Improve bus (#3)

* Improve bus
* Add ticket log

bus/databaseupdate.go

@@ -0,0 +1,42 @@
+package bus
+
+import (
+	"encoding/json"
+	"log"
+
+	"github.com/arangodb/go-driver"
+	emitter "github.com/emitter-io/go/v2"
+)
+
+const channelDatabaseUpdate = "databaseupdate"
+
+type DatabaseUpdateType string
+
+const (
+	DatabaseEntryRead    DatabaseUpdateType = "read"
+	DatabaseEntryCreated DatabaseUpdateType = "created"
+	DatabaseEntryUpdated DatabaseUpdateType = "updated"
+)
+
+type DatabaseUpdateMsg struct {
+	IDs  []driver.DocumentID `json:"ids"`
+	Type DatabaseUpdateType  `json:"type"`
+}
+
+func (b *Bus) PublishDatabaseUpdate(ids []driver.DocumentID, databaseUpdateType DatabaseUpdateType) error {
+	return b.jsonPublish(&DatabaseUpdateMsg{
+		IDs:  ids,
+		Type: databaseUpdateType,
+	}, channelDatabaseUpdate, b.config.databaseUpdateBusKey)
+}
+
+func (b *Bus) SubscribeDatabaseUpdate(f func(msg *DatabaseUpdateMsg)) error {
+	return b.safeSubscribe(b.config.databaseUpdateBusKey, channelDatabaseUpdate, func(c *emitter.Client, m emitter.Message) {
+		var msg DatabaseUpdateMsg
+		if err := json.Unmarshal(m.Payload(), &msg); err != nil {
+			log.Println(err)
+			return
+		}
+		go f(&msg)
+	})
+}