http: don't re-use connections when slots are full

theuni · theuni · commit 3b0ebb3578e8 · 2018-01-25T23:06:57.000-05:00
If we're unable to service a request, close the connection rather than
potentially keeping it alive longer. This helps to be slightly more fair to new
connections.
diff --git a/src/httpserver.cpp b/src/httpserver.cpp
@@ -313,6 +313,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
         bev = evhttp_connection_get_bufferevent(conn);
     }
     if (!bev) {
+        hreq->WriteHeader("Connection", "close");
         hreq->WriteReplyImmediate(HTTP_INTERNAL, "Unknown error\n");
         return;
     }
@@ -321,6 +322,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
     evhttp_connection_set_closecb(conn, connection_close_cb, limiter);
     limiter->AddConnection(bufferevent_getfd(bev));
     if (!limiter->IsReady()) {
+        hreq->WriteHeader("Connection", "close");
         hreq->WriteReplyImmediate(HTTP_SERVUNAVAIL, "No connection slots available\n");
         return;
     }
@@ -366,6 +368,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)
             item.release(); /* if true, queue took ownership */
         } else {
             LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");
+            item->req->WriteHeader("Connection", "close");
             item->req->WriteReplyImmediate(HTTP_INTERNAL, "Work queue depth exceeded");
         }
     } else {

Original file line number	Diff line number	Diff line change
`@@ -313,6 +313,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)`
`313`	`313`	`bev = evhttp_connection_get_bufferevent(conn);`
`314`	`314`	`}`
`315`	`315`	`if (!bev) {`
	`316`	`+ hreq->WriteHeader("Connection", "close");`
`316`	`317`	`hreq->WriteReplyImmediate(HTTP_INTERNAL, "Unknown error\n");`
`317`	`318`	`return;`
`318`	`319`	`}`
`@@ -321,6 +322,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)`
`321`	`322`	`evhttp_connection_set_closecb(conn, connection_close_cb, limiter);`
`322`	`323`	`limiter->AddConnection(bufferevent_getfd(bev));`
`323`	`324`	`if (!limiter->IsReady()) {`
	`325`	`+ hreq->WriteHeader("Connection", "close");`
`324`	`326`	`hreq->WriteReplyImmediate(HTTP_SERVUNAVAIL, "No connection slots available\n");`
`325`	`327`	`return;`
`326`	`328`	`}`
`@@ -366,6 +368,7 @@ static void http_request_cb(struct evhttp_request* req, void* arg)`
`366`	`368`	`item.release(); /* if true, queue took ownership */`
`367`	`369`	`} else {`
`368`	`370`	`LogPrintf("WARNING: request rejected because http work queue depth exceeded, it can be increased with the -rpcworkqueue= setting\n");`
	`371`	`+ item->req->WriteHeader("Connection", "close");`
`369`	`372`	`item->req->WriteReplyImmediate(HTTP_INTERNAL, "Work queue depth exceeded");`
`370`	`373`	`}`
`371`	`374`	`} else {`