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.net.JndiManager; 028import org.apache.logging.log4j.core.util.Loader; 029import org.apache.logging.log4j.core.util.ReflectionUtil; 030import org.apache.logging.log4j.status.StatusLogger; 031 032/** 033 * Proxies all the other {@link StrLookup}s. 034 */ 035public class Interpolator extends AbstractLookup { 036 037 private static final Logger LOGGER = StatusLogger.getLogger(); 038 039 /** Constant for the prefix separator. */ 040 static final char PREFIX_SEPARATOR = ':'; 041 042 private final Map<String, StrLookup> lookups = new HashMap<String, StrLookup>(); 043 044 private final StrLookup defaultLookup; 045 046 public Interpolator(final StrLookup defaultLookup) { 047 this(defaultLookup, null); 048 } 049 050 /** 051 * Constructs an Interpolator using a given StrLookup and a list of packages to find Lookup plugins in. 052 * 053 * @param defaultLookup the default StrLookup to use as a fallback 054 * @param pluginPackages a list of packages to scan for Lookup plugins 055 * @since 2.1 056 */ 057 public Interpolator(final StrLookup defaultLookup, final List<String> pluginPackages) { 058 this.defaultLookup = defaultLookup == null ? new MapLookup(new HashMap<String, String>()) : defaultLookup; 059 final PluginManager manager = new PluginManager(CATEGORY); 060 manager.collectPlugins(pluginPackages); 061 final Map<String, PluginType<?>> plugins = manager.getPlugins(); 062 063 for (final Map.Entry<String, PluginType<?>> entry : plugins.entrySet()) { 064 try { 065 final Class<? extends StrLookup> clazz = entry.getValue().getPluginClass().asSubclass(StrLookup.class); 066 if (!clazz.getName().equals("org.apache.logging.log4j.core.lookup.JndiLookup") 067 || JndiManager.isJndiLookupEnabled()) { 068 lookups.put(entry.getKey().toLowerCase(), ReflectionUtil.instantiate(clazz)); 069 } 070 } catch (final Exception ex) { 071 LOGGER.error("Unable to create Lookup for {}", entry.getKey(), ex); 072 } 073 } 074 } 075 076 /** 077 * Create the default Interpolator using only Lookups that work without an event. 078 */ 079 public Interpolator() { 080 this((Map<String, String>) null); 081 } 082 083 /** 084 * Creates the Interpolator using only Lookups that work without an event and initial properties. 085 */ 086 public Interpolator(final Map<String, String> properties) { 087 this.defaultLookup = new MapLookup(properties == null ? new HashMap<String, String>() : properties); 088 // TODO: this ought to use the PluginManager 089 lookups.put("sys", new SystemPropertiesLookup()); 090 lookups.put("env", new EnvironmentLookup()); 091 lookups.put("main", MapLookup.MAIN_SINGLETON); 092 lookups.put("java", new JavaLookup()); 093 // JNDI 094 if (JndiManager.isJndiLookupEnabled()) { 095 try { 096 // [LOG4J2-703] We might be on Android 097 lookups.put("jndi", Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JndiLookup", StrLookup.class)); 098 } catch (final Throwable e) { 099 // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JndiLookup 100 LOGGER.warn( 101 "JNDI lookup class is not available because this JRE does not support JNDI. JNDI string lookups will not be available, continuing configuration.", 102 e); 103 } 104 } 105 // JMX input args 106 try { 107 // We might be on Android 108 lookups.put("jvmrunargs", 109 Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JmxRuntimeInputArgumentsLookup", StrLookup.class)); 110 } catch (final Throwable e) { 111 // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JmxRuntimeInputArgumentsLookup 112 LOGGER.warn( 113 "JMX runtime input lookup class is not available because this JRE does not support JMX. JMX lookups will not be available, continuing configuration.", 114 e); 115 } 116 lookups.put("date", new DateLookup()); 117 lookups.put("ctx", new ContextMapLookup()); 118 if (Loader.isClassAvailable("javax.servlet.ServletContext")) { 119 try { 120 lookups.put("web", 121 Loader.newCheckedInstanceOf("org.apache.logging.log4j.web.WebLookup", StrLookup.class)); 122 } catch (final Exception ignored) { 123 LOGGER.info("Log4j appears to be running in a Servlet environment, but there's no log4j-web module " + 124 "available. If you want better web container support, please add the log4j-web JAR to your " + 125 "web archive or server lib directory."); 126 } 127 } else { 128 LOGGER.debug("Not in a ServletContext environment, thus not loading WebLookup plugin."); 129 } 130 } 131 132 /** 133 * Resolves the specified variable. This implementation will try to extract 134 * a variable prefix from the given variable name (the first colon (':') is 135 * used as prefix separator). It then passes the name of the variable with 136 * the prefix stripped to the lookup object registered for this prefix. If 137 * no prefix can be found or if the associated lookup object cannot resolve 138 * this variable, the default lookup object will be used. 139 * 140 * @param event The current LogEvent or null. 141 * @param var the name of the variable whose value is to be looked up 142 * @return the value of this variable or <b>null</b> if it cannot be 143 * resolved 144 */ 145 @Override 146 public String lookup(final LogEvent event, String var) { 147 if (var == null) { 148 return null; 149 } 150 151 final int prefixPos = var.indexOf(PREFIX_SEPARATOR); 152 if (prefixPos >= 0) { 153 final String prefix = var.substring(0, prefixPos); 154 final String name = var.substring(prefixPos + 1); 155 final StrLookup lookup = lookups.get(prefix); 156 String value = null; 157 if (lookup != null) { 158 value = event == null ? lookup.lookup(name) : lookup.lookup(event, name); 159 } 160 161 if (value != null) { 162 return value; 163 } 164 var = var.substring(prefixPos + 1); 165 } 166 if (defaultLookup != null) { 167 return event == null ? defaultLookup.lookup(var) : defaultLookup.lookup(event, var); 168 } 169 return null; 170 } 171 172 @Override 173 public String toString() { 174 final StringBuilder sb = new StringBuilder(); 175 for (final String name : lookups.keySet()) { 176 if (sb.length() == 0) { 177 sb.append('{'); 178 } else { 179 sb.append(", "); 180 } 181 182 sb.append(name); 183 } 184 if (sb.length() > 0) { 185 sb.append('}'); 186 } 187 return sb.toString(); 188 } 189}