Adds 'useIpFromEnv' parameter to registrator

bridge/bridge.go

@@ -309,6 +309,7 @@ func (b *Bridge) newService(port ServicePort, isgroup bool) *Service {
 	}
 
 	// NetworkMode can point to another container (kuberenetes pods)
+	var ipFromNetworkContainer string
 	networkMode := container.HostConfig.NetworkMode
 	if networkMode != "" {
 		if strings.HasPrefix(networkMode, "container:") {
@@ -318,8 +319,28 @@ func (b *Bridge) newService(port ServicePort, isgroup bool) *Service {
 			if err != nil {
 				log.Println("unable to inspect network container:", networkContainerId[:12], err)
 			} else {
-				service.IP = networkContainer.NetworkSettings.IPAddress
-				log.Println(service.Name + ": using network container IP " + service.IP)
+				ipFromNetworkContainer = networkContainer.NetworkSettings.IPAddress
+
+				if ipFromNetworkContainer != "" {
+					service.IP = networkContainer.NetworkSettings.IPAddress
+					log.Println(service.Name + ": using network container IP " + service.IP)
+				} else {
+					log.Println(service.Name + ": network container IP address is empty")
+				}
+			}
+		}
+	}
+
+	// Grab the container IP address from docker or kubernetes env
+	if b.config.UseIpFromEnv != "" && ipFromNetworkContainer == "" {
+		for _, requiredEnv := range container.Config.Env {
+			if strings.Contains(requiredEnv, b.config.UseIpFromEnv) {
+				service.IP = requiredEnv[len(b.config.UseIpFromEnv)+1:]
+				log.Println(service.Name + ": using container IP '" + service.IP +
+					"' from env '" + b.config.UseIpFromEnv  + "'")
+			} else {
+				log.Println(service.Name + ": could not found env '" + b.config.UseIpFromEnv  +
+					"' from docker env")
 			}
 		}
 	}

bridge/types.go

@@ -23,6 +23,7 @@ type Config struct {
 	HostIp          string
 	Internal        bool
 	UseIpFromLabel  string
+	UseIpFromEnv    string
 	ForceTags       string
 	RefreshTtl      int
 	RefreshInterval int

docs/user/run.md

@@ -44,6 +44,7 @@ Option                           | Since | Description
 `-ttl <seconds>`                 |       | TTL for services. Default: 0, no expiry (supported backends only)
 `-ttl-refresh <seconds>`         |       | Frequency service TTLs are refreshed (supported backends only)
 `-useIpFromLabel <label>`        |       | Uses the IP address stored in the given label, which is assigned to a container, for registration with Consul
+`-useIpFromEnv <env>`        	 |       | Uses the IP address from the given environment variable, which is assigned to a container, for registration with Consul
 
 If the `-internal` option is used, Registrator will register the docker0
 internal IP and port instead of the host mapped ones.

registrator.go

@@ -21,6 +21,7 @@ var versionChecker = usage.NewChecker("registrator", Version)
 var hostIp = flag.String("ip", "", "IP for ports mapped to the host")
 var internal = flag.Bool("internal", false, "Use internal ports instead of published ones")
 var useIpFromLabel = flag.String("useIpFromLabel", "", "Use IP which is stored in a label assigned to the container")
+var useIpFromEnv = flag.String("useIpFromEnv", "", "Use IP from the container environment variable")
 var refreshInterval = flag.Int("ttl-refresh", 0, "Frequency with which service TTLs are refreshed")
 var refreshTtl = flag.Int("ttl", 0, "TTL for services (default is no expiry)")
 var forceTags = flag.String("tags", "", "Append tags for all registered services")