Java tutorial
/** * 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.hadoop.hdfs.qjournal.server; import java.io.File; import java.io.FileInputStream; import java.io.IOException; import java.io.UnsupportedEncodingException; import java.net.URLEncoder; import java.util.HashSet; import java.util.Set; import javax.servlet.ServletContext; import javax.servlet.ServletException; import javax.servlet.http.HttpServlet; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.apache.commons.lang.StringEscapeUtils; import org.apache.commons.logging.Log; import org.apache.commons.logging.LogFactory; import org.apache.hadoop.classification.InterfaceAudience; import org.apache.hadoop.conf.Configuration; import org.apache.hadoop.hdfs.DFSConfigKeys; import org.apache.hadoop.hdfs.DFSUtil; import org.apache.hadoop.hdfs.qjournal.client.QuorumJournalManager; import org.apache.hadoop.hdfs.server.common.JspHelper; import org.apache.hadoop.hdfs.server.common.StorageInfo; import org.apache.hadoop.hdfs.server.namenode.FileJournalManager; import org.apache.hadoop.hdfs.server.namenode.FileJournalManager.EditLogFile; import org.apache.hadoop.hdfs.server.namenode.ImageServlet; import org.apache.hadoop.hdfs.server.namenode.SecondaryNameNode; import org.apache.hadoop.hdfs.server.namenode.TransferFsImage; import org.apache.hadoop.hdfs.server.protocol.NamespaceInfo; import org.apache.hadoop.hdfs.util.DataTransferThrottler; import org.apache.hadoop.io.IOUtils; import org.apache.hadoop.security.SecurityUtil; import org.apache.hadoop.security.UserGroupInformation; import org.apache.hadoop.util.ServletUtil; import org.apache.hadoop.util.StringUtils; /** * This servlet is used in two cases: * <ul> * <li>The QuorumJournalManager, when reading edits, fetches the edit streams * from the journal nodes.</li> * <li>During edits synchronization, one journal node will fetch edits from * another journal node.</li> * </ul> */ @InterfaceAudience.Private public class GetJournalEditServlet extends HttpServlet { private static final long serialVersionUID = -4635891628211723009L; private static final Log LOG = LogFactory.getLog(GetJournalEditServlet.class); static final String STORAGEINFO_PARAM = "storageInfo"; static final String JOURNAL_ID_PARAM = "jid"; static final String SEGMENT_TXID_PARAM = "segmentTxId"; protected boolean isValidRequestor(HttpServletRequest request, Configuration conf) throws IOException { String remotePrincipal = request.getUserPrincipal().getName(); String remoteShortName = request.getRemoteUser(); if (remotePrincipal == null) { // This really shouldn't happen... LOG.warn("Received null remoteUser while authorizing access to " + "GetJournalEditServlet"); return false; } if (LOG.isDebugEnabled()) { LOG.debug("Validating request made by " + remotePrincipal + " / " + remoteShortName + ". This user is: " + UserGroupInformation.getLoginUser()); } Set<String> validRequestors = new HashSet<String>(); validRequestors.addAll(DFSUtil.getAllNnPrincipals(conf)); try { validRequestors.add(SecurityUtil.getServerPrincipal( conf.get(DFSConfigKeys.DFS_SECONDARY_NAMENODE_KERBEROS_PRINCIPAL_KEY), SecondaryNameNode.getHttpAddress(conf).getHostName())); } catch (Exception e) { // Don't halt if SecondaryNameNode principal could not be added. LOG.debug("SecondaryNameNode principal could not be added", e); String msg = String.format("SecondaryNameNode principal not considered, %s = %s, %s = %s", DFSConfigKeys.DFS_SECONDARY_NAMENODE_KERBEROS_PRINCIPAL_KEY, conf.get(DFSConfigKeys.DFS_SECONDARY_NAMENODE_KERBEROS_PRINCIPAL_KEY), DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_KEY, conf.get(DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_KEY, DFSConfigKeys.DFS_NAMENODE_SECONDARY_HTTP_ADDRESS_DEFAULT)); LOG.warn(msg); } // Check the full principal name of all the configured valid requestors. for (String v : validRequestors) { if (LOG.isDebugEnabled()) LOG.debug("isValidRequestor is comparing to valid requestor: " + v); if (v != null && v.equals(remotePrincipal)) { if (LOG.isDebugEnabled()) LOG.debug("isValidRequestor is allowing: " + remotePrincipal); return true; } } // Additionally, we compare the short name of the requestor to this JN's // username, because we want to allow requests from other JNs during // recovery, but we can't enumerate the full list of JNs. if (remoteShortName.equals(UserGroupInformation.getLoginUser().getShortUserName())) { if (LOG.isDebugEnabled()) LOG.debug("isValidRequestor is allowing other JN principal: " + remotePrincipal); return true; } if (LOG.isDebugEnabled()) LOG.debug("isValidRequestor is rejecting: " + remotePrincipal); return false; } private boolean checkRequestorOrSendError(Configuration conf, HttpServletRequest request, HttpServletResponse response) throws IOException { if (UserGroupInformation.isSecurityEnabled() && !isValidRequestor(request, conf)) { response.sendError(HttpServletResponse.SC_FORBIDDEN, "Only Namenode and another JournalNode may access this servlet"); LOG.warn("Received non-NN/JN request for edits from " + request.getRemoteHost()); return false; } return true; } private boolean checkStorageInfoOrSendError(JNStorage storage, HttpServletRequest request, HttpServletResponse response) throws IOException { int myNsId = storage.getNamespaceID(); String myClusterId = storage.getClusterID(); String theirStorageInfoString = StringEscapeUtils.escapeHtml(request.getParameter(STORAGEINFO_PARAM)); if (theirStorageInfoString != null) { int theirNsId = StorageInfo.getNsIdFromColonSeparatedString(theirStorageInfoString); String theirClusterId = StorageInfo.getClusterIdFromColonSeparatedString(theirStorageInfoString); if (myNsId != theirNsId || !myClusterId.equals(theirClusterId)) { String msg = "This node has namespaceId '" + myNsId + " and clusterId '" + myClusterId + "' but the requesting node expected '" + theirNsId + "' and '" + theirClusterId + "'"; response.sendError(HttpServletResponse.SC_FORBIDDEN, msg); LOG.warn("Received an invalid request file transfer request from " + request.getRemoteAddr() + ": " + msg); return false; } } return true; } @Override public void doGet(final HttpServletRequest request, final HttpServletResponse response) throws ServletException, IOException { FileInputStream editFileIn = null; try { final ServletContext context = getServletContext(); final Configuration conf = (Configuration) getServletContext().getAttribute(JspHelper.CURRENT_CONF); final String journalId = request.getParameter(JOURNAL_ID_PARAM); QuorumJournalManager.checkJournalId(journalId); final JNStorage storage = JournalNodeHttpServer.getJournalFromContext(context, journalId).getStorage(); // Check security if (!checkRequestorOrSendError(conf, request, response)) { return; } // Check that the namespace info is correct if (!checkStorageInfoOrSendError(storage, request, response)) { return; } long segmentTxId = ServletUtil.parseLongParam(request, SEGMENT_TXID_PARAM); FileJournalManager fjm = storage.getJournalManager(); File editFile; synchronized (fjm) { // Synchronize on the FJM so that the file doesn't get finalized // out from underneath us while we're in the process of opening // it up. EditLogFile elf = fjm.getLogFile(segmentTxId); if (elf == null) { response.sendError(HttpServletResponse.SC_NOT_FOUND, "No edit log found starting at txid " + segmentTxId); return; } editFile = elf.getFile(); ImageServlet.setVerificationHeadersForGet(response, editFile); ImageServlet.setFileNameHeaders(response, editFile); editFileIn = new FileInputStream(editFile); } DataTransferThrottler throttler = ImageServlet.getThrottler(conf); // send edits TransferFsImage.copyFileToStream(response.getOutputStream(), editFile, editFileIn, throttler); } catch (Throwable t) { String errMsg = "getedit failed. " + StringUtils.stringifyException(t); response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR, errMsg); throw new IOException(errMsg); } finally { IOUtils.closeStream(editFileIn); } } public static String buildPath(String journalId, long segmentTxId, NamespaceInfo nsInfo) { StringBuilder path = new StringBuilder("/getJournal?"); try { path.append(JOURNAL_ID_PARAM).append("=").append(URLEncoder.encode(journalId, "UTF-8")); path.append("&" + SEGMENT_TXID_PARAM).append("=").append(segmentTxId); path.append("&" + STORAGEINFO_PARAM).append("=") .append(URLEncoder.encode(nsInfo.toColonSeparatedString(), "UTF-8")); } catch (UnsupportedEncodingException e) { // Never get here -- everyone supports UTF-8 throw new RuntimeException(e); } return path.toString(); } }