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.util;
18
19 import java.util.Map;
20
21 /**
22 * PropertySource implementation that uses environment variables as a source. All environment variables must begin
23 * with {@code LOG4J_} so as not to conflict with other variables. Normalized environment variables follow a scheme
24 * like this: {@code log4j2.fooBarProperty} would normalize to {@code LOG4J_FOO_BAR_PROPERTY}.
25 *
26 * @since 2.10.0
27 */
28 public class EnvironmentPropertySource implements PropertySource {
29 @Override
30 public int getPriority() {
31 return -100;
32 }
33
34 @Override
35 public void forEach(final BiConsumer<String, String> action) {
36 for (final Map.Entry<String, String> entry : System.getenv().entrySet()) {
37 final String key = entry.getKey();
38 if (key.startsWith("LOG4J_")) {
39 action.accept(key.substring(6), entry.getValue());
40 }
41 }
42 }
43
44 @Override
45 public CharSequence getNormalForm(final Iterable<? extends CharSequence> tokens) {
46 final StringBuilder sb = new StringBuilder("LOG4J");
47 for (final CharSequence token : tokens) {
48 sb.append('_');
49 for (int i = 0; i < token.length(); i++) {
50 sb.append(Character.toUpperCase(token.charAt(i)));
51 }
52 }
53 return sb.toString();
54 }
55 }