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.Locale;
022import java.util.Map;
023
024import org.apache.logging.log4j.Logger;
025import org.apache.logging.log4j.core.LogEvent;
026import org.apache.logging.log4j.core.config.ConfigurationAware;
027import org.apache.logging.log4j.core.config.plugins.util.PluginManager;
028import org.apache.logging.log4j.core.config.plugins.util.PluginType;
029import org.apache.logging.log4j.core.net.JndiManager;
030import org.apache.logging.log4j.core.util.Loader;
031import org.apache.logging.log4j.core.util.ReflectionUtil;
032import org.apache.logging.log4j.status.StatusLogger;
033import org.apache.logging.log4j.util.Constants;
034
035/**
036 * Proxies all the other {@link StrLookup}s.
037 */
038public class Interpolator extends AbstractConfigurationAwareLookup {
039
040    /** Constant for the prefix separator. */
041    public static final char PREFIX_SEPARATOR = ':';
042
043    private static final String LOOKUP_KEY_WEB = "web";
044
045    private static final String LOOKUP_KEY_DOCKER = "docker";
046
047    private static final String LOOKUP_KEY_KUBERNETES = "kubernetes";
048
049    private static final String LOOKUP_KEY_SPRING = "spring";
050
051    private static final String LOOKUP_KEY_JNDI = "jndi";
052
053    private static final String LOOKUP_KEY_JVMRUNARGS = "jvmrunargs";
054
055    private static final Logger LOGGER = StatusLogger.getLogger();
056
057    private final Map<String, StrLookup> strLookupMap = new HashMap<>();
058
059    private final StrLookup defaultLookup;
060
061    public Interpolator(final StrLookup defaultLookup) {
062        this(defaultLookup, null);
063    }
064
065    /**
066     * Constructs an Interpolator using a given StrLookup and a list of packages to find Lookup plugins in.
067     *
068     * @param defaultLookup  the default StrLookup to use as a fallback
069     * @param pluginPackages a list of packages to scan for Lookup plugins
070     * @since 2.1
071     */
072    public Interpolator(final StrLookup defaultLookup, final List<String> pluginPackages) {
073        this.defaultLookup = defaultLookup == null ? new MapLookup(new HashMap<String, String>()) : defaultLookup;
074        final PluginManager manager = new PluginManager(CATEGORY);
075        manager.collectPlugins(pluginPackages);
076        final Map<String, PluginType<?>> plugins = manager.getPlugins();
077
078        for (final Map.Entry<String, PluginType<?>> entry : plugins.entrySet()) {
079            try {
080                final Class<? extends StrLookup> clazz = entry.getValue().getPluginClass().asSubclass(StrLookup.class);
081                if (!clazz.getName().equals(JndiLookup.class.getName()) || JndiManager.isJndiEnabled()) {
082                    strLookupMap.put(entry.getKey().toLowerCase(), ReflectionUtil.instantiate(clazz));
083                }
084            } catch (final Throwable t) {
085                handleError(entry.getKey(), t);
086            }
087        }
088    }
089
090    /**
091     * Create the default Interpolator using only Lookups that work without an event.
092     */
093    public Interpolator() {
094        this((Map<String, String>) null);
095    }
096
097    /**
098     * Creates the Interpolator using only Lookups that work without an event and initial properties.
099     */
100    public Interpolator(final Map<String, String> properties) {
101        this.defaultLookup = new MapLookup(properties == null ? new HashMap<String, String>() : properties);
102        // TODO: this ought to use the PluginManager
103        strLookupMap.put("log4j", new Log4jLookup());
104        strLookupMap.put("sys", new SystemPropertiesLookup());
105        strLookupMap.put("env", new EnvironmentLookup());
106        strLookupMap.put("main", MainMapLookup.MAIN_SINGLETON);
107        strLookupMap.put("marker", new MarkerLookup());
108        strLookupMap.put("java", new JavaLookup());
109        strLookupMap.put("lower", new LowerLookup());
110        strLookupMap.put("upper", new UpperLookup());
111        // JNDI
112        if (JndiManager.isJndiEnabled()) {
113            try {
114                // [LOG4J2-703] We might be on Android
115                strLookupMap.put(LOOKUP_KEY_JNDI,
116                        Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JndiLookup", StrLookup.class));
117            } catch (final LinkageError | Exception e) {
118                handleError(LOOKUP_KEY_JNDI, e);
119            }
120        }
121        // JMX input args
122        try {
123            // We might be on Android
124            strLookupMap.put(LOOKUP_KEY_JVMRUNARGS,
125                Loader.newCheckedInstanceOf("org.apache.logging.log4j.core.lookup.JmxRuntimeInputArgumentsLookup",
126                        StrLookup.class));
127        } catch (final LinkageError | Exception e) {
128            handleError(LOOKUP_KEY_JVMRUNARGS, e);
129        }
130        strLookupMap.put("date", new DateLookup());
131        strLookupMap.put("ctx", new ContextMapLookup());
132        if (Constants.IS_WEB_APP) {
133            try {
134                strLookupMap.put(LOOKUP_KEY_WEB,
135                    Loader.newCheckedInstanceOf("org.apache.logging.log4j.web.WebLookup", StrLookup.class));
136            } catch (final Exception ignored) {
137                handleError(LOOKUP_KEY_WEB, ignored);
138            }
139        } else {
140            LOGGER.debug("Not in a ServletContext environment, thus not loading WebLookup plugin.");
141        }
142        try {
143            strLookupMap.put(LOOKUP_KEY_DOCKER,
144                Loader.newCheckedInstanceOf("org.apache.logging.log4j.docker.DockerLookup", StrLookup.class));
145        } catch (final Exception ignored) {
146            handleError(LOOKUP_KEY_DOCKER, ignored);
147        }
148        try {
149            strLookupMap.put(LOOKUP_KEY_SPRING,
150                    Loader.newCheckedInstanceOf("org.apache.logging.log4j.spring.cloud.config.client.SpringLookup", StrLookup.class));
151        } catch (final Exception ignored) {
152            handleError(LOOKUP_KEY_SPRING, ignored);
153        }
154        try {
155            strLookupMap.put(LOOKUP_KEY_KUBERNETES,
156                    Loader.newCheckedInstanceOf("org.apache.logging.log4j.kubernetes.KubernetesLookup", StrLookup.class));
157        } catch (final Exception | NoClassDefFoundError error) {
158            handleError(LOOKUP_KEY_KUBERNETES, error);
159        }
160    }
161
162    public Map<String, StrLookup> getStrLookupMap() {
163        return strLookupMap;
164    }
165
166    private void handleError(final String lookupKey, final Throwable t) {
167        switch (lookupKey) {
168            case LOOKUP_KEY_JNDI:
169                // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JndiLookup
170                LOGGER.warn( // LOG4J2-1582 don't print the whole stack trace (it is just a warning...)
171                        "JNDI lookup class is not available because this JRE does not support JNDI." +
172                        " JNDI string lookups will not be available, continuing configuration. Ignoring " + t);
173                break;
174            case LOOKUP_KEY_JVMRUNARGS:
175                // java.lang.VerifyError: org/apache/logging/log4j/core/lookup/JmxRuntimeInputArgumentsLookup
176                LOGGER.warn(
177                        "JMX runtime input lookup class is not available because this JRE does not support JMX. " +
178                        "JMX lookups will not be available, continuing configuration. Ignoring " + t);
179                break;
180            case LOOKUP_KEY_WEB:
181                LOGGER.info("Log4j appears to be running in a Servlet environment, but there's no log4j-web module " +
182                        "available. If you want better web container support, please add the log4j-web JAR to your " +
183                        "web archive or server lib directory.");
184                break;
185            case LOOKUP_KEY_DOCKER: case LOOKUP_KEY_SPRING:
186                break;
187            case LOOKUP_KEY_KUBERNETES:
188                if (t instanceof NoClassDefFoundError) {
189                    LOGGER.warn("Unable to create Kubernetes lookup due to missing dependency: {}", t.getMessage());
190                }
191                break;
192            default:
193                LOGGER.error("Unable to create Lookup for {}", lookupKey, t);
194        }
195    }
196
197    /**
198     * Resolves the specified variable. This implementation will try to extract
199     * a variable prefix from the given variable name (the first colon (':') is
200     * used as prefix separator). It then passes the name of the variable with
201     * the prefix stripped to the lookup object registered for this prefix. If
202     * no prefix can be found or if the associated lookup object cannot resolve
203     * this variable, the default lookup object will be used.
204     *
205     * @param event The current LogEvent or null.
206     * @param var the name of the variable whose value is to be looked up
207     * @return the value of this variable or <b>null</b> if it cannot be
208     * resolved
209     */
210    @Override
211    public String lookup(final LogEvent event, String var) {
212        if (var == null) {
213            return null;
214        }
215
216        final int prefixPos = var.indexOf(PREFIX_SEPARATOR);
217        if (prefixPos >= 0) {
218            final String prefix = var.substring(0, prefixPos).toLowerCase(Locale.US);
219            final String name = var.substring(prefixPos + 1);
220            final StrLookup lookup = strLookupMap.get(prefix);
221            if (lookup instanceof ConfigurationAware) {
222                ((ConfigurationAware) lookup).setConfiguration(configuration);
223            }
224            String value = null;
225            if (lookup != null) {
226                value = event == null ? lookup.lookup(name) : lookup.lookup(event, name);
227            }
228
229            if (value != null) {
230                return value;
231            }
232            var = var.substring(prefixPos + 1);
233        }
234        if (defaultLookup != null) {
235            return event == null ? defaultLookup.lookup(var) : defaultLookup.lookup(event, var);
236        }
237        return null;
238    }
239
240    @Override
241    public String toString() {
242        final StringBuilder sb = new StringBuilder();
243        for (final String name : strLookupMap.keySet()) {
244            if (sb.length() == 0) {
245                sb.append('{');
246            } else {
247                sb.append(", ");
248            }
249
250            sb.append(name);
251        }
252        if (sb.length() > 0) {
253            sb.append('}');
254        }
255        return sb.toString();
256    }
257
258}