使用boxfuse cloudwatchlogs-java-appender的appender作为起点，我创建了一个用于登录AWS CloudWatch的log4j2 appender的通用版本。但是，我遇到的问题是log4j2 appender根本没有关闭。
这是我的appender插件CloudwatchLogsLog4J2Appender.java -
package ...
imports ...
@Plugin(name = CloudwatchLogsLog4J2Appender.APPENDER_NAME, category = "Core", elementType = Appender.ELEMENT_TYPE, printObject = true)
public class CloudwatchLogsLog4J2Appender extends AbstractAppender {
static final String APPENDER_NAME = "CloudwatchLogs-Appender";
private final CloudwatchLogsConfig config = new CloudwatchLogsConfig();
private BlockingQueue<CloudwatchLogsLogEvent> eventQueue;
private CloudwatchLogsLogEventPutter putter;
private long discardedCount;
public CloudwatchLogsLog4J2Appender(String name, Filter filter, Layout<? extends Serializable> layout) {
super(name, filter, layout);
}
public CloudwatchLogsLog4J2Appender(String name, Filter filter, Layout<? extends Serializable> layout, boolean ignoreExceptions) {
super(name, filter, layout, ignoreExceptions);
}
// Your custom appender needs to declare a factory method
// annotated with `@PluginFactory`. Log4j will parse the configuration
// and call this factory method to construct an appender instance with
// the configured attributes.
@PluginFactory
public static CloudwatchLogsLog4J2Appender createAppender(
@PluginAttribute(value = "name", defaultString = APPENDER_NAME) String name,
@PluginElement("Filter") final Filter filter,
@PluginAttribute("debug") Boolean debug,
@PluginAttribute("stdoutFallback") Boolean stdoutFallback,
@PluginAttribute("endpoint") String endpoint,
@PluginAttribute("logGroupName") String logGroupName,
@PluginAttribute("module") String module,
@PluginAttribute(value = "maxEventQueueSize", defaultInt = CloudwatchLogsConfig.DEFAULT_MAX_EVENT_QUEUE_SIZE) Integer maxEventQueueSize,
@PluginAttribute("region") String region,
@PluginAttribute("flushDelayInMillis") int flushDelayInMillis) {
System.out.println("CloudwatchLogsLog4J2Appender:createAppender() called...");
CloudwatchLogsLog4J2Appender appender = new CloudwatchLogsLog4J2Appender(name, filter, null, true);
if (debug != null) {
appender.getConfig().setStdoutFallback(debug);
}
if (stdoutFallback != null) {
appender.getConfig().setStdoutFallback(stdoutFallback);
}
if (endpoint != null) {
appender.getConfig().setEndpoint(endpoint);
}
if (logGroupName != null) {
appender.getConfig().setLogGroupName(logGroupName);
}
if (module != null) {
appender.getConfig().setModule(module);
}
appender.getConfig().setMaxEventQueueSize(maxEventQueueSize);
if (region != null) {
appender.getConfig().setRegion(region);
}
if (flushDelayInMillis > 0) {
appender.getConfig().setFlushDelayInMills(flushDelayInMillis);
}
return appender;
}
/**
* @return The config of the appender. This instance can be modified to override defaults.
*/
public CloudwatchLogsConfig getConfig() {
return config;
}
@Override
public void start() {
System.out.println("CloudwatchLogsLog4J2Appender:start() called...");
super.start();
eventQueue = new LinkedBlockingQueue<>(config.getMaxEventQueueSize());
putter = CloudwatchLogsLogEventPutter.create(config, eventQueue);
new Thread(putter).start();
}
@Override
public void stop() {
System.out.println("CloudwatchLogsLog4J2Appender:stop() called...");
putter.terminate();
super.stop();
}
@Override
protected boolean stop(Future<?> future) {
System.out.println("CloudwatchLogsLog4J2Appender:stop(future) called...");
putter.terminate();
return super.stop(future);
}
@Override
public boolean stop(long timeout, TimeUnit timeUnit) {
System.out.println("CloudwatchLogsLog4J2Appender:stop(timeout, timeunit) called...");
putter.terminate();
System.out.println("CloudwatchLogsLog4J2Appender:stop(timeout, timeunit) Done calling terminate()... passing to super");
return super.stop(timeout, timeUnit);
}
/**
* @return The number of log events that had to be discarded because the event queue was full.
* If this number is non zero without having been affected by AWS CloudWatch Logs availability issues,
* you should consider increasing maxEventQueueSize in the config to allow more log events to be buffer before having to drop them.
*/
public long getDiscardedCount() {
return discardedCount;
}
@Override
public void append(LogEvent event) {
String message = event.getMessage().getFormattedMessage();
Throwable thrown = event.getThrown();
while (thrown != null) {
message += "\n" + dump(thrown);
thrown = thrown.getCause();
if (thrown != null) {
message += "\nCaused by:";
}
}
Marker marker = event.getMarker();
String eventId = marker == null ? null : marker.getName();
CloudwatchLogsLogEvent logEvent = new CloudwatchLogsLogEvent(event.getLevel().toString(), event.getLoggerName(), eventId, message, event.getTimeMillis(), event.getThreadName());
while (!eventQueue.offer(logEvent)) {
eventQueue.poll();
discardedCount++;
}
}
private String dump(Throwable throwableProxy) {
StringBuilder builder = new StringBuilder();
builder.append(throwableProxy.getClass().getName()).append(": ").append(throwableProxy.getMessage()).append("\n");
for (StackTraceElement step : throwableProxy.getStackTrace()) {
String string = step.toString();
builder.append("\t").append(string);
builder.append(step);
builder.append("\n");
}
return builder.toString();
}
}
这是CloudwatchLogsLogEventPutter
public class CloudwatchLogsLogEventPutter implements Runnable {
private static int MAX_FLUSH_DELAY = 500 * 1000 * 1000;
private static final int MAX_BATCH_COUNT = 10000;
private static final int MAX_BATCH_SIZE = 1048576;
private final CloudwatchLogsConfig config;
private final BlockingQueue<CloudwatchLogsLogEvent> eventQueue;
private final AWSLogs logsClient;
private final ObjectMapper objectMapper = new ObjectMapper().setSerializationInclusion(JsonInclude.Include.NON_NULL);
private final boolean enabled;
private boolean running;
private String module;
private String logGroupName;
private int batchSize;
private long lastFlush;
private List<InputLogEvent> eventBatch;
private String nextSequenceToken;
private final AtomicLong processedCount = new AtomicLong(0);
/**
* Creates a new EventPutter for the current AWS region.
*
* @param config The config to use.
* @param eventQueue The event queue to consume from.
* @return The new EventPutter.
*/
public static CloudwatchLogsLogEventPutter create(CloudwatchLogsConfig config, BlockingQueue<CloudwatchLogsLogEvent> eventQueue) {
boolean enabled = config.getRegion() != null || config.getEndpoint() != null;
AWSLogs logsClient = enabled ? createLogsClient(config) : null;
CloudwatchLogsLogEventPutter logPutter = new CloudwatchLogsLogEventPutter(config, eventQueue, logsClient, enabled);
return logPutter;
}
/**
* For internal use only. This constructor lets us switch the AWSLogs implementation for testing.
*/
public CloudwatchLogsLogEventPutter(CloudwatchLogsConfig config, BlockingQueue<CloudwatchLogsLogEvent> eventQueue,
AWSLogs awsLogs, boolean enabled) {
this.config = config;
module = config.getModule();
this.eventQueue = eventQueue;
this.enabled = enabled;
logsClient = awsLogs;
if(config.getFlushDelayInMills() > 0) {
MAX_FLUSH_DELAY = config.getFlushDelayInMills() * 1000;
}
logGroupName = config.getLogGroupName();
}
static AWSLogs createLogsClient(CloudwatchLogsConfig config) {
AWSLogsClientBuilder builder = AWSLogsClientBuilder.standard();
if (config.getEndpoint() != null) {
// Non-AWS mock endpoint
builder.setCredentials(new AWSStaticCredentialsProvider(new AnonymousAWSCredentials()));
builder.setEndpointConfiguration(new AwsClientBuilder.EndpointConfiguration(config.getEndpoint(), config.getRegion()));
} else {
builder.setRegion(config.getRegion());
}
return builder.build();
}
/**
* @return The number of log events that have been processed by this putter.
*/
public long getProcessedCount() {
return processedCount.get();
}
@Override
public void run() {
if (!enabled && !config.isStdoutFallback()) {
System.out.println("WARNING: AWS CloudWatch Logs appender is disabled (Unable to detect the AWS region and no CloudWatch Logs endpoint specified)");
return;
}
running = true;
nextSequenceToken = null;
eventBatch = new ArrayList<>();
batchSize = 0;
lastFlush = System.nanoTime();
printWithTimestamp(new Date(), "Initiating the while loop...");
while (running) {
CloudwatchLogsLogEvent event = eventQueue.poll();
printWithTimestamp(new Date(), "Inside Loopity loop...");
if (event != null) {
Map<String, Object> eventMap = new TreeMap<>();
eventMap.put("context", config.getContext());
eventMap.put("module", config.getModule());
eventMap.put("level", event.getLevel());
eventMap.put("event", event.getEvent());
eventMap.put("message", event.getMessage());
eventMap.put("logger", event.getLogger());
eventMap.put("thread", event.getThread());
String eventJson;
try {
eventJson = toJson(eventMap);
} catch (JsonProcessingException e) {
printWithTimestamp(new Date(), "Unable to serialize log event: " + eventMap);
continue;
}
// Source: http://docs.aws.amazon.com/AmazonCloudWatchLogs/latest/APIReference/API_PutLogEvents.html
// The maximum batch size is 1,048,576 bytes,
int eventSize =
// and this size is calculated as the sum of all event messages in UTF-8,
eventJson.getBytes(StandardCharsets.UTF_8).length
// plus 26 bytes for each log event.
+ 26;
if (eventSize > MAX_BATCH_SIZE) {
printWithTimestamp(new Date(), "Unable to send log event as its size (" + eventSize + " bytes)"
+ " exceeds the maximum size supported by AWS CloudWatch Logs (" + MAX_BATCH_SIZE + " bytes): " + eventMap);
continue;
}
if (config.isDebug()) {
printWithTimestamp(new Date(), "Event Size: " + eventSize + " bytes, Batch Size: " + batchSize
+ " bytes, Batch Count: " + eventBatch.size() + ", Event: " + eventJson);
}
if ((eventBatch.size() + 1) >= MAX_BATCH_COUNT || (batchSize + eventSize) >= MAX_BATCH_SIZE) {
flush();
}
eventBatch.add(new InputLogEvent().withMessage(eventJson).withTimestamp(event.getTimestamp()));
batchSize += eventSize;
printWithTimestamp(new Date(event.getTimestamp()), "batchSize = " + batchSize);
} else {
printWithTimestamp(new Date(), "No events, just flush attempts...");
if (!eventBatch.isEmpty() && isTimeToFlush()) {
printWithTimestamp(new Date(), "eventbatch is not empty and its time to flush");
flush();
}
try {
printWithTimestamp(new Date(), "going to sleep...");
Thread.sleep(100);
printWithTimestamp(new Date(), "done sleeping...");
} catch (InterruptedException e) {
printWithTimestamp(new Date(), "Exception while flusing and sleeping...");
running = false;
}
}
}
printWithTimestamp(new Date(), "Done with that while loop...");
}
private void finalFlush() {
printWithTimestamp(new Date(), "finalFlush() called...");
if (!eventBatch.isEmpty()) {
printWithTimestamp(new Date(), "finalFlush() ==> flush()...");
flush();
printWithTimestamp(new Date(), "finalFlush() ==> flush()... DONE");
}
try {
printWithTimestamp(new Date(), "finalFlush() ==> Sleeping...");
Thread.sleep(100);
printWithTimestamp(new Date(), "finalFlush() ==> Sleeping... DONE");
} catch (InterruptedException e) {
printWithTimestamp(new Date(), "Exception while finalFlusing and sleeping... setting running to false");
running = false;
}
}
private boolean isTimeToFlush() {
return lastFlush <= (System.nanoTime() - MAX_FLUSH_DELAY);
}
private void flush() {
printWithTimestamp(new Date(),"flush() called");
Collections.sort(eventBatch, new Comparator<InputLogEvent>() {
@Override
public int compare(InputLogEvent o1, InputLogEvent o2) {
return o1.getTimestamp().compareTo(o2.getTimestamp());
}
});
if (config.isStdoutFallback()) {
for (InputLogEvent event : eventBatch) {
printWithTimestamp(new Date(event.getTimestamp()), logGroupName + " " + module + " " + event.getMessage());
}
} else {
int retries = 15;
do {
printWithTimestamp(new Date(),"flush() - prepping PutLogEventsRequest");
PutLogEventsRequest request =
new PutLogEventsRequest(logGroupName, module, eventBatch).withSequenceToken(nextSequenceToken);
try {
long start = 0;
if (config.isDebug()) {
start = System.nanoTime();
}
PutLogEventsResult result = logsClient.putLogEvents(request);
if (config.isDebug()) {
long stop = System.nanoTime();
long elapsed = (stop - start) / 1000000;
printWithTimestamp(new Date(), "Sending " + eventBatch.size() + " events took " + elapsed + " ms");
}
processedCount.addAndGet(request.getLogEvents().size());
nextSequenceToken = result.getNextSequenceToken();
break;
} catch (DataAlreadyAcceptedException e) {
nextSequenceToken = e.getExpectedSequenceToken();
printWithTimestamp(new Date(),"flush() - received DataAlreadyAcceptedException");
} catch (InvalidSequenceTokenException e) {
nextSequenceToken = e.getExpectedSequenceToken();
printWithTimestamp(new Date(),"flush() - received InvalidSequenceTokenException");
} catch (ResourceNotFoundException e) {
printWithTimestamp(new Date(), "Unable to send logs to AWS CloudWatch Logs at "
+ logGroupName + ">" + module + " (" + e.getErrorMessage() + "). Dropping log events batch ...");
break;
} catch (SdkClientException e) {
try {
printWithTimestamp(new Date(),"flush() - received SDKClientException. Sleeping to retry");
Thread.sleep(1000);
printWithTimestamp(new Date(),"flush() - received SDKClientException. Sleeping DONE");
} catch (InterruptedException e1) {
System.out.println("SDKException while pushing logs to cloudwatch ...");
}
if (--retries > 0) {
printWithTimestamp(new Date(), "Attempt " + (15-retries) + "Unable to send logs to AWS CloudWatch Logs ("
+ e.getMessage() + "). Dropping log events batch ...");
}
}
} while (retries > 0); // && eventBatch.size() > 0
}
eventBatch = new ArrayList<>();
batchSize = 0;
lastFlush = System.nanoTime();
}
/* private -> for testing */
String toJson(Map<String, Object> eventMap) throws JsonProcessingException {
// Compensate for https://github.com/FasterXML/jackson-databind/issues/1442
Map<String, Object> nonNullMap = new TreeMap<>();
for (Map.Entry<String, Object> entry : eventMap.entrySet()) {
if (entry.getValue() != null) {
nonNullMap.put(entry.getKey(), entry.getValue());
}
}
return objectMapper.writeValueAsString(nonNullMap);
}
private void printWithTimestamp(Date date, String str) {
System.out.println(new SimpleDateFormat("YYYY-MM-dd HH:mm:ss.SSS").format(date) + " " + str);
}
public void terminate() {
printWithTimestamp(new Date(),"terminate() ==> finalFlush()");
//finalFlush();
printWithTimestamp(new Date(),"terminate() ==> finalFlush() DONE. Setting running=false");
running = false;
}
}
CloudwatchLogsLogEvent
public class CloudwatchLogsLogEvent {
private final String level;
private final String logger;
private final String event;
private final String message;
private final long timestamp;
private final String thread;
public CloudwatchLogsLogEvent(String level, String logger, String event, String message, long timestamp, String thread) {
this.level = level;
this.logger = logger;
this.event = event;
this.message = message;
this.timestamp = timestamp;
this.thread = thread;
}
public String getLevel() {
return level;
}
public String getLogger() {
return logger;
}
public String getEvent() {
return event;
}
public String getMessage() {
return message;
}
public long getTimestamp() {
return timestamp;
}
public String getThread() {
return thread;
}
}
最后是示例log4j2.xml配置
<?xml version="1.0" encoding="UTF-8"?>
<Configuration status="trace" package="com.cloudwatchlogs.appender.log4j2">
<Appenders>
<CloudwatchLogs-Appender name="myCloudWatchLogger">
<region>us-west-2</region>
<logGroupName>myCloudWatchLogGroup</logGroupName>
<module>myCloudWatchLogStream</module>
<flushDelayInMillis>1</flushDelayInMillis>
<!-- Optional config parameters -->
<!-- Whether to fall back to stdout instead of disabling the appender when running outside of a Boxfuse instance. Default: false -->
<stdoutFallback>false</stdoutFallback>
<!-- The maximum size of the async log event queue. Default: 1000000.
Increase to avoid dropping log events at very high throughput.
Decrease to reduce maximum memory usage at the risk if the occasional log event drop when it gets full. -->
<maxEventQueueSize>1000000</maxEventQueueSize>
</CloudwatchLogs-Appender>
<Console name="console" target="SYSTEM_OUT">
<PatternLayout pattern="%d{HH:mm:ss.SSS} [%t] %-5level %logger{36} - %msg%n"/>
</Console>
</Appenders>
<Loggers>
<Root level="DEBUG">
<AppenderRef ref="console"/>
</Root>
<Logger name="com.mycompany.src" level="DEBUG" additivity="false">
<AppenderRef ref="myCloudWatchLogger" level="DEBUG"/>
</Logger>
</Loggers>
</Configuration>
我尝试在一个非常简单的应用程序中使用此配置 -
package ...
import ...
public class MyApp
{
private static Logger logger = LogManager.getLogger(MyApp.class);
AmazonS3 s3Client = null;
AmazonDynamoDB dynamoDBClient = null;
MyApp() {
initS3Client(new DefaultAWSCredentialsProviderChain());
}
public void listObjects(String bucketName) {
ObjectListing objectListing = s3Client.listObjects(bucketName);
logger.info("Listing objects in bucket - " + bucketName);
List<String> commonPrefixes = objectListing.getCommonPrefixes();
commonPrefixes.stream().forEach(s -> System.out.println("commonPrefix - " + s));
List<S3ObjectSummary> objectSummaries = objectListing.getObjectSummaries();
for(S3ObjectSummary objectSummary : objectSummaries) {
logger.info("key = " + objectSummary.getKey());
logger.info("ETag = " + objectSummary.getETag());
logger.info("Size = " + objectSummary.getSize());
logger.info("Storage Class = " + objectSummary.getStorageClass());
logger.info("Last Modified = " + objectSummary.getLastModified());
}
s3Client.shutdown();
}
public static void main(String[] args){
MyApp myApp = new MyApp();
myApp.listObjects("test-bucket");
}
void initS3Client(AWSCredentialsProvider credentialsProvider) {
AmazonS3ClientBuilder clientBuilder = AmazonS3ClientBuilder.standard()
.withCredentials(credentialsProvider)
.withRegion(Regions.US_WEST_2);
s3Client = clientBuilder.build();
}
void initDynamoDBClient(AWSCredentialsProvider credentialsProvider) {
AmazonDynamoDBClientBuilder clientBuilder = AmazonDynamoDBClientBuilder.standard()
.withCredentials(credentialsProvider)
.withRegion(Regions.US_WEST_2);
dynamoDBClient = clientBuilder.build();
}
}
当我运行MyApp.java时，我发现在将所有相关日志传输到CloudWatch之后，CloudwatchLogsLogEventPutter.java的run（）方法中的while循环不会终止。我知道它是一个永远运行的独立线程，但是一旦MyApp.main（）方法中的应用程序相关任务完成，log4j2就不应该在生命周期中启动stop（）方法吗？
如果我尝试按Ctrl + C，我会看到被调用的CloudwatchLogsLog4J2Appender.java下面覆盖的stop（）方法 -
public boolean stop(long timeout, TimeUnit timeUnit)
我不确定我哪里出错了，似乎很少有关于处理Appender的各种生命周期方法和生命周期本身的文档。这是我第一次写一个appender。任何帮助表示赞赏。感谢。
更新1：示例日志文件 - https://gist.github.com/dev-usa/822309bcd8b4f8a5fb0f4e1eca70d67e
答案 0 :(得分：0)
所以，我已经修复了这个实现的几个问题。
要正常关闭记录器 - 需要使用appender从应用程序调用{{1}}。在发布此问题时，应用程序未使用关闭方法。使用它充当我上面解释的LogManager.shutdown()行为。完成后，我看到日志记录框架按预期关闭，并且appender已关闭。
我遇到的下一个问题是我丢失了一些未发送到CloudWatch的日志。经过一些调试后，我发现Ctrl+C的run（）方法中while循环的实现在run（）循环期间一次只获得1个日志。我更新了设计，以便在CloudwatchLogsLogEventPutter.java上使用drainTo方法获取整个事件列表并一次推送它们。这大大减少了将事件推送到CloudWatch的while循环次数。请参阅下面的更新实施 -
BlockingQueue最后，我还遇到了log4j2配置的问题，并且在将我的应用程序打包为胖罐时，在类路径中无法识别appender，采用建议的解决方案here解决了我的问题。