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// Copyright 2017 Yahoo Holdings. Licensed under the terms of the Apache 2.0 license. See LICENSE in the project root.
package com.yahoo.logserver.handlers.lasterrorsholder;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.yahoo.io.Connection;
import com.yahoo.io.ConnectionFactory;
import com.yahoo.io.Listener;
import com.yahoo.log.LogLevel;
import com.yahoo.log.LogMessage;
import com.yahoo.logserver.handlers.AbstractLogHandler;
import java.io.IOException;
import java.io.StringWriter;
import java.nio.channels.SocketChannel;
import java.nio.charset.StandardCharsets;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;
/**
* The LastErrorsHolder handler is used for holding the last n
* messages at level error or higher. Connecting to this handler
* will return a Json object with the last errors (default is last 100 errors)
*
* @author hmusum
*/
public class LastErrorsHolder extends AbstractLogHandler implements ConnectionFactory {
private static final Logger log = Logger.getLogger(LastErrorsHolder.class.getName());
private static final int maxNumErrors = 100;
private final Object lock = new Object();
private int port;
private Listener listener;
private final ArrayList<LogMessage> errors = new ArrayList<>();
private int numberOfErrors = 0;
/**
* @param port The port to which this handler listens to.
*/
public LastErrorsHolder(int port) throws IOException {
this.port = port;
listen(port);
}
public void listen(int port) throws IOException {
if (listener != null) {
throw new IllegalStateException("already listening to port " + this.port);
}
listener = new Listener("last-errors-holder");
listener.listen(this, port);
listener.start();
log.log(LogLevel.CONFIG, "port=" + port);
}
public boolean doHandle(LogMessage msg) {
if (msg.getLevel().equals(LogLevel.ERROR) || msg.getLevel().equals(LogLevel.FATAL)) {
synchronized (lock) {
numberOfErrors++;
if (errors.size() < maxNumErrors) {
errors.add(msg);
} else if (numberOfErrors == maxNumErrors) {
log.log(LogLevel.DEBUG, String.format("Not storing errors, have reached maximum number of errors: %d, total number of errors received: %d",
maxNumErrors, numberOfErrors));
}
}
}
return true;
}
public void close() {
try {
listener.interrupt();
listener.join();
log.log(LogLevel.DEBUG, "listener stopped");
} catch (InterruptedException e) {
log.log(LogLevel.WARNING, "listener was interrupted", e);
}
}
public void flush() {
}
/**
* Factory method for creating new connections. Since we just return a result
* when client connection happens, we also write the result here
*
* @param socket The new SocketChannel
* @param listener The Listener instance we want to use
*/
public Connection newConnection(SocketChannel socket, Listener listener) {
if (log.isLoggable(LogLevel.DEBUG)) {
log.log(LogLevel.DEBUG, "New last-errors-holder connection: " + socket);
}
LastErrorsHolderConnection connection = new LastErrorsHolderConnection(socket);
synchronized (lock) {
Messages messages = new Messages();
for (LogMessage error : errors) {
messages.addMessage(
new Message(error.getTime()/1000,
error.getHost(),
error.getService(),
error.getLevel().getName(),
error.getPayload()));
}
messages.setNumberOfErrors(numberOfErrors);
try {
ObjectMapper mapper = new ObjectMapper();
StringWriter stringWriter = new StringWriter();
mapper.writeValue(stringWriter, messages);
connection.enqueue(StandardCharsets.UTF_8.encode(stringWriter.toString()));
} catch (IOException e) {
log.log(LogLevel.WARNING, "Could not enqueue log message", e);
}
errors.clear();
numberOfErrors = 0;
}
return connection;
}
public String toString() {
return LastErrorsHolder.class.getName();
}
static class Messages {
private final List<Message> messages = new ArrayList<>();
private long errorCount = 0; // There might be more errors than number of messages
void addMessage(Message message) {
messages.add(message);
}
void setNumberOfErrors(long errorCount) {
this.errorCount = errorCount;
}
public List<Message> getMessages() {
return messages;
}
public long getErrorCount() {
return errorCount;
}
}
static class Message {
private final long time;
private final String hostname;
private final String service;
private final String logLevel;
private final String message;
Message(long time, String hostname, String service, String logLevel, String message) {
this.time = time;
this.hostname = hostname;
this.service = service;
this.logLevel = logLevel;
this.message = message;
}
public long getTime() {
return time;
}
public String getMessage() {
return message;
}
public String getLogLevel() {
return logLevel;
}
public String getHostname() {
return hostname;
}
public String getService() {
return service;
}
}
}
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