events: add API helpers for service events stream topics.

api/event_stream.go

@@ -16,6 +16,7 @@ const (
 	TopicAllocation Topic = "Allocation"
 	TopicJob        Topic = "Job"
 	TopicNode       Topic = "Node"
+	TopicService    Topic = "Service"
 	TopicAll        Topic = "*"
 )
 
@@ -91,12 +92,23 @@ func (e *Event) Node() (*Node, error) {
 	return out.Node, nil
 }
 
+// Service returns a ServiceRegistration struct from a given event payload. If
+// the Event Topic is Service this will return a valid ServiceRegistration.
+func (e *Event) Service() (*ServiceRegistration, error) {
+	out, err := e.decodePayload()
+	if err != nil {
+		return nil, err
+	}
+	return out.Service, nil
+}
+
 type eventPayload struct {
-	Allocation *Allocation `mapstructure:"Allocation"`
-	Deployment *Deployment `mapstructure:"Deployment"`
-	Evaluation *Evaluation `mapstructure:"Evaluation"`
-	Job        *Job        `mapstructure:"Job"`
-	Node       *Node       `mapstructure:"Node"`
+	Allocation *Allocation          `mapstructure:"Allocation"`
+	Deployment *Deployment          `mapstructure:"Deployment"`
+	Evaluation *Evaluation          `mapstructure:"Evaluation"`
+	Job        *Job                 `mapstructure:"Job"`
+	Node       *Node                `mapstructure:"Node"`
+	Service    *ServiceRegistration `mapstructure:"Service"`
 }
 
 func (e *Event) decodePayload() (*eventPayload, error) {

api/event_stream_test.go

@@ -258,6 +258,18 @@ func TestEventStream_PayloadValueHelpers(t *testing.T) {
 				}, n)
 			},
 		},
+		{
+			desc:  "service",
+			input: []byte(`{"Topic": "Service", "Payload": {"Service":{"ID":"some-service-id","Namespace":"some-service-namespace-id","Datacenter":"us-east-1a"}}}`),
+			expectFn: func(t *testing.T, event Event) {
+				require.Equal(t, TopicService, event.Topic)
+				a, err := event.Service()
+				require.NoError(t, err)
+				require.Equal(t, "us-east-1a", a.Datacenter)
+				require.Equal(t, "some-service-id", a.ID)
+				require.Equal(t, "some-service-namespace-id", a.Namespace)
+			},
+		},
 	}
 
 	for _, tc := range testCases {