create a Hub interface

_examples/helloworld/consumer/main.go

@@ -58,7 +58,7 @@ func main() {
 	}
 }
 
-func initHub() (*eventhub.Hub, []string) {
+func initHub() (eventhub.Hub, []string) {
 	namespace := mustGetenv("EVENTHUB_NAMESPACE")
 	hubMgmt, err := ensureEventHub(context.Background(), HubName)
 	if err != nil {

_examples/helloworld/producer/main.go

@@ -41,7 +41,7 @@ func main() {
 	}
 }
 
-func initHub() (*eventhub.Hub, []string) {
+func initHub() (eventhub.Hub, []string) {
 	namespace := mustGetenv("EVENTHUB_NAMESPACE")
 	hubMgmt, err := ensureEventHub(context.Background(), HubName)
 	if err != nil {

changelog.md

@@ -1,5 +1,9 @@
 # Change Log
 
+## Unreleased
+
+- Move Hub to an interface (#272)
+
 ## `v3.3.18`
 
 - Fixing issue where the LeaserCheckpointer could fail with a "ContainerAlreadyExists" error. (#253)

eph/eph.go

@@ -65,7 +65,7 @@ type (
 		name                string
 		consumerGroup       string
 		tokenProvider       auth.TokenProvider
-		client              *eventhub.Hub
+		client              eventhub.Hub
 		leaser              Leaser
 		checkpointer        Checkpointer
 		scheduler           *scheduler

eph/eph_test.go

@@ -258,15 +258,15 @@ func (s *testSuite) newInMemoryEPHWithOptions(hubName string, store *sharedStore
 	return processor, nil
 }
 
-func (s *testSuite) newClient(t *testing.T, hubName string, opts ...eventhub.HubOption) *eventhub.Hub {
+func (s *testSuite) newClient(t *testing.T, hubName string, opts ...eventhub.HubOption) eventhub.Hub {
 	provider, err := aad.NewJWTProvider(aad.JWTProviderWithEnvironmentVars(), aad.JWTProviderWithAzureEnvironment(&s.Env))
 	if err != nil {
 		t.Fatal(err)
 	}
 	return s.newClientWithProvider(t, hubName, provider, opts...)
 }
 
-func (s *testSuite) newClientWithProvider(t *testing.T, hubName string, provider auth.TokenProvider, opts ...eventhub.HubOption) *eventhub.Hub {
+func (s *testSuite) newClientWithProvider(t *testing.T, hubName string, provider auth.TokenProvider, opts ...eventhub.HubOption) eventhub.Hub {
 	opts = append(opts, eventhub.HubWithEnvironment(s.Env))
 	client, err := eventhub.NewHub(s.Namespace, hubName, provider, opts...)
 	if err != nil {

hub.go

@@ -57,7 +57,39 @@ const (
 
 type (
 	// Hub provides the ability to send and receive Event Hub messages
-	Hub struct {
+	Hub interface {
+		// GetRuntimeInformation fetches runtime information from the Event Hub management node
+		GetRuntimeInformation(ctx context.Context) (*HubRuntimeInformation, error)
+		// GetPartitionInformation fetches runtime information about a specific partition from the Event Hub management node
+		GetPartitionInformation(ctx context.Context, partitionID string) (*HubPartitionRuntimeInformation, error)
+		// Close drains and closes all of the existing senders, receivers and connections
+		Close(ctx context.Context) error
+		// Receive subscribes for messages sent to the provided entityPath.
+		//
+		// The context passed into Receive is only used to limit the amount of time the caller will wait for the Receive
+		// method to connect to the Event Hub. The context passed in does not control the lifetime of Receive after connection.
+		//
+		// If Receive encounters an initial error setting up the connection, an error will be returned.
+		//
+		// If Receive starts successfully, a *ListenerHandle and a nil error will be returned. The ListenerHandle exposes
+		// methods which will help manage the life span of the receiver.
+		//
+		// # ListenerHandle.Close(ctx) closes the receiver
+		//
+		// # ListenerHandle.Done() signals the consumer when the receiver has stopped
+		//
+		// ListenerHandle.Err() provides the last error the listener encountered and was unable to recover from
+		Receive(ctx context.Context, partitionID string, handler Handler, opts ...ReceiveOption) (*ListenerHandle, error)
+		// Send sends an event to the Event Hub
+		//
+		// Send will retry sending the message for as long as the context allows
+		Send(ctx context.Context, event *Event, opts ...SendOption) error
+		// SendBatch sends a batch of events to the Hub
+		SendBatch(ctx context.Context, iterator BatchIterator, opts ...BatchOption) error
+	}
+
+	// Hub provides the ability to send and receive Event Hub messages
+	hubImpl struct {
 		name               string
 		namespace          *namespace
 		receivers          map[string]*receiver
@@ -92,7 +124,7 @@ type (
 
 	// HubOption provides structure for configuring new Event Hub clients. For building new Event Hubs, see
 	// HubManagementOption.
-	HubOption func(h *Hub) error
+	HubOption func(h Hub) error
 
 	// HubManager provides CRUD functionality for Event Hubs
 	HubManager struct {
@@ -336,7 +368,7 @@ func hubEntryToEntity(entry *hubEntry) *HubEntity {
 // NOTE: If the AZURE_ENVIRONMENT variable is set, it will be used to set the ServiceBusEndpointSuffix
 // from the corresponding azure.Environment type at the end of the namespace host string. The default
 // is azure.PublicCloud.
-func NewHub(namespace, name string, tokenProvider auth.TokenProvider, opts ...HubOption) (*Hub, error) {
+func NewHub(namespace, name string, tokenProvider auth.TokenProvider, opts ...HubOption) (Hub, error) {
 	env := azure.PublicCloud
 	if e := os.Getenv("AZURE_ENVIRONMENT"); e != "" {
 		var err error
@@ -350,7 +382,7 @@ func NewHub(namespace, name string, tokenProvider auth.TokenProvider, opts ...Hu
 		return nil, err
 	}
 
-	h := &Hub{
+	h := &hubImpl{
 		name:               name,
 		namespace:          ns,
 		offsetPersister:    persist.NewMemoryPersister(),
@@ -385,10 +417,8 @@ func NewHub(namespace, name string, tokenProvider auth.TokenProvider, opts ...Hu
 //   2) Expected Environment Variable:
 //     - "EVENTHUB_CONNECTION_STRING" connection string from the Azure portal
 //
-//
 // AAD TokenProvider environment variables:
-//
-//   1. client Credentials: attempt to authenticate with a Service Principal via "AZURE_TENANT_ID", "AZURE_CLIENT_ID" and
+//    1. client Credentials: attempt to authenticate with a Service Principal via "AZURE_TENANT_ID", "AZURE_CLIENT_ID" and
 //     "AZURE_CLIENT_SECRET"
 //
 //   2. client Certificate: attempt to authenticate with a Service Principal via "AZURE_TENANT_ID", "AZURE_CLIENT_ID",
@@ -397,9 +427,8 @@ func NewHub(namespace, name string, tokenProvider auth.TokenProvider, opts ...Hu
 //   3. Managed Service Identity (MSI): attempt to authenticate via MSI on the default local MSI internally addressable IP
 //     and port. See: adal.GetMSIVMEndpoint()
 //
-//
 // The Azure Environment used can be specified using the name of the Azure Environment set in the AZURE_ENVIRONMENT var.
-func NewHubWithNamespaceNameAndEnvironment(namespace, name string, opts ...HubOption) (*Hub, error) {
+func NewHubWithNamespaceNameAndEnvironment(namespace, name string, opts ...HubOption) (Hub, error) {
 	var provider auth.TokenProvider
 	provider, sasErr := sas.NewTokenProvider(sas.TokenProviderWithEnvironmentVars())
 	if sasErr == nil {
@@ -420,7 +449,6 @@ func NewHubWithNamespaceNameAndEnvironment(namespace, name string, opts ...HubOp
 //   - "EVENTHUB_NAMESPACE" the namespace of the Event Hub instance
 //   - "EVENTHUB_NAME" the name of the Event Hub instance
 //
-//
 // This method depends on NewHubWithNamespaceNameAndEnvironment which will attempt to build a token provider from
 // environment variables. If unable to build a AAD Token Provider it will fall back to a SAS token provider. If neither
 // can be built, it will return error.
@@ -437,7 +465,6 @@ func NewHubWithNamespaceNameAndEnvironment(namespace, name string, opts ...HubOp
 //   2) Expected Environment Variable:
 //     - "EVENTHUB_CONNECTION_STRING" connection string from the Azure portal
 //
-//
 // AAD TokenProvider environment variables:
 //   1. client Credentials: attempt to authenticate with a Service Principal via "AZURE_TENANT_ID", "AZURE_CLIENT_ID" and
 //     "AZURE_CLIENT_SECRET"
@@ -449,7 +476,7 @@ func NewHubWithNamespaceNameAndEnvironment(namespace, name string, opts ...HubOp
 //
 //
 // The Azure Environment used can be specified using the name of the Azure Environment set in the AZURE_ENVIRONMENT var.
-func NewHubFromEnvironment(opts ...HubOption) (*Hub, error) {
+func NewHubFromEnvironment(opts ...HubOption) (Hub, error) {
 	const envErrMsg = "environment var %s must not be empty"
 	var namespace, name string
 
@@ -467,8 +494,38 @@ func NewHubFromEnvironment(opts ...HubOption) (*Hub, error) {
 // NewHubFromConnectionString creates a new Event Hub client for sending and receiving messages from a connection string
 // formatted like the following:
 //
-//   Endpoint=sb://namespace.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=superSecret1234=;EntityPath=hubName
-func NewHubFromConnectionString(connStr string, opts ...HubOption) (*Hub, error) {
+//	Endpoint=sb://namespace.servicebus.windows.net/;SharedAccessKeyName=RootManageSharedAccessKey;SharedAccessKey=superSecret1234=;EntityPath=hubName
+func NewHubFromConnectionString(connStr string, opts ...HubOption) (Hub, error) {
+	parsed, err := conn.ParsedConnectionFromStr(connStr)
+	if err != nil {
+		return nil, err
+	}
+
+	ns, err := newNamespace(namespaceWithConnectionString(connStr))
+	if err != nil {
+		return nil, err
+	}
+
+	h := &hubImpl{
+		name:               parsed.HubName,
+		namespace:          ns,
+		offsetPersister:    persist.NewMemoryPersister(),
+		userAgent:          rootUserAgent,
+		receivers:          make(map[string]*receiver),
+		senderRetryOptions: newSenderRetryOptions(),
+	}
+
+	for _, opt := range opts {
+		err := opt(h)
+		if err != nil {
+			return nil, err
+		}
+	}
+
+	return h, err
+}
+
+func NewMockHubFromConnectionString(connStr string, opts ...HubOption) (Hub, error) {
 	parsed, err := conn.ParsedConnectionFromStr(connStr)
 	if err != nil {
 		return nil, err
@@ -479,7 +536,7 @@ func NewHubFromConnectionString(connStr string, opts ...HubOption) (*Hub, error)
 		return nil, err
 	}
 
-	h := &Hub{
+	h := &hubImpl{
 		name:               parsed.HubName,
 		namespace:          ns,
 		offsetPersister:    persist.NewMemoryPersister(),
@@ -499,7 +556,7 @@ func NewHubFromConnectionString(connStr string, opts ...HubOption) (*Hub, error)
 }
 
 // GetRuntimeInformation fetches runtime information from the Event Hub management node
-func (h *Hub) GetRuntimeInformation(ctx context.Context) (*HubRuntimeInformation, error) {
+func (h *hubImpl) GetRuntimeInformation(ctx context.Context) (*HubRuntimeInformation, error) {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.GetRuntimeInformation")
 	defer span.End()
 	client := newClient(h.namespace, h.name)
@@ -525,7 +582,7 @@ func (h *Hub) GetRuntimeInformation(ctx context.Context) (*HubRuntimeInformation
 }
 
 // GetPartitionInformation fetches runtime information about a specific partition from the Event Hub management node
-func (h *Hub) GetPartitionInformation(ctx context.Context, partitionID string) (*HubPartitionRuntimeInformation, error) {
+func (h *hubImpl) GetPartitionInformation(ctx context.Context, partitionID string) (*HubPartitionRuntimeInformation, error) {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.GetPartitionInformation")
 	defer span.End()
 	client := newClient(h.namespace, h.name)
@@ -550,7 +607,7 @@ func (h *Hub) GetPartitionInformation(ctx context.Context, partitionID string) (
 }
 
 // Close drains and closes all of the existing senders, receivers and connections
-func (h *Hub) Close(ctx context.Context) error {
+func (h *hubImpl) Close(ctx context.Context) error {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.Close")
 	defer span.End()
 
@@ -582,7 +639,7 @@ func (h *Hub) Close(ctx context.Context) error {
 }
 
 // closeReceivers will close the receivers on the hub and return the last error
-func (h *Hub) closeReceivers(ctx context.Context) error {
+func (h *hubImpl) closeReceivers(ctx context.Context) error {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.closeReceivers")
 	defer span.End()
 
@@ -606,12 +663,12 @@ func (h *Hub) closeReceivers(ctx context.Context) error {
 // If Receive starts successfully, a *ListenerHandle and a nil error will be returned. The ListenerHandle exposes
 // methods which will help manage the life span of the receiver.
 //
-// ListenerHandle.Close(ctx) closes the receiver
+// # ListenerHandle.Close(ctx) closes the receiver
 //
-// ListenerHandle.Done() signals the consumer when the receiver has stopped
+// # ListenerHandle.Done() signals the consumer when the receiver has stopped
 //
 // ListenerHandle.Err() provides the last error the listener encountered and was unable to recover from
-func (h *Hub) Receive(ctx context.Context, partitionID string, handler Handler, opts ...ReceiveOption) (*ListenerHandle, error) {
+func (h *hubImpl) Receive(ctx context.Context, partitionID string, handler Handler, opts ...ReceiveOption) (*ListenerHandle, error) {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.Receive")
 	defer span.End()
 
@@ -639,7 +696,7 @@ func (h *Hub) Receive(ctx context.Context, partitionID string, handler Handler,
 // Send sends an event to the Event Hub
 //
 // Send will retry sending the message for as long as the context allows
-func (h *Hub) Send(ctx context.Context, event *Event, opts ...SendOption) error {
+func (h *hubImpl) Send(ctx context.Context, event *Event, opts ...SendOption) error {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.Send")
 	defer span.End()
 
@@ -652,7 +709,7 @@ func (h *Hub) Send(ctx context.Context, event *Event, opts ...SendOption) error
 }
 
 // SendBatch sends a batch of events to the Hub
-func (h *Hub) SendBatch(ctx context.Context, iterator BatchIterator, opts ...BatchOption) error {
+func (h *hubImpl) SendBatch(ctx context.Context, iterator BatchIterator, opts ...BatchOption) error {
 	span, ctx := h.startSpanFromContext(ctx, "eh.Hub.SendBatch")
 	defer span.End()
 
@@ -698,17 +755,17 @@ func (h *Hub) SendBatch(ctx context.Context, iterator BatchIterator, opts ...Bat
 
 // HubWithPartitionedSender configures the Hub instance to send to a specific event Hub partition
 func HubWithPartitionedSender(partitionID string) HubOption {
-	return func(h *Hub) error {
-		h.senderPartitionID = &partitionID
+	return func(h Hub) error {
+		h.(*hubImpl).senderPartitionID = &partitionID
 		return nil
 	}
 }
 
 // HubWithOffsetPersistence configures the Hub instance to read and write offsets so that if a Hub is interrupted, it
 // can resume after the last consumed event.
 func HubWithOffsetPersistence(offsetPersister persist.CheckpointPersister) HubOption {
-	return func(h *Hub) error {
-		h.offsetPersister = offsetPersister
+	return func(h Hub) error {
+		h.(*hubImpl).offsetPersister = offsetPersister
 		return nil
 	}
 }
@@ -719,25 +776,25 @@ func HubWithOffsetPersistence(offsetPersister persist.CheckpointPersister) HubOp
 //
 // Max user agent length is specified by the const maxUserAgentLen.
 func HubWithUserAgent(userAgent string) HubOption {
-	return func(h *Hub) error {
-		return h.appendAgent(userAgent)
+	return func(h Hub) error {
+		return h.(*hubImpl).appendAgent(userAgent)
 	}
 }
 
 // HubWithEnvironment configures the Hub to use the specified environment.
 //
 // By default, the Hub instance will use Azure US Public cloud environment
 func HubWithEnvironment(env azure.Environment) HubOption {
-	return func(h *Hub) error {
-		h.namespace.host = "amqps://" + h.namespace.name + "." + env.ServiceBusEndpointSuffix
+	return func(h Hub) error {
+		h.(*hubImpl).namespace.host = "amqps://" + h.(*hubImpl).namespace.name + "." + env.ServiceBusEndpointSuffix
 		return nil
 	}
 }
 
 // HubWithWebSocketConnection configures the Hub to use a WebSocket connection wss:// rather than amqps://
 func HubWithWebSocketConnection() HubOption {
-	return func(h *Hub) error {
-		h.namespace.useWebSocket = true
+	return func(h Hub) error {
+		h.(*hubImpl).namespace.useWebSocket = true
 		return nil
 	}
 }
@@ -746,13 +803,13 @@ func HubWithWebSocketConnection() HubOption {
 // in addition to the original attempt.
 // 0 indicates no retries, and < 0 will cause infinite retries.
 func HubWithSenderMaxRetryCount(maxRetryCount int) HubOption {
-	return func(h *Hub) error {
-		h.senderRetryOptions.maxRetries = maxRetryCount
+	return func(h Hub) error {
+		h.(*hubImpl).senderRetryOptions.maxRetries = maxRetryCount
 		return nil
 	}
 }
 
-func (h *Hub) appendAgent(userAgent string) error {
+func (h *hubImpl) appendAgent(userAgent string) error {
 	ua := path.Join(h.userAgent, userAgent)
 	if len(ua) > maxUserAgentLen {
 		return fmt.Errorf("user agent string has surpassed the max length of %d", maxUserAgentLen)
@@ -761,7 +818,7 @@ func (h *Hub) appendAgent(userAgent string) error {
 	return nil
 }
 
-func (h *Hub) getSender(ctx context.Context) (*sender, error) {
+func (h *hubImpl) getSender(ctx context.Context) (*sender, error) {
 	h.senderMu.Lock()
 	defer h.senderMu.Unlock()