Java tutorial
/* * Copyright (C) 2009 Peter Monks (pmonks@gmail.com) * * This program is free software; you can redistribute it and/or * modify it under the terms of the GNU General Public License * as published by the Free Software Foundation; either version 3 * of the License, or (at your option) any later version. * This program is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the * GNU General Public License for more details. * You should have received a copy of the GNU General Public License * along with this program; if not, write to the Free Software * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ package com.lowereast.guiceymongo.logging; import java.util.Arrays; import java.util.Date; import java.util.HashMap; import java.util.List; import java.util.Map; import org.apache.log4j.AppenderSkeleton; import org.apache.log4j.spi.ErrorCode; import org.apache.log4j.spi.LocationInfo; import org.apache.log4j.spi.LoggingEvent; import org.apache.log4j.spi.ThrowableInformation; import com.mongodb.BasicDBList; import com.mongodb.BasicDBObject; import com.mongodb.DB; import com.mongodb.DBCollection; import com.mongodb.DBObject; import com.mongodb.Mongo; /** * Log4J Appender that writes log events into the MongoDB document oriented database. Log events are fully parsed and stored * as structured records in MongoDB (this appender does not require, nor use a Log4J layout). * * The appender does <u>not</u> create any indexes on the data that's stored - it is assumed that if query performance is * required those would be created externally (eg. in the mongodb shell or an external reporting application). * * An example BSON structure for a single log entry is as follows: * * <pre> * { * "_id" : ObjectId("f1c0895fd5eee04a445deb00"), * "timestamp" : "Thu Oct 22 2009 16:46:29 GMT-0700 (Pacific Daylight Time)", * "level" : "ERROR", * "thread" : "main", * "message" : "Error entry", * "fileName" : "TestMongoDbAppender.java", * "method" : "testLogWithChainedExceptions", * "lineNumber" : "147", * "class" : { * "fullyQualifiedClassName" : "com.google.code.log4mongo.TestMongoDbAppender", * "package" : [ "com", "google", "code", "log4mongo" ], * "className" : "TestMongoDbAppender" * }, * "throwables" : [ * { * "message" : "I'm an innocent bystander.", * "stackTrace" : [ * { * "fileName" : "TestMongoDbAppender.java", * "method" : "testLogWithChainedExceptions", * "lineNumber" : 147, * "class" : { * "fullyQualifiedClassName" : "com.google.code.log4mongo.TestMongoDbAppender", * "package" : [ "com", "google", "code", "log4mongo" ], * "className" : "TestMongoDbAppender" * } * }, * { * "method" : "invoke0", * "lineNumber" : -2, * "class" : { * "fullyQualifiedClassName" : "sun.reflect.NativeMethodAccessorImpl", * "package" : [ "sun", "reflect" ], * "className" : "NativeMethodAccessorImpl" * } * }, * ... 8< ... * ] * }, * { * "message" : "I'm the real culprit!", * "stackTrace" : [ * { * "fileName" : "TestMongoDbAppender.java", * "method" : "testLogWithChainedExceptions", * "lineNumber" : 145, * "class" : { * "fullyQualifiedClassName" : "com.google.code.log4mongo.TestMongoDbAppender", * "package" : [ "com", "google", "code", "log4mongo" ], * "className" : "TestMongoDbAppender" * } * }, * ... 8< ... * ] * } * ] * } * </pre> * * @author Peter Monks (pmonks@gmail.com) * @see http://logging.apache.org/log4j/1.2/apidocs/org/apache/log4j/Appender.html * @see http://www.mongodb.org/ * @version $Id$ */ public class MongoDbAppender extends AppenderSkeleton { private final static String DEFAULT_MONGO_DB_HOSTNAME = "localhost"; private final static int DEFAULT_MONGO_DB_PORT = 27017; private final static String DEFAULT_MONGO_DB_DATABASE_NAME = "log4mongo"; private final static String DEFAULT_MONGO_DB_COLLECTION_NAME = "logevents"; private String hostname = DEFAULT_MONGO_DB_HOSTNAME; private int port = DEFAULT_MONGO_DB_PORT; private String databaseName = DEFAULT_MONGO_DB_DATABASE_NAME; private String collectionName = DEFAULT_MONGO_DB_COLLECTION_NAME; private String userName = null; private char[] password = null; private DBCollection collection = null; private Map<String, Object> extraInformation = new HashMap<String, Object>(); /** * @see org.apache.log4j.Appender#requiresLayout() */ public boolean requiresLayout() { return (false); } /** * @see org.apache.log4j.AppenderSkeleton#activateOptions() */ @Override public void activateOptions() { try { Mongo mongo = new Mongo(hostname, port); DB database = mongo.getDB(databaseName); if (userName != null && userName.trim().length() > 0) { if (!database.authenticate(userName, password)) { throw new RuntimeException("Unable to authenticate with MongoDB server."); } // Allow password to be GCed password = null; } setCollection(database.getCollection(collectionName)); } catch (Exception e) { errorHandler.error("Unexpected exception while initialising MongoDbAppender.", e, ErrorCode.GENERIC_FAILURE); } } /** * @see org.apache.log4j.AppenderSkeleton#append(org.apache.log4j.spi.LoggingEvent) */ @Override protected void append(final LoggingEvent loggingEvent) { DBObject bson = bsonifyLoggingEvent(loggingEvent); if (bson != null) { collection.insert(bson); } } /** * Note: this method is primarily intended for use by the unit tests. * * @param collection The MongoDB collection to use when logging events. */ public void setCollection(final DBCollection collection) { // PRECONDITIONS assert collection != null : "collection must not be null."; // Body this.collection = collection; } /** * BSONifies a single Log4J LoggingEvent object. * * @param loggingEvent The LoggingEvent object to BSONify <i>(may be null)</i>. * @return The BSONified equivalent of the LoggingEvent object <i>(may be null)</i>. */ private DBObject bsonifyLoggingEvent(final LoggingEvent loggingEvent) { DBObject result = null; if (loggingEvent != null) { result = new BasicDBObject(this.extraInformation); result.put("timestamp", new Date(loggingEvent.getTimeStamp())); nullSafePut(result, "level", loggingEvent.getLevel().toString()); nullSafePut(result, "thread", loggingEvent.getThreadName()); nullSafePut(result, "message", loggingEvent.getMessage()); addLocationInformation(result, loggingEvent.getLocationInformation()); addThrowableInformation(result, loggingEvent.getThrowableInformation()); } return (result); } /** * Adds the LocationInfo object to an existing BSON object. * * @param bson The BSON object to add the location info to <i>(must not be null)</i>. * @param locationInfo The LocationInfo object to add to the BSON object <i>(may be null)</i>. */ private void addLocationInformation(DBObject bson, final LocationInfo locationInfo) { if (locationInfo != null) { nullSafePut(bson, "fileName", locationInfo.getFileName()); nullSafePut(bson, "method", locationInfo.getMethodName()); nullSafePut(bson, "lineNumber", locationInfo.getLineNumber()); nullSafePut(bson, "class", bsonifyClassName(locationInfo.getClassName())); } } /** * Adds the ThrowableInformation object to an existing BSON object. * * @param bson The BSON object to add the throwable info to <i>(must not be null)</i>. * @param throwableInfo The ThrowableInformation object to add to the BSON object <i>(may be null)</i>. */ private void addThrowableInformation(DBObject bson, final ThrowableInformation throwableInfo) { if (throwableInfo != null) { Throwable currentThrowable = throwableInfo.getThrowable(); List throwables = new BasicDBList(); while (currentThrowable != null) { DBObject throwableBson = bsonifyThrowable(currentThrowable); if (throwableBson != null) { throwables.add(throwableBson); } currentThrowable = currentThrowable.getCause(); } if (throwables.size() > 0) { bson.put("throwables", throwables); } } } /** * BSONifies the given Throwable. * * @param throwable The throwable object to BSONify <i>(may be null)</i>. * @return The BSONified equivalent of the Throwable object <i>(may be null)</i>. */ private DBObject bsonifyThrowable(final Throwable throwable) { DBObject result = null; if (throwable != null) { result = new BasicDBObject(); nullSafePut(result, "message", throwable.getMessage()); nullSafePut(result, "stackTrace", bsonifyStackTrace(throwable.getStackTrace())); } return (result); } /** * BSONifies the given stack trace. * * @param stackTrace The stack trace object to BSONify <i>(may be null)</i>. * @return The BSONified equivalent of the stack trace object <i>(may be null)</i>. */ private DBObject bsonifyStackTrace(final StackTraceElement[] stackTrace) { BasicDBList result = null; if (stackTrace != null && stackTrace.length > 0) { result = new BasicDBList(); for (StackTraceElement element : stackTrace) { DBObject bson = bsonifyStackTraceElement(element); if (bson != null) { result.add(bson); } } } return (result); } /** * BSONifies the given stack trace element. * * @param element The stack trace element object to BSONify <i>(may be null)</i>. * @return The BSONified equivalent of the stack trace element object <i>(may be null)</i>. */ private DBObject bsonifyStackTraceElement(final StackTraceElement element) { DBObject result = null; if (element != null) { result = new BasicDBObject(); nullSafePut(result, "fileName", element.getFileName()); nullSafePut(result, "method", element.getMethodName()); nullSafePut(result, "lineNumber", element.getLineNumber()); nullSafePut(result, "class", bsonifyClassName(element.getClassName())); } return (result); } /** * BSONifies the given class name. * * @param className The class name to BSONify <i>(may be null)</i>. * @return The BSONified equivalent of the class name <i>(may be null)</i>. */ private DBObject bsonifyClassName(final String className) { DBObject result = null; if (className != null && className.trim().length() > 0) { result = new BasicDBObject(); result.put("fullyQualifiedClassName", className); List packageComponents = new BasicDBList(); String[] packageAndClassName = className.split("\\."); packageComponents .addAll(Arrays.asList(Arrays.copyOf(packageAndClassName, packageAndClassName.length - 1))); if (packageComponents.size() > 0) { result.put("package", packageComponents); } result.put("className", packageAndClassName[packageAndClassName.length - 1]); } return (result); } /** * Adds the given value to the given key, except if it's null (in which case this method does nothing). * * @param bson The BSON object to add the key/value to <i>(must not be null)</i>. * @param key The key of the object <i>(must not be null)</i>. * @param value The value of the object <i>(may be null)</i>. */ private void nullSafePut(DBObject bson, final String key, final Object value) { if (value != null) { if (value instanceof String) { String stringValue = (String) value; if (stringValue.trim().length() > 0) { bson.put(key, stringValue); } } else { bson.put(key, value); } } } /** * @see org.apache.log4j.Appender#close() */ public void close() { collection = null; } /** * @return The hostname of the MongoDB server <i>(will not be null, empty or blank)</i>. */ public String getHostname() { return (hostname); } /** * @param hostname The MongoDB hostname to set <i>(must not be null, empty or blank)</i>. */ private void setHostname(final String hostname) { // PRECONDITIONS assert hostname != null : "hostname must not be null"; assert hostname.trim().length() > 0 : "hostname must not be empty or blank"; // Body this.hostname = hostname; } /** * @return The port of the MongoDB server <i>(will be > 0)</i>. */ public int getPort() { return (port); } /** * @param port The port to set <i>(must be > 0)</i>. */ private void setPort(final int port) { // PRECONDITIONS assert port > 0 : "port must be > 0"; // Body this.port = port; } /** * @return The database used in the MongoDB server <i>(will not be null, empty or blank)</i>. */ public String getDatabaseName() { return (databaseName); } /** * @param databaseName The database to use in the MongoDB server <i>(must not be null, empty or blank)</i>. */ public void setDatabaseName(final String databaseName) { // PRECONDITIONS assert databaseName != null : "database must not be null"; assert databaseName.trim().length() > 0 : "database must not be empty or blank"; // Body this.databaseName = databaseName; } /** * @return The collection used within the database in the MongoDB server <i>(will not be null, empty or blank)</i>. */ public String getCollectionName() { return (collectionName); } /** * @param collectionName The collection used within the database in the MongoDB server <i>(must not be null, empty or blank)</i>. */ public void setCollectionName(final String collectionName) { // PRECONDITIONS assert collectionName != null : "collection must not be null"; assert collectionName.trim().length() > 0 : "collection must not be empty or blank"; // Body this.collectionName = collectionName; } /** * @return The userName used to authenticate with MongoDB <i>(may be null)</i>. */ public String getUserName() { return (userName); } /** * @param userName The userName to use when authenticating with MongoDB <i>(may be null)</i>. */ public void setUserName(final String userName) { this.userName = userName; } /** * @param password The password to use when authenticating with MongoDB <i>(may be null)</i>. */ public void setPassword(final char[] password) { this.password = password; } public void setExtraInfo(String key, Object value) { } }