Attempt to fix leaking conns

src/github.com/getlantern/flashlight/client/chained.go

@@ -15,9 +15,10 @@ import (
 )
 
 // Close connections idle for a period to avoid dangling connections.
-// 1 hour is long enough to avoid interrupt normal connections but short enough
-// to eliminate "too many open files" error.
-var idleTimeout = 1 * time.Hour
+// 45 seconds is long enough to avoid interrupt normal connections but shor
+// shorter than the server-side timeout and short enough to eliminate
+// "too many open files" error.
+var idleTimeout = 45 * time.Second
 
 // Lantern internal sites won't be used as check target.
 var internalSiteSuffixes = []string{"getlantern.org", "getiantem.org", "lantern.io"}

src/github.com/getlantern/flashlight/client/handler.go

@@ -114,22 +114,20 @@ func (client *Client) intercept(resp http.ResponseWriter, req *http.Request, op
 // pipeData pipes data between the client and proxy connections.  It's also
 // responsible for responding to the initial CONNECT request with a 200 OK.
 func pipeData(clientConn net.Conn, connOut net.Conn, op *ops.Op, closeFunc func()) {
-	writeErrCh := make(chan error)
+	writeErrCh := make(chan error, 1)
 	// Start piping from client to proxy
 	op.Go(func() {
 		_, writeErr := io.Copy(connOut, clientConn)
-		if writeErr != nil {
-			writeErrCh <- writeErr
-		}
+		writeErrCh <- writeErr
 	})
 
 	// Then start copying from proxy to client.
 	_, readErr := io.Copy(clientConn, connOut)
 	writeErr := <-writeErrCh
 	if readErr != nil {
-		op.FailIf(log.Errorf("Error piping data from proxy to client: %v", readErr))
+		log.Tracef("Error piping data from proxy to client: %v", readErr)
 	} else if writeErr != nil {
-		log.Error(errors.New("Error piping data from client to proxy: %v", writeErr))
+		log.Tracef("Error piping data from client to proxy: %v", writeErr)
 	}
 
 	closeFunc()

src/github.com/getlantern/flashlight/client/reverseproxy.go

@@ -18,7 +18,9 @@ import (
 func (client *Client) newReverseProxy(bal *balancer.Balancer) *httputil.ReverseProxy {
 	transport := &http.Transport{
 		TLSHandshakeTimeout: 40 * time.Second,
+		MaxIdleTime:         30 * time.Second,
 	}
+	transport.EnforceMaxIdleTime()
 
 	// TODO: would be good to make this sensitive to QOS, which
 	// right now is only respected for HTTPS connections. The

src/github.com/getlantern/flashlight/proxied/proxied.go

@@ -395,6 +395,10 @@ func chained(rootCA string, persistent bool) (http.RoundTripper, error) {
 		}
 		tr.TLSClientConfig.RootCAs = caCert.PoolContainingCert()
 	}
+	if persistent {
+		tr.MaxIdleTime = 30 * time.Second
+		tr.EnforceMaxIdleTime()
+	}
 
 	tr.Proxy = func(req *http.Request) (*url.URL, error) {
 		proxyAddr, ok := getProxyAddr()