Refactor cluster stats monitor

gateway-ha/src/main/java/io/trino/gateway/ha/clustermonitor/ClusterStatsHttpMonitor.java

@@ -44,11 +44,13 @@ public class ClusterStatsHttpMonitor
     private static final Logger log = LoggerFactory.getLogger(ClusterStatsHttpMonitor.class);
     private static final String SESSION_USER = "sessionUser";
 
-    private final BackendStateConfiguration backendStateConfiguration;
+    private final String username;
+    private final String password;
 
     public ClusterStatsHttpMonitor(BackendStateConfiguration backendStateConfiguration)
     {
-        this.backendStateConfiguration = backendStateConfiguration;
+        username = backendStateConfiguration.getUsername();
+        password = backendStateConfiguration.getPassword();
     }
 
     @Override
@@ -111,8 +113,8 @@ private OkHttpClient acquireClientWithCookie(String loginUrl)
         UiApiCookieJar cookieJar = new UiApiCookieJar();
         OkHttpClient client = new OkHttpClient.Builder().cookieJar(cookieJar).build();
         RequestBody formBody = new FormBody.Builder()
-                .add("username", backendStateConfiguration.getUsername())
-                .add("password", backendStateConfiguration.getPassword())
+                .add("username", username)
+                .add("password", password)
                 .build();
         Request loginRequest = new Request.Builder()
                 .url(HttpUrl.parse(loginUrl))
@@ -155,7 +157,7 @@ private String queryCluster(ProxyBackendConfiguration backend, String path)
                 case HttpStatus.UNAUTHORIZED_401:
                     log.info("Unauthorized to fetch cluster stats");
                     log.debug("username: {}, targetUrl: {}, cookieStore: {}",
-                            backendStateConfiguration.getUsername(),
+                            username,
                             targetUrl,
                             client.cookieJar().loadForRequest(HttpUrl.parse(targetUrl)));
                     return null;

gateway-ha/src/main/java/io/trino/gateway/ha/clustermonitor/ClusterStatsJdbcMonitor.java

@@ -16,7 +16,6 @@
 import com.google.common.util.concurrent.SimpleTimeLimiter;
 import io.trino.gateway.ha.config.BackendStateConfiguration;
 import io.trino.gateway.ha.config.ProxyBackendConfiguration;
-import jakarta.annotation.Nullable;
 import org.slf4j.Logger;
 import org.slf4j.LoggerFactory;
 
@@ -37,10 +36,8 @@ public class ClusterStatsJdbcMonitor
         implements ClusterStatsMonitor
 {
     private static final Logger log = LoggerFactory.getLogger(ClusterStatsJdbcMonitor.class);
-    @Nullable
-    private final Properties properties;
 
-    private final BackendStateConfiguration backendStateConfiguration;
+    private final Properties properties; // TODO Avoid using a mutable field
 
     private static final String STATE_QUERY = "SELECT state, COUNT(*) as count "
             + "FROM runtime.queries "
@@ -49,20 +46,11 @@ public class ClusterStatsJdbcMonitor
 
     public ClusterStatsJdbcMonitor(BackendStateConfiguration backendStateConfiguration)
     {
-        this.backendStateConfiguration = backendStateConfiguration;
-        if (backendStateConfiguration != null) {
-            properties = new Properties();
-            properties.setProperty("user", backendStateConfiguration.getUsername());
-            if (backendStateConfiguration.getPassword() != null) {
-                properties.setProperty("password", backendStateConfiguration.getPassword());
-            }
-            properties.setProperty("SSL", String.valueOf(backendStateConfiguration.getSsl()));
-            log.info("state check configured");
-        }
-        else {
-            log.warn("no state check configured");
-            properties = null;
-        }
+        properties = new Properties();
+        properties.setProperty("user", backendStateConfiguration.getUsername());
+        properties.setProperty("password", backendStateConfiguration.getPassword());
+        properties.setProperty("SSL", String.valueOf(backendStateConfiguration.getSsl()));
+        log.info("state check configured");
     }
 
     @Override
@@ -72,9 +60,6 @@ public ClusterStats monitor(ProxyBackendConfiguration backend)
         ClusterStats clusterStats = new ClusterStats();
         clusterStats.setClusterId(backend.getName());
         String jdbcUrl;
-        if (backendStateConfiguration == null) {
-            return clusterStats;
-        }
         try {
             URL parsedUrl = new URL(url);
             jdbcUrl = String
@@ -86,13 +71,13 @@ public ClusterStats monitor(ProxyBackendConfiguration backend)
         }
         catch (MalformedURLException e) {
             log.error("could not parse backend url {} ", url);
-            return clusterStats;
+            return clusterStats; // TODO Invalid configuration should fail
         }
 
         try (Connection conn = DriverManager.getConnection(jdbcUrl, properties)) {
             PreparedStatement stmt = SimpleTimeLimiter.create(Executors.newSingleThreadExecutor())
                     .callWithTimeout(() -> conn.prepareStatement(STATE_QUERY), 10, TimeUnit.SECONDS);
-            stmt.setString(1, backendStateConfiguration.getUsername());
+            stmt.setString(1, (String) properties.get("user"));
             Map<String, Integer> partialState = new HashMap<>();
             ResultSet rs = stmt.executeQuery();
             while (rs.next()) {

gateway-ha/src/main/java/io/trino/gateway/ha/clustermonitor/NoopClusterStatsMonitor.java

@@ -0,0 +1,28 @@
+/*
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+package io.trino.gateway.ha.clustermonitor;
+
+import io.trino.gateway.ha.config.ProxyBackendConfiguration;
+
+public class NoopClusterStatsMonitor
+        implements ClusterStatsMonitor
+{
+    @Override
+    public ClusterStats monitor(ProxyBackendConfiguration backend)
+    {
+        ClusterStats clusterStats = new ClusterStats();
+        clusterStats.setClusterId(backend.getName());
+        return clusterStats;
+    }
+}

gateway-ha/src/main/java/io/trino/gateway/ha/module/ClusterStatsMonitorModule.java

@@ -20,6 +20,7 @@
 import io.trino.gateway.ha.clustermonitor.ClusterStatsHttpMonitor;
 import io.trino.gateway.ha.clustermonitor.ClusterStatsJdbcMonitor;
 import io.trino.gateway.ha.clustermonitor.ClusterStatsMonitor;
+import io.trino.gateway.ha.clustermonitor.NoopClusterStatsMonitor;
 import io.trino.gateway.ha.config.ClusterStatsConfiguration;
 import io.trino.gateway.ha.config.HaGatewayConfiguration;
 
@@ -39,6 +40,9 @@ public ClusterStatsMonitorModule(HaGatewayConfiguration config, Environment env)
     public ClusterStatsMonitor getClusterStatsMonitor()
     {
         ClusterStatsConfiguration clusterStatsConfig = config.getClusterStatsConfiguration();
+        if (config.getBackendState() == null) {
+            return new NoopClusterStatsMonitor();
+        }
         if (clusterStatsConfig.isUseApi()) {
             return new ClusterStatsHttpMonitor(config.getBackendState());
         }