Introduce DataSourceResolver for multi-datasource support in JDBC per…

build.gradle.kts

@@ -53,6 +53,7 @@ if (System.getProperty("idea.sync.active").toBoolean()) {
 eclipse { project { name = ideName } }
 
 tasks.named<RatTask>("rat").configure {
+  mustRunAfter(":polaris-config-docs-site:copyConfigSectionsToSite")
   // Gradle
   excludes.add("**/build/**")
   excludes.add("gradle/wrapper/gradle-wrapper*")
@@ -147,6 +148,9 @@ tasks.named<RatTask>("rat").configure {
 
   // Rat can't scan binary images
   excludes.add("**/*.png")
+
+  // Auto-generated site content (copied from docs by copyConfigSectionsToSite)
+  excludes.add("site/content/**")
 }
 
 tasks.register<Exec>("buildPythonClient") {

persistence/relational-jdbc/src/main/java/org/apache/polaris/persistence/relational/jdbc/DataSourceResolver.java

@@ -0,0 +1,45 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.polaris.persistence.relational.jdbc;
+
+import javax.sql.DataSource;
+import org.apache.polaris.core.context.RealmContext;
+
+/**
+ * Service to resolve the correct {@link DataSource} for a given realm. Note: Currently this is
+ * implemented as a foundation for metastore routing.
+ */
+public interface DataSourceResolver {
+
+  /** The type of store representing the workload pattern. */
+  enum StoreType {
+    METASTORE,
+    METRICS,
+    EVENTS
+  }
+
+  /**
+   * Resolves the DataSource for a given realm and store type.
+   *
+   * @param realmContext the realm context
+   * @param storeType the type of store
+   * @return the resolved DataSource
+   */
+  DataSource resolve(RealmContext realmContext, StoreType storeType);
+}

persistence/relational-jdbc/src/main/java/org/apache/polaris/persistence/relational/jdbc/DatabaseType.java

@@ -149,6 +149,16 @@ public static DatabaseType inferFromConnection(
    * caller.
    */
   public InputStream openInitScriptResource(int schemaVersion) {
+    return openInitScriptResource(schemaVersion, null);
+  }
+
+  /**
+   * Open an InputStream that contains data from an init script for a specific {@link
+   * DataSourceResolver.StoreType}. If a specialized script (e.g., schema-v4-metrics.sql) is not
+   * found, it falls back to the main script (schema-v4.sql).
+   */
+  public InputStream openInitScriptResource(
+      int schemaVersion, DataSourceResolver.StoreType storeType) {
     // Validate schema version is within acceptable range for this database type
     int latestVersion = getLatestSchemaVersion();
     if (schemaVersion <= 0 || schemaVersion > latestVersion) {
@@ -158,10 +168,21 @@ public InputStream openInitScriptResource(int schemaVersion) {
               schemaVersion, this, latestVersion));
     }
 
+    ClassLoader classLoader = DatasourceOperations.class.getClassLoader();
+    if (storeType != null) {
+      String specializedResourceName =
+          String.format(
+              "%s/schema-v%d-%s.sql",
+              this.getDisplayName(), schemaVersion, storeType.name().toLowerCase(Locale.ROOT));
+      InputStream specializedStream = classLoader.getResourceAsStream(specializedResourceName);
+      if (specializedStream != null) {
+        return specializedStream;
+      }
+    }
+
     final String resourceName =
         String.format("%s/schema-v%d.sql", this.getDisplayName(), schemaVersion);
 
-    ClassLoader classLoader = DatasourceOperations.class.getClassLoader();
     InputStream stream = classLoader.getResourceAsStream(resourceName);
     if (stream == null) {
       throw new IllegalStateException(

persistence/relational-jdbc/src/main/java/org/apache/polaris/persistence/relational/jdbc/DefaultDataSourceResolver.java

@@ -0,0 +1,56 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one
+ * or more contributor license agreements.  See the NOTICE file
+ * distributed with this work for additional information
+ * regarding copyright ownership.  The ASF licenses this file
+ * to you 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 org.apache.polaris.persistence.relational.jdbc;
+
+import io.smallrye.common.annotation.Identifier;
+import jakarta.enterprise.context.ApplicationScoped;
+import jakarta.enterprise.inject.Any;
+import jakarta.enterprise.inject.Instance;
+import jakarta.inject.Inject;
+import javax.sql.DataSource;
+import org.apache.polaris.core.context.RealmContext;
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+/**
+ * Default implementation of {@link DataSourceResolver} that routes all realms to a single default
+ * {@link DataSource}.
+ */
+@ApplicationScoped
+@Identifier("default")
+public class DefaultDataSourceResolver implements DataSourceResolver {
+
+  private static final Logger LOGGER = LoggerFactory.getLogger(DefaultDataSourceResolver.class);
+
+  private final Instance<DataSource> defaultDataSource;
+
+  @Inject
+  public DefaultDataSourceResolver(@Any Instance<DataSource> defaultDataSource) {
+    this.defaultDataSource = defaultDataSource;
+  }
+
+  @Override
+  public DataSource resolve(RealmContext realmContext, StoreType storeType) {
+    LOGGER.debug(
+        "Using default DataSource for realm '{}' and store '{}'",
+        realmContext.getRealmIdentifier(),
+        storeType);
+    return defaultDataSource.get();
+  }
+}