| /* |
| * 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.samza.config; |
| |
| import org.slf4j.Logger; |
| import org.slf4j.LoggerFactory; |
| |
| import java.util.Arrays; |
| import java.util.HashMap; |
| import java.util.Map; |
| |
| /** |
| * A {@link org.apache.samza.config.ConfigRewriter} that takes system environment variables |
| * and adds them to the existing {@link org.apache.samza.config.Config}. It will over-ride any |
| * existing properties that were set before this rewriter is called. |
| * |
| * <p> |
| * The following mappings are applied to any environment variable that starts with the prefix |
| * {@value org.apache.samza.config.EnvironmentConfigRewriter#SAMZA_KEY_PREFIX}. |
| * </p> |
| * |
| * <ul> |
| * <li>The prefixed of {@value org.apache.samza.config.EnvironmentConfigRewriter#SAMZA_KEY_PREFIX} is stripped.</li> |
| * <li>The remaining key is downcased.</li> |
| * <li>All underscores are converted to full stops.</li> |
| * </ul> |
| * |
| * <p> |
| * For example the environment variable <i>SAMZA_FOO_BAR=baz</i> will be set as |
| * the<i>foo.bar=baz</i> samza property. |
| * </p> |
| * |
| */ |
| public class EnvironmentConfigRewriter implements ConfigRewriter { |
| public static final String SAMZA_KEY_PREFIX = "SAMZA_"; |
| public static final Logger LOGGER = LoggerFactory.getLogger(EnvironmentConfigRewriter.class); |
| |
| @Override |
| public Config rewrite(String name, Config config) { |
| return rewrite(config, System.getenv()); |
| } |
| |
| protected Config rewrite(Config config, Map<String, String> env) { |
| Map<String, String> envConfig = new HashMap<>(); |
| |
| for (Map.Entry<String, String> entry: env.entrySet()) { |
| if (entry.getKey().startsWith(SAMZA_KEY_PREFIX)) { |
| String key = renameKey(entry.getKey()); |
| String value = entry.getValue(); |
| |
| if (config.containsKey(key)) { |
| LOGGER.info(String.format("Overriding property from environment: %s=%s", key, value)); |
| } else { |
| LOGGER.info(String.format("Setting property from environment: %s=%s", key, value)); |
| } |
| |
| envConfig.put(key, value); |
| } |
| } |
| |
| for (Map.Entry<String, String> entry: config.entrySet()) { |
| String key = entry.getKey(); |
| |
| if (!envConfig.containsKey(key) && envConfig.containsKey(key.toLowerCase())) { |
| throw new IllegalArgumentException(String.format( |
| "Can't override property from environment with mixed case: %s", key)); |
| } |
| } |
| |
| return new MapConfig(Arrays.asList(config, envConfig)); |
| } |
| |
| protected static String renameKey(String envName) { |
| if (envName.length() <= SAMZA_KEY_PREFIX.length()) { |
| throw new IllegalArgumentException(); |
| } |
| |
| String configName = envName.substring(SAMZA_KEY_PREFIX.length()); |
| return configName.toLowerCase().replace('_', '.'); |
| } |
| } |