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org.apache.logging.log4j.core.config.plugins.util.PluginBuilder Maven / Gradle / Ivy
/*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership.
* The ASF licenses this file to You under the Apache license, Version 2.0
* (the "License"); you may not use this file except in compliance with
* the License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the license for the specific language governing permissions and
* limitations under the license.
*/
package org.apache.logging.log4j.core.config.plugins.util;
import java.lang.annotation.Annotation;
import java.lang.reflect.AccessibleObject;
import java.lang.reflect.Field;
import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;
import java.lang.reflect.Modifier;
import java.util.Collection;
import java.util.List;
import java.util.Map;
import java.util.Objects;
import org.apache.logging.log4j.Logger;
import org.apache.logging.log4j.core.LogEvent;
import org.apache.logging.log4j.core.config.Configuration;
import org.apache.logging.log4j.core.config.ConfigurationException;
import org.apache.logging.log4j.core.config.Node;
import org.apache.logging.log4j.core.config.plugins.PluginAliases;
import org.apache.logging.log4j.core.config.plugins.PluginBuilderFactory;
import org.apache.logging.log4j.core.config.plugins.PluginFactory;
import org.apache.logging.log4j.core.config.plugins.validation.ConstraintValidator;
import org.apache.logging.log4j.core.config.plugins.validation.ConstraintValidators;
import org.apache.logging.log4j.core.config.plugins.visitors.PluginVisitor;
import org.apache.logging.log4j.core.config.plugins.visitors.PluginVisitors;
import org.apache.logging.log4j.core.lookup.ConfigurationStrSubstitutor;
import org.apache.logging.log4j.core.util.Builder;
import org.apache.logging.log4j.core.util.ReflectionUtil;
import org.apache.logging.log4j.core.util.TypeUtil;
import org.apache.logging.log4j.status.StatusLogger;
import org.apache.logging.log4j.util.StringBuilders;
/**
* Builder class to instantiate and configure a Plugin object using a PluginFactory method or PluginBuilderFactory
* builder class.
*/
public class PluginBuilder implements Builder {
private static final Logger LOGGER = StatusLogger.getLogger();
private final PluginType pluginType;
private final Class clazz;
private Configuration configuration;
private Node node;
private LogEvent event;
/**
* Constructs a PluginBuilder for a given PluginType.
*
* @param pluginType type of plugin to configure
*/
public PluginBuilder(final PluginType pluginType) {
this.pluginType = pluginType;
this.clazz = pluginType.getPluginClass();
}
/**
* Specifies the Configuration to use for constructing the plugin instance.
*
* @param configuration the configuration to use.
* @return {@code this}
*/
public PluginBuilder withConfiguration(final Configuration configuration) {
this.configuration = configuration;
return this;
}
/**
* Specifies the Node corresponding to the plugin object that will be created.
*
* @param node the plugin configuration node to use.
* @return {@code this}
*/
public PluginBuilder withConfigurationNode(final Node node) {
this.node = node;
return this;
}
/**
* Specifies the LogEvent that may be used to provide extra context for string substitutions.
*
* @param event the event to use for extra information.
* @return {@code this}
*/
public PluginBuilder forLogEvent(final LogEvent event) {
this.event = event;
return this;
}
/**
* Builds the plugin object.
*
* @return the plugin object or {@code null} if there was a problem creating it.
*/
@Override
public Object build() {
verify();
// first try to use a builder class if one is available
try {
LOGGER.debug("Building Plugin[name={}, class={}].", pluginType.getElementName(),
pluginType.getPluginClass().getName());
final Builder builder = createBuilder(this.clazz);
if (builder != null) {
injectFields(builder);
return builder.build();
}
} catch (final ConfigurationException e) { // LOG4J2-1908
LOGGER.error("Could not create plugin of type {} for element {}", this.clazz, node.getName(), e);
return null; // no point in trying the factory method
} catch (final Throwable t) {
LOGGER.error("Could not create plugin of type {} for element {}: {}",
this.clazz, node.getName(),
(t instanceof InvocationTargetException ? ((InvocationTargetException) t).getCause() : t).toString(), t);
}
// or fall back to factory method if no builder class is available
try {
final Method factory = findFactoryMethod(this.clazz);
final Object[] params = generateParameters(factory);
return factory.invoke(null, params);
} catch (final Throwable t) {
LOGGER.error("Unable to invoke factory method in {} for element {}: {}",
this.clazz, this.node.getName(),
(t instanceof InvocationTargetException ? ((InvocationTargetException) t).getCause() : t).toString(), t);
return null;
}
}
private void verify() {
Objects.requireNonNull(this.configuration, "No Configuration object was set.");
Objects.requireNonNull(this.node, "No Node object was set.");
}
private static Builder createBuilder(final Class clazz)
throws InvocationTargetException, IllegalAccessException {
for (final Method method : clazz.getDeclaredMethods()) {
if (method.isAnnotationPresent(PluginBuilderFactory.class) &&
Modifier.isStatic(method.getModifiers()) &&
TypeUtil.isAssignable(Builder.class, method.getReturnType())) {
ReflectionUtil.makeAccessible(method);
return (Builder) method.invoke(null);
}
}
return null;
}
private void injectFields(final Builder builder) throws IllegalAccessException {
final List fields = TypeUtil.getAllDeclaredFields(builder.getClass());
AccessibleObject.setAccessible(fields.toArray(new Field[] {}), true);
final StringBuilder log = new StringBuilder();
boolean invalid = false;
String reason = "";
for (final Field field : fields) {
log.append(log.length() == 0 ? simpleName(builder) + "(" : ", ");
final Annotation[] annotations = field.getDeclaredAnnotations();
final String[] aliases = extractPluginAliases(annotations);
for (final Annotation a : annotations) {
if (a instanceof PluginAliases) {
continue; // already processed
}
final PluginVisitor visitor =
PluginVisitors.findVisitor(a.annotationType());
if (visitor != null) {
final Object value = visitor.setAliases(aliases)
.setAnnotation(a)
.setConversionType(field.getType())
.setStrSubstitutor(event == null
? new ConfigurationStrSubstitutor(configuration.getStrSubstitutor())
: configuration.getStrSubstitutor())
.setMember(field)
.visit(configuration, node, event, log);
// don't overwrite default values if the visitor gives us no value to inject
if (value != null) {
field.set(builder, value);
}
}
}
final Collection> validators =
ConstraintValidators.findValidators(annotations);
final Object value = field.get(builder);
for (final ConstraintValidator validator : validators) {
if (!validator.isValid(field.getName(), value)) {
invalid = true;
if (!reason.isEmpty()) {
reason += ", ";
}
reason += "field '" + field.getName() + "' has invalid value '" + value + "'";
}
}
}
log.append(log.length() == 0 ? builder.getClass().getSimpleName() + "()" : ")");
LOGGER.debug(log.toString());
if (invalid) {
throw new ConfigurationException("Arguments given for element " + node.getName() + " are invalid: " + reason);
}
checkForRemainingAttributes();
verifyNodeChildrenUsed();
}
/**
* {@code object.getClass().getSimpleName()} returns {@code Builder}, when we want {@code PatternLayout$Builder}.
*/
private static String simpleName(final Object object) {
if (object == null) {
return "null";
}
final String cls = object.getClass().getName();
final int index = cls.lastIndexOf('.');
return index < 0 ? cls : cls.substring(index + 1);
}
private static Method findFactoryMethod(final Class clazz) {
for (final Method method : clazz.getDeclaredMethods()) {
if (method.isAnnotationPresent(PluginFactory.class) &&
Modifier.isStatic(method.getModifiers())) {
ReflectionUtil.makeAccessible(method);
return method;
}
}
throw new IllegalStateException("No factory method found for class " + clazz.getName());
}
private Object[] generateParameters(final Method factory) {
final StringBuilder log = new StringBuilder();
final Class[] types = factory.getParameterTypes();
final Annotation[][] annotations = factory.getParameterAnnotations();
final Object[] args = new Object[annotations.length];
boolean invalid = false;
for (int i = 0; i < annotations.length; i++) {
log.append(log.length() == 0 ? factory.getName() + "(" : ", ");
final String[] aliases = extractPluginAliases(annotations[i]);
for (final Annotation a : annotations[i]) {
if (a instanceof PluginAliases) {
continue; // already processed
}
final PluginVisitor visitor = PluginVisitors.findVisitor(
a.annotationType());
if (visitor != null) {
final Object value = visitor.setAliases(aliases)
.setAnnotation(a)
.setConversionType(types[i])
.setStrSubstitutor(event == null
? new ConfigurationStrSubstitutor(configuration.getStrSubstitutor())
: configuration.getStrSubstitutor())
.setMember(factory)
.visit(configuration, node, event, log);
// don't overwrite existing values if the visitor gives us no value to inject
if (value != null) {
args[i] = value;
}
}
}
final Collection> validators =
ConstraintValidators.findValidators(annotations[i]);
final Object value = args[i];
final String argName = "arg[" + i + "](" + simpleName(value) + ")";
for (final ConstraintValidator validator : validators) {
if (!validator.isValid(argName, value)) {
invalid = true;
}
}
}
log.append(log.length() == 0 ? factory.getName() + "()" : ")");
checkForRemainingAttributes();
verifyNodeChildrenUsed();
LOGGER.debug(log.toString());
if (invalid) {
throw new ConfigurationException("Arguments given for element " + node.getName() + " are invalid");
}
return args;
}
private static String[] extractPluginAliases(final Annotation... parmTypes) {
String[] aliases = null;
for (final Annotation a : parmTypes) {
if (a instanceof PluginAliases) {
aliases = ((PluginAliases) a).value();
}
}
return aliases;
}
private void checkForRemainingAttributes() {
final Map attrs = node.getAttributes();
if (!attrs.isEmpty()) {
final StringBuilder sb = new StringBuilder();
for (final String key : attrs.keySet()) {
if (sb.length() == 0) {
sb.append(node.getName());
sb.append(" contains ");
if (attrs.size() == 1) {
sb.append("an invalid element or attribute ");
} else {
sb.append("invalid attributes ");
}
} else {
sb.append(", ");
}
StringBuilders.appendDqValue(sb, key);
}
LOGGER.error(sb.toString());
}
}
private void verifyNodeChildrenUsed() {
final List children = node.getChildren();
if (!(pluginType.isDeferChildren() || children.isEmpty())) {
for (final Node child : children) {
final String nodeType = node.getType().getElementName();
final String start = nodeType.equals(node.getName()) ? node.getName() : nodeType + ' ' + node.getName();
LOGGER.error("{} has no parameter that matches element {}", start, child.getName());
}
}
}
}
