001/* 002 * Licensed to the Apache Software Foundation (ASF) under one or more 003 * contributor license agreements. See the NOTICE file distributed with 004 * this work for additional information regarding copyright ownership. 005 * The ASF licenses this file to You under the Apache license, Version 2.0 006 * (the "License"); you may not use this file except in compliance with 007 * the License. You may obtain a copy of the License at 008 * 009 * http://www.apache.org/licenses/LICENSE-2.0 010 * 011 * Unless required by applicable law or agreed to in writing, software 012 * distributed under the License is distributed on an "AS IS" BASIS, 013 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 014 * See the license for the specific language governing permissions and 015 * limitations under the license. 016 */ 017package org.apache.logging.log4j.core.lookup; 018 019import java.util.HashMap; 020import java.util.List; 021import java.util.Map; 022 023import org.apache.logging.log4j.Logger; 024import org.apache.logging.log4j.core.LogEvent; 025import org.apache.logging.log4j.core.config.plugins.util.PluginManager; 026import org.apache.logging.log4j.core.config.plugins.util.PluginType; 027import org.apache.logging.log4j.core.util.Loader; 028import org.apache.logging.log4j.core.util.ReflectionUtil; 029import org.apache.logging.log4j.status.StatusLogger; 030 031/** 032 * Proxies all the other {@link StrLookup}s. 033 */ 034public class Interpolator extends AbstractLookup { 035 036 private static final Logger LOGGER = StatusLogger.getLogger(); 037 038 /** Constant for the prefix separator. */ 039 private static final char PREFIX_SEPARATOR = ':'; 040 041 private final Map<String, StrLookup> lookups = new HashMap<>(); 042 043 private final StrLookup defaultLookup; 044 045 public Interpolator(final StrLookup defaultLookup) { 046 this(defaultLookup, null); 047 } 048 049 /** 050 * Constructs an Interpolator using a given StrLookup and a list of packages to find Lookup plugins in. 051 * 052 * @param defaultLookup the default StrLookup to use as a fallback 053 * @param pluginPackages a list of packages to scan for Lookup plugins 054 * @since 2.1 055 */ 056 public Interpolator(final StrLookup defaultLookup, final List<String> pluginPackages) { 057 this.defaultLookup = defaultLookup == null ? new MapLookup(new HashMap<String, String>()) : defaultLookup; 058 final PluginManager manager = new PluginManager(CATEGORY); 059 manager.collectPlugins(pluginPackages); 060 final Map<String, PluginType<?>> plugins = manager.getPlugins(); 061 062 for (final Map.Entry<String, PluginType<?>> entry : plugins.entrySet()) { 063 try { 064 final Class<? extends StrLookup> clazz = entry.getValue().getPluginClass().asSubclass(StrLookup.class); 065 lookups.put(entry.getKey(), ReflectionUtil.instantiate(clazz)); 066 } catch (final Exception ex) { 067 LOGGER.error("Unable to create Lookup for {}", entry.getKey(), ex); 068 } 069 } 070 } 071 072 /** 073 * Create the default Interpolator using only Lookups that work without an event. 074 */ 075 public Interpolator() { 076 this((Map<String, String>) null); 077 } 078 079 /** 080 * Creates the Interpolator using only Lookups that work without an event and initial properties. 081 */ 082 public Interpolator(final Map<String, String> properties) { 083 this.defaultLookup = new MapLookup(properties == null ? new HashMap<String, String>() : properties); 084 // TODO: this ought to use the PluginManager 085 lookups.put("log4j", new Log4jLookup()); 086 lookups.put("sys", new SystemPropertiesLookup()); 087 lookups.put("env", new EnvironmentLookup()); 088 lookups.put("main", MainMapLookup.MAIN_SINGLETON); 089 lookups.put("marker", new MarkerLookup()); 090 lookups.put("java", new JavaLookup()); 091 // JNDI 092 try { 093 // [LOG4J2-703] We might be on Android 094 lookups.put("jndi", 095 Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JndiLookup", StrLookup.class)); 096 } catch (final Throwable e) { 097 // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JndiLookup 098 LOGGER.warn( 099 "JNDI lookup class is not available because this JRE does not support JNDI. JNDI string lookups will not be available, continuing configuration.", 100 e); 101 } 102 // JMX input args 103 try { 104 // We might be on Android 105 lookups.put("jvmrunargs", 106 Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JmxRuntimeInputArgumentsLookup", StrLookup.class)); 107 } catch (final Throwable e) { 108 // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JmxRuntimeInputArgumentsLookup 109 LOGGER.warn( 110 "JMX runtime input lookup class is not available because this JRE does not support JMX. JMX lookups will not be available, continuing configuration.", 111 e); 112 } 113 lookups.put("date", new DateLookup()); 114 lookups.put("ctx", new ContextMapLookup()); 115 if (Loader.isClassAvailable("javax.servlet.ServletContext")) { 116 try { 117 lookups.put("web", 118 Loader.newCheckedInstanceOf("org.apache.logging.log4j.web.WebLookup", StrLookup.class)); 119 } catch (final Exception ignored) { 120 LOGGER.info("Log4j appears to be running in a Servlet environment, but there's no log4j-web module " + 121 "available. If you want better web container support, please add the log4j-web JAR to your " + 122 "web archive or server lib directory."); 123 } 124 } else { 125 LOGGER.debug("Not in a ServletContext environment, thus not loading WebLookup plugin."); 126 } 127 } 128 129 /** 130 * Resolves the specified variable. This implementation will try to extract 131 * a variable prefix from the given variable name (the first colon (':') is 132 * used as prefix separator). It then passes the name of the variable with 133 * the prefix stripped to the lookup object registered for this prefix. If 134 * no prefix can be found or if the associated lookup object cannot resolve 135 * this variable, the default lookup object will be used. 136 * 137 * @param event The current LogEvent or null. 138 * @param var the name of the variable whose value is to be looked up 139 * @return the value of this variable or <b>null</b> if it cannot be 140 * resolved 141 */ 142 @Override 143 public String lookup(final LogEvent event, String var) { 144 if (var == null) { 145 return null; 146 } 147 148 final int prefixPos = var.indexOf(PREFIX_SEPARATOR); 149 if (prefixPos >= 0) { 150 final String prefix = var.substring(0, prefixPos); 151 final String name = var.substring(prefixPos + 1); 152 final StrLookup lookup = lookups.get(prefix); 153 String value = null; 154 if (lookup != null) { 155 value = event == null ? lookup.lookup(name) : lookup.lookup(event, name); 156 } 157 158 if (value != null) { 159 return value; 160 } 161 var = var.substring(prefixPos + 1); 162 } 163 if (defaultLookup != null) { 164 return event == null ? defaultLookup.lookup(var) : defaultLookup.lookup(event, var); 165 } 166 return null; 167 } 168 169 @Override 170 public String toString() { 171 final StringBuilder sb = new StringBuilder(); 172 for (final String name : lookups.keySet()) { 173 if (sb.length() == 0) { 174 sb.append('{'); 175 } else { 176 sb.append(", "); 177 } 178 179 sb.append(name); 180 } 181 if (sb.length() > 0) { 182 sb.append('}'); 183 } 184 return sb.toString(); 185 } 186}