src/main/java/org/apache/sling/tracer/internal/TracerLogServlet.java - sling-org-apache-sling-tracer - Git at Google

 /*
  * Licensed to the Apache Software Foundation (ASF) under one
  * or more contributor license agreements.  See the NOTICE file
  * distributed with this work for additional information
  * regarding copyright ownership.  The ASF 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.apache.sling.tracer.internal;

 import java.io.IOException;
 import java.io.PrintWriter;
 import java.text.SimpleDateFormat;
 import java.util.ArrayList;
 import java.util.Collections;
 import java.util.Date;
 import java.util.List;
 import java.util.UUID;
 import java.util.concurrent.TimeUnit;

 import javax.annotation.Nonnull;
 import javax.servlet.ServletException;
 import javax.servlet.http.HttpServletRequest;
 import javax.servlet.http.HttpServletResponse;

 import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 import com.google.common.cache.Weigher;
 import org.apache.commons.io.FileUtils;
 import org.apache.felix.webconsole.SimpleWebConsolePlugin;
 import org.apache.sling.commons.json.JSONException;
 import org.apache.sling.commons.json.io.JSONWriter;
 import org.osgi.framework.BundleContext;

 class TracerLogServlet extends SimpleWebConsolePlugin implements TraceLogRecorder {
     static final String ATTR_RECORDING = TracerLogServlet.class.getName();

     public static final String CLEAR = "clear";

     private static final String LABEL = "tracer";

     public static final String HEADER_TRACER_RECORDING = "Sling-Tracer-Record";

     public static final String HEADER_TRACER_REQUEST_ID = "Sling-Tracer-Request-Id";

     public static final String HEADER_TRACER_PROTOCOL_VERSION = "Sling-Tracer-Protocol-Version";

     public static final int TRACER_PROTOCOL_VERSION = 1;

     private final Cache<String, JSONRecording> cache;

     private final boolean compressRecording;

     private final int cacheSizeInMB;

     private final long cacheDurationInSecs;

     private final boolean gzipResponse;

     public TracerLogServlet(BundleContext context){
         this(context,
                 LogTracer.PROP_TRACER_SERVLET_CACHE_SIZE_DEFAULT,
                 LogTracer.PROP_TRACER_SERVLET_CACHE_DURATION_DEFAULT,
                 LogTracer.PROP_TRACER_SERVLET_COMPRESS_DEFAULT,
                 LogTracer.PROP_TRACER_SERVLET_GZIP_RESPONSE_DEFAULT
         );
     }

     public TracerLogServlet(BundleContext context, int cacheSizeInMB, long cacheDurationInSecs,
                             boolean compressionEnabled, boolean gzipResponse) {
         super(LABEL, "Sling Tracer", "Sling", null);
         this.compressRecording = compressionEnabled;
         this.cacheDurationInSecs = cacheDurationInSecs;
         this.cacheSizeInMB = cacheSizeInMB;
         this.gzipResponse = compressionEnabled && gzipResponse;
         this.cache = CacheBuilder.newBuilder()
                 .maximumWeight(cacheSizeInMB * FileUtils.ONE_MB)
                 .weigher(new Weigher<String, JSONRecording>() {
                     @Override
                     public int weigh(@Nonnull  String key, @Nonnull JSONRecording value) {
                         return value.size();
                     }
                 })
                 .expireAfterAccess(cacheDurationInSecs, TimeUnit.SECONDS)
                 .recordStats()
                 .build();
         register(context);
     }

     boolean isCompressRecording() {
         return compressRecording;
     }

     public boolean isGzipResponse() {
         return gzipResponse;
     }

     int getCacheSizeInMB() {
         return cacheSizeInMB;
     }

     long getCacheDurationInSecs() {
         return cacheDurationInSecs;
     }

     //~-----------------------------------------------< WebConsole Plugin >

     @Override
     protected void renderContent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
         if (isHtmlRequest(request)){
             PrintWriter pw = response.getWriter();
             renderStatus(pw);
             renderRequests(pw);
         } else {
             String requestId = getRequestId(request);
             prepareJSONResponse(response);
             try {
                 boolean responseDone = false;
                 if (requestId != null) {
                     JSONRecording recording = cache.getIfPresent(requestId);
                     if (recording != null){
                         boolean shouldGZip = prepareForGZipResponse(request, response);
                         responseDone = recording.render(response.getOutputStream(), shouldGZip);
                     }
                 }

                 if (!responseDone) {
                     PrintWriter pw = response.getWriter();
                     JSONWriter jw = new JSONWriter(pw);
                     jw.object();
                     jw.key("error").value("Not found");
                     jw.endObject();
                 }
             } catch (JSONException e) {
                 throw new ServletException(e);
             }
         }
     }

     @Override
     protected void doPost(HttpServletRequest req, HttpServletResponse resp)
             throws IOException {
         if (req.getParameter(CLEAR) != null) {
             resetCache();
             resp.sendRedirect(req.getRequestURI());
         }
     }

     @Override
     protected boolean isHtmlRequest(HttpServletRequest request) {
         return request.getRequestURI().endsWith(LABEL);
     }

     private boolean prepareForGZipResponse(HttpServletRequest request, HttpServletResponse response) {
         if (!gzipResponse) {
             return false;
         }

         String acceptEncoding = request.getHeader("Accept-Encoding");
         boolean acceptsGzip = acceptEncoding != null && accepts(acceptEncoding, "gzip");

         if (acceptsGzip) {
             response.setHeader("Content-Encoding", "gzip");
         }
         return acceptsGzip;
     }

     /**
      * Returns true if the given accept header accepts the given value.
      * @param acceptHeader The accept header.
      * @param toAccept The value to be accepted.
      * @return True if the given accept header accepts the given value.
      */
     private static boolean accepts(String acceptHeader, String toAccept) {
         return acceptHeader.contains(toAccept) || acceptHeader.contains("*/*");
     }

     private static void prepareJSONResponse(HttpServletResponse response) {
         response.setContentType("application/json");
         response.setCharacterEncoding("UTF-8");
     }

     private void renderStatus(PrintWriter pw) {
         pw.printf("<p class='statline'>Log Tracer Recordings: %d recordings, %s memory " +
                 "(Max %dMB, Expired in %d secs)</p>%n", cache.size(),
                 memorySize(), cacheSizeInMB, cacheDurationInSecs);

         pw.println("<div class='ui-widget-header ui-corner-top buttonGroup'>");
         pw.println("<span style='float: left; margin-left: 1em'>Tracer Recordings</span>");
         pw.println("<form method='POST'><input type='hidden' name='clear' value='clear'><input type='submit' value='Clear' class='ui-state-default ui-corner-all'></form>");
         pw.println("</div>");
     }

     private String memorySize() {
         long size = 0;
         for (JSONRecording r : cache.asMap().values()){
             size += r.size();
         }
         return humanReadableByteCount(size);
     }

     private void renderRequests(PrintWriter pw) {
         if (cache.size() > 0){
             pw.println("<ol>");
             List<JSONRecording> recordings = new ArrayList<JSONRecording>(cache.asMap().values());
             SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss");
             Collections.sort(recordings);
             for (JSONRecording r : recordings){
                 String id = r.getRequestId();
                 String date = sdf.format(new Date(r.getStart()));
                 pw.printf("<li>%s - <a href='%s/%s.json'>%s</a> - %s (%s) (%dms)</li>",
                         date, LABEL, id, id,
                         r.getUri(),
                         humanReadableByteCount(r.size()),
                         r.getTimeTaken());
             }
             pw.println("</ol>");
         }
     }

     private static String getRequestId(HttpServletRequest request) {
         String requestUri = request.getRequestURI();
         int lastSlash = requestUri.lastIndexOf('/');
         int lastDot = requestUri.indexOf('.', lastSlash + 1);
         if (lastDot > 0){
             return requestUri.substring(lastSlash + 1, lastDot);
         }
         return null;
     }

     //~-----------------------------------------------< TraceLogRecorder >

     @Override
     public Recording startRecording(HttpServletRequest request, HttpServletResponse response) {
         if (request.getHeader(HEADER_TRACER_RECORDING) == null){
             return Recording.NOOP;
         }

         if (request.getAttribute(ATTR_RECORDING) != null){
             //Already processed
             return getRecordingForRequest(request);
         }

         String requestId = generateRequestId();
         JSONRecording recording = record(requestId, request);

         response.setHeader(HEADER_TRACER_REQUEST_ID, requestId);
         response.setHeader(HEADER_TRACER_PROTOCOL_VERSION, String.valueOf(TRACER_PROTOCOL_VERSION));

         return recording;
     }

     @Override
     public Recording getRecordingForRequest(HttpServletRequest request) {
         Recording recording = (Recording) request.getAttribute(ATTR_RECORDING);
         if (recording == null){
             recording = Recording.NOOP;
         }
         return recording;
     }

     @Override
     public void endRecording(HttpServletRequest httpRequest, Recording recording) {
         if (recording instanceof JSONRecording) {
             JSONRecording r = (JSONRecording) recording;
             r.done();
             cache.put(r.getRequestId(), r);
         }
         httpRequest.removeAttribute(ATTR_RECORDING);
     }

     Recording getRecording(String requestId) {
         Recording recording = cache.getIfPresent(requestId);
         return recording == null ? Recording.NOOP : recording;
     }

     private JSONRecording record(String requestId, HttpServletRequest request) {
         JSONRecording data = new JSONRecording(requestId, request, compressRecording);
         request.setAttribute(ATTR_RECORDING, data);
         return data;
     }

     private static String generateRequestId() {
         return UUID.randomUUID().toString();
     }

     /**
      * Returns a human-readable version of the file size, where the input represents
      * a specific number of bytes. Based on http://stackoverflow.com/a/3758880/1035417
      */
     @SuppressWarnings("Duplicates")
     private static String humanReadableByteCount(long bytes) {
         if (bytes < 0) {
             return "0";
         }
         int unit = 1000;
         if (bytes < unit) {
             return bytes + " B";
         }
         int exp = (int) (Math.log(bytes) / Math.log(unit));
         char pre = "kMGTPE".charAt(exp - 1);
         return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
     }

     void resetCache(){
         cache.invalidateAll();
     }
 }
	/*
	* Licensed to the Apache Software Foundation (ASF) under one
	* or more contributor license agreements. See the NOTICE file
	* distributed with this work for additional information
	* regarding copyright ownership. The ASF 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.apache.sling.tracer.internal;

	import java.io.IOException;
	import java.io.PrintWriter;
	import java.text.SimpleDateFormat;
	import java.util.ArrayList;
	import java.util.Collections;
	import java.util.Date;
	import java.util.List;
	import java.util.UUID;
	import java.util.concurrent.TimeUnit;

	import javax.annotation.Nonnull;
	import javax.servlet.ServletException;
	import javax.servlet.http.HttpServletRequest;
	import javax.servlet.http.HttpServletResponse;

	import com.google.common.cache.Cache;
	import com.google.common.cache.CacheBuilder;
	import com.google.common.cache.Weigher;
	import org.apache.commons.io.FileUtils;
	import org.apache.felix.webconsole.SimpleWebConsolePlugin;
	import org.apache.sling.commons.json.JSONException;
	import org.apache.sling.commons.json.io.JSONWriter;
	import org.osgi.framework.BundleContext;

	class TracerLogServlet extends SimpleWebConsolePlugin implements TraceLogRecorder {
	static final String ATTR_RECORDING = TracerLogServlet.class.getName();

	public static final String CLEAR = "clear";

	private static final String LABEL = "tracer";

	public static final String HEADER_TRACER_RECORDING = "Sling-Tracer-Record";

	public static final String HEADER_TRACER_REQUEST_ID = "Sling-Tracer-Request-Id";

	public static final String HEADER_TRACER_PROTOCOL_VERSION = "Sling-Tracer-Protocol-Version";

	public static final int TRACER_PROTOCOL_VERSION = 1;

	private final Cache<String, JSONRecording> cache;

	private final boolean compressRecording;

	private final int cacheSizeInMB;

	private final long cacheDurationInSecs;

	private final boolean gzipResponse;

	public TracerLogServlet(BundleContext context){
	this(context,
	LogTracer.PROP_TRACER_SERVLET_CACHE_SIZE_DEFAULT,
	LogTracer.PROP_TRACER_SERVLET_CACHE_DURATION_DEFAULT,
	LogTracer.PROP_TRACER_SERVLET_COMPRESS_DEFAULT,
	LogTracer.PROP_TRACER_SERVLET_GZIP_RESPONSE_DEFAULT
	);
	}

	public TracerLogServlet(BundleContext context, int cacheSizeInMB, long cacheDurationInSecs,
	boolean compressionEnabled, boolean gzipResponse) {
	super(LABEL, "Sling Tracer", "Sling", null);
	this.compressRecording = compressionEnabled;
	this.cacheDurationInSecs = cacheDurationInSecs;
	this.cacheSizeInMB = cacheSizeInMB;
	this.gzipResponse = compressionEnabled && gzipResponse;
	this.cache = CacheBuilder.newBuilder()
	.maximumWeight(cacheSizeInMB * FileUtils.ONE_MB)
	.weigher(new Weigher<String, JSONRecording>() {
	@Override
	public int weigh(@Nonnull String key, @Nonnull JSONRecording value) {
	return value.size();
	}
	})
	.expireAfterAccess(cacheDurationInSecs, TimeUnit.SECONDS)
	.recordStats()
	.build();
	register(context);
	}

	boolean isCompressRecording() {
	return compressRecording;
	}

	public boolean isGzipResponse() {
	return gzipResponse;
	}

	int getCacheSizeInMB() {
	return cacheSizeInMB;
	}

	long getCacheDurationInSecs() {
	return cacheDurationInSecs;
	}

	//~-----------------------------------------------< WebConsole Plugin >

	@Override
	protected void renderContent(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
	if (isHtmlRequest(request)){
	PrintWriter pw = response.getWriter();
	renderStatus(pw);
	renderRequests(pw);
	} else {
	String requestId = getRequestId(request);
	prepareJSONResponse(response);
	try {
	boolean responseDone = false;
	if (requestId != null) {
	JSONRecording recording = cache.getIfPresent(requestId);
	if (recording != null){
	boolean shouldGZip = prepareForGZipResponse(request, response);
	responseDone = recording.render(response.getOutputStream(), shouldGZip);
	}
	}

	if (!responseDone) {
	PrintWriter pw = response.getWriter();
	JSONWriter jw = new JSONWriter(pw);
	jw.object();
	jw.key("error").value("Not found");
	jw.endObject();
	}
	} catch (JSONException e) {
	throw new ServletException(e);
	}
	}
	}

	@Override
	protected void doPost(HttpServletRequest req, HttpServletResponse resp)
	throws IOException {
	if (req.getParameter(CLEAR) != null) {
	resetCache();
	resp.sendRedirect(req.getRequestURI());
	}
	}

	@Override
	protected boolean isHtmlRequest(HttpServletRequest request) {
	return request.getRequestURI().endsWith(LABEL);
	}

	private boolean prepareForGZipResponse(HttpServletRequest request, HttpServletResponse response) {
	if (!gzipResponse) {
	return false;
	}

	String acceptEncoding = request.getHeader("Accept-Encoding");
	boolean acceptsGzip = acceptEncoding != null && accepts(acceptEncoding, "gzip");

	if (acceptsGzip) {
	response.setHeader("Content-Encoding", "gzip");
	}
	return acceptsGzip;
	}

	/**
	* Returns true if the given accept header accepts the given value.
	* @param acceptHeader The accept header.
	* @param toAccept The value to be accepted.
	* @return True if the given accept header accepts the given value.
	*/
	private static boolean accepts(String acceptHeader, String toAccept) {
	return acceptHeader.contains(toAccept) \|\| acceptHeader.contains("/");
	}

	private static void prepareJSONResponse(HttpServletResponse response) {
	response.setContentType("application/json");
	response.setCharacterEncoding("UTF-8");
	}

	private void renderStatus(PrintWriter pw) {
	pw.printf("<p class='statline'>Log Tracer Recordings: %d recordings, %s memory " +
	"(Max %dMB, Expired in %d secs)</p>%n", cache.size(),
	memorySize(), cacheSizeInMB, cacheDurationInSecs);

	pw.println("<div class='ui-widget-header ui-corner-top buttonGroup'>");
	pw.println("<span style='float: left; margin-left: 1em'>Tracer Recordings</span>");
	pw.println("<form method='POST'><input type='hidden' name='clear' value='clear'><input type='submit' value='Clear' class='ui-state-default ui-corner-all'></form>");
	pw.println("</div>");
	}

	private String memorySize() {
	long size = 0;
	for (JSONRecording r : cache.asMap().values()){
	size += r.size();
	}
	return humanReadableByteCount(size);
	}

	private void renderRequests(PrintWriter pw) {
	if (cache.size() > 0){
	pw.println("<ol>");
	List<JSONRecording> recordings = new ArrayList<JSONRecording>(cache.asMap().values());
	SimpleDateFormat sdf = new SimpleDateFormat("dd.MM.yyyy HH:mm:ss");
	Collections.sort(recordings);
	for (JSONRecording r : recordings){
	String id = r.getRequestId();
	String date = sdf.format(new Date(r.getStart()));
	pw.printf("<li>%s - <a href='%s/%s.json'>%s</a> - %s (%s) (%dms)</li>",
	date, LABEL, id, id,
	r.getUri(),
	humanReadableByteCount(r.size()),
	r.getTimeTaken());
	}
	pw.println("</ol>");
	}
	}

	private static String getRequestId(HttpServletRequest request) {
	String requestUri = request.getRequestURI();
	int lastSlash = requestUri.lastIndexOf('/');
	int lastDot = requestUri.indexOf('.', lastSlash + 1);
	if (lastDot > 0){
	return requestUri.substring(lastSlash + 1, lastDot);
	}
	return null;
	}

	//~-----------------------------------------------< TraceLogRecorder >

	@Override
	public Recording startRecording(HttpServletRequest request, HttpServletResponse response) {
	if (request.getHeader(HEADER_TRACER_RECORDING) == null){
	return Recording.NOOP;
	}

	if (request.getAttribute(ATTR_RECORDING) != null){
	//Already processed
	return getRecordingForRequest(request);
	}

	String requestId = generateRequestId();
	JSONRecording recording = record(requestId, request);

	response.setHeader(HEADER_TRACER_REQUEST_ID, requestId);
	response.setHeader(HEADER_TRACER_PROTOCOL_VERSION, String.valueOf(TRACER_PROTOCOL_VERSION));

	return recording;
	}

	@Override
	public Recording getRecordingForRequest(HttpServletRequest request) {
	Recording recording = (Recording) request.getAttribute(ATTR_RECORDING);
	if (recording == null){
	recording = Recording.NOOP;
	}
	return recording;
	}

	@Override
	public void endRecording(HttpServletRequest httpRequest, Recording recording) {
	if (recording instanceof JSONRecording) {
	JSONRecording r = (JSONRecording) recording;
	r.done();
	cache.put(r.getRequestId(), r);
	}
	httpRequest.removeAttribute(ATTR_RECORDING);
	}

	Recording getRecording(String requestId) {
	Recording recording = cache.getIfPresent(requestId);
	return recording == null ? Recording.NOOP : recording;
	}

	private JSONRecording record(String requestId, HttpServletRequest request) {
	JSONRecording data = new JSONRecording(requestId, request, compressRecording);
	request.setAttribute(ATTR_RECORDING, data);
	return data;
	}

	private static String generateRequestId() {
	return UUID.randomUUID().toString();
	}

	/**
	* Returns a human-readable version of the file size, where the input represents
	* a specific number of bytes. Based on http://stackoverflow.com/a/3758880/1035417
	*/
	@SuppressWarnings("Duplicates")
	private static String humanReadableByteCount(long bytes) {
	if (bytes < 0) {
	return "0";
	}
	int unit = 1000;
	if (bytes < unit) {
	return bytes + " B";
	}
	int exp = (int) (Math.log(bytes) / Math.log(unit));
	char pre = "kMGTPE".charAt(exp - 1);
	return String.format("%.1f %sB", bytes / Math.pow(unit, exp), pre);
	}

	void resetCache(){
	cache.invalidateAll();
	}
	}