getlantern/lantern#2196 Added support for MinQOS configuration

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

@@ -31,6 +31,9 @@ type Client struct {
 	// WriteTimeout: (optional) timeout for write ops
 	WriteTimeout time.Duration
 
+	// MinQOS: (optional) the minimum QOS to require from proxies.
+	MinQOS int
+
 	priorCfg        *ClientConfig
 	priorTrustedCAs *x509.CertPool
 	cfgMutex        sync.RWMutex
@@ -73,6 +76,8 @@ func (client *Client) Configure(cfg *ClientConfig) {
 		log.Debugf("Client configuration initialized")
 	}
 
+	log.Debugf("Requiring minimum QOS of %d", cfg.MinQOS)
+	client.MinQOS = cfg.MinQOS
 	bal := client.initBalancer(cfg)
 	client.initReverseProxy(bal, cfg.DumpHeaders)
 	client.initNatty(cfg)

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

@@ -14,6 +14,7 @@ var (
 
 // ClientConfig captures configuration information for a Client
 type ClientConfig struct {
+	MinQOS         int
 	DumpHeaders    bool // whether or not to dump headers of requests and responses
 	FrontedServers []*FrontedServerInfo
 	ChainedServers map[string]*ChainedServerInfo

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

@@ -43,7 +43,7 @@ func (client *Client) intercept(resp http.ResponseWriter, req *http.Request) {
 	addr := hostIncludingPort(req, 443)
 
 	// Establish outbound connection
-	connOut, err := client.getBalancer().DialQOS("tcp", addr, targetQOS(req))
+	connOut, err := client.getBalancer().DialQOS("tcp", addr, client.targetQOS(req))
 	if err != nil {
 		respondBadGateway(clientConn, fmt.Sprintf("Unable to handle CONNECT request: %s", err))
 		return
@@ -55,8 +55,8 @@ func (client *Client) intercept(resp http.ResponseWriter, req *http.Request) {
 }
 
 // targetQOS determines the target quality of service given the X-Flashlight-QOS
-// header if available, else returns 0.
-func targetQOS(req *http.Request) int {
+// header if available, else returns MinQOS.
+func (client *Client) targetQOS(req *http.Request) int {
 	requestedQOS := req.Header.Get(XFlashlightQOS)
 	if requestedQOS != "" {
 		rqos, err := strconv.Atoi(requestedQOS)
@@ -65,7 +65,7 @@ func targetQOS(req *http.Request) int {
 		}
 	}
 
-	return 0
+	return client.MinQOS
 }
 
 // pipeData pipes data between the client and proxy connections.  It's also

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

@@ -296,6 +296,7 @@ func (cfg Config) doFetchCloudConfig(proxyAddr string) ([]byte, error) {
 	}
 	defer resp.Body.Close()
 	if resp.StatusCode == 304 {
+		log.Debugf("Config unchanged in cloud")
 		return nil, nil
 	} else if resp.StatusCode != 200 {
 		return nil, fmt.Errorf("Unexpected response status: %d", resp.StatusCode)