NoSQL: "standalone" Persistence configuration helper

bom/build.gradle.kts

@@ -50,6 +50,7 @@ dependencies {
 
     api(project(":polaris-persistence-nosql-api"))
     api(project(":polaris-persistence-nosql-impl"))
+    api(project(":polaris-persistence-nosql-standalone"))
     api(project(":polaris-persistence-nosql-testextension"))
 
     api(project(":polaris-persistence-nosql-inmemory"))

gradle/projects.main.properties

@@ -65,6 +65,7 @@ polaris-nodes-spi=persistence/nosql/nodes/spi
 # persistence / database agnostic
 polaris-persistence-nosql-api=persistence/nosql/persistence/api
 polaris-persistence-nosql-impl=persistence/nosql/persistence/impl
+polaris-persistence-nosql-standalone=persistence/nosql/persistence/standalone
 polaris-persistence-nosql-testextension=persistence/nosql/persistence/testextension
 polaris-persistence-nosql-varint=persistence/nosql/persistence/varint
 # persistence / database specific implementations

persistence/nosql/persistence/standalone/build.gradle.kts

@@ -0,0 +1,39 @@
+/*
+ * 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.
+ */
+
+plugins { id("polaris-server") }
+
+description =
+  "Polaris NoSQL persistence, standalone non-CDI configuration helpers using smallrye-config"
+
+dependencies {
+  implementation(project(":polaris-persistence-nosql-api"))
+  implementation(project(":polaris-nodes-api"))
+
+  implementation(libs.smallrye.config.core)
+
+  implementation(libs.guava)
+  implementation(libs.slf4j.api)
+
+  compileOnly(platform(libs.jackson.bom))
+  compileOnly("com.fasterxml.jackson.core:jackson-annotations")
+
+  compileOnly(libs.jakarta.annotation.api)
+  compileOnly(libs.jakarta.validation.api)
+}

persistence/nosql/persistence/standalone/src/main/java/org/apache/polaris/persistence/nosql/standalone/PersistenceConfigurer.java

@@ -0,0 +1,99 @@
+/*
+ * 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.nosql.standalone;
+
+import io.smallrye.config.PropertiesConfigSource;
+import io.smallrye.config.SmallRyeConfig;
+import io.smallrye.config.SmallRyeConfigBuilder;
+import java.util.Map;
+import org.apache.polaris.persistence.nosql.api.backend.Backend;
+import org.apache.polaris.persistence.nosql.api.backend.BackendConfiguration;
+import org.apache.polaris.persistence.nosql.api.backend.BackendFactory;
+import org.apache.polaris.persistence.nosql.api.backend.BackendLoader;
+import org.apache.polaris.persistence.nosql.nodeids.api.NodeManagementConfig;
+
+/**
+ * Leverages smallrye-config to get a {@link BackendConfiguration} instance populated with the
+ * necessary settings to build a {@link Backend} instance.
+ *
+ * <p>{@link #defaultBackendConfigurer()} is especially useful in standalone runnable Java code like
+ * JMH based benchmarks and in the manually run correctness tests.
+ */
+@SuppressWarnings({"unchecked", "rawtypes"})
+public class PersistenceConfigurer {
+  private final SmallRyeConfigBuilder smallRyeConfigBuilder;
+  private final String name;
+
+  private PersistenceConfigurer(SmallRyeConfigBuilder smallRyeConfigBuilder) {
+    this.smallRyeConfigBuilder = smallRyeConfigBuilder;
+
+    SmallRyeConfig rootConfig =
+        smallRyeConfigBuilder
+            .withMapping(BackendConfiguration.class)
+            .withMapping(NodeManagementConfig.class)
+            .build();
+
+    var backendConfiguration = rootConfig.getConfigMapping(BackendConfiguration.class);
+
+    this.name =
+        backendConfiguration
+            .type()
+            .orElseThrow(
+                () ->
+                    new IllegalArgumentException(
+                        "No backend name provided, for example via the system property 'polaris.persistence.backend.type', available backend names: "
+                            + BackendLoader.availableFactories()
+                                .map(BackendFactory::name)
+                                .toList()));
+  }
+
+  public <RUNTIME_CONFIG, CONFIG_INTERFACE>
+      BackendFactory<RUNTIME_CONFIG, CONFIG_INTERFACE> buildBackendFactory() {
+    return (BackendFactory) BackendLoader.findFactoryByName(name);
+  }
+
+  public Backend buildBackendFromConfiguration(BackendFactory factory) {
+    var configInterface = (Class<Object>) factory.configurationInterface();
+    var backendConfigObject =
+        smallRyeConfigBuilder
+            .withMapping(configInterface)
+            .build()
+            .getConfigMapping(configInterface);
+
+    Object backendConfig = factory.buildConfiguration(backendConfigObject);
+    return factory.buildBackend(backendConfig);
+  }
+
+  /**
+   * Sets up a default {@link PersistenceConfigurer} instance that uses smallrye-config default
+   * sources, which include environment variables and Java system properties as config sources.
+   */
+  public static PersistenceConfigurer defaultBackendConfigurer() {
+    return backendConfigurer(Map.of());
+  }
+
+  public static PersistenceConfigurer backendConfigurer(Map<String, String> configMap) {
+    return new PersistenceConfigurer(
+        new SmallRyeConfigBuilder()
+            .setAddDefaultSources(true)
+            .setAddDiscoveredSources(true)
+            .withValidateUnknown(false)
+            .withSources(new PropertiesConfigSource(configMap, "configMap")));
+  }
+}