Refactorization of Module API

core/app.go

@@ -0,0 +1,33 @@
+package core
+
+// Marathon independant application definitions
+
+type AppCluster struct {
+	Name        string            // Marathon's human reaable AppId (i.e. /path/to/app)
+	Id          string            // globally unique ID that identifies this application
+	ServicePort uint              // service port to listen to in service discovery
+	Protocol    string            // service protocol
+	PortName    string            // user filled port name
+	Labels      map[string]string // key/value pairs of labels (port-local | global)
+	HealthCheck *AppHealthCheck   // healthcheck, if available, or nil
+	Backends    []AppBackend      // ordered list of backend tasks
+	PortIndex   int               // Marathon's application port index
+}
+
+type AppHealthCheck struct {
+	Protocol               string
+	Path                   string
+	Command                *string
+	GracePeriodSeconds     uint
+	IntervalSeconds        uint
+	TimeoutSeconds         uint
+	MaxConsecutiveFailures uint
+	IgnoreHttp1xx          bool
+}
+
+type AppBackend struct {
+	Id    string
+	Host  string
+	Port  uint
+	State string
+}

core/event_listener.go

@@ -0,0 +1,30 @@
+package core
+
+// EventListener provides an interface for hooking into
+// standard service discovery API calls, such as adding and removing
+// backends from load balancers (app clusters).
+type EventListener interface {
+	// Startup is invoked upon application startup
+	Startup()
+
+	// Shutdown is invoked upon application shutdown
+	Shutdown()
+
+	// Apply installs the load balancer for all apps.
+	//
+	// This function is invoked upon startup to synchronize with the current
+	// state.
+	Apply(apps []*AppCluster)
+
+	// AddTask must add the given backend to the cluster.
+	//
+	// It is assured that the task to be added is also already added to the
+	// given AppCluster.
+	AddTask(task *AppBackend, app *AppCluster)
+
+	// RemoveTask must remove the given backend from the cluster.
+	//
+	// It is ensured that the task to be removed is not present in the given
+	// AppCluster.
+	RemoveTask(task *AppBackend, app *AppCluster)
+}