wire

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Wire

This directory contains internal implementation details for Cloud Pub/Sub Lite. Its exported interface can change at any time.

Conventions

The following are general conventions used in this package:

• Capitalized methods and fields of a struct denotes its public interface. They are safe to call from outside the struct (e.g. accesses immutable fields or guarded by a mutex). All other methods are considered internal implementation details that should not be called from outside the struct.
• unsafeFoo() methods indicate that the caller is expected to have already acquired the struct's mutex. Since Go does not support re-entrant locks, they do not acquire the mutex. These are typically common util methods that need to be atomic with other operations.

Documentation

Index

• Constants
• Variables
• func NewAdminClient(ctx context.Context, region string, opts ...option.ClientOption) (*vkit.AdminClient, error)
• func ValidateRegion(input string) error
• func ValidateZone(input string) error
• func ZoneToRegion(zone string) (string, error)
• type AckConsumer
• type FrameworkType
• type LocationPath
  • func ParseLocationPath(input string) (LocationPath, error)
  • func (l LocationPath) String() string
• type MessageMetadata
  • func (m *MessageMetadata) String() string
• type MessageReceiverFunc
• type PublishResultFunc
• type PublishSettings
• type Publisher
  • func NewPublisher(ctx context.Context, settings PublishSettings, region, topicPath string, ...) (Publisher, error)
• type ReceiveSettings
• type ReceivedMessage
• type Subscriber
  • func NewSubscriber(ctx context.Context, settings ReceiveSettings, receiver MessageReceiverFunc, ...) (Subscriber, error)
• type SubscriptionPath
  • func ParseSubscriptionPath(input string) (SubscriptionPath, error)
  • func (s SubscriptionPath) Location() LocationPath
  • func (s SubscriptionPath) String() string
• type TopicPath
  • func ParseTopicPath(input string) (TopicPath, error)
  • func (t TopicPath) Location() LocationPath
  • func (t TopicPath) String() string

Constants

const (
	// MaxPublishRequestCount is the maximum number of messages that can be
	// batched in a single publish request.
	MaxPublishRequestCount = 1000

	// MaxPublishRequestBytes is the maximum allowed serialized size of a single
	// publish request (containing a batch of messages) in bytes. Must be lower
	// than the gRPC limit of 4 MiB.
	MaxPublishRequestBytes int = 3.5 * 1024 * 1024
)

Variables

var (
	// ErrOverflow indicates that the publish buffers have overflowed. See
	// comments for PublishSettings.BufferedByteLimit.
	ErrOverflow = errors.New("pubsublite: client-side publish buffers have overflowed")

	// ErrOversizedMessage indicates that the user published a message over the
	// allowed serialized byte size limit. It is wrapped in another error.
	ErrOversizedMessage = fmt.Errorf("maximum allowed message size is MaxPublishRequestBytes (%d)", MaxPublishRequestBytes)

	// ErrServiceUninitialized indicates that a service (e.g. publisher or
	// subscriber) cannot perform an operation because it is uninitialized.
	ErrServiceUninitialized = errors.New("pubsublite: service must be started")

	// ErrServiceStarting indicates that a service (e.g. publisher or subscriber)
	// cannot perform an operation because it is starting up.
	ErrServiceStarting = errors.New("pubsublite: service is starting up")

	// ErrServiceStopped indicates that a service (e.g. publisher or subscriber)
	// cannot perform an operation because it has stopped or is in the process of
	// stopping.
	ErrServiceStopped = errors.New("pubsublite: service has stopped or is stopping")

	// ErrBackendUnavailable indicates that the backend service has been
	// unavailable for a period of time. The timeout can be configured using
	// PublishSettings.Timeout or ReceiveSettings.Timeout.
	ErrBackendUnavailable = errors.New("pubsublite: backend service is unavailable")
)

Errors exported from this package.

var DefaultPublishSettings = PublishSettings{
	DelayThreshold: 10 * time.Millisecond,
	CountThreshold: 100,
	ByteThreshold:  1e6,
	Timeout:        7 * 24 * time.Hour,

	BufferedByteLimit: 1 << 30,
	ConfigPollPeriod:  10 * time.Minute,
}

DefaultPublishSettings holds the default values for PublishSettings.

var DefaultReceiveSettings = ReceiveSettings{
	MaxOutstandingMessages: 1000,
	MaxOutstandingBytes:    1e9,
	Timeout:                7 * 24 * time.Hour,
}

DefaultReceiveSettings holds the default values for ReceiveSettings.

Functions

func NewAdminClient

func NewAdminClient(ctx context.Context, region string, opts ...option.ClientOption) (*vkit.AdminClient, error)

NewAdminClient creates a new gapic AdminClient for a region.

func ValidateRegion

func ValidateRegion(input string) error

ValidateRegion verifies that the `input` string has the format of a valid Google Cloud region. An example region is "europe-west1". See https://cloud.google.com/compute/docs/regions-zones for more information.

func ValidateZone

func ValidateZone(input string) error

ValidateZone verifies that the `input` string has the format of a valid Google Cloud zone. An example zone is "europe-west1-b". See https://cloud.google.com/compute/docs/regions-zones for more information.

func ZoneToRegion

func ZoneToRegion(zone string) (string, error)

ZoneToRegion returns the region that the given zone is in.

Types

type AckConsumer

type AckConsumer interface {
	Ack()
}

AckConsumer is the interface exported from this package for acking messages.

type FrameworkType

type FrameworkType string

FrameworkType is the user-facing API for Cloud Pub/Sub Lite.

const FrameworkCloudPubSubShim FrameworkType = "CLOUD_PUBSUB_SHIM"

FrameworkCloudPubSubShim is the API that emulates Cloud Pub/Sub.

type LocationPath

type LocationPath struct {
	// A Google Cloud project. The project ID (e.g. "my-project") or the project
	// number (e.g. "987654321") can be provided.
	Project string

	// A Google Cloud zone, for example "us-central1-a".
	Zone string
}

LocationPath stores a path consisting of a project and zone.

func ParseLocationPath

func ParseLocationPath(input string) (LocationPath, error)

ParseLocationPath parses a project/location path.

func (LocationPath) String

func (l LocationPath) String() string

type MessageMetadata

type MessageMetadata struct {
	// The topic partition the message was published to.
	Partition int

	// The offset the message was assigned.
	Offset int64
}

MessageMetadata holds properties of a message published to the Pub/Sub Lite service.

NOTE: This is duplicated in the pscompat package in order to generate nicer docs and should be kept consistent.

func (*MessageMetadata) String

func (m *MessageMetadata) String() string

type MessageReceiverFunc

type MessageReceiverFunc func(*ReceivedMessage)

MessageReceiverFunc receives a Pub/Sub message from a topic partition.

type PublishResultFunc

type PublishResultFunc func(*MessageMetadata, error)

PublishResultFunc receives the result of a publish.

type PublishSettings

type PublishSettings struct {
	// Publish a non-empty batch after this delay has passed. Must be > 0.
	DelayThreshold time.Duration

	// Publish a batch when it has this many messages. Must be > 0. The maximum is
	// MaxPublishRequestCount.
	CountThreshold int

	// Publish a batch when its size in bytes reaches this value. Must be > 0. The
	// maximum is MaxPublishRequestBytes.
	ByteThreshold int

	// The maximum time that the client will attempt to establish a publish stream
	// connection to the server. Must be > 0.
	//
	// The timeout is exceeded, the publisher will terminate with the last error
	// that occurred while trying to reconnect. Note that if the timeout duration
	// is long, ErrOverflow may occur first.
	Timeout time.Duration

	// The maximum number of bytes that the publisher will keep in memory before
	// returning ErrOverflow. Must be > 0.
	//
	// Note that Pub/Sub Lite topics are provisioned a publishing throughput
	// capacity, per partition, shared by all publisher clients. Setting a large
	// buffer size can mitigate transient publish spikes. However, consistently
	// attempting to publish messages at a much higher rate than the publishing
	// throughput capacity can cause the buffers to overflow. For more
	// information, see https://cloud.google.com/pubsub/lite/docs/topics.
	BufferedByteLimit int

	// The polling interval to watch for topic partition count updates. Set to 0
	// to disable polling if the number of partitions will never update.
	ConfigPollPeriod time.Duration

	// The user-facing API type.
	Framework FrameworkType
}

PublishSettings control the batching of published messages. These settings apply per partition.

type Publisher

type Publisher interface {
	Publish(*pb.PubSubMessage, PublishResultFunc)

	Start()
	WaitStarted() error
	Stop()
	WaitStopped() error
	Error() error
}

Publisher is the client interface exported from this package for publishing messages.

func NewPublisher

func NewPublisher(ctx context.Context, settings PublishSettings, region, topicPath string, opts ...option.ClientOption) (Publisher, error)

NewPublisher creates a new client for publishing messages.

type ReceiveSettings

type ReceiveSettings struct {
	// MaxOutstandingMessages is the maximum number of unacknowledged messages.
	// Must be > 0.
	MaxOutstandingMessages int

	// MaxOutstandingBytes is the maximum size (in quota bytes) of unacknowledged
	// messages. Must be > 0.
	MaxOutstandingBytes int

	// The maximum time that the client will attempt to establish a subscribe
	// stream connection to the server. Must be > 0.
	//
	// The timeout is exceeded, the subscriber will terminate with the last error
	// that occurred while trying to reconnect.
	Timeout time.Duration

	// The topic partition numbers (zero-indexed) to receive messages from.
	// Values must be less than the number of partitions for the topic. If not
	// specified, the client will use the partition assignment service to
	// determine which partitions it should connect to.
	Partitions []int

	// The user-facing API type.
	Framework FrameworkType
}

ReceiveSettings control the receiving of messages. These settings apply per partition.

type ReceivedMessage

type ReceivedMessage struct {
	Msg       *pb.SequencedMessage
	Ack       AckConsumer
	Partition int
}

ReceivedMessage stores a received Pub/Sub message and AckConsumer for acknowledging the message.

type Subscriber

type Subscriber interface {
	Start()
	WaitStarted() error
	Stop()
	WaitStopped() error
	Terminate()
}

Subscriber is the client interface exported from this package for receiving messages.

func NewSubscriber

func NewSubscriber(ctx context.Context, settings ReceiveSettings, receiver MessageReceiverFunc, region, subscriptionPath string, opts ...option.ClientOption) (Subscriber, error)

NewSubscriber creates a new client for receiving messages.

type SubscriptionPath

type SubscriptionPath struct {
	// A Google Cloud project. The project ID (e.g. "my-project") or the project
	// number (e.g. "987654321") can be provided.
	Project string

	// A Google Cloud zone. An example zone is "us-central1-a".
	Zone string

	// The ID of the Pub/Sub Lite subscription, for example
	// "my-subscription-name".
	SubscriptionID string
}

SubscriptionPath stores the full path of a Pub/Sub Lite subscription.

func ParseSubscriptionPath

func ParseSubscriptionPath(input string) (SubscriptionPath, error)

ParseSubscriptionPath parses the full path of a Pub/Sub Lite subscription.

func (SubscriptionPath) Location

func (s SubscriptionPath) Location() LocationPath

Location returns the subscription's location path.

func (SubscriptionPath) String

func (s SubscriptionPath) String() string

type TopicPath

type TopicPath struct {
	// A Google Cloud project. The project ID (e.g. "my-project") or the project
	// number (e.g. "987654321") can be provided.
	Project string

	// A Google Cloud zone, for example "us-central1-a".
	Zone string

	// The ID of the Pub/Sub Lite topic, for example "my-topic-name".
	TopicID string
}

TopicPath stores the full path of a Pub/Sub Lite topic.

func ParseTopicPath

func ParseTopicPath(input string) (TopicPath, error)

ParseTopicPath parses the full path of a Pub/Sub Lite topic.

func (TopicPath) Location

func (t TopicPath) Location() LocationPath

Location returns the topic's location path.

func (TopicPath) String

func (t TopicPath) String() string