azservicebus

package module
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 Go to latest Published: Oct 5, 2021 License: MIT Imports: 14 Imported by: 50

README

Azure Service Bus Client Module for Go

Azure Service Bus is a highly-reliable cloud messaging service from Microsoft.

Use the client library github.com/Azure/azure-sdk-for-go/sdk/messaging/azservicebus in your application to:

  • Send messages to an Azure Service Bus Queue or Topic
  • Receive messages from an Azure Service Bus Queue or Subscription

NOTE: This library is currently a preview. There may be breaking interface changes until it reaches semantic version v1.0.0.

Key links:

Getting started

Install the package

Install the Azure Service Bus client module for Go with go get:

go get github.com/Azure/azure-sdk-for-go/sdk/messaging/azservicebus
Prerequisites
Authenticate the client

The Service Bus Client can be created using a Service Bus connection string or a credential from the Azure Identity package, like DefaultAzureCredential.

Using a connection string
import (
  "log"
  "github.com/Azure/azure-sdk-for-go/sdk/messaging/azservicebus"
)

func main() {
  client, err := azservicebus.NewClientWithConnectionString("<Service Bus connection string>")
 
  if err != nil {
    log.Fatalf("Failed to create Service Bus Client: %s", err.Error())
  }
}
Using an Azure Active Directory Credential
import (
  "log"
  "github.com/Azure/azure-sdk-for-go/sdk/azidentity"
  "github.com/Azure/azure-sdk-for-go/sdk/messaging/azservicebus"
)

func main() {
  // For more information about the DefaultAzureCredential:
  // https://pkg.go.dev/github.com/Azure/azure-sdk-for-go/sdk/azidentity#NewDefaultAzureCredential
  cred, err := azidentity.NewDefaultAzureCredential(nil)

  if err != nil {
    log.Fatalf("Failed creating DefaultAzureCredential: %s", err.Error())
  }

  client, err := azservicebus.NewClient("<ex: my-service-bus.servicebus.windows.net>", cred)

  if err != nil {
    log.Fatalf("Failed to create Service Bus Client: %s", err.Error())
  }
}

Key concepts

Once you've created a Client, you can interact with resources within a Service Bus Namespace:

  • Queues: Allows for sending and receiving messages. Often used for point-to-point communication.
  • Topics: As opposed to Queues, Topics are better suited to publish/subscribe scenarios. A topic can be sent to, but requires a subscription, of which there can be multiple in parallel, to consume from.
  • Subscriptions: The mechanism to consume from a Topic. Each subscription is independent, and receives a copy of each message sent to the topic. Rules and Filters can be used to tailor which messages are received by a specific subscription.

For more information about these resources, see What is Azure Service Bus?.

Using a Client you can do the following:

Please note that the Queues, Topics and Subscriptions should be created prior to using this library.

Examples

The following sections provide code snippets that cover some of the common tasks using Azure Service Bus

Send messages

Once you've created a Client you can create a Sender, which will allow you to send messages.

NOTE: Creating a client is covered in the "Authenticate the client" section of the readme.

sender, err := client.NewSender("<queue or topic>")

if err != nil {
  log.Fatalf("Failed to create Sender: %s", err.Error())
}

// send a single message
err = sender.SendMessage(context.TODO(), &azservicebus.Message{
  Body: []byte("hello world!"),
})

You can also send messages in batches, which can be more efficient than sending them individually

// Create a message batch. It will automatically be sized for the Service Bus
// Namespace's maximum message size.
messageBatch, err := sender.NewMessageBatch(context.TODO())

if err != nil {
  log.Fatalf("Failed to create a message batch: %s", err.Error())
}

// Add a message using TryAdd.
// This can be called multiple times, and will return (false, nil)
// if the message cannot be added because the batch is full.
added, err := messageBatch.TryAdd(&azservicebus.Message{
    Body: []byte(fmt.Sprintf("hello world")),
})

if err != nil {
  log.Fatalf("Failed to add message to batch because of an error: %s", err.Error())
}

if !added {
  log.Printf("Message batch is full. We should send it and create a new one.")
  err := sender.SendMessageBatch(context.TODO(), messageBatch)

  if err != nil {
    log.Fatalf("Failed to send message batch: %s", err.Error())
  }

  // add the next message to a new batch and start again.
}
Receive messages

Once you've created a Client you can create a Processor, which will allow you to receive messages.

The Processor handles error recovery internally, making it a good fit for applications where the intention is to stream and process events for an extended period of time.

NOTE: Creating a client is covered in the "Authenticate the client" section of the readme.

processor, err := client.NewProcessorForQueue(
  "<queue>",
  &azservicebus.ProcessorOptions{
    // NOTE: this is a parameter you'll want to tune. It controls the number of
    // active message `handleMessage` calls that the processor will allow at any time.
    MaxConcurrentCalls: 1,
    ReceiveMode:        azservicebus.PeekLock,
    ManualComplete:     false,
  },
)
// or
// client.NewProcessorForSubscription("<topic>", "<subscription>")

if err != nil {
  log.Fatalf("Failed to create the processor: %s", err.Error())
}

handleMessage := func(message *azservicebus.ReceivedMessage) error {
  // This is where your logic for handling messages goes
  yourLogicForProcessing(message)
  return nil
}

handleError := func(err error) {
  // handleError will be called on errors that are noteworthy
  // but the Processor internally will continue to attempt to 
  // recover.
  
  // NOTE: errors returned from `handleMessage` above will also be 
  // sent here, but do not affect the running of the Processor
  // itself.

  // We'll just print these out, as they're informational and
  // can indicate if there are longer lived problems that we might
  // want to resolve manually (for instance, longer term network
  // outages, or issues affecting your `handleMessage` handler)
  log.Printf("Error: %s", err.Error())
}

err := processor.Start(context.TODO(), handleMessage, handleError)

if err != nil {
  log.Printf("Processor loop has exited: %s", err.Error())
}

err := processor.Close(context.TODO())

if err != nil {
  log.Printf("Processor failed to close: %s", err.Error())
}

Once you've created a Client you can create a Receiver, which will allow you to receive messages.

The Receiver is a good fit for applications that want to receive messages in fixed increments, rather than continually streaming messages, as the Processor does.

NOTE: Creating a client is covered in the "Authenticate the client" section of the readme.

receiver, err := client.NewReceiverForQueue(
  "<queue>",
  &azservicebus.ReceiverOptions{
    ReceiveMode: azservicebus.PeekLock,
  },
)
// or
// client.NewReceiverForSubscription("<topic>", "<subscription>")

if err != nil {
  log.Fatalf("Failed to create the receiver: %s", err.Error())
}

// Receive a fixed set of messages. Note that the number of messages
// to receive and the amount of time to wait are upper bounds. 
messages, err := receiver.ReceiveMessages(context.TODO(), 
  // The number of messages to receive. Note this is merely an upper
  // bound. It is possible to get fewer message (or zero), depending
  // on the contents of the remote queue or subscription and network
  // conditions.
  10, 
  &azservicebus.ReceiveOptions{
		// This configures the amount of time to wait for messages to arrive.
		// Note that this is merely an upper bound. It is possible to get messages
		// faster than the duration specified.
		MaxWaitTime: 60 * time.Second,
	},
)

if err != nil {
  log.Fatalf("Failed to get messages: %s", err.Error())
}

for _, message := range messages {
  // process the message here (or in parallel)
  yourLogicForProcessing(message)  

  // For more information about settling messages:
  // https://docs.microsoft.com/azure/service-bus-messaging/message-transfers-locks-settlement#settling-receive-operations
  if err := receiver.CompleteMessage(message); err != nil {
    log.Printf("Error completing message: %s", err.Error())
  }
}
Dead letter queue

The dead letter queue is a sub-queue. Each queue or subscription has its own dead letter queue. Dead letter queues store messages that have been explicitly dead lettered via the Processor.DeadLetterMessage or Receiver.DeadLetterMessage functions.

Opening a dead letter queue is just a configuration option when creating a Processor or Receiver.

NOTE: Creating a client is covered in the "Authenticate the client" section of the readme.


deadLetterReceiver, err := client.NewProcessorForQueue("<queue>",
  &azservicebus.ProcessorOptions{
    SubQueue: azservicebus.SubQueueDeadLetter,
  })
// or 
// client.NewProcessorForSubscription("<topic>", "<subscription>", 
//   &azservicebus.ProcessorOptions{
//      SubQueue: azservicebus.SubQueueDeadLetter,
//   })

deadLetterReceiver, err := client.NewReceiverForQueue("<queue>",
  &azservicebus.ReceiverOptions{
	  SubQueue: azservicebus.SubQueueDeadLetter,
  })
// or 
// client.NewReceiverForSubscription("<topic>", "<subscription>", 
//   &azservicebus.ReceiverOptions{
//     SubQueue: azservicebus.SubQueueDeadLetter,
//   })

To see some example code for receiving messages using the Processor or Receiver see the "Receive messages" sample.

Next steps

Please take a look at the samples for detailed examples on how to use this library to send and receive messages to/from Service Bus Queues, Topics and Subscriptions.

Contributing

If you'd like to contribute to this library, please read the contributing guide to learn more about how to build and test the code.

Impressions

Documentation

Overview

Package azservicebus provides clients for sending and receiving messages with Azure ServiceBus as well as modifying resources like Queues, Topics and Subscriptions.

Index

Examples

Constants

This section is empty.

Variables

This section is empty.

Functions

This section is empty.

Types

type Client 

type Client struct {
	// contains filtered or unexported fields
}

Client provides methods to create Sender, Receiver and Processor instances to send and receive messages from Service Bus.

func NewClient 

func NewClient(fullyQualifiedNamespace string, credential azcore.TokenCredential, options *ClientOptions) (*Client, error)

NewClient creates a new Client for a Service Bus namespace, using a TokenCredential. A Client allows you create receivers (for queues or subscriptions) and senders (for queues and topics). fullyQualifiedNamespace is the Service Bus namespace name (ex: myservicebus.servicebus.windows.net) credential is one of the credentials in the `github.com/Azure/azure-sdk-for-go/sdk/azidentity` package.

Example 
// NOTE: If you'd like to authenticate using a Service Bus connection string
// look at `NewClientWithConnectionString` instead.

credential, err := azidentity.NewDefaultAzureCredential(nil)
exitOnError("Failed to create a DefaultAzureCredential", err)

client, err = azservicebus.NewClient("<ex: myservicebus.servicebus.windows.net>", credential, nil)
exitOnError("Failed to create ServiceBusClient in example", err)

Output:

func NewClientWithConnectionString 

func NewClientWithConnectionString(connectionString string, options *ClientOptions) (*Client, error)

NewClient creates a new Client for a Service Bus namespace, using a TokenCredential. A Client allows you create receivers (for queues or subscriptions) and senders (for queues and topics). connectionString is a Service Bus connection string for the namespace or for an entity.

Example 
// NOTE: If you'd like to authenticate via Azure Active Directory look at
// the `NewClient` function instead.

client, err = azservicebus.NewClientWithConnectionString(connectionString, nil)
exitOnError("Failed to create ServiceBusClient in example", err)

Output:

func (*Client) Close 

func (client *Client) Close(ctx context.Context) error

Close closes the current connection Service Bus as well as any Sender, Receiver or Processors created using this client.

func (*Client) NewProcessorForQueue 

func (client *Client) NewProcessorForQueue(queue string, options *ProcessorOptions) (*Processor, error)

NewProcessor creates a Processor for a queue.

Example 
processor, err = client.NewProcessorForQueue(
	queueName,
	&azservicebus.ProcessorOptions{
		// NOTE: this is a parameter you'll want to tune. It controls the number of
		// active message `handleMessage` calls that the processor will allow at any time.
		MaxConcurrentCalls: 1,
		ReceiveMode:        azservicebus.PeekLock,
		ManualComplete:     false,
	},
)
exitOnError("Failed to create Processor", err)

Output:

func (*Client) NewProcessorForSubscription 

func (client *Client) NewProcessorForSubscription(topic string, subscription string, options *ProcessorOptions) (*Processor, error)

NewProcessor creates a Processor for a subscription.

Example 
processor, err = client.NewProcessorForSubscription(
	topicName,
	subscriptionName,
	&azservicebus.ProcessorOptions{
		// NOTE: this is a parameter you'll want to tune. It controls the number of
		// active message `handleMessage` calls that the processor will allow at any time.
		MaxConcurrentCalls: 1,
		ReceiveMode:        azservicebus.PeekLock,
		ManualComplete:     false,
	},
)
exitOnError("Failed to create Processor", err)

Output:

func (*Client) NewReceiverForQueue 

func (client *Client) NewReceiverForQueue(queue string, options *ReceiverOptions) (*Receiver, error)

NewReceiver creates a Receiver for a queue. A receiver allows you to receive messages.

Example 
receiver, err = client.NewReceiverForQueue(
	queueName,
	&azservicebus.ReceiverOptions{
		ReceiveMode: azservicebus.PeekLock,
	},
)
exitOnError("Failed to create Receiver", err)

Output:

func (*Client) NewReceiverForSubscription 

func (client *Client) NewReceiverForSubscription(topic string, subscription string, options *ReceiverOptions) (*Receiver, error)

NewReceiver creates a Receiver for a subscription. A receiver allows you to receive messages.

Example 
receiver, err = client.NewReceiverForSubscription(
	topicName,
	subscriptionName,
	&azservicebus.ReceiverOptions{
		ReceiveMode: azservicebus.PeekLock,
	},
)
exitOnError("Failed to create receiver", err)

Output:

func (*Client) NewSender 

func (client *Client) NewSender(queueOrTopic string) (*Sender, error)

NewSender creates a Sender, which allows you to send messages or schedule messages.

Example 
sender, err = client.NewSender(queueName) // or topicName
exitOnError("Failed to create sender", err)

Output:

type ClientOptions 

type ClientOptions struct {
	// TLSConfig configures a client with a custom *tls.Config.
	TLSConfig *tls.Config
}

ClientOptions contains options for the `NewClient` and `NewClientWithConnectionString` functions.

type DeadLetterOptions 

type DeadLetterOptions struct {
	// ErrorDescription that caused the dead lettering of the message.
	ErrorDescription *string

	// Reason for dead lettering the message.
	Reason *string

	// PropertiesToModify specifies properties to modify in the message when it is dead lettered.
	PropertiesToModify map[string]interface{}
}

DeadLetterOptions describe the reason and error description for dead lettering a message using the `Receiver.DeadLetterMessage()`

type Message 

type Message struct {
	ID string

	ContentType   string
	CorrelationID string
	// Body corresponds to the first []byte array in the Data section of an AMQP message.
	Body             []byte
	SessionID        *string
	Subject          string
	ReplyTo          string
	ReplyToSessionID string
	To               string
	TimeToLive       *time.Duration

	PartitionKey            *string
	TransactionPartitionKey *string
	ScheduledEnqueueTime    *time.Time

	ApplicationProperties map[string]interface{}
	Format                uint32
}

Message is a SendableMessage which can be sent using a Client.NewSender().

func (*Message) GetKeyValues 

func (m *Message) GetKeyValues() map[string]interface{}

GetKeyValues implements tab.Carrier

func (*Message) Set 

func (m *Message) Set(key string, value interface{})

Set implements tab.Carrier

type MessageBatch 

type MessageBatch struct {
	// contains filtered or unexported fields
}

MessageBatch represents a batch of messages to send to Service Bus in a single message

func (*MessageBatch) Add 

func (mb *MessageBatch) Add(m *Message) (bool, error)

Add adds a message to the batch if the message will not exceed the max size of the batch This function will return: (true, nil) if the message was added. (false, nil) if the message was too large to fit into the batch. (false, err) if an error occurs when adding the message.

func (*MessageBatch) Len 

func (mb *MessageBatch) Len() int

Len returns the # of messages in the batch.

func (*MessageBatch) Size 

func (mb *MessageBatch) Size() int

Size is the number of bytes in the message batch

type MessageBatchOptions 

type MessageBatchOptions struct {
	// MaxSizeInBytes overrides the max size (in bytes) for a batch.
	// By default NewMessageBatch will use the max message size provided by the service.
	MaxSizeInBytes int
}

MessageBatchOptions contains options for the `Sender.NewMessageBatch` function.

type PeekOptions 

type PeekOptions struct {
	// FromSequenceNumber is the sequence number to start with when peeking messages.
	FromSequenceNumber *int64
}

PeekOptions contains options for the `Receiver.PeekMessages` function.

type Processor 

type Processor struct {
	// contains filtered or unexported fields
}

Processor is a push-based receiver for Service Bus.

func (*Processor) AbandonMessage 

func (p *Processor) AbandonMessage(ctx context.Context, message *ReceivedMessage) error

AbandonMessage will cause a message to be returned to the queue or subscription. This will increment its delivery count, and potentially cause it to be dead lettered depending on your queue or subscription's configuration.

func (*Processor) Close 

func (p *Processor) Close(ctx context.Context) error

Close will wait for any pending callbacks to complete. NOTE: Close() cannot be called synchronously in a message or error handler. You must run it asynchronously using `go processor.Close(ctx)` or similar.

Example 
err = processor.Close(context.TODO())
exitOnError("Processor failed to close", err)

Output:

func (*Processor) CompleteMessage 

func (p *Processor) CompleteMessage(ctx context.Context, message *ReceivedMessage) error

CompleteMessage completes a message, deleting it from the queue or subscription.

func (*Processor) DeadLetterMessage 

func (p *Processor) DeadLetterMessage(ctx context.Context, message *ReceivedMessage, options *DeadLetterOptions) error

DeadLetterMessage settles a message by moving it to the dead letter queue for a queue or subscription. To receive these messages create a processor with `Client.NewProcessorForQueue()` or `Client.NewProcessorForSubscription()` using the `ProcessorOptions.SubQueue` option.

func (*Processor) DeferMessage 

func (p *Processor) DeferMessage(ctx context.Context, message *ReceivedMessage) error

DeferMessage will cause a message to be deferred. Deferred messages can be received using `Receiver.ReceiveDeferredMessages`.

func (*Processor) Start 

func (p *Processor) Start(ctx context.Context, handleMessage func(message *ReceivedMessage) error, handleError func(err error)) error

Start will start receiving messages from the queue or subscription. 

if err := processor.Start(context.TODO(), messageHandler, errorHandler); err != nil {
  log.Fatalf("Processor failed to start: %s", err.Error())
}

Any errors that occur (such as network disconnects, failures in handleMessage) will be sent to your handleError function. The processor will retry and restart as needed - no user intervention is required.

Example 
handleMessage := func(message *azservicebus.ReceivedMessage) error {
	// This is where your logic for handling messages goes
	yourLogicForProcessing(message)

	// 'AutoComplete' (enabled by default, and controlled by `ProcessorWithAutoComplete`)
	// will use this return value to determine how it should settle your message.
	//
	// Non-nil errors will cause your message to be Abandon()'d.
	// Nil errors will cause your message to be Complete'd.
	return nil
}

handleError := func(err error) {
	// handleError will be called on errors that are noteworthy
	// but the Processor internally will continue to attempt to
	// recover.

	// NOTE: errors returned from `handleMessage` above will also be
	// sent here, but do not affect the running of the Processor
	// itself.

	// We'll just print these out, as they're informational and
	// can indicate if there are longer lived problems that we might
	// want to resolve manually (for instance, longer term network
	// outages, or issues affecting your `handleMessage` handler)
	log.Printf("Error: %s", err.Error())
}

err = processor.Start(context.TODO(), handleMessage, handleError)
exitOnError("Failed to start Processor", err)

Output:

type ProcessorOptions 

type ProcessorOptions struct {
	// ReceiveMode controls when a message is deleted from Service Bus.
	//
	// `azservicebus.PeekLock` is the default. The message is locked, preventing multiple
	// receivers from processing the message at once. You control the lock state of the message
	// using one of the message settlement functions like processor.CompleteMessage(), which removes
	// it from Service Bus, or processor.AbandonMessage(), which makes it available again.
	//
	// `azservicebus.ReceiveAndDelete` causes Service Bus to remove the message as soon
	// as it's received.
	//
	// More information about receive modes:
	// https://docs.microsoft.com/azure/service-bus-messaging/message-transfers-locks-settlement#settling-receive-operations
	ReceiveMode ReceiveMode

	// SubQueue should be set to connect to the sub queue (ex: dead letter queue)
	// of the queue or subscription.
	SubQueue SubQueue

	// ManualComplete controls whether messages must be settled explicitly via the
	// settlement methods (ie, Complete, Abandon) or if the
	// processor will automatically settle messages.
	//
	// If true, no automatic settlement is done.
	// If false, the return value of your `handleMessage` function will control if the
	// message is abandoned (non-nil error return) or completed (nil error return).
	//
	// This option is enabled, by default.
	ManualComplete bool

	// MaxConcurrentCalls controls the maximum number of message processing
	// goroutines that are active at any time.
	// Default is 1.
	MaxConcurrentCalls int
}

ProcessorOptions contains options for the `Client.NewProcessorForQueue` or `Client.NewProcessorForSubscription` functions.

type ReceiveMode 

type ReceiveMode = internal.ReceiveMode

ReceiveMode represents the lock style to use for a receiver - either `PeekLock` or `ReceiveAndDelete` 

const (
	// PeekLock will lock messages as they are received and can be settled
	// using the Receiver or Processor's (Complete|Abandon|DeadLetter|Defer)Message
	// functions.
	PeekLock ReceiveMode = internal.PeekLock
	// ReceiveAndDelete will delete messages as they are received.
	ReceiveAndDelete ReceiveMode = internal.ReceiveAndDelete
)

type ReceiveOptions 

type ReceiveOptions struct {
	// MaxWaitTime configures how long to wait for the first
	// message in a set of messages to arrive.
	// Default: 60 seconds
	MaxWaitTime time.Duration
	// contains filtered or unexported fields
}

ReceiveOptions are options for the ReceiveMessages function.

type ReceivedMessage 

type ReceivedMessage struct {
	Message

	LockToken              [16]byte
	DeliveryCount          uint32
	LockedUntil            *time.Time // `mapstructure:"x-opt-locked-until"`
	SequenceNumber         *int64     // :"x-opt-sequence-number"`
	EnqueuedSequenceNumber *int64     // :"x-opt-enqueue-sequence-number"`
	EnqueuedTime           *time.Time // :"x-opt-enqueued-time"`
	DeadLetterSource       *string    // :"x-opt-deadletter-source"`
	// contains filtered or unexported fields
}

ReceivedMessage is a received message from a Client.NewReceiver() or Client.NewProcessor().

type Receiver 

type Receiver struct {
	// contains filtered or unexported fields
}

Receiver receives messages using pull based functions (ReceiveMessages). For push-based receiving via callbacks look at the `Processor` type.

func (*Receiver) AbandonMessage 

func (r *Receiver) AbandonMessage(ctx context.Context, message *ReceivedMessage) error

AbandonMessage will cause a message to be returned to the queue or subscription. This will increment its delivery count, and potentially cause it to be dead lettered depending on your queue or subscription's configuration.

func (*Receiver) Close 

func (r *Receiver) Close(ctx context.Context) error

Close permanently closes the receiver.

func (*Receiver) CompleteMessage 

func (r *Receiver) CompleteMessage(ctx context.Context, message *ReceivedMessage) error

CompleteMessage completes a message, deleting it from the queue or subscription.

func (*Receiver) DeadLetterMessage 

func (r *Receiver) DeadLetterMessage(ctx context.Context, message *ReceivedMessage, options *DeadLetterOptions) error

DeadLetterMessage settles a message by moving it to the dead letter queue for a queue or subscription. To receive these messages create a receiver with `Client.NewReceiverForQueue()` or `Client.NewReceiverForSubscription()` using the `ReceiverOptions.SubQueue` option.

func (*Receiver) DeferMessage 

func (r *Receiver) DeferMessage(ctx context.Context, message *ReceivedMessage) error

DeferMessage will cause a message to be deferred. Deferred messages can be received using `Receiver.ReceiveDeferredMessages`.

func (*Receiver) PeekMessages 

func (r *Receiver) PeekMessages(ctx context.Context, maxMessageCount int, options *PeekOptions) ([]*ReceivedMessage, error)

PeekMessages will peek messages without locking or deleting messages. Messages that are peeked do not have lock tokens, so settlement methods like CompleteMessage, AbandonMessage, DeferMessage or DeadLetterMessage will not work with them.

func (*Receiver) ReceiveDeferredMessage 

func (r *Receiver) ReceiveDeferredMessage(ctx context.Context, sequenceNumber int64) (*ReceivedMessage, error)

ReceiveDeferredMessage receives a single message that was deferred using `Receiver.DeferMessage`.

func (*Receiver) ReceiveDeferredMessages 

func (r *Receiver) ReceiveDeferredMessages(ctx context.Context, sequenceNumbers []int64) ([]*ReceivedMessage, error)

ReceiveDeferredMessages receives messages that were deferred using `Receiver.DeferMessage`.

func (*Receiver) ReceiveMessage 

func (r *Receiver) ReceiveMessage(ctx context.Context, options *ReceiveOptions) (*ReceivedMessage, error)

ReceiveMessage receives a single message, waiting up to `ReceiveOptions.MaxWaitTime` (default: 60 seconds)

func (*Receiver) ReceiveMessages 

func (r *Receiver) ReceiveMessages(ctx context.Context, maxMessages int, options *ReceiveOptions) ([]*ReceivedMessage, error)

ReceiveMessages receives a fixed number of messages, up to numMessages. There are two timeouts involved in receiving messages:

  1. An explicit timeout set with `ReceiveOptions.MaxWaitTime` (default: 60 seconds)
  2. An implicit timeout (default: 1 second) that starts after the first message has been received.
Example 
// Receive a fixed set of messages. Note that the number of messages
// to receive and the amount of time to wait are upper bounds.
messages, err = receiver.ReceiveMessages(context.TODO(),
	// The number of messages to receive. Note this is merely an upper
	// bound. It is possible to get fewer message (or zero), depending
	// on the contents of the remote queue or subscription and network
	// conditions.
	1,
	&azservicebus.ReceiveOptions{
		// This configures the amount of time to wait for messages to arrive.
		// Note that this is merely an upper bound. It is possible to get messages
		// faster than the duration specified.
		MaxWaitTime: 60 * time.Second,
	},
)

exitOnError("Failed to receive messages", err)

for _, message := range messages {
	err = receiver.CompleteMessage(context.TODO(), message)
	fmt.Printf("Received and completed message\n")
	exitOnError("Failed to complete message", err)
}

Output:

type ReceiverOptions 

type ReceiverOptions struct {
	// ReceiveMode controls when a message is deleted from Service Bus.
	//
	// `azservicebus.PeekLock` is the default. The message is locked, preventing multiple
	// receivers from processing the message at once. You control the lock state of the message
	// using one of the message settlement functions like processor.CompleteMessage(), which removes
	// it from Service Bus, or processor.AbandonMessage(), which makes it available again.
	//
	// `azservicebus.ReceiveAndDelete` causes Service Bus to remove the message as soon
	// as it's received.
	//
	// More information about receive modes:
	// https://docs.microsoft.com/azure/service-bus-messaging/message-transfers-locks-settlement#settling-receive-operations
	ReceiveMode ReceiveMode

	// SubQueue should be set to connect to the sub queue (ex: dead letter queue)
	// of the queue or subscription.
	SubQueue SubQueue
}

ReceiverOptions contains options for the `Client.NewReceiverForQueue` or `Client.NewReceiverForSubscription` functions.

type SendableMessage 

type SendableMessage interface {
	// contains filtered or unexported methods
}

SendableMessage are sendable using Sender.SendMessage. Message, MessageBatch implement this interface.

type Sender 

type Sender struct {
	// contains filtered or unexported fields
}

Sender is used to send messages as well as schedule them to be delivered at a later date.

func (*Sender) Close 

func (s *Sender) Close(ctx context.Context) error

Close permanently closes the Sender.

func (*Sender) NewMessageBatch 

func (s *Sender) NewMessageBatch(ctx context.Context, options *MessageBatchOptions) (*MessageBatch, error)

NewMessageBatch can be used to create a batch that contain multiple messages. Sending a batch of messages is more efficient than sending the messages one at a time.

func (*Sender) SendMessage 

func (s *Sender) SendMessage(ctx context.Context, message SendableMessage) error

SendMessage sends a message to a queue or topic. Message can be a MessageBatch (created using `Sender.CreateMessageBatch`) or a Message.

Example (Message) 
message := &azservicebus.Message{
	Body: []byte("hello, this is a message"),
}

err = sender.SendMessage(context.TODO(), message)
exitOnError("Failed to send message", err)

Output:
Example (MessageBatch) 
client, err := azservicebus.NewClientWithConnectionString(connectionString, nil)
exitOnError("Failed to create client", err)

sender, err := client.NewSender(queueName)
exitOnError("Failed to create sender", err)

batch, err := sender.NewMessageBatch(context.TODO(), nil)
exitOnError("Failed to create message batch", err)

messagesToSend := []*azservicebus.Message{
	{Body: []byte("hello world")},
	{Body: []byte("hello world as well")},
}

for i := 0; i < len(messagesToSend); i++ {
	added, err := batch.Add(messagesToSend[i])

	if added {
		continue
	}

	if err == nil {
		// At this point you can do a few things:
		// 1. Ignore this message
		// 2. Send this batch (it's full) and create a new batch.
		//
		// The batch can still be used after this error.
		log.Fatal("Failed to add message to batch (batch is full)")
	}

	exitOnError("Error while trying to add message to batch", err)
}

// now let's send the batch
err = sender.SendMessage(context.TODO(), batch)
exitOnError("Failed to send message batch", err)

Output:

type SubQueue 

type SubQueue int

SubQueue allows you to target a subqueue of a queue or subscription. Ex: the dead letter queue (SubQueueDeadLetter). 

const (
	// SubQueueNone means no sub queue.
	SubQueueNone SubQueue = 0
	// SubQueueDeadLetter targets the dead letter queue for a queue or subscription.
	SubQueueDeadLetter SubQueue = 1
	// SubQueueTransfer targets the transfer dead letter queue for a queue or subscription.
	SubQueueTransfer SubQueue = 2
)

Source Files

View all Source files

Directories

Path Synopsis
atom
test
utils
samples
processor

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