git.m6w6.name Git - awesomized/libmemcached/blob - testing/lib/Cluster.cpp

   1 #include "Cluster.hpp"
   2 #include "Retry.hpp"
   3
   4 #include <sys/wait.h>
   5
   6 Cluster::Cluster(Server serv, uint16_t cnt)
   7 : count{cnt}
   8 , proto{move(serv)}
   9 {
  10   if (!cnt) {
  11     count = thread::hardware_concurrency()/2 ?: 4;
  12   }
  13   reset();
  14 }
  15
  16 Cluster::~Cluster() {
  17   stop();
  18   wait();
  19 }
  20
  21 const vector<Server> &Cluster::getServers() const {
  22   return cluster;
  23 }
  24
  25 void Cluster::reset() {
  26   pids.clear();
  27   cluster.clear();
  28   for (int i = 0; i < count; ++i) {
  29     cluster.push_back(proto);
  30   }
  31 }
  32
  33 bool Cluster::start() {
  34   bool started = true;
  35
  36   for (auto &server : cluster) {
  37     if (!startServer(server)) {
  38       started = false;
  39     }
  40   }
  41
  42   return started;
  43 }
  44
  45 void Cluster::stop() {
  46   for (auto &server : cluster) {
  47     // no cookies for memcached; TERM is just too slow
  48     server.signal(SIGKILL);
  49   }
  50 }
  51
  52 bool Cluster::isStopped() {
  53   for (auto &server : cluster) {
  54     if (server.getPid() && !server.tryWait()) {
  55       return false;
  56     }
  57   }
  58   return true;
  59 }
  60
  61 bool Cluster::isListening() {
  62   for (auto &server : cluster) {
  63     Retry server_is_listening{[&] {
  64       if (!server.isListening()) {
  65         // zombie?
  66         auto old_pid = server.getPid();
  67         if (server.tryWait()) {
  68           cerr << "zombie collected (old pid=" << old_pid << "): " << server << "\n";
  69           pids.erase(old_pid);
  70           // restart
  71           startServer(server);
  72         }
  73         if (!server.isListening()) {
  74           return false;
  75         }
  76       }
  77       return true;
  78     }};
  79     if (!server_is_listening()) {
  80       return false;
  81     }
  82   }
  83
  84   return true;
  85 }
  86
  87 bool Cluster::startServer(Server &server) {
  88   auto pid = server.start();
  89   if (pid.has_value()) {
  90     pids[*pid] = &server;
  91     return true;
  92   }
  93   return false;
  94 }
  95
  96 void Cluster::wait() {
  97   siginfo_t inf;
  98
  99   while (!isStopped()) {
 100     if (waitid(P_ALL, 0, &inf, WEXITED | WNOWAIT)) {
 101       perror("Cluster::wait waitid()");
 102       return;
 103     }
 104
 105     auto server = pids.find(inf.si_pid);
 106     if (server != pids.end()) {
 107       server->second->wait();
 108     }
 109   }
 110 }