Enable TCP Keep Alive for Marathon Client and make value configurable (#784)

* Resolve rebase conflicts

* Fix imports that VSCode messed up

configuration.go

@@ -327,6 +327,7 @@ func NewTraefikDefaultPointersConfiguration() *TraefikConfiguration {
 	defaultMarathon.ExposedByDefault = true
 	defaultMarathon.Constraints = []types.Constraint{}
 	defaultMarathon.DialerTimeout = 60
+	defaultMarathon.KeepAlive = 10
 
 	// default Consul
 	var defaultConsul provider.Consul

docs/toml.md

@@ -845,6 +845,12 @@ domain = "marathon.localhost"
 # Default: 60
 # dialerTimeout = 5
 
+# Set the TCP Keep Alive interval (in seconds) for the Marathon HTTP Client
+#
+# Optional
+# Default: 10
+#
+# keepAlive = 10
 ```
 
 Labels can be used on containers to override default behaviour:

provider/marathon.go

@@ -35,6 +35,7 @@ type Marathon struct {
 	MarathonLBCompatibility bool          `description:"Add compatibility with marathon-lb labels"`
 	TLS                     *ClientTLS    `description:"Enable Docker TLS support"`
 	DialerTimeout           time.Duration `description:"Set a non-default connection timeout for Marathon"`
+	KeepAlive               time.Duration `description:"Set a non-default TCP Keep Alive time in seconds"`
 	Basic                   *MarathonBasic
 	marathonClient          marathon.Marathon
 }
@@ -71,10 +72,11 @@ func (provider *Marathon) Provide(configurationChan chan<- types.ConfigMessage,
 		}
 		config.HTTPClient = &http.Client{
 			Transport: &http.Transport{
-				TLSClientConfig: TLSConfig,
 				DialContext: (&net.Dialer{
+					KeepAlive: provider.KeepAlive * time.Second,
 					Timeout:   time.Second * provider.DialerTimeout,
 				}).DialContext,
+				TLSClientConfig: TLSConfig,
 			},
 		}
 		client, err := marathon.NewClient(config)

traefik.sample.toml

@@ -510,6 +510,13 @@
 # dcosToken = "xxxxxx"
 
 
+# Set the TCP Keep Alive interval (in seconds) for the Marathon HTTP Client
+#
+# Optional
+# Default: 10
+#
+# keepAlive = 10
+
 ################################################################
 # Mesos configuration backend
 ################################################################