2 * Copyright 2001-2009 Internet2
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4 * Licensed under the Apache License, Version 2.0 (the "License");
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5 * you may not use this file except in compliance with the License.
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6 * You may obtain a copy of the License at
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8 * http://www.apache.org/licenses/LICENSE-2.0
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10 * Unless required by applicable law or agreed to in writing, software
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11 * distributed under the License is distributed on an "AS IS" BASIS,
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12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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13 * See the License for the specific language governing permissions and
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14 * limitations under the License.
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18 * @file ReloadableXMLFile.cpp
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20 * Base class for file-based XML configuration.
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23 #include "internal.h"
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24 #include "util/NDC.h"
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25 #include "util/PathResolver.h"
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26 #include "util/ReloadableXMLFile.h"
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27 #include "util/XMLConstants.h"
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28 #include "util/XMLHelper.h"
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31 #include <sys/types.h>
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32 #include <sys/stat.h>
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34 #include <xercesc/framework/LocalFileInputSource.hpp>
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35 #include <xercesc/framework/Wrapper4InputSource.hpp>
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36 #include <xercesc/util/XMLUniDefs.hpp>
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38 using namespace xmltooling::logging;
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39 using namespace xmltooling;
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40 using namespace xercesc;
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41 using namespace std;
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43 static const XMLCh uri[] = UNICODE_LITERAL_3(u,r,i);
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44 static const XMLCh url[] = UNICODE_LITERAL_3(u,r,l);
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45 static const XMLCh path[] = UNICODE_LITERAL_4(p,a,t,h);
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46 static const XMLCh pathname[] = UNICODE_LITERAL_8(p,a,t,h,n,a,m,e);
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47 static const XMLCh file[] = UNICODE_LITERAL_4(f,i,l,e);
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48 static const XMLCh filename[] = UNICODE_LITERAL_8(f,i,l,e,n,a,m,e);
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49 static const XMLCh validate[] = UNICODE_LITERAL_8(v,a,l,i,d,a,t,e);
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50 static const XMLCh reloadChanges[] = UNICODE_LITERAL_13(r,e,l,o,a,d,C,h,a,n,g,e,s);
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51 static const XMLCh reloadInterval[] = UNICODE_LITERAL_14(r,e,l,o,a,d,I,n,t,e,r,v,a,l);
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52 static const XMLCh backingFilePath[] = UNICODE_LITERAL_15(b,a,c,k,i,n,g,F,i,l,e,P,a,t,h);
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55 ReloadableXMLFile::~ReloadableXMLFile()
60 ReloadableXMLFile::ReloadableXMLFile(const DOMElement* e, Category& log)
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61 : m_root(e), m_local(true), m_validate(false), m_filestamp(0), m_reloadInterval(0), m_lock(NULL), m_log(log)
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64 NDC ndc("ReloadableXMLFile");
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67 // Establish source of data...
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68 const XMLCh* source=e->getAttributeNS(NULL,uri);
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69 if (!source || !*source) {
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70 source=e->getAttributeNS(NULL,url);
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71 if (!source || !*source) {
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72 source=e->getAttributeNS(NULL,path);
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73 if (!source || !*source) {
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74 source=e->getAttributeNS(NULL,pathname);
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75 if (!source || !*source) {
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76 source=e->getAttributeNS(NULL,file);
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77 if (!source || !*source) {
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78 source=e->getAttributeNS(NULL,filename);
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89 if (source && *source) {
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90 const XMLCh* flag=e->getAttributeNS(NULL,validate);
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91 m_validate=(XMLString::equals(flag,xmlconstants::XML_TRUE) || XMLString::equals(flag,xmlconstants::XML_ONE));
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93 auto_ptr_char temp(source);
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94 m_source=temp.get();
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96 if (!m_local && !strstr(m_source.c_str(),"://")) {
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97 log.warn("deprecated usage of uri/url attribute for a local resource, use path instead");
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102 XMLToolingConfig::getConfig().getPathResolver()->resolve(m_source, PathResolver::XMLTOOLING_CFG_FILE);
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104 flag=e->getAttributeNS(NULL,reloadChanges);
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105 if (!XMLString::equals(flag,xmlconstants::XML_FALSE) && !XMLString::equals(flag,xmlconstants::XML_ZERO)) {
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107 struct _stat stat_buf;
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108 if (_stat(m_source.c_str(), &stat_buf) == 0)
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110 struct stat stat_buf;
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111 if (stat(m_source.c_str(), &stat_buf) == 0)
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113 m_filestamp=stat_buf.st_mtime;
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115 throw IOException("Unable to access local file ($1)", params(1,m_source.c_str()));
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116 m_lock=RWLock::create();
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118 log.debug("using local resource (%s), will %smonitor for changes", m_source.c_str(), m_lock ? "" : "not ");
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121 log.debug("using remote resource (%s)", m_source.c_str());
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122 source = e->getAttributeNS(NULL,backingFilePath);
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123 if (source && *source) {
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124 auto_ptr_char temp2(source);
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125 m_backing=temp2.get();
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126 XMLToolingConfig::getConfig().getPathResolver()->resolve(m_backing, PathResolver::XMLTOOLING_RUN_FILE);
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127 log.debug("backup remote resource with (%s)", m_backing.c_str());
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129 source = e->getAttributeNS(NULL,reloadInterval);
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130 if (source && *source) {
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131 m_reloadInterval = XMLString::parseInt(source);
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132 if (m_reloadInterval > 0) {
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133 m_log.debug("will reload remote resource at most every %d seconds", m_reloadInterval);
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134 m_lock=RWLock::create();
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137 m_filestamp = time(NULL); // assume it gets loaded initially
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141 log.debug("no resource uri/path/name supplied, will load inline configuration");
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145 pair<bool,DOMElement*> ReloadableXMLFile::load(bool backup)
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152 if (m_source.empty()) {
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153 // Data comes from the DOM we were handed.
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154 m_log.debug("loading inline configuration...");
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155 return make_pair(false,XMLHelper::getFirstChildElement(m_root));
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158 // Data comes from a file we have to parse.
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160 m_log.warn("using local backup of remote resource");
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162 m_log.debug("loading configuration from external resource...");
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164 DOMDocument* doc=NULL;
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165 if (m_local || backup) {
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166 auto_ptr_XMLCh widenit(backup ? m_backing.c_str() : m_source.c_str());
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167 LocalFileInputSource src(widenit.get());
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168 Wrapper4InputSource dsrc(&src,false);
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170 doc=XMLToolingConfig::getConfig().getValidatingParser().parse(dsrc);
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172 doc=XMLToolingConfig::getConfig().getParser().parse(dsrc);
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175 URLInputSource src(m_root);
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176 Wrapper4InputSource dsrc(&src,false);
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178 doc=XMLToolingConfig::getConfig().getValidatingParser().parse(dsrc);
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180 doc=XMLToolingConfig::getConfig().getParser().parse(dsrc);
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183 m_log.infoStream() << "loaded XML resource (" << (backup ? m_backing : m_source) << ")" << logging::eol;
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185 if (!backup && !m_backing.empty()) {
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186 m_log.debug("backing up remote resource to (%s)", m_backing.c_str());
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188 ofstream backer(m_backing.c_str());
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191 catch (exception& ex) {
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192 m_log.crit("exception while backing up resource: %s", ex.what());
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196 return make_pair(true,doc->getDocumentElement());
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199 catch (XMLException& e) {
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200 auto_ptr_char msg(e.getMessage());
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201 m_log.errorStream() << "Xerces error while loading resource (" << (backup ? m_backing : m_source) << "): "
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202 << msg.get() << logging::eol;
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203 if (!backup && !m_backing.empty())
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205 throw XMLParserException(msg.get());
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207 catch (exception& e) {
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208 m_log.errorStream() << "error while loading configuration from ("
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209 << (m_source.empty() ? "inline" : (backup ? m_backing : m_source)) << "): " << e.what() << logging::eol;
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210 if (!backup && !m_backing.empty())
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216 Lockable* ReloadableXMLFile::lock()
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223 // Check if we need to refresh.
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226 struct _stat stat_buf;
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227 if (_stat(m_source.c_str(), &stat_buf) != 0)
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230 struct stat stat_buf;
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231 if (stat(m_source.c_str(), &stat_buf) != 0)
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234 if (m_filestamp>=stat_buf.st_mtime)
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237 // Elevate lock and recheck.
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238 m_log.debug("timestamp of local resource changed, elevating to a write lock");
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241 if (m_filestamp>=stat_buf.st_mtime) {
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242 // Somebody else handled it, just downgrade.
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243 m_log.debug("update of local resource handled by another thread, downgrading lock");
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249 // Update the timestamp regardless. No point in repeatedly trying.
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250 m_filestamp=stat_buf.st_mtime;
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251 m_log.info("change detected, reloading local resource...");
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254 time_t now = time(NULL);
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256 // Time to reload? If we have no data, filestamp is zero
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257 // and there's no way current time is less than the interval.
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258 if (now - m_filestamp < m_reloadInterval)
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261 // Elevate lock and recheck.
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262 m_log.debug("reload interval for remote resource elapsed, elevating to a write lock");
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265 if (now - m_filestamp < m_reloadInterval) {
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266 // Somebody else handled it, just downgrade.
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267 m_log.debug("update of remote resource handled by another thread, downgrading lock");
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274 m_log.info("reloading remote resource...");
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279 // At this point we're holding the write lock, so make sure we pop it.
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280 SharedLock lockwrap(m_lock,false);
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281 pair<bool,DOMElement*> ret=load();
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283 ret.second->getOwnerDocument()->release();
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284 } catch (exception& ex) {
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285 m_log.crit("maintaining existing configuration, error reloading resource (%s): %s", m_source.c_str(), ex.what());
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288 // If we made it here, the swap may or may not have worked, but we need to relock.
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289 m_log.debug("attempt to update resource complete, relocking");
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294 void ReloadableXMLFile::unlock()
300 pair<bool,DOMElement*> ReloadableXMLFile::load()