refactor: Break core package into multiple packages under config/endpoint (#759)

* refactor: Partially break core package into dns, result and ssh packages

* refactor: Move core package to config/endpoint

* refactor: Fix warning about overlapping imported package name with endpoint variable

* refactor: Rename EndpointStatus to Status

* refactor: Merge result pkg back into endpoint pkg, because it makes more sense

* refactor: Rename parameter r to result in Condition.evaluate

* refactor: Rename parameter r to result

* refactor: Revert accidental change to endpoint.TypeDNS

* refactor: Rename parameter r to result

* refactor: Merge util package into endpoint package

* refactor: Rename parameter r to result

config/endpoint/event.go

@@ -0,0 +1,39 @@
+package endpoint
+
+import (
+	"time"
+)
+
+// Event is something that happens at a specific time
+type Event struct {
+	// Type is the kind of event
+	Type EventType `json:"type"`
+
+	// Timestamp is the moment at which the event happened
+	Timestamp time.Time `json:"timestamp"`
+}
+
+// EventType is, uh, the types of events?
+type EventType string
+
+var (
+	// EventStart is a type of event that represents when an endpoint starts being monitored
+	EventStart EventType = "START"
+
+	// EventHealthy is a type of event that represents an endpoint passing all of its conditions
+	EventHealthy EventType = "HEALTHY"
+
+	// EventUnhealthy is a type of event that represents an endpoint failing one or more of its conditions
+	EventUnhealthy EventType = "UNHEALTHY"
+)
+
+// NewEventFromResult creates an Event from a Result
+func NewEventFromResult(result *Result) *Event {
+	event := &Event{Timestamp: result.Timestamp}
+	if result.Success {
+		event.Type = EventHealthy
+	} else {
+		event.Type = EventUnhealthy
+	}
+	return event
+}