skoppu22 commented on code in PR #358: URL: https://github.com/apache/cassandra-sidecar/pull/358#discussion_r3374765114
########## server/src/main/java/org/apache/cassandra/sidecar/configmanagement/ConfigUtils.java: ########## @@ -0,0 +1,157 @@ +/* + * 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.cassandra.sidecar.configmanagement; + +import java.io.IOException; +import java.io.UncheckedIOException; +import java.nio.file.Files; +import java.nio.file.Path; +import java.time.Instant; +import java.util.Collections; +import java.util.Map; + +import com.fasterxml.jackson.core.JsonParser; +import com.fasterxml.jackson.dataformat.yaml.YAMLFactory; +import com.fasterxml.jackson.dataformat.yaml.YAMLGenerator; +import io.vertx.core.json.JsonObject; +import io.vertx.core.json.jackson.DatabindCodec; + +/** + * Utility methods for configuration operations: YAML loading and deep merge. + */ +public final class ConfigUtils +{ + static final YAMLFactory YAML_FACTORY = new YAMLFactory() + .disable(YAMLGenerator.Feature.WRITE_DOC_START_MARKER); + + private ConfigUtils() + { + throw new UnsupportedOperationException(); + } + + /** + * Loads a YAML configuration file and returns it as a {@link ConfigurationOverlaySnapshot}. + * The snapshot's {@code lastModified} is set to the file's modification time and + * {@code extraJvmOpts} is empty. + * + * <p>If {@code yamlPath} is {@code null}, returns an {@linkplain ConfigurationOverlaySnapshot#emptySnapshot() + * empty snapshot}. + * + * @param yamlPath path to the YAML configuration file, or {@code null} for an empty snapshot + * @return a snapshot representing the file contents + */ + public static ConfigurationOverlaySnapshot loadConfiguration(Path yamlPath) + { + if (yamlPath == null) + { + return ConfigurationOverlaySnapshot.emptySnapshot(); + } + JsonObject yaml = loadYaml(yamlPath); + Instant lastModified; + try + { + lastModified = Files.getLastModifiedTime(yamlPath).toInstant(); + } + catch (IOException e) + { + throw new UncheckedIOException("Failed to read modification time of " + yamlPath, e); + } + CassandraConfigurationOverlay overlay = new CassandraConfigurationOverlay(yaml, Collections.emptyMap()); + return new ConfigurationOverlaySnapshot(lastModified, overlay); + } + + /** + * Loads a YAML file into a Vert.x {@link JsonObject}. + * + * @param yamlPath path to the YAML file + * @return the parsed configuration as a JsonObject + */ + @SuppressWarnings("unchecked") + public static JsonObject loadYaml(Path yamlPath) + { + try (JsonParser parser = YAML_FACTORY.createParser(yamlPath.toFile())) + { + Map<String, Object> map = DatabindCodec.mapper().readValue(parser, Map.class); + return map != null ? new JsonObject(map) : new JsonObject(); + } + catch (IOException e) + { + throw new UncheckedIOException("Failed to load YAML from " + yamlPath, e); + } + } + + /** + * Deep-merges the overlay onto the base configuration. For nested objects both base and overlay + * contain, fields are merged recursively. For all other node types (scalars, arrays, nulls), + * the overlay value replaces the base value. The base node is not modified. + * + * @param base the base configuration tree + * @param overlay the overlay tree whose values take precedence + * @return a new tree with the merged result + */ + public static JsonObject mergeConfigurations(JsonObject base, JsonObject overlay) + { + if (base == null) + { + return overlay.copy(); + } + if (overlay == null || overlay.isEmpty()) + { + return base.copy(); + } + + JsonObject result = base.copy(); + JsonObject overlayCopy = overlay.copy(); Review Comment: Why do we need to make a copy of overlay when we are not modifying it? -- This is an automated message from the Apache Git Service. To respond to the message, please log on to GitHub and use the URL above to go to the specific comment. To unsubscribe, e-mail: [email protected] For queries about this service, please contact Infrastructure at: [email protected] --------------------------------------------------------------------- To unsubscribe, e-mail: [email protected] For additional commands, e-mail: [email protected]
