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 */ 017 package org.apache.logging.log4j.core.lookup; 018 019 import java.util.HashMap; 020 import java.util.List; 021 import java.util.Map; 022 023 import org.apache.logging.log4j.Logger; 024 import org.apache.logging.log4j.core.LogEvent; 025 import org.apache.logging.log4j.core.config.plugins.util.PluginManager; 026 import org.apache.logging.log4j.core.config.plugins.util.PluginType; 027 import org.apache.logging.log4j.core.util.Loader; 028 import org.apache.logging.log4j.core.util.ReflectionUtil; 029 import org.apache.logging.log4j.status.StatusLogger; 030 031 /** 032 * Proxies all the other {@link StrLookup}s. 033 */ 034 public 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<String, StrLookup>(); 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("sys", new SystemPropertiesLookup()); 086 lookups.put("env", new EnvironmentLookup()); 087 lookups.put("main", MapLookup.MAIN_SINGLETON); 088 lookups.put("java", new JavaLookup()); 089 // JNDI 090 try { 091 // [LOG4J2-703] We might be on Android 092 lookups.put("jndi", 093 Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JndiLookup", StrLookup.class)); 094 } catch (final Throwable e) { 095 // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JndiLookup 096 LOGGER.warn( 097 "JNDI lookup class is not available because this JRE does not support JNDI. JNDI string lookups will not be available, continuing configuration.", 098 e); 099 } 100 // JMX input args 101 try { 102 // We might be on Android 103 lookups.put("jvmrunargs", 104 Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JmxRuntimeInputArgumentsLookup", StrLookup.class)); 105 } catch (final Throwable e) { 106 // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JmxRuntimeInputArgumentsLookup 107 LOGGER.warn( 108 "JMX runtime input lookup class is not available because this JRE does not support JMX. JMX lookups will not be available, continuing configuration.", 109 e); 110 } 111 lookups.put("date", new DateLookup()); 112 lookups.put("ctx", new ContextMapLookup()); 113 if (Loader.isClassAvailable("javax.servlet.ServletContext")) { 114 try { 115 lookups.put("web", 116 Loader.newCheckedInstanceOf("org.apache.logging.log4j.web.WebLookup", StrLookup.class)); 117 } catch (final Exception ignored) { 118 LOGGER.info("Log4j appears to be running in a Servlet environment, but there's no log4j-web module " + 119 "available. If you want better web container support, please add the log4j-web JAR to your " + 120 "web archive or server lib directory."); 121 } 122 } else { 123 LOGGER.debug("Not in a ServletContext environment, thus not loading WebLookup plugin."); 124 } 125 } 126 127 /** 128 * Resolves the specified variable. This implementation will try to extract 129 * a variable prefix from the given variable name (the first colon (':') is 130 * used as prefix separator). It then passes the name of the variable with 131 * the prefix stripped to the lookup object registered for this prefix. If 132 * no prefix can be found or if the associated lookup object cannot resolve 133 * this variable, the default lookup object will be used. 134 * 135 * @param event The current LogEvent or null. 136 * @param var the name of the variable whose value is to be looked up 137 * @return the value of this variable or <b>null</b> if it cannot be 138 * resolved 139 */ 140 @Override 141 public String lookup(final LogEvent event, String var) { 142 if (var == null) { 143 return null; 144 } 145 146 final int prefixPos = var.indexOf(PREFIX_SEPARATOR); 147 if (prefixPos >= 0) { 148 final String prefix = var.substring(0, prefixPos); 149 final String name = var.substring(prefixPos + 1); 150 final StrLookup lookup = lookups.get(prefix); 151 String value = null; 152 if (lookup != null) { 153 value = event == null ? lookup.lookup(name) : lookup.lookup(event, name); 154 } 155 156 if (value != null) { 157 return value; 158 } 159 var = var.substring(prefixPos + 1); 160 } 161 if (defaultLookup != null) { 162 return event == null ? defaultLookup.lookup(var) : defaultLookup.lookup(event, var); 163 } 164 return null; 165 } 166 167 @Override 168 public String toString() { 169 final StringBuilder sb = new StringBuilder(); 170 for (final String name : lookups.keySet()) { 171 if (sb.length() == 0) { 172 sb.append('{'); 173 } else { 174 sb.append(", "); 175 } 176 177 sb.append(name); 178 } 179 if (sb.length() > 0) { 180 sb.append('}'); 181 } 182 return sb.toString(); 183 } 184 }