amqp

package
v0.8.2 Latest Latest
Warning

This package is not in the latest version of its module.

 Go to latest Published: Nov 20, 2018 License: MIT Imports: 7 Imported by: 0

Documentation

Overview

Package amqp implements an AMQP transport.

Index

Constants

View Source 
const (
	// ContextKeyExchange is the value of the reply Exchange in
	// amqp.Publish.
	ContextKeyExchange contextKey = iota
	// ContextKeyPublishKey is the value of the ReplyTo field in
	// amqp.Publish.
	ContextKeyPublishKey
	// ContextKeyNackSleepDuration is the duration to sleep for if the
	// service Nack and requeues a message.
	// This is to prevent sporadic send-resending of message
	// when a message is constantly Nack'd and requeued.
	ContextKeyNackSleepDuration
	// ContextKeyAutoAck is the value of autoAck field when calling
	// amqp.Channel.Consume.
	ContextKeyAutoAck
	// ContextKeyConsumeArgs is the value of consumeArgs field when calling
	// amqp.Channel.Consume.
	ContextKeyConsumeArgs
)

Variables

This section is empty.

Functions

func DefaultErrorEncoder 

func DefaultErrorEncoder(ctx context.Context,
	err error, deliv *amqp.Delivery, ch Channel, pub *amqp.Publishing)

DefaultErrorEncoder simply ignores the message. It does not reply nor Ack/Nack the message.

func EncodeJSONResponse 

func EncodeJSONResponse(
	ctx context.Context,
	pub *amqp.Publishing,
	response interface{},
) error

EncodeJSONResponse marshals the response as JSON as part of the payload of the AMQP Publishing object.

func EncodeNopResponse 

func EncodeNopResponse(
	ctx context.Context,
	pub *amqp.Publishing,
	response interface{},
) error

EncodeNopResponse is a response function that does nothing.

func ReplyAndAckErrorEncoder 

func ReplyAndAckErrorEncoder(ctx context.Context, err error, deliv *amqp.Delivery, ch Channel, pub *amqp.Publishing)

ReplyAndAckErrorEncoder serializes the error message as a DefaultErrorResponse JSON and sends the message to the ReplyTo address then Acks the original message.

func ReplyErrorEncoder 

func ReplyErrorEncoder(
	ctx context.Context,
	err error,
	deliv *amqp.Delivery,
	ch Channel,
	pub *amqp.Publishing,
)

ReplyErrorEncoder serializes the error message as a DefaultErrorResponse JSON and sends the message to the ReplyTo address.

func SingleNackRequeueErrorEncoder 

func SingleNackRequeueErrorEncoder(ctx context.Context,
	err error, deliv *amqp.Delivery, ch Channel, pub *amqp.Publishing)

SingleNackRequeueErrorEncoder issues a Nack to the delivery with multiple flag set as false and requeue flag set as true. It does not reply the message.

Types

type Channel 

type Channel interface {
	Publish(exchange, key string, mandatory, immediate bool, msg amqp.Publishing) error
	Consume(queue, consumer string, autoAck, exclusive, noLocal, noWail bool, args amqp.Table) (<-chan amqp.Delivery, error)
}

Channel is a channel interface to make testing possible. It is highly recommended to use *amqp.Channel as the interface implementation.

type DecodeRequestFunc 

type DecodeRequestFunc func(context.Context, *amqp.Delivery) (request interface{}, err error)

DecodeRequestFunc extracts a user-domain request object from an AMQP Delivery object. It is designed to be used in AMQP Subscribers.

type DecodeResponseFunc 

type DecodeResponseFunc func(context.Context, *amqp.Delivery) (response interface{}, err error)

DecodeResponseFunc extracts a user-domain response object from an AMQP Delivery object. It is designed to be used in AMQP Publishers.

type DefaultErrorResponse 

type DefaultErrorResponse struct {
	Error string `json:"err"`
}

DefaultErrorResponse is the default structure of responses in the event of an error.

type EncodeRequestFunc 

type EncodeRequestFunc func(context.Context, *amqp.Publishing, interface{}) error

EncodeRequestFunc encodes the passed request object into an AMQP Publishing object. It is designed to be used in AMQP Publishers.

type EncodeResponseFunc 

type EncodeResponseFunc func(context.Context, *amqp.Publishing, interface{}) error

EncodeResponseFunc encodes the passed reponse object to an AMQP Publishing object. It is designed to be used in AMQP Subscribers.

type ErrorEncoder 

type ErrorEncoder func(ctx context.Context,
	err error, deliv *amqp.Delivery, ch Channel, pub *amqp.Publishing)

ErrorEncoder is responsible for encoding an error to the subscriber reply. Users are encouraged to use custom ErrorEncoders to encode errors to their replies, and will likely want to pass and check for their own error types.

type Publisher 

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

Publisher wraps an AMQP channel and queue, and provides a method that implements endpoint.Endpoint.

func NewPublisher 

func NewPublisher(
	ch Channel,
	q *amqp.Queue,
	enc EncodeRequestFunc,
	dec DecodeResponseFunc,
	options ...PublisherOption,
) *Publisher

NewPublisher constructs a usable Publisher for a single remote method.

func (Publisher) Endpoint 

func (p Publisher) Endpoint() endpoint.Endpoint

Endpoint returns a usable endpoint that invokes the remote endpoint.

type PublisherOption 

type PublisherOption func(*Publisher)

PublisherOption sets an optional parameter for clients.

func PublisherAfter 

func PublisherAfter(after ...PublisherResponseFunc) PublisherOption

PublisherAfter sets the ClientResponseFuncs applied to the incoming AMQP request prior to it being decoded. This is useful for obtaining anything off of the response and adding onto the context prior to decoding.

func PublisherBefore 

func PublisherBefore(before ...RequestFunc) PublisherOption

PublisherBefore sets the RequestFuncs that are applied to the outgoing AMQP request before it's invoked.

func PublisherTimeout 

func PublisherTimeout(timeout time.Duration) PublisherOption

PublisherTimeout sets the available timeout for an AMQP request.

type PublisherResponseFunc 

type PublisherResponseFunc func(context.Context, *amqp.Delivery) context.Context

PublisherResponseFunc may take information from an AMQP request and make the response available for consumption. PublisherResponseFunc are only executed in publishers, after a request has been made, but prior to it being decoded.

type RequestFunc 

type RequestFunc func(context.Context, *amqp.Publishing, *amqp.Delivery) context.Context

RequestFunc may take information from a publisher request and put it into a request context. In Subscribers, RequestFuncs are executed prior to invoking the endpoint.

func SetConsumeArgs 

func SetConsumeArgs(args amqp.Table) RequestFunc

SetConsumeArgs returns a RequestFunc that set the arguments for amqp Consume function. It is designed to be used by Publishers.

func SetConsumeAutoAck 

func SetConsumeAutoAck(autoAck bool) RequestFunc

SetConsumeAutoAck returns a RequestFunc that sets whether or not to autoAck messages when consuming. When set to false, the publisher will Ack the first message it receives with a matching correlationId. It is designed to be used by Publishers.

func SetContentEncoding 

func SetContentEncoding(contentEncoding string) RequestFunc

SetContentEncoding returns a RequestFunc that sets the ContentEncoding field of an AMQP Publishing.

func SetContentType 

func SetContentType(contentType string) RequestFunc

SetContentType returns a RequestFunc that sets the ContentType field of an AMQP Publishing.

func SetCorrelationID 

func SetCorrelationID(cid string) RequestFunc

SetCorrelationID returns a RequestFunc that sets the CorrelationId field of an AMQP Publishing.

func SetNackSleepDuration 

func SetNackSleepDuration(duration time.Duration) RequestFunc

SetNackSleepDuration returns a RequestFunc that sets the amount of time to sleep in the event of a Nack. This has to be used in conjunction with an error encoder that Nack and sleeps. One example is the SingleNackRequeueErrorEncoder. It is designed to be used by Subscribers.

func SetPublishDeliveryMode 

func SetPublishDeliveryMode(dmode uint8) RequestFunc

SetPublishDeliveryMode sets the delivery mode of a Publishing. Please refer to AMQP delivery mode constants in the AMQP package.

func SetPublishExchange 

func SetPublishExchange(publishExchange string) RequestFunc

SetPublishExchange returns a RequestFunc that sets the Exchange field of an AMQP Publish call.

func SetPublishKey 

func SetPublishKey(publishKey string) RequestFunc

SetPublishKey returns a RequestFunc that sets the Key field of an AMQP Publish call.

type Subscriber 

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

Subscriber wraps an endpoint and provides a handler for AMQP Delivery messages.

func NewSubscriber 

func NewSubscriber(
	e endpoint.Endpoint,
	dec DecodeRequestFunc,
	enc EncodeResponseFunc,
	options ...SubscriberOption,
) *Subscriber

NewSubscriber constructs a new subscriber, which provides a handler for AMQP Delivery messages.

func (Subscriber) ServeDelivery 

func (s Subscriber) ServeDelivery(ch Channel) func(deliv *amqp.Delivery)

ServeDelivery handles AMQP Delivery messages It is strongly recommended to use *amqp.Channel as the Channel interface implementation.

type SubscriberFinalizerFunc added in v0.8.1 

type SubscriberFinalizerFunc func(ctx context.Context, err error)

ServerFinalizerFunc can be used to perform work at the end of an MQ request, after the response has been written to the client. The principal intended use is for request logging. In addition to the response code provided in the function signature, additional response parameters are provided in the context under keys with the ContextKeyResponse prefix.

type SubscriberOption 

type SubscriberOption func(*Subscriber)

SubscriberOption sets an optional parameter for subscribers.

func ServerFinalizer added in v0.8.1 

func ServerFinalizer(f ...SubscriberFinalizerFunc) SubscriberOption

ServerFinalizer is executed at the end of every MQ request. By default, no finalizer is registered.

func SubscriberAfter 

func SubscriberAfter(after ...SubscriberResponseFunc) SubscriberOption

SubscriberAfter functions are executed on the subscriber reply after the endpoint is invoked, but before anything is published to the reply.

func SubscriberBefore 

func SubscriberBefore(before ...RequestFunc) SubscriberOption

SubscriberBefore functions are executed on the publisher delivery object before the request is decoded.

func SubscriberErrorEncoder 

func SubscriberErrorEncoder(ee ErrorEncoder) SubscriberOption

SubscriberErrorEncoder is used to encode errors to the subscriber reply whenever they're encountered in the processing of a request. Clients can use this to provide custom error formatting. By default, errors will be published with the DefaultErrorEncoder.

func SubscriberErrorLogger 

func SubscriberErrorLogger(logger log.Logger) SubscriberOption

SubscriberErrorLogger is used to log non-terminal errors. By default, no errors are logged. This is intended as a diagnostic measure. Finer-grained control of error handling, including logging in more detail, should be performed in a custom SubscriberErrorEncoder which has access to the context.

type SubscriberResponseFunc 

type SubscriberResponseFunc func(context.Context,
	*amqp.Delivery,
	Channel,
	*amqp.Publishing,
) context.Context

SubscriberResponseFunc may take information from a request context and use it to manipulate a Publisher. SubscriberResponseFuncs are only executed in subscribers, after invoking the endpoint but prior to publishing a reply.

func SetAckAfterEndpoint 

func SetAckAfterEndpoint(multiple bool) SubscriberResponseFunc

SetAckAfterEndpoint returns a SubscriberResponseFunc that prompts the service to Ack the Delivery object after successfully evaluating the endpoint, and before it encodes the response. It is designed to be used by Subscribers.

Source Files

View all Source files

Jump to

Keyboard shortcuts

? : This menu
/ : Search site
f or F : Jump to
y or Y : Canonical URL
go.dev uses cookies from Google to deliver and enhance the quality of its services and to analyze traffic. Learn more.