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/*
* Copyright 2016-2020 the original author or authors from the JHipster project.
*
* This file is part of the JHipster project, see https://www.jhipster.tech/
* for more information.
*
* Licensed 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 io.github.jhipster.test;
import ch.qos.logback.classic.Level;
import ch.qos.logback.classic.Logger;
import ch.qos.logback.classic.LoggerContext;
import ch.qos.logback.classic.spi.ILoggingEvent;
import ch.qos.logback.classic.spi.IThrowableProxy;
import ch.qos.logback.core.AppenderBase;
import org.slf4j.LoggerFactory;
import org.slf4j.Marker;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import java.util.WeakHashMap;
/**
* Utility, mainly for unit tests, to assert content written to logback. A classical usage would be
* the following.
*
* {@code
* LogbackRecorder recorder = LogbackRecorder.forClass(TestedClass.class)
* .reset()
* .capture(Level.WARN.name());
* // do something that logs
* List events = recorder.release().play();
* // perform assertions on the events
* }
*/
@ConditionalOnClass({LoggerContext.class})
public class LogbackRecorder {
/** Constant DEFAULT_MUTE=true */
public static final boolean DEFAULT_MUTE = true;
/** Constant DEFAULT_LEVEL="ALL" */
public static final String DEFAULT_LEVEL = "ALL";
/** Constant LOGBACK_EXCEPTION_MESSAGE="Expected logback" */
public static final String LOGBACK_EXCEPTION_MESSAGE = "Expected logback";
/** Constant CAPTURE_EXCEPTION_MESSAGE="Already capturing" */
public static final String CAPTURE_EXCEPTION_MESSAGE = "Already capturing";
/** Constant RELEASE_EXCEPTION_MESSAGE="Not currently capturing" */
public static final String RELEASE_EXCEPTION_MESSAGE = "Not currently capturing";
private static final LoggerContext context = (LoggerContext) LoggerFactory.getILoggerFactory();
private static final Object lock = context.getConfigurationLock();
private static final Map instances = new WeakHashMap<>(32, 0.75F);
/**
* Create a recorder for a logback logger identified by the class name. Instances of a recorder are cached per logger.
* Make sure to reset it before starting capture.
*
* @param clazz class whose logger as its name
* @return the recorder for this class
*/
public static final LogbackRecorder forClass(Class clazz) {
return forLogger(context.getLogger(clazz));
}
/**
* Create a recorder for a logback logger identified by its name. Instances of a recorder are cached per logger.
* Make sure to reset it before starting capture.
*
* @param name the name of the logger
* @return the recorder for this class
*/
public static final LogbackRecorder forName(String name) {
return forLogger(context.getLogger(name));
}
/**
* Create a recorder for a logback logger. Instances of a recorder are cached per logger.
* Make sure to reset it before starting capture.
*
* @param logger the logger to record
* @return the recorder for this logger
*/
public static final LogbackRecorder forLogger(org.slf4j.Logger logger) {
synchronized (instances) {
if (!(logger instanceof Logger)) {
throw new IllegalArgumentException(LOGBACK_EXCEPTION_MESSAGE);
}
LogbackRecorder recorder = instances.get(logger);
if (recorder == null) {
recorder = new LogbackRecorder((Logger) logger);
instances.put(recorder.logger, recorder);
}
return recorder;
}
}
private final Logger logger;
private final List events;
private final AppenderBase appender;
private boolean active;
private boolean additive;
private Level level;
private LogbackRecorder(Logger logger) {
this.logger = logger;
this.events = new ArrayList<>();
this.appender = new AppenderBase() {
@Override
protected synchronized void append(ILoggingEvent event) {
events.add(new Event(event));
}
};
}
/**
* Resets the logger by clearing everything that was recorded so far.
*
* @return this
*/
public synchronized LogbackRecorder reset() {
this.events.clear();
return this;
}
/**
* Start capturing whatever is logged for this level of worse.
*
* @param level the level at which to start capturing
* @return this
*/
public LogbackRecorder capture(String level) {
synchronized (lock) {
if (this.active) {
throw new IllegalStateException(CAPTURE_EXCEPTION_MESSAGE);
}
this.active = true;
this.additive = logger.isAdditive();
this.logger.setAdditive(false);
this.level = logger.getLevel();
this.logger.setLevel(Level.valueOf(level.toUpperCase()));
this.logger.addAppender(this.appender);
this.appender.start();
}
return this;
}
/**
* Stop recording and detach from the logger.
*
* @return this
*/
public synchronized LogbackRecorder release() {
synchronized (lock) {
if (!this.active) {
throw new IllegalStateException(RELEASE_EXCEPTION_MESSAGE);
}
this.appender.stop();
this.logger.detachAppender(this.appender);
this.logger.setLevel(this.level);
this.logger.setAdditive(this.additive);
}
this.active = false;
return this;
}
/**
* Return all recorded events.
*
* @return all recorded events so far
*/
public List play() {
return new ArrayList<>(this.events);
}
/**
* A recorded event. It contains all information sent to the logger.
*/
public static final class Event {
private final Marker marker;
private final String level;
private final String message;
private final Object[] arguments;
private final String thrown;
Event(ILoggingEvent event) {
this.marker = event.getMarker();
this.level = event.getLevel().toString();
this.message = event.getMessage();
this.arguments = event.getArgumentArray();
final IThrowableProxy proxy = event.getThrowableProxy();
this.thrown = proxy == null ? null : proxy.getClassName() + ": " + proxy.getMessage();
}
/**
* Slf4j market used.
*
* @return the marker
*/
public Marker getMarker() {
return this.marker;
}
/**
* Level of the log.
*
* @return the level
*/
public String getLevel() {
return this.level;
}
/**
* Message passed to the logger with the original placeholders ('{}').
*
* @return the logged message
*/
public String getMessage() {
return this.message;
}
/**
* The arguments passed to the logger to be used by a placeholder. Logged exceptions are not included.
*
* @return the parameters passed to the logger
*/
public Object[] getArguments() {
return this.arguments;
}
/**
* Logged exception passed in argument to the logger or null if none.
*
* @return the logged exception as {@code exception.getClass().getName() + ": " + exception.getMessage()}
*/
public String getThrown() {
return this.thrown;
}
}
}