Shulou(Shulou.com)06/02 Report--

What is the role of AccessLogFilter in dubbo? I believe many inexperienced people don't know what to do about it. Therefore, this paper summarizes the causes and solutions of the problem. Through this article, I hope you can solve this problem.

AccessLogFilter

Dubbo-2.7.3/dubbo-rpc/dubbo-rpc-api/src/main/java/org/apache/dubbo/rpc/filter/AccessLogFilter.java

@ Activate (group = PROVIDER, value = ACCESS_LOG_KEY) public class AccessLogFilter implements Filter {private static final Logger logger = LoggerFactory.getLogger (AccessLogFilter.class); private static final String ACCESS_LOG_KEY = "dubbo.accesslog"; private static final int LOG_MAX_BUFFER = 5000; private static final long LOG_OUTPUT_INTERVAL = 5000; private static final String FILE_DATE_FORMAT = "yyyyMMdd" / / It's safe to declare it as singleton since it runs on single thread only private static final DateFormat FILE_NAME_FORMATTER = new SimpleDateFormat (FILE_DATE_FORMAT); private static final Map LOG_ENTRIES = new ConcurrentHashMap (); private static final ScheduledExecutorService LOG_SCHEDULED = Executors.newSingleThreadScheduledExecutor (new NamedThreadFactory ("Dubbo-Access-Log", true)) / * Default constructor initialize demon thread for writing into accesslog file with names with accesslog key * defined in url accesslog * / public AccessLogFilter () {LOG_SCHEDULED.scheduleWithFixedDelay (this::writeLogToFile, LOG_OUTPUT_INTERVAL, LOG_OUTPUT_INTERVAL, TimeUnit.MILLISECONDS);} / * * This method logs the accesslog for service method invocation call. * * @ param invoker service * @ param inv Invocation service method. * @ return Result from service method. * @ throws RpcException * / @ Override public Result invoke (Invoker invoker, Invocation inv) throws RpcException {try {String accessLogKey = invoker.getUrl () .getParameter (ACCESS_LOG_KEY); if (ConfigUtils.isNotEmpty (accessLogKey)) {AccessLogData logData = buildAccessLogData (invoker, inv); log (accessLogKey, logData) } catch (Throwable t) {logger.warn ("Exception in AccessLogFilter of service (" + invoker + "- >" + inv + "), t);} return invoker.invoke (inv);} private void log (String accessLog, AccessLogData accessLogData) {Set logSet = LOG_ENTRIES.computeIfAbsent (accessLog, k-> new ConcurrentHashSet ()); if (logSet.size ())

< LOG_MAX_BUFFER) { logSet.add(accessLogData); } else { //TODO we needs use force writing to file so that buffer gets clear and new log can be written. logger.warn("AccessLog buffer is full skipping buffer "); } } private void writeLogToFile() { if (!LOG_ENTRIES.isEmpty()) { for (Map.Entry entry : LOG_ENTRIES.entrySet()) { try { String accessLog = entry.getKey(); Set logSet = entry.getValue(); if (ConfigUtils.isDefault(accessLog)) { processWithServiceLogger(logSet); } else { File file = new File(accessLog); createIfLogDirAbsent(file); if (logger.isDebugEnabled()) { logger.debug("Append log to " + accessLog); } renameFile(file); processWithAccessKeyLogger(logSet, file); } } catch (Exception e) { logger.error(e.getMessage(), e); } } } } private void processWithAccessKeyLogger(Set logSet, File file) throws IOException { try (FileWriter writer = new FileWriter(file, true)) { for (Iterator iterator = logSet.iterator(); iterator.hasNext(); iterator.remove()) { writer.write(iterator.next().getLogMessage()); writer.write("\r\n"); } writer.flush(); } } private AccessLogData buildAccessLogData(Invoker invoker, Invocation inv) { RpcContext context = RpcContext.getContext(); AccessLogData logData = AccessLogData.newLogData(); logData.setServiceName(invoker.getInterface().getName()); logData.setMethodName(inv.getMethodName()); logData.setVersion(invoker.getUrl().getParameter(VERSION_KEY)); logData.setGroup(invoker.getUrl().getParameter(GROUP_KEY)); logData.setInvocationTime(new Date()); logData.setTypes(inv.getParameterTypes()); logData.setArguments(inv.getArguments()); return logData; } private void processWithServiceLogger(Set logSet) { for (Iterator iterator = logSet.iterator(); iterator.hasNext(); iterator.remove()) { AccessLogData logData = iterator.next(); LoggerFactory.getLogger(ACCESS_LOG_KEY + "." + logData.getServiceName()).info(logData.getLogMessage()); } } private void createIfLogDirAbsent(File file) { File dir = file.getParentFile(); if (null != dir && !dir.exists()) { dir.mkdirs(); } } private void renameFile(File file) { if (file.exists()) { String now = FILE_NAME_FORMATTER.format(new Date()); String last = FILE_NAME_FORMATTER.format(new Date(file.lastModified())); if (!now.equals(last)) { File archive = new File(file.getAbsolutePath() + "." + last); file.renameTo(archive); } } }} AccessLogFilter实现了org.apache.dubbo.rpc.Filter接口，其构造器注册了一个定时任务，每隔LOG_OUTPUT_INTERVAL执行一次writeLogToFile invoke方法从invoker.getUrl()获取accessLogKey，如果不为空则使用buildAccessLogData构建AccessLogData，然后放入到LOG_ENTRIES中，如果超出LOG_MAX_BUFFER则对其并打印warn日志 writeLogToFile方法遍历LOG_ENTRIES，将AccessLogData写入文件，如果是default的则使用processWithServiceLogger，否则使用processWithAccessKeyLogger方法 AccessLogFilterTest dubbo-2.7.3/dubbo-rpc/dubbo-rpc-api/src/test/java/org/apache/dubbo/rpc/filter/AccessLogFilterTest.java public class AccessLogFilterTest { Filter accessLogFilter = new AccessLogFilter(); // Test filter won't throw an exception @Test public void testInvokeException() { Invoker invoker = new MyInvoker(null); Invocation invocation = new MockInvocation(); LogUtil.start(); accessLogFilter.invoke(invoker, invocation); assertEquals(1, LogUtil.findMessage("Exception in AccessLogFilter of service")); LogUtil.stop(); } // TODO how to assert thread action @Test public void testDefault() { URL url = URL.valueOf("test://test:11/test?accesslog=true&group=dubbo&version=1.1"); Invoker invoker = new MyInvoker(url); Invocation invocation = new MockInvocation(); accessLogFilter.invoke(invoker, invocation); } @Test public void testCustom() { URL url = URL.valueOf("test://test:11/test?accesslog=custom-access.log"); Invoker invoker = new MyInvoker(url); Invocation invocation = new MockInvocation(); accessLogFilter.invoke(invoker, invocation); }} 这里验证了invokeException、default、custom场景 AccessLogData dubbo-2.7.3/dubbo-rpc/dubbo-rpc-api/src/main/java/org/apache/dubbo/rpc/support/AccessLogData.java public final class AccessLogData { private static final String MESSAGE_DATE_FORMAT = "yyyy-MM-dd HH:mm:ss"; private static final DateFormat MESSAGE_DATE_FORMATTER = new SimpleDateFormat(MESSAGE_DATE_FORMAT); private static final String VERSION = "version"; private static final String GROUP = "group"; private static final String SERVICE = "service"; private static final String METHOD_NAME = "method-name"; private static final String INVOCATION_TIME = "invocation-time"; private static final String TYPES = "types"; private static final String ARGUMENTS = "arguments"; private static final String REMOTE_HOST = "remote-host"; private static final String REMOTE_PORT = "remote-port"; private static final String LOCAL_HOST = "localhost"; private static final String LOCAL_PORT = "local-port"; /** * This is used to store log data in key val format. */ private Map data; /** * Default constructor. */ private AccessLogData() { RpcContext context = RpcContext.getContext(); data = new HashMap(); setLocalHost(context.getLocalHost()); setLocalPort(context.getLocalPort()); setRemoteHost(context.getRemoteHost()); setRemotePort(context.getRemotePort()); } //...... public String getLogMessage() { StringBuilder sn = new StringBuilder(); sn.append("[") .append(MESSAGE_DATE_FORMATTER.format(getInvocationTime())) .append("] ") .append(get(REMOTE_HOST)) .append(":") .append(get(REMOTE_PORT)) .append(" ->

) .append (get (LOCAL_HOST)) .append (":") .append (get (LOCAL_PORT)) .append ("-"); String group = get (GROUP)! = null? Get (GROUP). ToString (): "; if (StringUtils.isNotEmpty (group.toString () {sn.append (group) .append (" / ");} sn.append (get (SERVICE)); String version = get (VERSION)! = null? Get (VERSION). ToString (): "; if (StringUtils.isNotEmpty (version.toString () {sn.append (": ") .append (version);} sn.append ("); sn.append (get (METHOD_NAME)); sn.append ("("); Class [] types = get (TYPES)! = null? (Class []) get (TYPES): new Class [0]; boolean first = true; for (Class type: types) {if (first) {first = false;} else {sn.append (",");} sn.append (type.getName ());} sn.append (")") Object [] args = get (ARGUMENTS)! = null? (Object []) get (ARGUMENTS): null; if (args! = null & & args.length > 0) {sn.append (JSON.toJSONString (args));} return sn.toString ();} / /.}

AccessLogData defines version, group, service, method-name, invocation-time, types, arguments, remote-host, remote-port, localhost, local-port constants, while getLogMessage builds the output of log.

Summary

AccessLogFilter implements the org.apache.dubbo.rpc.Filter interface, and its constructor registers a scheduled task that executes writeLogToFile every LOG_OUTPUT_INTERVAL

The invoke method of AccessLogFilter takes the accessLogKey from invoker.getUrl (), builds the AccessLogData using buildAccessLogData if it is not empty, then puts it into the LOG_ENTRIES, and prints the warn log if the LOG_MAX_BUFFER is exceeded

The writeLogToFile method of AccessLogFilter iterates through the LOG_ENTRIES, writes AccessLogData to the file, and uses processWithServiceLogger if it is default, otherwise uses the processWithAccessKeyLogger method

After reading the above, have you mastered the role of AccessLogFilter in dubbo? If you want to learn more skills or want to know more about it, you are welcome to follow the industry information channel, thank you for reading!

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