Add weighted round robin load balancer on TCP

Co-authored-by: Mathieu Lonjaret <mathieu.lonjaret@gmail.com>

integration/fixtures/tcp/wrr.toml

@@ -0,0 +1,42 @@
+[global]
+  checkNewVersion = false
+  sendAnonymousUsage = false
+
+[log]
+  level = "DEBUG"
+
+[entryPoints]
+  [entryPoints.tcp]
+    address = ":8093"
+
+[api]
+  insecure = true
+
+[providers.file]
+  filename = "{{ .SelfFilename }}"
+
+## dynamic configuration ##
+[tcp]
+  [tcp.routers]
+    [tcp.routers.to-whoami-a]
+      rule = "HostSNI(`whoami-a.test`)"
+      service = "whoami"
+      entryPoints = [ "tcp" ]
+      [tcp.routers.to-whoami-a.tls]
+        passthrough=true
+
+    [[tcp.services.whoami.weighted.services]]
+        name="whoami-a"
+        weight=3
+    [[tcp.services.whoami.weighted.services]]
+        name="whoami-b"
+        weight=1
+
+    [tcp.services.whoami-a.loadBalancer]
+      [[tcp.services.whoami-a.loadBalancer.servers]]
+        address = "localhost:8081"
+
+    [tcp.services.whoami-b.loadBalancer]
+      [[tcp.services.whoami-b.loadBalancer.servers]]
+        address = "localhost:8082"
+

integration/rest_test.go

@@ -79,7 +79,7 @@ func (s *RestSuite) TestSimpleConfigurationInsecure(c *check.C) {
 					},
 					Services: map[string]*dynamic.TCPService{
 						"service1": {
-							LoadBalancer: &dynamic.TCPLoadBalancerService{
+							LoadBalancer: &dynamic.TCPServersLoadBalancer{
 								Servers: []dynamic.TCPServer{
 									{
 										Address: s.composeProject.Container(c, "whoami1").NetworkSettings.IPAddress + ":80",
@@ -183,7 +183,7 @@ func (s *RestSuite) TestSimpleConfiguration(c *check.C) {
 					},
 					Services: map[string]*dynamic.TCPService{
 						"service1": {
-							LoadBalancer: &dynamic.TCPLoadBalancerService{
+							LoadBalancer: &dynamic.TCPServersLoadBalancer{
 								Servers: []dynamic.TCPServer{
 									{
 										Address: s.composeProject.Container(c, "whoami1").NetworkSettings.IPAddress + ":80",

integration/tcp_test.go

@@ -6,6 +6,7 @@ import (
 	"net/http"
 	"net/http/httptest"
 	"os"
+	"strings"
 	"time"
 
 	"github.com/containous/traefik/v2/integration/try"
@@ -266,3 +267,35 @@ func guessWhoTLSMaxVersion(addr, serverName string, tlsCall bool, tlsMaxVersion
 
 	return string(out[:n]), nil
 }
+
+func (s *TCPSuite) TestWRR(c *check.C) {
+	file := s.adaptFile(c, "fixtures/tcp/wrr.toml", struct{}{})
+	defer os.Remove(file)
+
+	cmd, display := s.traefikCmd(withConfigFile(file))
+	defer display(c)
+
+	err := cmd.Start()
+	c.Assert(err, checker.IsNil)
+	defer cmd.Process.Kill()
+
+	err = try.GetRequest("http://127.0.0.1:8080/api/rawdata", 5*time.Second, try.StatusCodeIs(http.StatusOK), try.BodyContains("HostSNI"))
+	c.Assert(err, checker.IsNil)
+
+	call := map[string]int{}
+	for i := 0; i < 4; i++ {
+		// Traefik passes through, termination handled by whoami-a
+		out, err := guessWho("127.0.0.1:8093", "whoami-a.test", true)
+		c.Assert(err, checker.IsNil)
+		switch {
+		case strings.Contains(out, "whoami-a"):
+			call["whoami-a"]++
+		case strings.Contains(out, "whoami-b"):
+			call["whoami-b"]++
+		default:
+			call["unknown"]++
+		}
+	}
+
+	c.Assert(call, checker.DeepEquals, map[string]int{"whoami-a": 3, "whoami-b": 1})
+}