MemoryCacheConfigClient implements ConfigSourceClient {
      * @return A Config with a payload.
      */
     @Override
-    public RawConfig getConfig(RawConfig input, JRTServerConfigRequest request) {
-        log.log(Level.FINE, () -> "Getting config from cache");
+    public Optional<RawConfig> getConfig(RawConfig input, JRTServerConfigRequest request) {
         ConfigKey<?> key = input.getKey();
-        RawConfig cached = cache.get(new ConfigCacheKey(key, input.getDefMd5()));
-        if (cached != null) {
+
+        Optional<RawConfig> cached = cache.get(new ConfigCacheKey(key, input.getDefMd5()));
+        if (cached.isPresent())
             log.log(Level.FINE, () -> "Found config " + key + " in cache");
-            return cached;
-        } else {
-            return null;
-        }
+        return cached;
     }
 
     @Override
diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ProxyServer.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ProxyServer.java
index 9340363def8..a559f3025ed 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ProxyServer.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/ProxyServer.java
@@ -15,6 +15,7 @@ import com.yahoo.yolean.system.CatchSignals;
 
 import java.util.List;
 import java.util.Objects;
+import java.util.Optional;
 import java.util.concurrent.Callable;
 import java.util.concurrent.ExecutorService;
 import java.util.concurrent.Executors;
@@ -71,11 +72,11 @@ public class ProxyServer implements Runnable {
         }
     }
 
-    RawConfig resolveConfig(JRTServerConfigRequest req) {
+    Optional<RawConfig> resolveConfig(JRTServerConfigRequest req) {
         // Calling getConfig() will either return with an answer immediately or
         // create a background thread that retrieves config from the server and
-        // calls updateSubscribers when new config is returned from the config source.
-        // In the last case the method below will return null.
+        // calls updateSubscribers when new config is returned from the config server.
+        // In the last case the method below will return empty.
         return configClient.getConfig(RawConfig.createFromServerRequest(req), req);
     }
 
diff --git a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/RpcConfigSourceClient.java b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/RpcConfigSourceClient.java
index f022ed11f3d..8f844fdd3ee 100644
--- a/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/RpcConfigSourceClient.java
+++ b/config-proxy/src/main/java/com/yahoo/vespa/config/proxy/RpcConfigSourceClient.java
@@ -110,7 +110,7 @@ class RpcConfigSourceClient implements ConfigSourceClient, Runnable {
      * @return A Config with a payload.
      */
     @Override
-    public RawConfig getConfig(RawConfig input, JRTServerConfigRequest request) {
+    public Optional<RawConfig> getConfig(RawConfig input, JRTServerConfigRequest request) {
         // Always add to delayed responses (we remove instead if we find config in cache)
         // This is to avoid a race where we might end up not adding to delayed responses
         // nor subscribing to config if another request for the same config
@@ -119,29 +119,29 @@ class RpcConfigSourceClient implements ConfigSourceClient, Runnable {
         delayedResponses.add(delayedResponse);
 
         ConfigCacheKey configCacheKey = new ConfigCacheKey(input.getKey(), input.getDefMd5());
-        RawConfig cachedConfig = memoryCache.get(configCacheKey);
+        Optional<RawConfig> cachedConfig = memoryCache.get(configCacheKey);
         boolean needToGetConfig = true;
 
-        RawConfig ret = null;
-        if (cachedConfig != null) {
-            log.log(Level.FINE, () -> "Found config " + configCacheKey + " in cache, generation=" + cachedConfig.getGeneration() +
-                    ",config checksums=" + cachedConfig.getPayloadChecksums());
-            log.log(Level.FINEST, () -> "input config=" + input + ",cached config=" + cachedConfig);
-            if (ProxyServer.configOrGenerationHasChanged(cachedConfig, request)) {
+        if (cachedConfig.isPresent()) {
+            RawConfig config = cachedConfig.get();
+            log.log(Level.FINE, () -> "Found config " + configCacheKey + " in cache, generation=" + config.getGeneration() +
+                    ",config checksums=" + config.getPayloadChecksums());
+            log.log(Level.FINEST, () -> "input config=" + input + ",cached config=" + config);
+            if (ProxyServer.configOrGenerationHasChanged(config, request)) {
                 log.log(Level.FINEST, () -> "Cached config is not equal to requested, will return it");
                 if (delayedResponses.remove(delayedResponse)) {
                     // unless another thread already did it
-                    ret = cachedConfig;
+                    return cachedConfig;
                 }
             }
-            if (!cachedConfig.isError() && cachedConfig.getGeneration() > 0) {
+            if (!config.isError() && config.getGeneration() > 0) {
                 needToGetConfig = false;
             }
         }
         if (needToGetConfig) {
             subscribeToConfig(input, configCacheKey);
         }
-        return ret;
+        return Optional.empty();
     }
 
     private void subscribeToConfig(RawConfig input, ConfigCacheKey configCacheKey) {
diff --git a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClientTest.java b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClientTest.java
index f84d447e3a1..d243d9c6dff 100644
--- a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClientTest.java
+++ b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheConfigClientTest.java
@@ -6,7 +6,7 @@ import org.junit.Test;
 import java.util.List;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNull;
+import static org.junit.Assert.assertTrue;
 
 /**
  * @author hmusum
@@ -17,8 +17,8 @@ public class MemoryCacheConfigClientTest {
     public void basic() {
         MemoryCacheConfigClient client = new MemoryCacheConfigClient(new MemoryCache());
         client.memoryCache().update(ConfigTester.fooConfig);
-        assertEquals(ConfigTester.fooConfig, client.getConfig(ConfigTester.fooConfig, null));
-        assertNull(client.getConfig(ConfigTester.barConfig, null));
+        assertEquals(ConfigTester.fooConfig, client.getConfig(ConfigTester.fooConfig, null).orElseThrow());
+        assertTrue(client.getConfig(ConfigTester.barConfig, null).isEmpty());
 
         assertEquals("N/A", client.getActiveSourceConnection());
         assertEquals(List.of("N/A"), client.getSourceConnections());
diff --git a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheTest.java b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheTest.java
index 1a919ad3988..b0cba728a0c 100644
--- a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheTest.java
+++ b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MemoryCacheTest.java
@@ -15,7 +15,6 @@ import java.util.ArrayList;
 import java.util.Optional;
 
 import static org.junit.Assert.assertEquals;
-import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
 
 /**
@@ -84,14 +83,12 @@ public class MemoryCacheTest {
         assertTrue(cache.containsKey(cacheKey));
         assertTrue(cache.containsKey(cacheKey2));
 
-        RawConfig response = cache.get(cacheKey);
-        assertNotNull(response);
+        RawConfig response = cache.get(cacheKey).orElseThrow();
         assertEquals(defName, response.getName());
         assertEquals(payload.toString(), response.getPayload().toString());
         assertEquals(generation, response.getGeneration());
 
-        response = cache.get(cacheKey2);
-        assertNotNull(response);
+        response = cache.get(cacheKey2).orElseThrow();
         assertEquals(defName2, response.getName());
         assertEquals(payload2.toString(), response.getPayload().toString());
         assertEquals(generation, response.getGeneration());
@@ -108,14 +105,12 @@ public class MemoryCacheTest {
         assertEquals(2, cache.size());
         assertTrue(cache.containsKey(cacheKey));
 
-        RawConfig response = cache.get(cacheKey);
-        assertNotNull(response);
+        RawConfig response = cache.get(cacheKey).orElseThrow();
         assertEquals(defName, response.getName());
         assertEquals(payload.getData(), response.getPayload().getData());
         assertEquals(generation, response.getGeneration());
 
-        response = cache.get(cacheKeyDifferentMd5);
-        assertNotNull(response);
+        response = cache.get(cacheKeyDifferentMd5).orElseThrow();
         assertEquals(defName, response.getName());
         assertEquals(payloadDifferentMd5.getData(), response.getPayload().getData());
         assertEquals(generation, response.getGeneration());
diff --git a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MockConfigSourceClient.java b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MockConfigSourceClient.java
index d0724b9dbd0..e02ca22d0a0 100644
--- a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MockConfigSourceClient.java
+++ b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/MockConfigSourceClient.java
@@ -7,6 +7,7 @@ import com.yahoo.vespa.config.protocol.JRTServerConfigRequest;
 
 import java.util.Collections;
 import java.util.List;
+import java.util.Optional;
 
 /**
  * Mock client that always returns with config immediately
@@ -24,10 +25,10 @@ public class MockConfigSourceClient implements ConfigSourceClient{
     }
 
     @Override
-    public RawConfig getConfig(RawConfig input, JRTServerConfigRequest request) {
-        final RawConfig config = getConfig(input.getKey());
+    public Optional<RawConfig> getConfig(RawConfig input, JRTServerConfigRequest request) {
+        RawConfig config = getConfig(input.getKey());
         memoryCache.update(config);
-        return config;
+        return Optional.of(config);
     }
 
     private RawConfig getConfig(ConfigKey<?> configKey) {
diff --git a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java
index 09eae6a297d..1bcd1562a85 100644
--- a/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java
+++ b/config-proxy/src/test/java/com/yahoo/vespa/config/proxy/ProxyServerTest.java
@@ -62,11 +62,10 @@ public class ProxyServerTest {
         ConfigTester tester = new ConfigTester();
         MemoryCache memoryCache = proxy.memoryCache();
         assertEquals(0, memoryCache.size());
-        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig));
-        assertNotNull(res);
+        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertEquals(ConfigTester.fooPayload.toString(), res.getPayload().toString());
         assertEquals(1, memoryCache.size());
-        assertEquals(res, memoryCache.get(new ConfigCacheKey(fooConfig.getKey(), fooConfig.getDefMd5())));
+        assertEquals(res, memoryCache.get(new ConfigCacheKey(fooConfig.getKey(), fooConfig.getDefMd5())).orElseThrow());
     }
 
     /**
@@ -111,15 +110,14 @@ public class ProxyServerTest {
         ConfigTester tester = new ConfigTester();
         MemoryCache memoryCache = proxy.memoryCache();
         assertEquals(0, memoryCache.size());
-        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig));
-        assertNotNull(res);
+        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertEquals(ConfigTester.fooPayload.toString(), res.getPayload().toString());
         assertEquals(1, memoryCache.size());
-        assertEquals(res, memoryCache.get(new ConfigCacheKey(fooConfig.getKey(), fooConfig.getDefMd5())));
+        assertEquals(res, memoryCache.get(new ConfigCacheKey(fooConfig.getKey(), fooConfig.getDefMd5())).orElseThrow());
 
         // Trying same config again
         JRTServerConfigRequest newRequestBasedOnResponse = tester.createRequest(res);
-        RawConfig res2 = proxy.resolveConfig(newRequestBasedOnResponse);
+        RawConfig res2 = proxy.resolveConfig(newRequestBasedOnResponse).orElseThrow();
         assertFalse(ProxyServer.configOrGenerationHasChanged(res2, newRequestBasedOnResponse));
         assertEquals(1, memoryCache.size());
     }
@@ -137,8 +135,7 @@ public class ProxyServerTest {
         MemoryCache memoryCache = proxy.memoryCache();
         assertEquals(0, memoryCache.size());
 
-        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig));
-        assertNotNull(res);
+        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertNotNull(res.getPayload());
         assertTrue(res.isError());
         assertEquals(0, memoryCache.size());
@@ -148,14 +145,13 @@ public class ProxyServerTest {
         source.put(fooConfig.getKey(), createConfigWithNextConfigGeneration(fooConfig, 0));
 
         // Verify that we get the config now and that it is cached
-        res = proxy.resolveConfig(tester.createRequest(fooConfig));
-        assertNotNull(res);
+        res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertNotNull(res.getPayload().getData());
         assertEquals(ConfigTester.fooPayload.toString(), res.getPayload().toString());
         assertEquals(1, memoryCache.size());
 
         JRTServerConfigRequest newRequestBasedOnResponse = tester.createRequest(res);
-        RawConfig res2 = proxy.resolveConfig(newRequestBasedOnResponse);
+        RawConfig res2 = proxy.resolveConfig(newRequestBasedOnResponse).orElseThrow();
         assertFalse(ProxyServer.configOrGenerationHasChanged(res2, newRequestBasedOnResponse));
         assertEquals(1, memoryCache.size());
     }
@@ -172,7 +168,7 @@ public class ProxyServerTest {
         MemoryCache cache = proxy.memoryCache();
 
         assertEquals(0, cache.size());
-        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig));
+        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertNotNull(res);
         assertEquals(ConfigTester.fooPayload.toString(), res.getPayload().toString());
         assertEquals(1, cache.size());
@@ -183,8 +179,7 @@ public class ProxyServerTest {
                                               0, fooConfig.getDefContent(), Optional.empty());
         source.put(fooConfig.getKey(), emptyConfig);
 
-        res = proxy.resolveConfig(tester.createRequest(fooConfig));
-        assertNotNull(res.getPayload());
+        res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertEquals(emptyConfig.getPayload().toString(), res.getPayload().toString());
         assertEquals(0, cache.size());
 
@@ -193,7 +188,7 @@ public class ProxyServerTest {
         source.put(fooConfig.getKey(), createConfigWithNextConfigGeneration(fooConfig, 0));
 
         // Verify that we get the config now and that it is cached
-        res = proxy.resolveConfig(tester.createRequest(fooConfig));
+        res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertNotNull(res.getPayload().getData());
         assertEquals(ConfigTester.fooPayload.toString(), res.getPayload().toString());
         assertEquals(1, cache.size());
@@ -202,15 +197,14 @@ public class ProxyServerTest {
     @Test
     public void testReconfiguration() {
         ConfigTester tester = new ConfigTester();
-        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig));
-        assertNotNull(res);
+        RawConfig res = proxy.resolveConfig(tester.createRequest(fooConfig)).orElseThrow();
         assertEquals(ConfigTester.fooPayload.toString(), res.getPayload().toString());
 
         // Simulate deployment, add config with new config generation
         long previousGeneration = res.getGeneration();
         source.put(fooConfig.getKey(), createConfigWithNextConfigGeneration(res, 0));
         JRTServerConfigRequest newRequestBasedOnResponse = tester.createRequest(res);
-        RawConfig res2 = proxy.resolveConfig(newRequestBasedOnResponse);
+        RawConfig res2 = proxy.resolveConfig(newRequestBasedOnResponse).orElseThrow();
         assertEquals(previousGeneration + 1, res2.getGeneration());
         assertTrue(ProxyServer.configOrGenerationHasChanged(res2, newRequestBasedOnResponse));
     }