2 * Copyright 2001-2010 Internet2
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
8 * http://www.apache.org/licenses/LICENSE-2.0
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
18 * @file ReloadableXMLFile.cpp
20 * Base class for file-based XML configuration.
24 #include "io/HTTPResponse.h"
26 #include "util/PathResolver.h"
27 #include "util/ReloadableXMLFile.h"
28 #include "util/Threads.h"
29 #include "util/XMLConstants.h"
30 #include "util/XMLHelper.h"
32 #if defined(XMLTOOLING_LOG4SHIB)
33 # include <log4shib/NDC.hh>
34 #elif defined(XMLTOOLING_LOG4CPP)
35 # include <log4cpp/NDC.hh>
40 #include <sys/types.h>
43 #include <xercesc/framework/LocalFileInputSource.hpp>
44 #include <xercesc/framework/Wrapper4InputSource.hpp>
45 #include <xercesc/util/XMLUniDefs.hpp>
47 using namespace xmltooling::logging;
48 using namespace xmltooling;
49 using namespace xercesc;
52 static const XMLCh id[] = UNICODE_LITERAL_2(i,d);
53 static const XMLCh uri[] = UNICODE_LITERAL_3(u,r,i);
54 static const XMLCh url[] = UNICODE_LITERAL_3(u,r,l);
55 static const XMLCh path[] = UNICODE_LITERAL_4(p,a,t,h);
56 static const XMLCh pathname[] = UNICODE_LITERAL_8(p,a,t,h,n,a,m,e);
57 static const XMLCh file[] = UNICODE_LITERAL_4(f,i,l,e);
58 static const XMLCh filename[] = UNICODE_LITERAL_8(f,i,l,e,n,a,m,e);
59 static const XMLCh validate[] = UNICODE_LITERAL_8(v,a,l,i,d,a,t,e);
60 static const XMLCh reloadChanges[] = UNICODE_LITERAL_13(r,e,l,o,a,d,C,h,a,n,g,e,s);
61 static const XMLCh reloadInterval[] = UNICODE_LITERAL_14(r,e,l,o,a,d,I,n,t,e,r,v,a,l);
62 static const XMLCh backingFilePath[] = UNICODE_LITERAL_15(b,a,c,k,i,n,g,F,i,l,e,P,a,t,h);
65 ReloadableXMLFile::ReloadableXMLFile(const DOMElement* e, Category& log)
66 : m_root(e), m_local(true), m_validate(false), m_backupIndicator(true), m_filestamp(0), m_reloadInterval(0), m_lock(NULL), m_log(log),
67 m_shutdown(false), m_reload_wait(NULL), m_reload_thread(NULL)
70 NDC ndc("ReloadableXMLFile");
73 // Establish source of data...
74 const XMLCh* source=e->getAttributeNS(NULL,uri);
75 if (!source || !*source) {
76 source=e->getAttributeNS(NULL,url);
77 if (!source || !*source) {
78 source=e->getAttributeNS(NULL,path);
79 if (!source || !*source) {
80 source=e->getAttributeNS(NULL,pathname);
81 if (!source || !*source) {
82 source=e->getAttributeNS(NULL,file);
83 if (!source || !*source) {
84 source=e->getAttributeNS(NULL,filename);
95 if (source && *source) {
96 const XMLCh* flag=e->getAttributeNS(NULL,validate);
97 m_validate=(XMLString::equals(flag,xmlconstants::XML_TRUE) || XMLString::equals(flag,xmlconstants::XML_ONE));
99 auto_ptr_char temp(source);
102 if (!m_local && !strstr(m_source.c_str(),"://")) {
103 log.warn("deprecated usage of uri/url attribute for a local resource, use path instead");
108 XMLToolingConfig::getConfig().getPathResolver()->resolve(m_source, PathResolver::XMLTOOLING_CFG_FILE);
110 flag=e->getAttributeNS(NULL,reloadChanges);
111 if (!XMLString::equals(flag,xmlconstants::XML_FALSE) && !XMLString::equals(flag,xmlconstants::XML_ZERO)) {
113 struct _stat stat_buf;
114 if (_stat(m_source.c_str(), &stat_buf) == 0)
116 struct stat stat_buf;
117 if (stat(m_source.c_str(), &stat_buf) == 0)
119 m_filestamp=stat_buf.st_mtime;
121 throw IOException("Unable to access local file ($1)", params(1,m_source.c_str()));
122 m_lock=RWLock::create();
124 log.debug("using local resource (%s), will %smonitor for changes", m_source.c_str(), m_lock ? "" : "not ");
127 log.debug("using remote resource (%s)", m_source.c_str());
128 source = e->getAttributeNS(NULL,backingFilePath);
129 if (source && *source) {
130 auto_ptr_char temp2(source);
131 m_backing=temp2.get();
132 XMLToolingConfig::getConfig().getPathResolver()->resolve(m_backing, PathResolver::XMLTOOLING_RUN_FILE);
133 log.debug("backup remote resource to (%s)", m_backing.c_str());
135 source = e->getAttributeNS(NULL,reloadInterval);
136 if (source && *source) {
137 m_reloadInterval = XMLString::parseInt(source);
138 if (m_reloadInterval > 0) {
139 m_log.debug("will reload remote resource at most every %d seconds", m_reloadInterval);
140 m_lock=RWLock::create();
143 m_filestamp = time(NULL); // assume it gets loaded initially
147 m_reload_wait = CondWait::create();
148 m_reload_thread = Thread::create(&reload_fn, this);
152 log.debug("no resource uri/path/name supplied, will load inline configuration");
155 source = e->getAttributeNS(NULL, id);
156 if (source && *source) {
157 auto_ptr_char tempid(source);
162 ReloadableXMLFile::~ReloadableXMLFile()
168 void ReloadableXMLFile::shutdown()
170 if (m_reload_thread) {
171 // Shut down the reload thread and let it know.
173 m_reload_wait->signal();
174 m_reload_thread->join(NULL);
175 delete m_reload_thread;
176 delete m_reload_wait;
177 m_reload_thread = NULL;
178 m_reload_wait = NULL;
182 void* ReloadableXMLFile::reload_fn(void* pv)
184 ReloadableXMLFile* r = reinterpret_cast<ReloadableXMLFile*>(pv);
187 // First, let's block all signals
188 Thread::mask_all_signals();
191 if (!r->m_id.empty()) {
192 string threadid("[");
193 threadid += r->m_id + ']';
194 logging::NDC::push(threadid);
201 auto_ptr<Mutex> mutex(Mutex::create());
205 r->m_log.info("reload thread started...running when signaled");
207 r->m_log.info("reload thread started...running every %d seconds", r->m_reloadInterval);
209 while (!r->m_shutdown) {
211 r->m_reload_wait->wait(mutex.get());
213 r->m_reload_wait->timedwait(mutex.get(), r->m_reloadInterval);
218 r->m_log.info("reloading %s resource...", r->m_local ? "local" : "remote");
219 pair<bool,DOMElement*> ret = r->background_load();
221 ret.second->getOwnerDocument()->release();
224 if (ex == HTTPResponse::XMLTOOLING_HTTP_STATUS_NOTMODIFIED) {
225 r->m_log.info("remote resource (%s) unchanged from cached version", r->m_source.c_str());
228 // Shouldn't happen, we should only get codes intended to be gracefully handled.
229 r->m_log.crit("maintaining existing configuration, remote resource fetch returned atypical status code (%d)", ex);
232 catch (exception& ex) {
233 r->m_log.crit("maintaining existing configuration, error reloading resource (%s): %s", r->m_source.c_str(), ex.what());
237 r->m_log.info("reload thread finished");
241 if (!r->m_id.empty()) {
248 Lockable* ReloadableXMLFile::lock()
256 // Check if we need to refresh.
258 struct _stat stat_buf;
259 if (_stat(m_source.c_str(), &stat_buf) != 0)
262 struct stat stat_buf;
263 if (stat(m_source.c_str(), &stat_buf) != 0)
266 if (m_filestamp >= stat_buf.st_mtime)
269 // Elevate lock and recheck.
270 m_log.debug("timestamp of local resource changed, elevating to a write lock");
273 if (m_filestamp >= stat_buf.st_mtime) {
274 // Somebody else handled it, just downgrade.
275 m_log.debug("update of local resource handled by another thread, downgrading lock");
281 // Update the timestamp regardless.
282 m_filestamp = stat_buf.st_mtime;
283 m_log.info("change detected, signaling reload thread...");
284 m_reload_wait->signal();
290 void ReloadableXMLFile::unlock()
296 pair<bool,DOMElement*> ReloadableXMLFile::load(bool backup)
303 if (m_source.empty()) {
304 // Data comes from the DOM we were handed.
305 m_log.debug("loading inline configuration...");
306 return make_pair(false, XMLHelper::getFirstChildElement(m_root));
309 // Data comes from a file we have to parse.
311 m_log.warn("using local backup of remote resource");
313 m_log.debug("loading configuration from external resource...");
315 DOMDocument* doc=NULL;
316 if (m_local || backup) {
317 auto_ptr_XMLCh widenit(backup ? m_backing.c_str() : m_source.c_str());
318 // Use library-wide lock for now, nothing else is using it anyway.
319 Locker locker(backup ? getBackupLock() : NULL);
320 LocalFileInputSource src(widenit.get());
321 Wrapper4InputSource dsrc(&src, false);
323 doc=XMLToolingConfig::getConfig().getValidatingParser().parse(dsrc);
325 doc=XMLToolingConfig::getConfig().getParser().parse(dsrc);
328 URLInputSource src(m_root, NULL, &m_cacheTag);
329 Wrapper4InputSource dsrc(&src, false);
331 doc=XMLToolingConfig::getConfig().getValidatingParser().parse(dsrc);
333 doc=XMLToolingConfig::getConfig().getParser().parse(dsrc);
335 // Check for a response code signal.
336 if (XMLHelper::isNodeNamed(doc->getDocumentElement(), xmlconstants::XMLTOOLING_NS, URLInputSource::utf16StatusCodeElementName)) {
337 int responseCode = XMLString::parseInt(doc->getDocumentElement()->getFirstChild()->getNodeValue());
339 if (responseCode == HTTPResponse::XMLTOOLING_HTTP_STATUS_NOTMODIFIED) {
340 throw (long)responseCode; // toss out as a "known" case to handle gracefully
343 m_log.warn("remote resource fetch returned atypical status code (%d)", responseCode);
344 throw IOException("remote resource fetch failed, check log for status code of response");
349 m_log.infoStream() << "loaded XML resource (" << (backup ? m_backing : m_source) << ")" << logging::eol;
351 if (!backup && !m_backing.empty()) {
352 // If the indicator is true, we're responsible for the backup.
353 if (m_backupIndicator) {
354 m_log.debug("backing up remote resource to (%s)", m_backing.c_str());
356 Locker locker(getBackupLock());
357 ofstream backer(m_backing.c_str());
360 catch (exception& ex) {
361 m_log.crit("exception while backing up resource: %s", ex.what());
365 // If the indicator was false, set true to signal that a backup is needed.
366 // The caller will presumably flip it back to false once that's done.
367 m_backupIndicator = true;
371 return make_pair(true, doc->getDocumentElement());
374 catch (XMLException& e) {
375 auto_ptr_char msg(e.getMessage());
376 m_log.errorStream() << "Xerces error while loading resource (" << (backup ? m_backing : m_source) << "): "
377 << msg.get() << logging::eol;
378 if (!backup && !m_backing.empty())
380 throw XMLParserException(msg.get());
382 catch (exception& e) {
383 m_log.errorStream() << "error while loading resource ("
384 << (m_source.empty() ? "inline" : (backup ? m_backing : m_source)) << "): " << e.what() << logging::eol;
385 if (!backup && !m_backing.empty())
391 pair<bool,DOMElement*> ReloadableXMLFile::load()
396 pair<bool,DOMElement*> ReloadableXMLFile::background_load()
398 // If this method isn't overridden, we acquire a write lock
399 // and just call the old override.
402 SharedLock locker(m_lock, false);
406 Lockable* ReloadableXMLFile::getBackupLock()
408 return &XMLToolingConfig::getConfig();