异常堆栈
java.io.IOException: Connection reset by peer
at sun.nio.ch.FileDispatcherImpl.read0(Native Method)
at sun.nio.ch.SocketDispatcher.read(SocketDispatcher.java:39)
at sun.nio.ch.IOUtil.readIntoNativeBuffer(IOUtil.java:223)
at sun.nio.ch.IOUtil.read(IOUtil.java:197)
at sun.nio.ch.SocketChannelImpl.read(SocketChannelImpl.java:379)
at org.apache.http.impl.nio.reactor.SessionInputBufferImpl.fill(SessionInputBufferImpl.java:231)
at org.apache.http.impl.nio.codecs.AbstractMessageParser.fillBuffer(AbstractMessageParser.java:136)
at org.apache.http.impl.nio.DefaultNHttpClientConnection.consumeInput(DefaultNHttpClientConnection.java:241)
at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:81)
at org.apache.http.impl.nio.client.InternalIODispatch.onInputReady(InternalIODispatch.java:39)
at org.apache.http.impl.nio.reactor.AbstractIODispatch.inputReady(AbstractIODispatch.java:114)
at org.apache.http.impl.nio.reactor.BaseIOReactor.readable(BaseIOReactor.java:162)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvent(AbstractIOReactor.java:337)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.processEvents(AbstractIOReactor.java:315)
at org.apache.http.impl.nio.reactor.AbstractIOReactor.execute(AbstractIOReactor.java:276)
at org.apache.http.impl.nio.reactor.BaseIOReactor.execute(BaseIOReactor.java:104)
at org.apache.http.impl.nio.reactor.AbstractMultiworkerIOReactor$Worker.run(AbstractMultiworkerIOReactor.java:591)
at java.lang.Thread.run(Thread.java:748)
Suppressed: java.io.IOException: Connection reset by peer
... 18 more
Suppressed: java.io.IOException: Connection reset by peer
... 18 more
1.长连接请求
以浏览器发起请求为例，在Request Headers中会包含Connection: keep-alive信息
image
当tomcat收到浏览器端的长连接请求后，如在限制范围内，则会在Response Headers中返回Connection: keep-alive以保持连接不断开
image
如要断开长连接则在Request Headers中的信息为Connection: close
2、了解了长连接原理后查看源码ElasticsearchSinkBase.java的创建restclient的open
@Override
public void open(Configuration parameters) throws Exception {
client = callBridge.createClient(userConfig);
bulkProcessor = buildBulkProcessor(new BulkProcessorListener());
requestIndexer = callBridge.createBulkProcessorIndexer(bulkProcessor, flushOnCheckpoint, numPendingRequests);
failureRequestIndexer = new BufferingNoOpRequestIndexer();
}
@Override
public RestHighLevelClient createClient(Map clientConfig) throws IOException {
RestClientBuilder builder = RestClient.builder(httpHosts.toArray(new HttpHost[httpHosts.size()]));
restClientFactory.configureRestClientBuilder(builder);
RestHighLevelClient rhlClient = new RestHighLevelClient(builder);
if (LOG.isInfoEnabled()) {
LOG.info("Pinging Elasticsearch cluster via hosts {} ...", httpHosts);
}
if (!rhlClient.ping(RequestOptions.DEFAULT)) {
throw new RuntimeException("There are no reachable Elasticsearch nodes!");
}
if (LOG.isInfoEnabled()) {
LOG.info("Created Elasticsearch RestHighLevelClient connected to {}", httpHosts.toString());
}
return rhlClient;
}
可以看到这里创建了一个RestHighLevelClient，继续查看构造函数
/**
* Creates a {@link RestHighLevelClient} given the low level {@link RestClientBuilder} that allows to build the
* {@link RestClient} to be used to perform requests.
*/
public RestHighLevelClient(RestClientBuilder restClientBuilder) {
this(restClientBuilder, Collections.emptyList());
}
/**
* Creates a {@link RestHighLevelClient} given the low level {@link RestClientBuilder} that allows to build the
* {@link RestClient} to be used to perform requests and parsers for custom response sections added to Elasticsearch through plugins.
*/
protected RestHighLevelClient(RestClientBuilder restClientBuilder, List namedXContentEntries) {
this(restClientBuilder.build(), RestClient::close, namedXContentEntries);
}
//进入restClientBuilder.build()
/**
* Creates a new {@link RestClient} based on the provided configuration.
*/
public RestClient build() {
if (failureListener == null) {
failureListener = new RestClient.FailureListener();
}
CloseableHttpAsyncClient httpClient = AccessController.doPrivileged(
(PrivilegedAction) this::createHttpClient);
RestClient restClient = new RestClient(httpClient, defaultHeaders, nodes,
pathPrefix, failureListener, nodeSelector, strictDeprecationMode);
httpClient.start();
return restClient;
}
//进入 this::createHttpClient
private CloseableHttpAsyncClient createHttpClient() {
//default timeouts are all infinite
RequestConfig.Builder requestConfigBuilder = RequestConfig.custom()
.setConnectTimeout(DEFAULT_CONNECT_TIMEOUT_MILLIS)
.setSocketTimeout(DEFAULT_SOCKET_TIMEOUT_MILLIS);
if (requestConfigCallback != null) {
requestConfigBuilder = requestConfigCallback.customizeRequestConfig(requestConfigBuilder);
}
try {
HttpAsyncClientBuilder httpClientBuilder = HttpAsyncClientBuilder.create().setDefaultRequestConfig(requestConfigBuilder.build())
//default settings for connection pooling may be too constraining
.setMaxConnPerRoute(DEFAULT_MAX_CONN_PER_ROUTE).setMaxConnTotal(DEFAULT_MAX_CONN_TOTAL)
.setSSLContext(SSLContext.getDefault())
.setTargetAuthenticationStrategy(new PersistentCredentialsAuthenticationStrategy());
if (httpClientConfigCallback != null) {
httpClientBuilder = httpClientConfigCallback.customizeHttpClient(httpClientBuilder);
}
final HttpAsyncClientBuilder finalBuilder = httpClientBuilder;
return AccessController.doPrivileged((PrivilegedAction) finalBuilder::build);
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("could not create the default ssl context", e);
}
}
// finalBuilder::build可以看到
ConnectionKeepAliveStrategy keepAliveStrategy = this.keepAliveStrategy;
if (keepAliveStrategy == null) {
keepAliveStrategy = DefaultConnectionKeepAliveStrategy.INSTANCE;
}
如果客户端使用的是apache httpclient 4.x版本，默认的keep-alive是读取response heade中Keep-Alive字段,没有的话就是无限（代码中返回-1）。"If the Keep-Alive header is not present in the response, HttpClient assumes the connection can be kept alive indefinitely"，详细代码DefaultConnectionKeepAliveStrategy.class类设置的，代码如下：
@Contract(threading = ThreadingBehavior.IMMUTABLE)
public class DefaultConnectionKeepAliveStrategy implements ConnectionKeepAliveStrategy {
public static final DefaultConnectionKeepAliveStrategy INSTANCE = new DefaultConnectionKeepAliveStrategy();
@Override
public long getKeepAliveDuration(final HttpResponse response, final HttpContext context) {
Args.notNull(response, "HTTP response");
final HeaderElementIterator it = new BasicHeaderElementIterator(
response.headerIterator(HTTP.CONN_KEEP_ALIVE));
while (it.hasNext()) {
final HeaderElement he = it.nextElement();
final String param = he.getName();
final String value = he.getValue();
if (value != null && param.equalsIgnoreCase("timeout")) {
try {
return Long.parseLong(value) * 1000;
} catch(final NumberFormatException ignore) {
}
}
}
return -1;
}
}
网上搜了一下这个的含义，具体如下
image.png
这里需要自定义实现ConnectionKeepAliveStrategy
public class CustomConnectionKeepAliveStrategy extends DefaultConnectionKeepAliveStrategy {
/**
* 最大keep alive的时间（分钟）
* 这里默认为10分钟，可以根据实际情况设置。可以观察客户端机器状态为TIME_WAIT的TCP连接数，如果太多，可以增大此值。
*/
private final static long MAX_KEEP_ALIVE_MINUTES = 10;
public static final CustomConnectionKeepAliveStrategy INSTANCE = new CustomConnectionKeepAliveStrategy();
private CustomConnectionKeepAliveStrategy() {
super();
}
@Override
public long getKeepAliveDuration(HttpResponse response, HttpContext context) {
long keepAliveDuration = super.getKeepAliveDuration(response, context);
// <0 为无限期keepalive,将无限期替换成一个默认的时间
if (keepAliveDuration < 0) {
return TimeUnit.MINUTES.toMillis(MAX_KEEP_ALIVE_MINUTES);
}
return keepAliveDuration;
}
}
// 在客户端创建的时候设置KeepAlive策略为自定义策略即可
esSinkBuilder.setRestClientFactory(restClientBuilder -> {
restClientBuilder.setHttpClientConfigCallback(httpClientBuilder -> {
httpClientBuilder.setKeepAliveStrategy(CustomConnectionKeepAliveStrategy.INSTANCE);
return httpClientBuilder;
});
});
参考链接：【Elasticsearch】解决Elasticsearch HTTP方式查询报SocketTimeoutException的问题 Connection reset by peer
两种由java http长连接(keep-alive)导致的问题
Connection keep alive strategy