Java tutorial
/* * 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.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.http.Header; import org.apache.http.HttpEntity; import org.apache.http.HttpEntityEnclosingRequest; import org.apache.http.HttpHost; import org.apache.http.HttpResponse; import org.apache.http.RequestLine; import org.apache.http.client.methods.HttpUriRequest; import org.apache.http.entity.BufferedHttpEntity; import org.apache.http.entity.ContentType; import org.apache.http.util.EntityUtils; import java.io.BufferedReader; import java.io.IOException; import java.io.InputStreamReader; import java.nio.charset.Charset; import java.nio.charset.StandardCharsets; /** * Helper class that exposes static methods to unify the way requests are logged. * Includes trace logging to log complete requests and responses in curl format. * Useful for debugging, manually sending logged requests via curl and checking their responses. * Trace logging is a feature that all the language clients provide. */ final class RequestLogger { private static final Log tracer = LogFactory.getLog("tracer"); private RequestLogger() { } /** * Logs a request that yielded a response */ static void logResponse(Log logger, HttpUriRequest request, HttpHost host, HttpResponse httpResponse) { if (logger.isDebugEnabled()) { logger.debug("request [" + request.getMethod() + " " + host + getUri(request.getRequestLine()) + "] returned [" + httpResponse.getStatusLine() + "]"); } if (logger.isWarnEnabled()) { Header[] warnings = httpResponse.getHeaders("Warning"); if (warnings != null && warnings.length > 0) { logger.warn(buildWarningMessage(request, host, warnings)); } } if (tracer.isTraceEnabled()) { String requestLine; try { requestLine = buildTraceRequest(request, host); } catch (IOException e) { requestLine = ""; tracer.trace("error while reading request for trace purposes", e); } String responseLine; try { responseLine = buildTraceResponse(httpResponse); } catch (IOException e) { responseLine = ""; tracer.trace("error while reading response for trace purposes", e); } tracer.trace(requestLine + '\n' + responseLine); } } /** * Logs a request that failed */ static void logFailedRequest(Log logger, HttpUriRequest request, HttpHost host, Exception e) { if (logger.isDebugEnabled()) { logger.debug( "request [" + request.getMethod() + " " + host + getUri(request.getRequestLine()) + "] failed", e); } if (tracer.isTraceEnabled()) { String traceRequest; try { traceRequest = buildTraceRequest(request, host); } catch (IOException e1) { tracer.trace("error while reading request for trace purposes", e); traceRequest = ""; } tracer.trace(traceRequest); } } static String buildWarningMessage(HttpUriRequest request, HttpHost host, Header[] warnings) { StringBuilder message = new StringBuilder("request [").append(request.getMethod()).append(" ").append(host) .append(getUri(request.getRequestLine())).append("] returned ").append(warnings.length) .append(" warnings: "); for (int i = 0; i < warnings.length; i++) { if (i > 0) { message.append(","); } message.append("[").append(warnings[i].getValue()).append("]"); } return message.toString(); } /** * Creates curl output for given request */ static String buildTraceRequest(HttpUriRequest request, HttpHost host) throws IOException { String requestLine = "curl -iX " + request.getMethod() + " '" + host + getUri(request.getRequestLine()) + "'"; if (request instanceof HttpEntityEnclosingRequest) { HttpEntityEnclosingRequest enclosingRequest = (HttpEntityEnclosingRequest) request; if (enclosingRequest.getEntity() != null) { requestLine += " -d '"; HttpEntity entity = enclosingRequest.getEntity(); if (entity.isRepeatable() == false) { entity = new BufferedHttpEntity(enclosingRequest.getEntity()); enclosingRequest.setEntity(entity); } requestLine += EntityUtils.toString(entity, StandardCharsets.UTF_8) + "'"; } } return requestLine; } /** * Creates curl output for given response */ static String buildTraceResponse(HttpResponse httpResponse) throws IOException { StringBuilder responseLine = new StringBuilder(); responseLine.append("# ").append(httpResponse.getStatusLine()); for (Header header : httpResponse.getAllHeaders()) { responseLine.append("\n# ").append(header.getName()).append(": ").append(header.getValue()); } responseLine.append("\n#"); HttpEntity entity = httpResponse.getEntity(); if (entity != null) { if (entity.isRepeatable() == false) { entity = new BufferedHttpEntity(entity); } httpResponse.setEntity(entity); ContentType contentType = ContentType.get(entity); Charset charset = StandardCharsets.UTF_8; if (contentType != null && contentType.getCharset() != null) { charset = contentType.getCharset(); } try (BufferedReader reader = new BufferedReader(new InputStreamReader(entity.getContent(), charset))) { String line; while ((line = reader.readLine()) != null) { responseLine.append("\n# ").append(line); } } } return responseLine.toString(); } private static String getUri(RequestLine requestLine) { if (requestLine.getUri().charAt(0) != '/') { return "/" + requestLine.getUri(); } return requestLine.getUri(); } }