Merge pull request #2 from ripienaar/1

(#1) add a shutdown event

Author: ripienaar

event.go

@@ -6,4 +6,5 @@ type Event interface {
 	String() string
 	Component() string
 	Type() Type
+	SetIdentity(string)
 }

lifecycle.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"errors"
 	"fmt"
+	"sort"
 	"strings"
 
 	"github.com/tidwall/gjson"
@@ -22,6 +23,9 @@ const (
 
 	// Startup is an event components should publish when they start
 	Startup Type = iota
+
+	// Shutdown is an event components should publish when they shutdown
+	Shutdown
 )
 
 var eventTypes = make(map[string]Type)
@@ -46,6 +50,8 @@ func EventTypeNames() []string {
 		names = append(names, k)
 	}
 
+	sort.Strings(names)
+
 	return names
 }
 

events_test.go renamed to lifecycle_test.go

@@ -49,7 +49,7 @@ var _ = Describe("Events", func() {
 
 	Describe("EventTypeNames", func() {
 		It("Should list all known types", func() {
-			Expect(EventTypeNames()).To(Equal([]string{"startup"}))
+			Expect(EventTypeNames()).To(Equal([]string{"shutdown", "startup"}))
 		})
 	})
 

options.go

@@ -7,11 +7,6 @@ import (
 // Option configures events
 type Option func(e interface{}) error
 
-// IdentityEvent is an event that has an identity
-type IdentityEvent interface {
-	SetIdentity(string)
-}
-
 // VersionEvent is an event that has a version
 type VersionEvent interface {
 	SetVersion(string)
@@ -53,9 +48,9 @@ func Version(version string) Option {
 // Identity sets the identity for events
 func Identity(identity string) Option {
 	return func(e interface{}) error {
-		event, ok := e.(IdentityEvent)
+		event, ok := e.(Event)
 		if !ok {
-			return errors.New("cannot set component, event does not implement IdentityEvent")
+			return errors.New("cannot set component, event does not implement Event")
 		}
 
 		event.SetIdentity(identity)

shutdown.go

@@ -0,0 +1,87 @@
+package lifecycle
+
+import (
+	"encoding/json"
+	"fmt"
+)
+
+// ShutdownEvent is a choria:lifecycle:shutdown:1 event
+type ShutdownEvent struct {
+	Protocol  string `json:"protocol"`
+	Identity  string `json:"identity"`
+	Comp      string `json:"component"`
+	Timestamp int64  `json:"timestamp"`
+}
+
+func init() {
+	eventTypes["shutdown"] = Shutdown
+
+	eventJSONParsers[Shutdown] = func(j []byte) (Event, error) {
+		return newShutdownEventFromJSON(j)
+	}
+
+	eventFactories[Shutdown] = func(opts ...Option) Event {
+		return newShutdownEvent(opts...)
+	}
+}
+
+func newShutdownEvent(opts ...Option) *ShutdownEvent {
+	event := &ShutdownEvent{
+		Protocol:  "choria:lifecycle:shutdown:1",
+		Timestamp: timeStamp(),
+	}
+
+	for _, o := range opts {
+		o(event)
+	}
+
+	return event
+}
+
+func newShutdownEventFromJSON(j []byte) (*ShutdownEvent, error) {
+	event := &ShutdownEvent{}
+	err := json.Unmarshal(j, event)
+	if err != nil {
+		return nil, err
+	}
+
+	if event.Protocol != "choria:lifecycle:shutdown:1" {
+		return nil, fmt.Errorf("invalid protocol '%s'", event.Protocol)
+	}
+
+	return event, nil
+}
+
+// Component is the component that produced the event
+func (e *ShutdownEvent) Component() string {
+	return e.Comp
+}
+
+// SetComponent sets the component for the event
+func (e *ShutdownEvent) SetComponent(c string) {
+	e.Comp = c
+}
+
+// SetIdentity sets the identity for the event
+func (e *ShutdownEvent) SetIdentity(i string) {
+	e.Identity = i
+}
+
+// Target is where to publish the event to
+func (e *ShutdownEvent) Target() (string, error) {
+	if e.Comp == "" {
+		return "", fmt.Errorf("event is not complete, component has not been set")
+	}
+
+	return fmt.Sprintf("choria.lifecycle.event.shutdown.%s", e.Comp), nil
+}
+
+// String is text suitable to display on the console etc
+func (e *ShutdownEvent) String() string {
+	return fmt.Sprintf("[shutdown] %s: %s", e.Identity, e.Component())
+}
+
+// Type is the type of event
+func (e *ShutdownEvent) Type() Type {
+	return Shutdown
+}

shutdown_test.go

@@ -0,0 +1,80 @@
+package lifecycle
+
+import (
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+)
+
+var _ = Describe("ShutdownEvent", func() {
+	Describe("newShutdownEvent", func() {
+		It("Should create the event and set options", func() {
+			event := newShutdownEvent(Component("ginkgo"))
+			Expect(event.Component()).To(Equal("ginkgo"))
+		})
+	})
+
+	Describe("newShutdownEventFromJSON", func() {
+		It("Should detect invalid protocols", func() {
+			_, err := newShutdownEventFromJSON([]byte(`{"protocol":"x"}`))
+			Expect(err).To(MatchError("invalid protocol 'x'"))
+		})
+
+		It("Should parse valid events", func() {
+			event, err := newShutdownEventFromJSON([]byte(`{"protocol":"choria:lifecycle:shutdown:1", "component":"ginkgo"}`))
+			Expect(err).ToNot(HaveOccurred())
+			Expect(event.Component()).To(Equal("ginkgo"))
+		})
+	})
+
+	Describe("Component", func() {
+		It("Should return the right component", func() {
+			e := &ShutdownEvent{Comp: "test"}
+			Expect(e.Component()).To(Equal("test"))
+		})
+	})
+
+	Describe("SetComponent", func() {
+		It("Should set the component", func() {
+			e := &ShutdownEvent{}
+			e.SetComponent("component")
+			Expect(e.Comp).To(Equal("component"))
+		})
+	})
+
+	Describe("SetIdentity", func() {
+		It("Should set the identity", func() {
+			e := &ShutdownEvent{}
+			e.SetIdentity("node.example")
+			Expect(e.Identity).To(Equal("node.example"))
+		})
+	})
+
+	Describe("Target", func() {
+		It("Should detect incomplete events", func() {
+			e := &ShutdownEvent{}
+			_, err := e.Target()
+			Expect(err).To(MatchError("event is not complete, component has not been set"))
+		})
+
+		It("Should return the right target", func() {
+			e := newShutdownEvent(Component("ginkgo"))
+			t, err := e.Target()
+			Expect(err).ToNot(HaveOccurred())
+			Expect(t).To(Equal("choria.lifecycle.event.shutdown.ginkgo"))
+		})
+	})
+
+	Describe("String", func() {
+		It("Should return the right string", func() {
+			e := newShutdownEvent(Component("ginkgo"), Identity("node.example"))
+			Expect(e.String()).To(Equal("[shutdown] node.example: ginkgo"))
+		})
+	})
+
+	Describe("Type", func() {
+		It("Should return the right Type", func() {
+			e := &ShutdownEvent{}
+			Expect(e.Type()).To(Equal(Shutdown))
+		})
+	})
+})