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/*
* Licensed to Elasticsearch under one or more contributor
* license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright
* ownership. Elasticsearch licenses this file to you under
* the Apache License, Version 2.0 (the "License"); you may
* not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing,
* software distributed under the License is distributed on an
* "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
* KIND, either express or implied. See the License for the
* specific language governing permissions and limitations
* under the License.
*/
package org.elasticsearch.client;
import org.apache.http.Header;
import org.apache.http.HttpHost;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClientBuilder;
import org.apache.http.impl.nio.client.CloseableHttpAsyncClient;
import org.apache.http.impl.nio.client.HttpAsyncClientBuilder;
import org.apache.http.nio.conn.SchemeIOSessionStrategy;
import javax.net.ssl.SSLContext;
import java.security.AccessController;
import java.security.NoSuchAlgorithmException;
import java.security.PrivilegedAction;
import java.util.Objects;
/**
* Helps creating a new {@link RestClient}. Allows to set the most common http client configuration options when internally
* creating the underlying {@link org.apache.http.nio.client.HttpAsyncClient}. Also allows to provide an externally created
* {@link org.apache.http.nio.client.HttpAsyncClient} in case additional customization is needed.
*/
public final class RestClientBuilder {
public static final int DEFAULT_CONNECT_TIMEOUT_MILLIS = 1000;
public static final int DEFAULT_SOCKET_TIMEOUT_MILLIS = 30000;
public static final int DEFAULT_MAX_RETRY_TIMEOUT_MILLIS = DEFAULT_SOCKET_TIMEOUT_MILLIS;
public static final int DEFAULT_CONNECTION_REQUEST_TIMEOUT_MILLIS = 500;
public static final int DEFAULT_MAX_CONN_PER_ROUTE = 10;
public static final int DEFAULT_MAX_CONN_TOTAL = 30;
private static final Header[] EMPTY_HEADERS = new Header[0];
private final HttpHost[] hosts;
private int maxRetryTimeout = DEFAULT_MAX_RETRY_TIMEOUT_MILLIS;
private Header[] defaultHeaders = EMPTY_HEADERS;
private RestClient.FailureListener failureListener;
private HttpClientConfigCallback httpClientConfigCallback;
private RequestConfigCallback requestConfigCallback;
private String pathPrefix;
/**
* Creates a new builder instance and sets the hosts that the client will send requests to.
*
* @throws NullPointerException if {@code hosts} or any host is {@code null}.
* @throws IllegalArgumentException if {@code hosts} is empty.
*/
RestClientBuilder(HttpHost... hosts) {
Objects.requireNonNull(hosts, "hosts must not be null");
if (hosts.length == 0) {
throw new IllegalArgumentException("no hosts provided");
}
for (HttpHost host : hosts) {
Objects.requireNonNull(host, "host cannot be null");
}
this.hosts = hosts;
}
/**
* Sets the default request headers, which will be sent along with each request.
*
* Request-time headers will always overwrite any default headers.
*
* @throws NullPointerException if {@code defaultHeaders} or any header is {@code null}.
*/
public RestClientBuilder setDefaultHeaders(Header[] defaultHeaders) {
Objects.requireNonNull(defaultHeaders, "defaultHeaders must not be null");
for (Header defaultHeader : defaultHeaders) {
Objects.requireNonNull(defaultHeader, "default header must not be null");
}
this.defaultHeaders = defaultHeaders;
return this;
}
/**
* Sets the {@link RestClient.FailureListener} to be notified for each request failure
*
* @throws NullPointerException if {@code failureListener} is {@code null}.
*/
public RestClientBuilder setFailureListener(RestClient.FailureListener failureListener) {
Objects.requireNonNull(failureListener, "failureListener must not be null");
this.failureListener = failureListener;
return this;
}
/**
* Sets the maximum timeout (in milliseconds) to honour in case of multiple retries of the same request.
* {@link #DEFAULT_MAX_RETRY_TIMEOUT_MILLIS} if not specified.
*
* @throws IllegalArgumentException if {@code maxRetryTimeoutMillis} is not greater than 0
*/
public RestClientBuilder setMaxRetryTimeoutMillis(int maxRetryTimeoutMillis) {
if (maxRetryTimeoutMillis <= 0) {
throw new IllegalArgumentException("maxRetryTimeoutMillis must be greater than 0");
}
this.maxRetryTimeout = maxRetryTimeoutMillis;
return this;
}
/**
* Sets the {@link HttpClientConfigCallback} to be used to customize http client configuration
*
* @throws NullPointerException if {@code httpClientConfigCallback} is {@code null}.
*/
public RestClientBuilder setHttpClientConfigCallback(HttpClientConfigCallback httpClientConfigCallback) {
Objects.requireNonNull(httpClientConfigCallback, "httpClientConfigCallback must not be null");
this.httpClientConfigCallback = httpClientConfigCallback;
return this;
}
/**
* Sets the {@link RequestConfigCallback} to be used to customize http client configuration
*
* @throws NullPointerException if {@code requestConfigCallback} is {@code null}.
*/
public RestClientBuilder setRequestConfigCallback(RequestConfigCallback requestConfigCallback) {
Objects.requireNonNull(requestConfigCallback, "requestConfigCallback must not be null");
this.requestConfigCallback = requestConfigCallback;
return this;
}
/**
* Sets the path's prefix for every request used by the http client.
*
* For example, if this is set to "/my/path", then any client request will become "/my/path/" + endpoint.
*
* In essence, every request's {@code endpoint} is prefixed by this {@code pathPrefix}. The path prefix is useful for when
* Elasticsearch is behind a proxy that provides a base path; it is not intended for other purposes and it should not be supplied in
* other scenarios.
*
* @throws NullPointerException if {@code pathPrefix} is {@code null}.
* @throws IllegalArgumentException if {@code pathPrefix} is empty, only '/', or ends with more than one '/'.
*/
public RestClientBuilder setPathPrefix(String pathPrefix) {
Objects.requireNonNull(pathPrefix, "pathPrefix must not be null");
String cleanPathPrefix = pathPrefix;
if (cleanPathPrefix.startsWith("/") == false) {
cleanPathPrefix = "/" + cleanPathPrefix;
}
// best effort to ensure that it looks like "/base/path" rather than "/base/path/"
if (cleanPathPrefix.endsWith("/")) {
cleanPathPrefix = cleanPathPrefix.substring(0, cleanPathPrefix.length() - 1);
if (cleanPathPrefix.endsWith("/")) {
throw new IllegalArgumentException("pathPrefix is malformed. too many trailing slashes: [" + pathPrefix + "]");
}
}
if (cleanPathPrefix.isEmpty() || "/".equals(cleanPathPrefix)) {
throw new IllegalArgumentException("pathPrefix must not be empty or '/': [" + pathPrefix + "]");
}
this.pathPrefix = cleanPathPrefix;
return this;
}
/**
* Creates a new {@link RestClient} based on the provided configuration.
*/
public RestClient build() {
if (failureListener == null) {
failureListener = new RestClient.FailureListener();
}
CloseableHttpAsyncClient httpClient = AccessController.doPrivileged(new PrivilegedAction() {
@Override
public CloseableHttpAsyncClient run() {
return createHttpClient();
}
});
RestClient restClient = new RestClient(httpClient, maxRetryTimeout, defaultHeaders, hosts, pathPrefix, failureListener);
httpClient.start();
return restClient;
}
private CloseableHttpAsyncClient createHttpClient() {
//default timeouts are all infinite
RequestConfig.Builder requestConfigBuilder = RequestConfig.custom()
.setConnectTimeout(DEFAULT_CONNECT_TIMEOUT_MILLIS)
.setSocketTimeout(DEFAULT_SOCKET_TIMEOUT_MILLIS)
.setConnectionRequestTimeout(DEFAULT_CONNECTION_REQUEST_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());
if (httpClientConfigCallback != null) {
httpClientBuilder = httpClientConfigCallback.customizeHttpClient(httpClientBuilder);
}
final HttpAsyncClientBuilder finalBuilder = httpClientBuilder;
return AccessController.doPrivileged(new PrivilegedAction() {
@Override
public CloseableHttpAsyncClient run() {
return finalBuilder.build();
}
});
} catch (NoSuchAlgorithmException e) {
throw new IllegalStateException("could not create the default ssl context", e);
}
}
/**
* Callback used the default {@link RequestConfig} being set to the {@link CloseableHttpClient}
* @see HttpClientBuilder#setDefaultRequestConfig
*/
public interface RequestConfigCallback {
/**
* Allows to customize the {@link RequestConfig} that will be used with each request.
* It is common to customize the different timeout values through this method without losing any other useful default
* value that the {@link RestClientBuilder} internally sets.
*/
RequestConfig.Builder customizeRequestConfig(RequestConfig.Builder requestConfigBuilder);
}
/**
* Callback used to customize the {@link CloseableHttpClient} instance used by a {@link RestClient} instance.
* Allows to customize default {@link RequestConfig} being set to the client and any parameter that
* can be set through {@link HttpClientBuilder}
*/
public interface HttpClientConfigCallback {
/**
* Allows to customize the {@link CloseableHttpAsyncClient} being created and used by the {@link RestClient}.
* Commonly used to customize the default {@link org.apache.http.client.CredentialsProvider} for authentication
* or the {@link SchemeIOSessionStrategy} for communication through ssl without losing any other useful default
* value that the {@link RestClientBuilder} internally sets, like connection pooling.
*/
HttpAsyncClientBuilder customizeHttpClient(HttpAsyncClientBuilder httpClientBuilder);
}
}