1 /* This file is part of Metaproxy.
2 Copyright (C) 2005-2009 Index Data
4 Metaproxy is free software; you can redistribute it and/or modify it under
5 the terms of the GNU General Public License as published by the Free
6 Software Foundation; either version 2, or (at your option) any later
9 Metaproxy is distributed in the hope that it will be useful, but WITHOUT ANY
10 WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
14 You should have received a copy of the GNU General Public License
15 along with this program; if not, write to the Free Software
16 Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
20 #include "session.hpp"
21 #include "package.hpp"
23 #include "filter_load_balance.hpp"
27 #include <boost/thread/mutex.hpp>
31 // remove max macro if already defined (defined later in <limits>)
41 namespace mp = metaproxy_1;
42 namespace yf = mp::filter;
48 class LoadBalance::Impl
53 void process(metaproxy_1::Package & package);
54 void configure(const xmlNode * ptr);
56 // statistic manipulating functions,
57 void add_dead(unsigned long session_id);
58 //void clear_dead(unsigned long session_id);
59 void add_package(unsigned long session_id);
60 void remove_package(unsigned long session_id);
61 void add_session(unsigned long session_id, std::string target);
62 void remove_session(unsigned long session_id);
63 std::string find_session_target(unsigned long session_id);
66 unsigned int cost(std::string target);
67 unsigned int dead(std::string target);
72 unsigned int sessions;
73 unsigned int packages;
76 unsigned int c = sessions + packages + deads;
77 //std::cout << "stats c:" << c
78 // << " s:" << sessions
79 // << " p:" << packages
86 // local protected databases
88 std::map<std::string, TargetStat> m_target_stat;
89 std::map<unsigned long, std::string> m_session_target;
94 // define Pimpl wrapper forwarding to Impl
96 yf::LoadBalance::LoadBalance() : m_p(new Impl)
100 yf::LoadBalance::~LoadBalance()
101 { // must have a destructor because of boost::scoped_ptr
104 void yf::LoadBalance::configure(const xmlNode *xmlnode, bool test_only)
106 m_p->configure(xmlnode);
109 void yf::LoadBalance::process(mp::Package &package) const
111 m_p->process(package);
115 yf::LoadBalance::Impl::Impl()
119 yf::LoadBalance::Impl::~Impl()
123 void yf::LoadBalance::Impl::configure(const xmlNode *xmlnode)
127 void yf::LoadBalance::Impl::process(mp::Package &package)
130 bool is_closed_front = false;
131 bool is_closed_back = false;
133 // checking for closed front end packages
134 if (package.session().is_closed())
136 is_closed_front = true;
139 Z_GDU *gdu_req = package.request().get();
141 // passing anything but z3950 packages
142 if (gdu_req && gdu_req->which == Z_GDU_Z3950)
144 // target selecting only on Z39.50 init request
145 if (gdu_req->u.z3950->which == Z_APDU_initRequest)
147 mp::odr odr_en(ODR_ENCODE);
148 Z_InitRequest *org_init = gdu_req->u.z3950->u.initRequest;
150 // extracting virtual hosts
151 std::list<std::string> vhosts;
153 mp::util::remove_vhost_otherinfo(&(org_init->otherInfo), vhosts);
155 // choosing one target according to load-balancing algorithm
160 unsigned int cost = std::numeric_limits<unsigned int>::max();
161 { //locking scope for local databases
162 boost::mutex::scoped_lock scoped_lock(m_mutex);
164 // load-balancing algorithm goes here
165 //target = *vhosts.begin();
166 for (std::list<std::string>::const_iterator ivh
171 if ((*ivh).size() != 0)
174 = yf::LoadBalance::Impl::cost(*ivh);
183 // updating local database
184 add_session(package.session().id(), target);
185 yf::LoadBalance::Impl::cost(target);
186 add_package(package.session().id());
189 // copying new target into init package
190 mp::util::set_vhost_otherinfo(&(org_init->otherInfo),
192 package.request() = gdu_req;
195 // frontend Z39.50 close request is added to statistics and marked
196 else if (gdu_req->u.z3950->which == Z_APDU_close)
198 is_closed_front = true;
199 boost::mutex::scoped_lock scoped_lock(m_mutex);
200 add_package(package.session().id());
202 // any other Z39.50 package is added to statistics
205 boost::mutex::scoped_lock scoped_lock(m_mutex);
206 add_package(package.session().id());
210 // moving all package types
213 // checking for closed back end packages
214 if (package.session().is_closed())
215 is_closed_back = true;
217 Z_GDU *gdu_res = package.response().get();
219 // passing anything but z3950 packages
220 if (gdu_res && gdu_res->which == Z_GDU_Z3950)
222 // session closing only on Z39.50 close response
223 if (gdu_res->u.z3950->which == Z_APDU_close)
225 is_closed_back = true;
226 boost::mutex::scoped_lock scoped_lock(m_mutex);
227 remove_package(package.session().id());
229 // any other Z39.50 package is removed from statistics
232 boost::mutex::scoped_lock scoped_lock(m_mutex);
233 remove_package(package.session().id());
237 // finally removing sessions and marking deads
238 if (is_closed_back || is_closed_front)
240 boost::mutex::scoped_lock scoped_lock(m_mutex);
242 // marking backend dead if backend closed without fronted close
243 if (is_closed_front == false)
244 add_dead(package.session().id());
246 remove_session(package.session().id());
248 // making sure that package is closed
249 package.session().close();
253 // statistic manipulating functions,
254 void yf::LoadBalance::Impl::add_dead(unsigned long session_id)
256 std::string target = find_session_target(session_id);
258 if (target.size() != 0)
260 std::map<std::string, TargetStat>::iterator itarg;
261 itarg = m_target_stat.find(target);
262 if (itarg != m_target_stat.end()
263 && itarg->second.deads < std::numeric_limits<unsigned int>::max())
265 itarg->second.deads += 1;
266 // std:.cout << "add_dead " << session_id << " " << target
267 // << " d:" << itarg->second.deads << "\n";
272 //void yf::LoadBalance::Impl::clear_dead(unsigned long session_id){
273 // std::cout << "clear_dead " << session_id << "\n";
276 void yf::LoadBalance::Impl::add_package(unsigned long session_id)
278 std::string target = find_session_target(session_id);
280 if (target.size() != 0)
282 std::map<std::string, TargetStat>::iterator itarg;
283 itarg = m_target_stat.find(target);
284 if (itarg != m_target_stat.end()
285 && itarg->second.packages
286 < std::numeric_limits<unsigned int>::max())
288 itarg->second.packages += 1;
289 // std:.cout << "add_package " << session_id << " " << target
290 // << " p:" << itarg->second.packages << "\n";
295 void yf::LoadBalance::Impl::remove_package(unsigned long session_id)
297 std::string target = find_session_target(session_id);
299 if (target.size() != 0)
301 std::map<std::string, TargetStat>::iterator itarg;
302 itarg = m_target_stat.find(target);
303 if (itarg != m_target_stat.end()
304 && itarg->second.packages > 0)
306 itarg->second.packages -= 1;
307 // std:.cout << "remove_package " << session_id << " " << target
308 // << " p:" << itarg->second.packages << "\n";
313 void yf::LoadBalance::Impl::add_session(unsigned long session_id,
316 // finding and adding session
317 std::map<unsigned long, std::string>::iterator isess;
318 isess = m_session_target.find(session_id);
319 if (isess == m_session_target.end())
321 m_session_target.insert(std::make_pair(session_id, target));
324 // finding and adding target statistics
325 std::map<std::string, TargetStat>::iterator itarg;
326 itarg = m_target_stat.find(target);
327 if (itarg == m_target_stat.end())
331 stat.packages = 0; // no idea why the defaut constructor TargetStat()
332 stat.deads = 0; // is not initializig this correctly to zero ??
333 m_target_stat.insert(std::make_pair(target, stat));
334 // std:.cout << "add_session " << session_id << " " << target
337 else if (itarg->second.sessions < std::numeric_limits<unsigned int>::max())
339 itarg->second.sessions += 1;
340 // std:.cout << "add_session " << session_id << " " << target
341 // << " s:" << itarg->second.sessions << "\n";
345 void yf::LoadBalance::Impl::remove_session(unsigned long session_id)
350 std::map<unsigned long, std::string>::iterator isess;
351 isess = m_session_target.find(session_id);
352 if (isess == m_session_target.end())
355 target = isess->second;
357 // finding target statistics
358 std::map<std::string, TargetStat>::iterator itarg;
359 itarg = m_target_stat.find(target);
360 if (itarg == m_target_stat.end())
362 m_session_target.erase(isess);
366 // counting session down
367 if (itarg->second.sessions > 0)
368 itarg->second.sessions -= 1;
370 // std:.cout << "remove_session " << session_id << " " << target
371 // << " s:" << itarg->second.sessions << "\n";
373 // clearing empty sessions and targets
374 if (itarg->second.sessions == 0 && itarg->second.deads == 0)
376 m_target_stat.erase(itarg);
377 m_session_target.erase(isess);
381 std::string yf::LoadBalance::Impl::find_session_target(unsigned long session_id)
384 std::map<unsigned long, std::string>::iterator isess;
385 isess = m_session_target.find(session_id);
386 if (isess != m_session_target.end())
387 target = isess->second;
393 unsigned int yf::LoadBalance::Impl::cost(std::string target)
395 unsigned int cost = 0;
397 if (target.size() != 0)
399 std::map<std::string, TargetStat>::iterator itarg;
400 itarg = m_target_stat.find(target);
401 if (itarg != m_target_stat.end())
402 cost = itarg->second.cost();
405 //std::cout << "cost " << target << " c:" << cost << "\n";
409 unsigned int yf::LoadBalance::Impl::dead(std::string target)
411 unsigned int dead = 0;
413 if (target.size() != 0)
415 std::map<std::string, TargetStat>::iterator itarg;
416 itarg = m_target_stat.find(target);
417 if (itarg != m_target_stat.end())
418 dead = itarg->second.deads;
421 //std::cout << "dead " << target << " d:" << dead << "\n";
426 static mp::filter::Base* filter_creator()
428 return new mp::filter::LoadBalance;
432 struct metaproxy_1_filter_struct metaproxy_1_filter_load_balance = {
443 * c-file-style: "Stroustrup"
444 * indent-tabs-mode: nil
446 * vim: shiftwidth=4 tabstop=8 expandtab