SPDY: Use keep-alive connection to downstream server

examples/shrpx_client_handler.cc

@@ -66,7 +66,7 @@ void upstream_eventcb(bufferevent *bev, short events, void *arg)
   bool finish = false;
   if(events & BEV_EVENT_EOF) {
     if(ENABLE_LOG) {
-      LOG(INFO) << "Upstream handshake EOF";
+      LOG(INFO) << "Upstream EOF";
     }
     finish = true;
   }

examples/shrpx_downstream.cc

@@ -117,6 +117,10 @@ void Downstream::idle()
   chunked_response_ = false;
   response_connection_close_ = false;
   response_headers_.clear();
+  if(response_body_buf_) {
+    size_t len = evbuffer_get_length(response_body_buf_);
+    evbuffer_drain(response_body_buf_, len);
+  }
 }
 
 void Downstream::pause_read(IOCtrlReason reason)
@@ -543,4 +547,9 @@ evbuffer* Downstream::get_response_body_buf()
   return response_body_buf_;
 }
 
+void Downstream::set_priority(int pri)
+{
+  priority_ = pri;
+}
+
 } // namespace shrpx

examples/shrpx_downstream.h

@@ -54,6 +54,7 @@ public:
   int start_connection();
   Upstream* get_upstream() const;
   int32_t get_stream_id() const;
+  void set_priority(int pri);
   void pause_read(IOCtrlReason reason);
   bool resume_read(IOCtrlReason reason);
   void force_resume_read();

examples/shrpx_downstream_queue.cc

@@ -24,6 +24,8 @@
  */
 #include "shrpx_downstream_queue.h"
 
+#include <cassert>
+
 #include "shrpx_downstream.h"
 
 namespace shrpx {
@@ -37,6 +39,10 @@ DownstreamQueue::~DownstreamQueue()
       i != downstreams_.end(); ++i) {
     delete (*i).second;
   }
+  for(std::set<Downstream*>::iterator i = idle_downstreams_.begin();
+      i != idle_downstreams_.end(); ++i) {
+    delete *i;
+  }
 }
 
 void DownstreamQueue::add(Downstream *downstream)
@@ -51,8 +57,12 @@ int DownstreamQueue::start(Downstream *downstream)
 
 void DownstreamQueue::remove(Downstream *downstream)
 {
+  if(downstream->get_request_state() == Downstream::IDLE) {
+    idle_downstreams_.erase(downstream);
+  } else {
     downstreams_.erase(downstream->get_stream_id());
   }
+}
 
 Downstream* DownstreamQueue::find(int32_t stream_id)
 {
@@ -64,4 +74,24 @@ Downstream* DownstreamQueue::find(int32_t stream_id)
   }
 }
 
+Downstream* DownstreamQueue::reuse(int32_t stream_id)
+{
+  if(idle_downstreams_.empty()) {
+    return 0;
+  }
+  Downstream* downstream = *idle_downstreams_.begin();
+  idle_downstreams_.erase(downstream);
+  downstream->reuse(stream_id);
+  add(downstream);
+  return downstream;
+}
+
+void DownstreamQueue::idle(Downstream *downstream)
+{
+  assert(downstream->get_request_state() != Downstream::IDLE);
+  remove(downstream);
+  downstream->idle();
+  idle_downstreams_.insert(downstream);
+}
+
 } // namespace shrpx

examples/shrpx_downstream_queue.h

@@ -30,6 +30,7 @@
 #include <stdint.h>
 
 #include <map>
+#include <set>
 
 namespace shrpx {
 
@@ -43,8 +44,11 @@ public:
   int start(Downstream *downstream);
   void remove(Downstream *downstream);
   Downstream* find(int32_t stream_id);
+  Downstream* reuse(int32_t stream_id);
+  void idle(Downstream *downstream);
 private:
   std::map<int32_t, Downstream*> downstreams_;
+  std::set<Downstream*> idle_downstreams_;
 };
 
 } // namespace shrpx

examples/shrpx_https_upstream.cc

@@ -79,8 +79,14 @@ int htp_msg_begin(htparser *htp)
   Downstream *downstream = upstream->get_top_downstream();
   if(downstream) {
     // Keep-Alived connection
+    if(ENABLE_LOG) {
+      LOG(INFO) << "Reusing downstream";
+    }
     downstream->reuse(0);
   } else {
+    if(ENABLE_LOG) {
+      LOG(INFO) << "Creating new downstream";
+    }
     downstream = new Downstream(upstream, 0, 0);
     upstream->add_downstream(downstream);
   }

examples/shrpx_spdy_upstream.cc

@@ -93,16 +93,15 @@ void on_stream_close_callback
     LOG(INFO) << "Upstream spdy Stream " << stream_id << " is being closed";
   }
   SpdyUpstream *upstream = reinterpret_cast<SpdyUpstream*>(user_data);
-  Downstream *downstream = upstream->get_downstream_queue()->find(stream_id);
+  Downstream *downstream = upstream->find_downstream(stream_id);
   if(downstream) {
     if(downstream->get_request_state() == Downstream::CONNECT_FAIL) {
-      upstream->get_downstream_queue()->remove(downstream);
+      upstream->remove_downstream(downstream);
       delete downstream;
     } else {
       downstream->set_request_state(Downstream::STREAM_CLOSED);
       if(downstream->get_response_state() == Downstream::MSG_COMPLETE) {
-        upstream->get_downstream_queue()->remove(downstream);
+        upstream->remove_or_idle_downstream(downstream);
-        delete downstream;
       } else {
         // At this point, downstream read may be paused. To reclaim
         // file descriptor, enable read here and catch read
@@ -126,9 +125,23 @@ void on_ctrl_recv_callback
       LOG(INFO) << "Upstream spdy received upstream SYN_STREAM stream_id="
                 << frame->syn_stream.stream_id;
     }
-    Downstream *downstream = new Downstream(upstream,
+    Downstream *downstream;
+    downstream = upstream->reuse_downstream(frame->syn_stream.stream_id);
+    if(downstream) {
+      if(ENABLE_LOG) {
+        LOG(INFO) << "Reusing downstream for stream_id="
+                  << frame->syn_stream.stream_id;
+      }
+      downstream->set_priority(frame->syn_stream.pri);
+    } else {
+      if(ENABLE_LOG) {
+        LOG(INFO) << "Creating new downstream for stream_id="
+                  << frame->syn_stream.stream_id;
+      }
+      downstream = new Downstream(upstream,
                                   frame->syn_stream.stream_id,
                                   frame->syn_stream.pri);
+    }
     downstream->init_response_body_buf();
 
     char **nv = frame->syn_stream.nv;
@@ -161,12 +174,14 @@ void on_ctrl_recv_callback
       }
       downstream->set_request_state(Downstream::MSG_COMPLETE);
     }
+    if(downstream->get_counter() == 1) {
       upstream->add_downstream(downstream);
       if(upstream->start_downstream(downstream) != 0) {
         // If downstream connection fails, issue RST_STREAM.
         upstream->rst_stream(downstream, SPDYLAY_INTERNAL_ERROR);
         downstream->set_request_state(Downstream::CONNECT_FAIL);
       }
+    }
     break;
   }
   default:
@@ -186,7 +201,7 @@ void on_data_chunk_recv_callback(spdylay_session *session,
               << stream_id;
   }
   SpdyUpstream *upstream = reinterpret_cast<SpdyUpstream*>(user_data);
-  Downstream *downstream = upstream->get_downstream_queue()->find(stream_id);
+  Downstream *downstream = upstream->find_downstream(stream_id);
   if(downstream) {
     downstream->push_upload_data_chunk(data, len);
     if(flags & SPDYLAY_DATA_FLAG_FIN) {
@@ -285,6 +300,11 @@ void spdy_downstream_readcb(bufferevent *bev, void *ptr)
   Downstream *downstream = reinterpret_cast<Downstream*>(ptr);
   SpdyUpstream *upstream;
   upstream = static_cast<SpdyUpstream*>(downstream->get_upstream());
+  if(downstream->get_request_state() == Downstream::IDLE) {
+    upstream->remove_downstream(downstream);
+    delete downstream;
+    return;
+  }
   // If upstream SPDY stream was closed, we just close downstream,
   // because there is no consumer now.
   if(downstream->get_request_state() == Downstream::STREAM_CLOSED) {
@@ -320,13 +340,20 @@ void spdy_downstream_eventcb(bufferevent *bev, short events, void *ptr)
   Downstream *downstream = reinterpret_cast<Downstream*>(ptr);
   SpdyUpstream *upstream;
   upstream = static_cast<SpdyUpstream*>(downstream->get_upstream());
+  if(downstream->get_request_state() == Downstream::IDLE) {
+    if(ENABLE_LOG) {
+      LOG(INFO) << "Delete idle downstream in spdy_downstream_eventcb";
+    }
+    upstream->remove_downstream(downstream);
+    delete downstream;
+    return;
+  }
   if(events & BEV_EVENT_CONNECTED) {
     if(ENABLE_LOG) {
       LOG(INFO) << "Downstream connection established. Downstream "
                 << downstream;
     }
-  }
+  } else if(events & BEV_EVENT_EOF) {
-  if(events & BEV_EVENT_EOF) {
     if(ENABLE_LOG) {
       LOG(INFO) << "Downstream EOF stream_id="
                 << downstream->get_stream_id();
@@ -479,6 +506,26 @@ void SpdyUpstream::remove_downstream(Downstream *downstream)
   downstream_queue_.remove(downstream);
 }
 
+Downstream* SpdyUpstream::find_downstream(int32_t stream_id)
+{
+  return downstream_queue_.find(stream_id);
+}
+
+Downstream* SpdyUpstream::reuse_downstream(int32_t stream_id)
+{
+  return downstream_queue_.reuse(stream_id);
+}
+
+void SpdyUpstream::remove_or_idle_downstream(Downstream *downstream)
+{
+  if(downstream->get_response_connection_close()) {
+    downstream_queue_.remove(downstream);
+    delete downstream;
+  } else {
+    downstream_queue_.idle(downstream);
+  }
+}
+
 spdylay_session* SpdyUpstream::get_spdy_session()
 {
   return session_;
@@ -564,9 +611,4 @@ int SpdyUpstream::on_downstream_body_complete(Downstream *downstream)
   return 0;
 }
 
-DownstreamQueue* SpdyUpstream::get_downstream_queue()
-{
-  return &downstream_queue_;
-}
-
 } // namespace shrpx

examples/shrpx_spdy_upstream.h

@@ -51,8 +51,11 @@ public:
   void add_downstream(Downstream *downstream);
   void remove_downstream(Downstream *downstream);
   int start_downstream(Downstream *downstream);
+  Downstream* find_downstream(int32_t stream_id);
+  Downstream* reuse_downstream(int32_t stream_id);
+  void remove_or_idle_downstream(Downstream *downstream);
+
   spdylay_session* get_spdy_session();
-  DownstreamQueue* get_downstream_queue();
 
   int rst_stream(Downstream *downstream, int status_code);
   int error_reply(Downstream *downstream, int status_code);