src/filter_load_balance.cpp

   1 /* $Id: filter_load_balance.cpp,v 1.1 2007-01-02 15:35:36 marc Exp $
   2    Copyright (c) 2005-2006, Index Data.
   3
   4    See the LICENSE file for details
   5  */
   6
   7 #include "config.hpp"
   8 #include "filter.hpp"
   9 #include "filter_load_balance.hpp"
  10 #include "package.hpp"
  11 #include "util.hpp"
  12
  13 #include <boost/thread/mutex.hpp>
  14 #include <boost/date_time/posix_time/posix_time.hpp>
  15
  16 #include <yaz/zgdu.h>
  17
  18 #include <iostream>
  19
  20 namespace mp = metaproxy_1;
  21 namespace yf = mp::filter;
  22
  23 namespace metaproxy_1 {
  24     namespace filter {
  25         class LoadBalance::Impl {
  26         public:
  27             Impl();
  28             ~Impl();
  29             void process(metaproxy_1::Package & package);
  30             void configure(const xmlNode * ptr);
  31         private:
  32             boost::mutex m_mutex;
  33         };
  34     }
  35 }
  36
  37 // define Pimpl wrapper forwarding to Impl
  38
  39 yf::LoadBalance::LoadBalance() : m_p(new Impl)
  40 {
  41 }
  42
  43 yf::LoadBalance::~LoadBalance()
  44 {  // must have a destructor because of boost::scoped_ptr
  45 }
  46
  47 void yf::LoadBalance::configure(const xmlNode *xmlnode)
  48 {
  49     m_p->configure(xmlnode);
  50 }
  51
  52 void yf::LoadBalance::process(mp::Package &package) const
  53 {
  54     m_p->process(package);
  55 }
  56
  57
  58 // define Implementation stuff
  59
  60
  61
  62 yf::LoadBalance::Impl::Impl()
  63 {
  64 }
  65
  66 yf::LoadBalance::Impl::~Impl()
  67 {
  68 }
  69
  70 void yf::LoadBalance::Impl::configure(const xmlNode *xmlnode)
  71 {
  72 }
  73
  74 void yf::LoadBalance::Impl::process(mp::Package &package)
  75 {
  76     Z_GDU *gdu_req = package.request().get();
  77
  78
  79     // passing anything but z3950 packages
  80     if (!gdu_req
  81         || !(gdu_req->which == Z_GDU_Z3950))
  82     {
  83         package.move();
  84         return;
  85     }
  86
  87
  88     // target selecting only on Z39.50 init request
  89     if (gdu_req->u.z3950->which == Z_APDU_initRequest){
  90
  91         mp::odr odr_en(ODR_ENCODE);
  92         Z_InitRequest *org_init = gdu_req->u.z3950->u.initRequest;
  93
  94         // extracting virtual hosts
  95         std::list<std::string> vhosts;
  96
  97         mp::util::remove_vhost_otherinfo(&(org_init->otherInfo), vhosts);
  98
  99         //std::cout << "LoadBalance::Impl::process() vhosts: "
 100         //          << vhosts.size()  << "\n";
 101         //std::cout << "LoadBalance::Impl::process()" << *gdu_req << "\n";
 102
 103         // choosing one target according to load-balancing algorithm
 104
 105         if (vhosts.size()){
 106             std::string target;
 107
 108             // getting timestamp for receiving of package
 109             boost::posix_time::ptime receive_time
 110                 = boost::posix_time::microsec_clock::local_time();
 111
 112             // //<< receive_time << " "
 113             // //<< to_iso_string(receive_time) << " "
 114             //<< to_iso_extended_string(receive_time) << " "
 115             // package.session().id();
 116
 117             { // scope for locking local target database
 118                 boost::mutex::scoped_lock scoped_lock(m_mutex);
 119                 target = *vhosts.begin();
 120             }
 121
 122
 123             // copying new target into init package
 124             mp::util::set_vhost_otherinfo(&(org_init->otherInfo), odr_en, target);
 125             package.request() = gdu_req;
 126         }
 127
 128     }
 129
 130
 131     // moving all Z39.50 package typess
 132     package.move();
 133
 134
 135
 136     //boost::posix_time::ptime send_time
 137     //    = boost::posix_time::microsec_clock::local_time();
 138
 139     //boost::posix_time::time_duration duration = send_time - receive_time;
 140
 141
 142     //    { // scope for locking local target database
 143     //        boost::mutex::scoped_lock scoped_lock(m_mutex);
 144     //        target = *vhosts.begin();
 145     //    }
 146
 147
 148 }
 149
 150
 151 static mp::filter::Base* filter_creator()
 152 {
 153     return new mp::filter::LoadBalance;
 154 }
 155
 156 extern "C" {
 157     struct metaproxy_1_filter_struct metaproxy_1_filter_load_balance = {
 158         0,
 159         "load_balance",
 160         filter_creator
 161     };
 162 }
 163
 164
 165 /*
 166  * Local variables:
 167  * c-basic-offset: 4
 168  * indent-tabs-mode: nil
 169  * c-file-style: "stroustrup"
 170  * End:
 171  * vim: shiftwidth=4 tabstop=8 expandtab
 172  */