Bootstrap autodetection and swarm zero conf

Fixed #9

This PR bootstrap the autodetection feature:

1. It works when the configuration file is not setup. Right know I am
not going to manage the merge of double sources (autodetection and
configuration file).

2. At the moment only Docker Swarm will support this feature.

cmd/daemon.go

@@ -25,7 +25,7 @@ func (c *DaemonCmd) Run(args []string) int {
 	var debug bool
 	cmdFlags := flag.NewFlagSet("event", flag.ExitOnError)
 	cmdFlags.StringVar(&port, "port", ":8000", "port")
-	cmdFlags.StringVar(&configPath, "config", "/etc/deamon.yml", "config")
+	cmdFlags.StringVar(&configPath, "config", "", "config")
 	cmdFlags.BoolVar(&debug, "debug", false, "debug")
 	if err := cmdFlags.Parse(args); err != nil {
 		logrus.WithField("error", err).Warn("Problem to parse arguments.")
@@ -35,15 +35,22 @@ func (c *DaemonCmd) Run(args []string) int {
 		logrus.SetLevel(logrus.DebugLevel)
 		logrus.Debug("Daemon started in debug mode")
 	}
-	config, err := readConfiguration(configPath)
-	if err != nil {
-		logrus.WithField("error", err).Warn("Configuration file malformed.")
-		return 1
-	}
-	core, err := core.NewCore(config.AutoscalersConf)
-	if err != nil {
-		logrus.WithField("error", err).Warn(err)
-		return 1
+	var coreEngine core.Core
+	if configPath != "" {
+		config, err := readConfiguration(configPath)
+		if err != nil {
+			logrus.WithField("error", err).Warn("Configuration file malformed.")
+			return 1
+		}
+		logrus.Infof("Starting from configuration file located %s", configPath)
+		coreEngine, err = core.NewCoreByConfig(config.AutoscalersConf)
+		if err != nil {
+			logrus.WithField("error", err).Warn(err)
+			return 1
+		}
+	} else {
+		logrus.Info("Starting in auto-detection mode.")
+		coreEngine, err = core.Autodetect()
 	}
 	go func() {
 		sigchan := make(chan os.Signal, 10)
@@ -52,7 +59,7 @@ func (c *DaemonCmd) Run(args []string) int {
 		logrus.Info("Stopping and cleaning. Bye!")
 		os.Exit(0)
 	}()
-	router := api.GetRouter(core, c.EventChannel)
+	router := api.GetRouter(coreEngine, c.EventChannel)
 	logrus.Infof("API Server run on port %s", port)
 	http.ListenAndServe(port, router)
 	return 0

core/autodetect.go

@@ -0,0 +1,21 @@
+package core
+
+import "github.com/gianarb/orbiter/autoscaler"
+
+// This function use diferent strategies to get information from
+// the system itself to configure the autoloader.
+// They can be environment variables for example or other systems.
+func Autodetect() (Core error) {
+	scalers := autoscaler.Autoscalers{}
+	var core Core
+	autoDetectSwarmMode(&scalers)
+	return core, nil
+}
+
+func autoDetectSwarmMode(a *autoscaler.Autoscalers) {
+	// Create Docker Client by EnvVar and check if it's working.
+
+	// Get List of Services
+
+	// Check which services has labels and register them to orbiter.
+}

core/daemon.go

@@ -11,7 +11,7 @@ type Core struct {
 	Autoscalers autoscaler.Autoscalers
 }
 
-func NewCore(c map[string]AutoscalerConf) (Core, error) {
+func NewCoreByConfig(c map[string]AutoscalerConf) (Core, error) {
 	scalers := autoscaler.Autoscalers{}
 	var core Core
 	for scalerName, scaler := range c {

core/daemon_test.go

@@ -29,7 +29,7 @@ func TestNewCore(t *testing.T) {
 			},
 		},
 	}
-	core, err := NewCore(conf)
+	core, err := NewCoreByConfig(conf)
 	if err != nil {
 		t.Fatal(err)
 	}
@@ -55,7 +55,7 @@ func TestGetSingleAutoscaler(t *testing.T) {
 			},
 		},
 	}
-	core, _ := NewCore(conf)
+	core, _ := NewCoreByConfig(conf)
 	_, ok := core.Autoscalers["second/micro"]
 	if ok == false {
 		t.Fatal("micro exist")
@@ -89,7 +89,7 @@ func TestNewCoreWithUnsupportedProvider(t *testing.T) {
 			},
 		},
 	}
-	_, err := NewCore(conf)
+	_, err := NewCoreByConfig(conf)
 	if err.Error() != "lalala not supported." {
 		t.Fatal(err)
 	}