Enable loadbalancer.sticky for ECS

docs/toml.md

@@ -1777,6 +1777,8 @@ Labels can be used on task containers to override default behaviour:
 - `traefik.protocol=https`: override the default `http` protocol
 - `traefik.weight=10`: assign this weight to the container
 - `traefik.enable=false`: disable this container in Træfik
+- `traefik.backend.loadbalancer.method=drr`: override the default `wrr` load balancer algorithm
+- `traefik.backend.loadbalancer.sticky=true`: enable backend sticky sessions
 - `traefik.frontend.rule=Host:test.traefik.io`: override the default frontend rule (Default: `Host:{containerName}.{domain}`).
 - `traefik.frontend.passHostHeader=true`: forward client `Host` header to the backend.
 - `traefik.frontend.priority=10`: override default frontend priority

provider/ecs/ecs.go

@@ -182,6 +182,8 @@ func (p *Provider) loadECSConfig(ctx context.Context, client *awsClient) (*types
 	var ecsFuncMap = template.FuncMap{
 		"filterFrontends":       p.filterFrontends,
 		"getFrontendRule":       p.getFrontendRule,
+		"getLoadBalancerSticky": p.getLoadBalancerSticky,
+		"getLoadBalancerMethod": p.getLoadBalancerMethod,
 	}
 
 	instances, err := p.listInstances(ctx, client)
@@ -191,10 +193,20 @@ func (p *Provider) loadECSConfig(ctx context.Context, client *awsClient) (*types
 
 	instances = fun.Filter(p.filterInstance, instances).([]ecsInstance)
 
+	services := make(map[string][]ecsInstance)
+
+	for _, instance := range instances {
+		if serviceInstances, ok := services[instance.Name]; ok {
+			services[instance.Name] = append(serviceInstances, instance)
+		} else {
+			services[instance.Name] = []ecsInstance{instance}
+		}
+	}
+
 	return p.GetConfiguration("templates/ecs.tmpl", ecsFuncMap, struct {
-		Instances []ecsInstance
+		Services map[string][]ecsInstance
 	}{
-		instances,
+		services,
 	})
 }
 
@@ -457,6 +469,26 @@ func (p *Provider) getFrontendRule(i ecsInstance) string {
 	return "Host:" + strings.ToLower(strings.Replace(i.Name, "_", "-", -1)) + "." + p.Domain
 }
 
+func (p *Provider) getLoadBalancerSticky(instances []ecsInstance) string {
+	if len(instances) > 0 {
+		label := instances[0].label(types.LabelBackendLoadbalancerSticky)
+		if label != "" {
+			return label
+		}
+	}
+	return "false"
+}
+
+func (p *Provider) getLoadBalancerMethod(instances []ecsInstance) string {
+	if len(instances) > 0 {
+		label := instances[0].label(types.LabelBackendLoadbalancerMethod)
+		if label != "" {
+			return label
+		}
+	}
+	return "wrr"
+}
+
 // Provider expects no more than 100 parameters be passed to a DescribeTask call; thus, pack
 // each string into an array capped at 100 elements
 func (p *Provider) chunkedTaskArns(tasks []*string) [][]*string {

templates/ecs.tmpl

@@ -1,17 +1,25 @@
-[backends]{{range .Instances}}
+[backends]{{range $serviceName, $instances := .Services}}
-    [backends.backend-{{ .Name }}.servers.server-{{ .Name }}{{ .ID }}]
+  [backends.backend-{{ $serviceName }}.loadbalancer]
-    url = "{{ .Protocol }}://{{ .Host }}:{{ .Port }}"
+    sticky = {{ getLoadBalancerSticky $instances}}
-    weight = {{ .Weight }}
+    method = "{{ getLoadBalancerMethod $instances}}"
+
+  {{range $index, $i := $instances}}
+    [backends.backend-{{ $i.Name }}.servers.server-{{ $i.Name }}{{ $i.ID }}]
+      url = "{{ $i.Protocol }}://{{ $i.Host }}:{{ $i.Port }}"
+      weight = {{ $i.Weight }}
+  {{end}}
 {{end}}
 
-[frontends]{{range filterFrontends .Instances}}
+[frontends]{{range $serviceName, $instances := .Services}}
-  [frontends.frontend-{{ .Name }}]
+  {{range filterFrontends $instances}}
-  backend = "backend-{{ .Name }}"
+    [frontends.frontend-{{ $serviceName }}]
+      backend = "backend-{{ $serviceName }}"
       passHostHeader = {{ .PassHostHeader }}
       priority = {{ .Priority }}
       entryPoints = [{{range  .EntryPoints }}
       "{{.}}",
     {{end}}]
-    [frontends.frontend-{{ .Name }}.routes.route-frontend-{{ .Name }}]
+    [frontends.frontend-{{ $serviceName }}.routes.route-frontend-{{ $serviceName }}]
       rule = "{{getFrontendRule .}}"
   {{end}}
+{{end}}