Client example: Renamed concept "Session" to "Client"

The concept of a session does not exist in AMQP/RabbitMQ.
This client connect example names the library wrapper "session".
The name can be confusing, because it is not usually known in
the AMQP/RabbitMQ env or Go env.

example_client_test.go

@@ -15,7 +15,7 @@ import (
 	amqp "github.com/rabbitmq/amqp091-go"
 )
 
-// This exports a Session object that wraps this library. It
+// This exports a Client object that wraps this library. It
 // automatically reconnects when the connection fails, and
 // blocks all pushes until the connection succeeds. It also
 // confirms every outgoing message, so none are lost.
@@ -40,7 +40,7 @@ func Example() {
 	}
 }
 
-type Session struct {
+type Client struct {
 	name            string
 	logger          *log.Logger
 	connection      *amqp.Connection
@@ -66,93 +66,93 @@ const (
 var (
 	errNotConnected  = errors.New("not connected to a server")
 	errAlreadyClosed = errors.New("already closed: not connected to the server")
-	errShutdown      = errors.New("session is shutting down")
+	errShutdown      = errors.New("client is shutting down")
 )
 
 // New creates a new consumer state instance, and automatically
 // attempts to connect to the server.
-func New(name string, addr string) *Session {
-	session := Session{
+func New(name string, addr string) *Client {
+	client := Client{
 		logger: log.New(os.Stdout, "", log.LstdFlags),
 		name:   name,
 		done:   make(chan bool),
 	}
-	go session.handleReconnect(addr)
-	return &session
+	go client.handleReconnect(addr)
+	return &client
 }
 
 // handleReconnect will wait for a connection error on
 // notifyConnClose, and then continuously attempt to reconnect.
-func (session *Session) handleReconnect(addr string) {
+func (client *Client) handleReconnect(addr string) {
 	for {
-		session.isReady = false
-		session.logger.Println("Attempting to connect")
+		client.isReady = false
+		client.logger.Println("Attempting to connect")
 
-		conn, err := session.connect(addr)
+		conn, err := client.connect(addr)
 
 		if err != nil {
-			session.logger.Println("Failed to connect. Retrying...")
+			client.logger.Println("Failed to connect. Retrying...")
 
 			select {
-			case <-session.done:
+			case <-client.done:
 				return
 			case <-time.After(reconnectDelay):
 			}
 			continue
 		}
 
-		if done := session.handleReInit(conn); done {
+		if done := client.handleReInit(conn); done {
 			break
 		}
 	}
 }
 
 // connect will create a new AMQP connection
-func (session *Session) connect(addr string) (*amqp.Connection, error) {
+func (client *Client) connect(addr string) (*amqp.Connection, error) {
 	conn, err := amqp.Dial(addr)
 
 	if err != nil {
 		return nil, err
 	}
 
-	session.changeConnection(conn)
-	session.logger.Println("Connected!")
+	client.changeConnection(conn)
+	client.logger.Println("Connected!")
 	return conn, nil
 }
 
 // handleReconnect will wait for a channel error
 // and then continuously attempt to re-initialize both channels
-func (session *Session) handleReInit(conn *amqp.Connection) bool {
+func (client *Client) handleReInit(conn *amqp.Connection) bool {
 	for {
-		session.isReady = false
+		client.isReady = false
 
-		err := session.init(conn)
+		err := client.init(conn)
 
 		if err != nil {
-			session.logger.Println("Failed to initialize channel. Retrying...")
+			client.logger.Println("Failed to initialize channel. Retrying...")
 
 			select {
-			case <-session.done:
+			case <-client.done:
 				return true
 			case <-time.After(reInitDelay):
 			}
 			continue
 		}
 
 		select {
-		case <-session.done:
+		case <-client.done:
 			return true
-		case <-session.notifyConnClose:
-			session.logger.Println("Connection closed. Reconnecting...")
+		case <-client.notifyConnClose:
+			client.logger.Println("Connection closed. Reconnecting...")
 			return false
-		case <-session.notifyChanClose:
-			session.logger.Println("Channel closed. Re-running init...")
+		case <-client.notifyChanClose:
+			client.logger.Println("Channel closed. Re-running init...")
 		}
 	}
 }
 
 // init will initialize channel & declare queue
-func (session *Session) init(conn *amqp.Connection) error {
+func (client *Client) init(conn *amqp.Connection) error {
 	ch, err := conn.Channel()
 
 	if err != nil {
@@ -165,7 +165,7 @@ func (session *Session) init(conn *amqp.Connection) error {
 		return err
 	}
 	_, err = ch.QueueDeclare(
-		session.name,
+		client.name,
 		false, // Durable
 		false, // Delete when unused
 		false, // Exclusive
@@ -177,76 +177,76 @@ func (session *Session) init(conn *amqp.Connection) error {
 		return err
 	}
 
-	session.changeChannel(ch)
-	session.isReady = true
-	session.logger.Println("Setup!")
+	client.changeChannel(ch)
+	client.isReady = true
+	client.logger.Println("Setup!")
 
 	return nil
 }
 
 // changeConnection takes a new connection to the queue,
 // and updates the close listener to reflect this.
-func (session *Session) changeConnection(connection *amqp.Connection) {
-	session.connection = connection
-	session.notifyConnClose = make(chan *amqp.Error)
-	session.connection.NotifyClose(session.notifyConnClose)
+func (client *Client) changeConnection(connection *amqp.Connection) {
+	client.connection = connection
+	client.notifyConnClose = make(chan *amqp.Error)
+	client.connection.NotifyClose(client.notifyConnClose)
 }
 
 // changeChannel takes a new channel to the queue,
 // and updates the channel listeners to reflect this.
-func (session *Session) changeChannel(channel *amqp.Channel) {
-	session.channel = channel
-	session.notifyChanClose = make(chan *amqp.Error)
-	session.notifyConfirm = make(chan amqp.Confirmation, 1)
-	session.channel.NotifyClose(session.notifyChanClose)
-	session.channel.NotifyPublish(session.notifyConfirm)
+func (client *Client) changeChannel(channel *amqp.Channel) {
+	client.channel = channel
+	client.notifyChanClose = make(chan *amqp.Error)
+	client.notifyConfirm = make(chan amqp.Confirmation, 1)
+	client.channel.NotifyClose(client.notifyChanClose)
+	client.channel.NotifyPublish(client.notifyConfirm)
 }
 
 // Push will push data onto the queue, and wait for a confirm.
 // If no confirms are received until within the resendTimeout,
 // it continuously re-sends messages until a confirm is received.
 // This will block until the server sends a confirm. Errors are
 // only returned if the push action itself fails, see UnsafePush.
-func (session *Session) Push(data []byte) error {
-	if !session.isReady {
+func (client *Client) Push(data []byte) error {
+	if !client.isReady {
 		return errors.New("failed to push: not connected")
 	}
 	for {
-		err := session.UnsafePush(data)
+		err := client.UnsafePush(data)
 		if err != nil {
-			session.logger.Println("Push failed. Retrying...")
+			client.logger.Println("Push failed. Retrying...")
 			select {
-			case <-session.done:
+			case <-client.done:
 				return errShutdown
 			case <-time.After(resendDelay):
 			}
 			continue
 		}
 		select {
-		case confirm := <-session.notifyConfirm:
+		case confirm := <-client.notifyConfirm:
 			if confirm.Ack {
-				session.logger.Println("Push confirmed!")
+				client.logger.Println("Push confirmed!")
 				return nil
 			}
 		case <-time.After(resendDelay):
 		}
-		session.logger.Println("Push didn't confirm. Retrying...")
+		client.logger.Println("Push didn't confirm. Retrying...")
 	}
 }
 
 // UnsafePush will push to the queue without checking for
 // confirmation. It returns an error if it fails to connect.
 // No guarantees are provided for whether the server will
 // receive the message.
-func (session *Session) UnsafePush(data []byte) error {
-	if !session.isReady {
+func (client *Client) UnsafePush(data []byte) error {
+	if !client.isReady {
 		return errNotConnected
 	}
-	return session.channel.Publish(
-		"",           // Exchange
-		session.name, // Routing key
-		false,        // Mandatory
-		false,        // Immediate
+	return client.channel.Publish(
+		"",          // Exchange
+		client.name, // Routing key
+		false,       // Mandatory
+		false,       // Immediate
 		amqp.Publishing{
 			ContentType: "text/plain",
 			Body:        data,
@@ -258,12 +258,12 @@ func (session *Session) UnsafePush(data []byte) error {
 // It is required to call delivery.Ack when it has been
 // successfully processed, or delivery.Nack when it fails.
 // Ignoring this will cause data to build up on the server.
-func (session *Session) Stream() (<-chan amqp.Delivery, error) {
-	if !session.isReady {
+func (client *Client) Stream() (<-chan amqp.Delivery, error) {
+	if !client.isReady {
 		return nil, errNotConnected
 	}
-	return session.channel.Consume(
-		session.name,
+	return client.channel.Consume(
+		client.name,
 		"",    // Consumer
 		false, // Auto-Ack
 		false, // Exclusive
@@ -274,20 +274,20 @@ func (session *Session) Stream() (<-chan amqp.Delivery, error) {
 }
 
 // Close will cleanly shutdown the channel and connection.
-func (session *Session) Close() error {
-	if !session.isReady {
+func (client *Client) Close() error {
+	if !client.isReady {
 		return errAlreadyClosed
 	}
-	close(session.done)
-	err := session.channel.Close()
+	close(client.done)
+	err := client.channel.Close()
 	if err != nil {
 		return err
 	}
-	err = session.connection.Close()
+	err = client.connection.Close()
 	if err != nil {
 		return err
 	}
 
-	session.isReady = false
+	client.isReady = false
 	return nil
 }