1 /* 2 * Licensed to the Apache Software Foundation (ASF) under one or more 3 * contributor license agreements. See the NOTICE file distributed with 4 * this work for additional information regarding copyright ownership. 5 * The ASF licenses this file to You under the Apache license, Version 2.0 6 * (the "License"); you may not use this file except in compliance with 7 * the License. You may obtain a copy of the License at 8 * 9 * http://www.apache.org/licenses/LICENSE-2.0 10 * 11 * Unless required by applicable law or agreed to in writing, software 12 * distributed under the License is distributed on an "AS IS" BASIS, 13 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 14 * See the license for the specific language governing permissions and 15 * limitations under the license. 16 */ 17 package org.apache.logging.log4j.core.lookup; 18 19 import org.apache.logging.log4j.core.LogEvent; 20 import org.apache.logging.log4j.core.config.plugins.Plugin; 21 22 /** 23 * Looks up keys from environment variables. 24 */ 25 @Plugin(name = "env", category = "Lookup") 26 public class EnvironmentLookup implements StrLookup { 27 28 /** 29 * Looks up the value of the environment variable. 30 * @param key the key to be looked up, may be null 31 * @return The value of the environment variable. 32 */ 33 @Override 34 public String lookup(final String key) { 35 return System.getenv(key); 36 } 37 38 /** 39 * Looks up the value of the environment variable. 40 * @param event The current LogEvent (is ignored by this StrLookup). 41 * @param key the key to be looked up, may be null 42 * @return The value of the environment variable. 43 */ 44 @Override 45 public String lookup(final LogEvent event, final String key) { 46 return System.getenv(key); 47 } 48 }