diff --git a/api.go b/api.go
index 5d4f748..fb614af 100644
--- a/api.go
+++ b/api.go
@@ -108,12 +108,17 @@
 	deploymentsChanged  chan interface{}
 	addSubscriber       chan chan deploymentsResult
 	removeSubscriber    chan chan deploymentsResult
+	apiInitialized      bool
 }
 
 func (a *apiManager) InitAPI() {
-	log.Debug("API endpoints initialized")
+	if a.apiInitialized {
+		return
+	}
 	services.API().HandleFunc(a.deploymentsEndpoint, a.apiGetCurrentDeployments).Methods("GET")
 	services.API().HandleFunc(a.blobEndpoint, a.apiReturnBlobData).Methods("GET")
+	a.apiInitialized = true
+	log.Debug("API endpoints initialized")
 }
 
 func (a *apiManager) addChangedDeployment(id string) {
diff --git a/api_test.go b/api_test.go
index 66e790d..8899f69 100644
--- a/api_test.go
+++ b/api_test.go
@@ -338,10 +338,11 @@
 	readyDeployments []DataDeployment
 	localFSLocation  string
 	fileResponse     chan string
+	version          string
 }
 
 func (d *dummyDbManager) setDbVersion(version string) {
-
+	d.version = version
 }
 
 func (d *dummyDbManager) initDb() error {
diff --git a/bundle_test.go b/bundle_test.go
index fa44b03..e848cec 100644
--- a/bundle_test.go
+++ b/bundle_test.go
@@ -132,9 +132,11 @@
 })
 
 type dummyApiManager struct {
+	initCalled bool
 }
 
 func (a *dummyApiManager) InitAPI() {
+	a.initCalled = true
 }
 
 type dummyBlobServer struct {
diff --git a/data_test.go b/data_test.go
index d678828..208dac8 100644
--- a/data_test.go
+++ b/data_test.go
@@ -47,7 +47,8 @@
 		}
 		testDbMan.setDbVersion("test" + strconv.Itoa(testCount))
 		initTestDb(testDbMan.getDb())
-		testDbMan.initDb()
+		err := testDbMan.initDb()
+		Expect(err).Should(Succeed())
 		time.Sleep(100 * time.Millisecond)
 	})
 
@@ -57,6 +58,11 @@
 	})
 
 	Context("db tests", func() {
+		It("initDb() should be idempotent", func() {
+			err := testDbMan.initDb()
+			Expect(err).Should(Succeed())
+		})
+
 		It("should succefully initialized tables", func() {
 			// edgex_blob_available
 			rows, err := testDbMan.getDb().Query(`
diff --git a/init.go b/init.go
index d70963d..0d2376d 100644
--- a/init.go
+++ b/init.go
@@ -48,8 +48,7 @@
 	bundlePath       string
 	debounceDuration time.Duration
 	apiServerBaseURI *url.URL
-	apidInstanceID   string
-	apidClusterID    string
+	eventHandler     *apigeeSyncHandler
 )
 
 func init() {
@@ -77,16 +76,6 @@
 		return pluginData, fmt.Errorf("%s value %s parse err: %v", configApiServerBaseURI, apiServerBaseURI, err)
 	}
 
-	if !config.IsSet(configApidInstanceID) {
-		return pluginData, fmt.Errorf("Missing required config value: %s", configApidInstanceID)
-	}
-	apidInstanceID = config.GetString(configApidInstanceID)
-
-	if !config.IsSet(configApidClusterID) {
-		return pluginData, fmt.Errorf("Missing required config value: %s", configApidClusterID)
-	}
-	apidClusterID = config.GetString(configApidClusterID)
-
 	config.SetDefault(configBundleDirKey, "bundles")
 	config.SetDefault(configDebounceDuration, time.Second)
 	config.SetDefault(configBundleCleanupDelay, time.Minute)
@@ -134,6 +123,7 @@
 		deploymentsChanged:  make(chan interface{}, 5),
 		addSubscriber:       make(chan chan deploymentsResult),
 		removeSubscriber:    make(chan chan deploymentsResult),
+		apiInitialized:      false,
 	}
 
 	// initialize bundle manager
@@ -166,7 +156,15 @@
 	//TODO initialize apiMan.distributeEvents() for api call with "block"
 	//go apiMan.distributeEvents()
 
-	initListener(services, dbMan, apiMan, bundleMan)
+	// initialize event handler
+	eventHandler = &apigeeSyncHandler{
+		dbMan:     dbMan,
+		apiMan:    apiMan,
+		bundleMan: bundleMan,
+		closed:    false,
+	}
+
+	eventHandler.initListener(services)
 
 	log.Debug("end init")
 
diff --git a/listener.go b/listener.go
index a6b637c..c2b05df 100644
--- a/listener.go
+++ b/listener.go
@@ -25,16 +25,15 @@
 	CONFIG_METADATA_TABLE = "project.runtime_blob_metadata"
 )
 
-var apiInitialized bool
+func (h *apigeeSyncHandler) initListener(services apid.Services) {
+	services.Events().Listen(APIGEE_SYNC_EVENT, h)
+}
 
-func initListener(services apid.Services, dbMan dbManagerInterface, apiMan apiManagerInterface, bundleMan bundleManagerInterface) {
-	handler := &apigeeSyncHandler{
-		dbMan:     dbMan,
-		apiMan:    apiMan,
-		bundleMan: bundleMan,
+func (h *apigeeSyncHandler) stopListener(services apid.Services) {
+	if !h.closed {
+		services.Events().StopListening(APIGEE_SYNC_EVENT, h)
+		h.closed = true
 	}
-
-	services.Events().Listen(APIGEE_SYNC_EVENT, handler)
 }
 
 type bundleConfigJson struct {
@@ -48,6 +47,7 @@
 	dbMan     dbManagerInterface
 	apiMan    apiManagerInterface
 	bundleMan bundleManagerInterface
+	closed    bool
 }
 
 func (h *apigeeSyncHandler) String() string {
@@ -72,10 +72,7 @@
 	h.dbMan.setDbVersion(snapshot.SnapshotInfo)
 
 	h.startupOnExistingDatabase()
-	if !apiInitialized {
-		h.apiMan.InitAPI()
-		apiInitialized = true
-	}
+	h.apiMan.InitAPI()
 	log.Debug("Snapshot processed")
 }
 
diff --git a/listener_test.go b/listener_test.go
new file mode 100644
index 0000000..0cced6f
--- /dev/null
+++ b/listener_test.go
@@ -0,0 +1,128 @@
+// Copyright 2017 Google Inc.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//      http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+package apiGatewayConfDeploy
+
+import (
+	"fmt"
+	"github.com/30x/apid-core"
+	"github.com/apigee-labs/transicator/common"
+	. "github.com/onsi/ginkgo"
+	. "github.com/onsi/gomega"
+	"math/rand"
+	"time"
+)
+
+var _ = Describe("listener", func() {
+	var dummyDbMan *dummyDbManager
+	var dummyApiMan *dummyApiManager
+	var dummyBundleMan *dummyBundleManager
+	var testHandler *apigeeSyncHandler
+	var _ = BeforeEach(func() {
+		// stop handler created by initPlugin()
+		eventHandler.stopListener(services)
+
+		dummyApiMan = &dummyApiManager{}
+		dummyDbMan = &dummyDbManager{}
+		dummyBundleMan = &dummyBundleManager{
+			requestChan: make(chan *DownloadRequest),
+		}
+		testHandler = &apigeeSyncHandler{
+			dbMan:     dummyDbMan,
+			apiMan:    dummyApiMan,
+			bundleMan: dummyBundleMan,
+		}
+		testHandler.initListener(services)
+		time.Sleep(100 * time.Millisecond)
+	})
+
+	var _ = AfterEach(func() {
+		testHandler.stopListener(services)
+	})
+	Context("Snapshot", func() {
+
+		It("Snapshot event shoud enqueue download requests for all unready blobs", func() {
+			// init unready blob ids
+			unreadyBlobIds := make([]string, 0)
+			blobMap := make(map[string]int)
+			for i := 0; i < rand.Intn(10); i++ {
+				id := GenerateUUID()
+				blobMap[id] = 1
+				unreadyBlobIds = append(unreadyBlobIds, id)
+			}
+			dummyDbMan.unreadyBlobIds = unreadyBlobIds
+
+			// emit snapshot
+			snapshot := &common.Snapshot{
+				SnapshotInfo: fmt.Sprint(rand.Uint32()),
+			}
+
+			apid.Events().Emit(APIGEE_SYNC_EVENT, snapshot)
+
+			for i := 0; i < len(unreadyBlobIds); i++ {
+				req := <-dummyBundleMan.requestChan
+				blobMap[req.blobId]++
+			}
+
+			// verify all unready blobids are enqueued
+			for _, val := range blobMap {
+				Expect(val).Should(Equal(2))
+			}
+		})
+
+		It("Snapshot events shoud set db version, and should only init API endpoint once", func() {
+
+			// emit snapshot
+			for i := 0; i < 2+rand.Intn(5); i++ {
+				version := fmt.Sprint(rand.Uint32())
+				snapshot := &common.Snapshot{
+					SnapshotInfo: version,
+				}
+				<-apid.Events().Emit(APIGEE_SYNC_EVENT, snapshot)
+				Expect(dummyDbMan.version).Should(Equal(version))
+			}
+
+			// verify init API called
+			Expect(dummyApiMan.initCalled).Should(BeTrue())
+		})
+
+	})
+
+})
+
+type dummyBundleManager struct {
+	requestChan chan *DownloadRequest
+}
+
+func (bm *dummyBundleManager) initializeBundleDownloading() {
+
+}
+
+func (bm *dummyBundleManager) queueDownloadRequest(dep *DataDeployment) {
+
+}
+
+func (bm *dummyBundleManager) enqueueRequest(req *DownloadRequest) {
+	bm.requestChan <- req
+}
+
+func (bm *dummyBundleManager) makeDownloadRequest(blobId string) *DownloadRequest {
+	return &DownloadRequest{
+		blobId: blobId,
+	}
+}
+
+func (bm *dummyBundleManager) Close() {
+
+}