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
)
func DefaultDeliverer(
ctx context.Context,
p Publisher,
pub *amqp.Publishing,
) (*amqp.Delivery, error)
DefaultDeliverer is a deliverer that publishes the specified Publishing and returns the first Delivery object with the matching correlationId. If the context times out while waiting for a reply, an error will be returned.
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 DefaultResponsePublisher(
ctx context.Context,
deliv *amqp.Delivery,
ch Channel,
pub *amqp.Publishing,
) error
DefaultResponsePublisher extracts the reply exchange and reply key from the request, and sends the response object to that destination.
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(
ctx context.Context,
pub *amqp.Publishing,
response interface{},
) error
EncodeNopResponse is a response function that does nothing.
func NopResponsePublisher(
ctx context.Context,
deliv *amqp.Delivery,
ch Channel,
pub *amqp.Publishing,
) error
NopResponsePublisher does not deliver a response to the original sender. This response publisher is used when the user wants the subscriber to receive and forget.
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(
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 SendAndForgetDeliverer(
ctx context.Context,
p Publisher,
pub *amqp.Publishing,
) (*amqp.Delivery, error)
SendAndForgetDeliverer delivers the supplied publishing and returns a nil response. When using this deliverer please ensure that the supplied DecodeResponseFunc and PublisherResponseFunc are able to handle nil-type responses.
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.
Channel is a channel interface to make testing possible. It is highly recommended to use *amqp.Channel as the interface implementation.
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)
}
DecodeRequestFunc extracts a user-domain request object from an AMQP Delivery object. It is designed to be used in AMQP Subscribers.
type DecodeRequestFunc func(context.Context, *amqp.Delivery) (request 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 DecodeResponseFunc func(context.Context, *amqp.Delivery) (response interface{}, err error)
DefaultErrorResponse is the default structure of responses in the event of an error.
type DefaultErrorResponse struct {
Error string `json:"err"`
}
Deliverer is invoked by the Publisher to publish the specified Publishing, and to retrieve the appropriate response Delivery object.
type Deliverer func(
context.Context,
Publisher,
*amqp.Publishing,
) (*amqp.Delivery, error)
EncodeRequestFunc encodes the passed request object into an AMQP Publishing object. It is designed to be used in AMQP Publishers.
type EncodeRequestFunc func(context.Context, *amqp.Publishing, interface{}) error
EncodeResponseFunc encodes the passed response object to an AMQP Publishing object. It is designed to be used in AMQP Subscribers.
type EncodeResponseFunc func(context.Context, *amqp.Publishing, interface{}) error
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 ErrorEncoder func(ctx context.Context, err error, deliv *amqp.Delivery, ch Channel, pub *amqp.Publishing)
Publisher wraps an AMQP channel and queue, and provides a method that implements endpoint.Endpoint.
type Publisher struct {
// contains filtered or unexported fields
}
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 (p Publisher) Endpoint() endpoint.Endpoint
Endpoint returns a usable endpoint that invokes the remote endpoint.
PublisherOption sets an optional parameter for clients.
type PublisherOption func(*Publisher)
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(before ...RequestFunc) PublisherOption
PublisherBefore sets the RequestFuncs that are applied to the outgoing AMQP request before it's invoked.
func PublisherDeliverer(deliverer Deliverer) PublisherOption
PublisherDeliverer sets the deliverer function that the Publisher invokes.
func PublisherTimeout(timeout time.Duration) PublisherOption
PublisherTimeout sets the available timeout for an AMQP request.
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 PublisherResponseFunc func(context.Context, *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.
type RequestFunc func(context.Context, *amqp.Publishing, *amqp.Delivery) context.Context
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(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(contentEncoding string) RequestFunc
SetContentEncoding returns a RequestFunc that sets the ContentEncoding field of an AMQP Publishing.
func SetContentType(contentType string) RequestFunc
SetContentType returns a RequestFunc that sets the ContentType field of an AMQP Publishing.
func SetCorrelationID(cid string) RequestFunc
SetCorrelationID returns a RequestFunc that sets the CorrelationId field of an AMQP Publishing.
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(dmode uint8) RequestFunc
SetPublishDeliveryMode sets the delivery mode of a Publishing. Please refer to AMQP delivery mode constants in the AMQP package.
func SetPublishExchange(publishExchange string) RequestFunc
SetPublishExchange returns a RequestFunc that sets the Exchange field of an AMQP Publish call.
func SetPublishKey(publishKey string) RequestFunc
SetPublishKey returns a RequestFunc that sets the Key field of an AMQP Publish call.
ResponsePublisher functions are executed by the subscriber to publish response object to the original sender. Please note that the word "publisher" does not refer to the publisher of pub/sub. Rather, publisher is merely a function that publishes, or sends responses.
type ResponsePublisher func(
context.Context,
*amqp.Delivery,
Channel,
*amqp.Publishing,
) error
Subscriber wraps an endpoint and provides a handler for AMQP Delivery messages.
type Subscriber struct {
// contains filtered or unexported fields
}
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 (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.
SubscriberOption sets an optional parameter for subscribers.
type SubscriberOption func(*Subscriber)
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(before ...RequestFunc) SubscriberOption
SubscriberBefore functions are executed on the publisher delivery object before the request is decoded.
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 SubscriberErrorHandler(errorHandler transport.ErrorHandler) SubscriberOption
SubscriberErrorHandler is used to handle non-terminal errors. By default, non-terminal errors are ignored. 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.
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. Deprecated: Use SubscriberErrorHandler instead.
func SubscriberResponsePublisher(rp ResponsePublisher) SubscriberOption
SubscriberResponsePublisher is used by the subscriber to deliver response objects to the original sender. By default, the DefaultResponsePublisher is used.
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.
type SubscriberResponseFunc func(context.Context, *amqp.Delivery, Channel, *amqp.Publishing, ) context.Context
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.