f248089523
* Implement basic S3 notifications through queues Supports multiple queues and three basic queue types: 1. NilQueue -- messages don't get sent anywhere 2. LogQueue -- messages get logged 3. AmqpQueue -- messages are sent to an AMQP queue * api: Implement bucket notification. Supports two different queue types - AMQP - ElasticSearch. * Add support for redis
109 lines
4.8 KiB
Go
109 lines
4.8 KiB
Go
// Copyright (c) 2012, Sean Treadway, SoundCloud Ltd.
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// Use of this source code is governed by a BSD-style
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// license that can be found in the LICENSE file.
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// Source code and contact info at http://github.com/streadway/amqp
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/*
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AMQP 0.9.1 client with RabbitMQ extensions
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Understand the AMQP 0.9.1 messaging model by reviewing these links first. Much
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of the terminology in this library directly relates to AMQP concepts.
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Resources
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http://www.rabbitmq.com/tutorials/amqp-concepts.html
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http://www.rabbitmq.com/getstarted.html
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http://www.rabbitmq.com/amqp-0-9-1-reference.html
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Design
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Most other broker clients publish to queues, but in AMQP, clients publish
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Exchanges instead. AMQP is programmable, meaning that both the producers and
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consumers agree on the configuration of the broker, instead requiring an
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operator or system configuration that declares the logical topology in the
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broker. The routing between producers and consumer queues is via Bindings.
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These bindings form the logical topology of the broker.
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In this library, a message sent from publisher is called a "Publishing" and a
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message received to a consumer is called a "Delivery". The fields of
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Publishings and Deliveries are close but not exact mappings to the underlying
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wire format to maintain stronger types. Many other libraries will combine
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message properties with message headers. In this library, the message well
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known properties are strongly typed fields on the Publishings and Deliveries,
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whereas the user defined headers are in the Headers field.
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The method naming closely matches the protocol's method name with positional
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parameters mapping to named protocol message fields. The motivation here is to
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present a comprehensive view over all possible interactions with the server.
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Generally, methods that map to protocol methods of the "basic" class will be
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elided in this interface, and "select" methods of various channel mode selectors
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will be elided for example Channel.Confirm and Channel.Tx.
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The library is intentionally designed to be synchronous, where responses for
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each protocol message are required to be received in an RPC manner. Some
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methods have a noWait parameter like Channel.QueueDeclare, and some methods are
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asynchronous like Channel.Publish. The error values should still be checked for
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these methods as they will indicate IO failures like when the underlying
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connection closes.
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Asynchronous Events
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Clients of this library may be interested in receiving some of the protocol
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messages other than Deliveries like basic.ack methods while a channel is in
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confirm mode.
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The Notify* methods with Connection and Channel receivers model the pattern of
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asynchronous events like closes due to exceptions, or messages that are sent out
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of band from an RPC call like basic.ack or basic.flow.
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Any asynchronous events, including Deliveries and Publishings must always have
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a receiver until the corresponding chans are closed. Without asynchronous
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receivers, the sychronous methods will block.
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Use Case
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It's important as a client to an AMQP topology to ensure the state of the
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broker matches your expectations. For both publish and consume use cases,
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make sure you declare the queues, exchanges and bindings you expect to exist
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prior to calling Channel.Publish or Channel.Consume.
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// Connections start with amqp.Dial() typically from a command line argument
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// or environment variable.
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connection, err := amqp.Dial(os.Getenv("AMQP_URL"))
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// To cleanly shutdown by flushing kernel buffers, make sure to close and
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// wait for the response.
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defer connection.Close()
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// Most operations happen on a channel. If any error is returned on a
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// channel, the channel will no longer be valid, throw it away and try with
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// a different channel. If you use many channels, it's useful for the
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// server to
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channel, err := connection.Channel()
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// Declare your topology here, if it doesn't exist, it will be created, if
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// it existed already and is not what you expect, then that's considered an
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// error.
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// Use your connection on this topology with either Publish or Consume, or
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// inspect your queues with QueueInspect. It's unwise to mix Publish and
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// Consume to let TCP do its job well.
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SSL/TLS - Secure connections
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When Dial encounters an amqps:// scheme, it will use the zero value of a
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tls.Config. This will only perform server certificate and host verification.
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Use DialTLS when you wish to provide a client certificate (recommended),
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include a private certificate authority's certificate in the cert chain for
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server validity, or run insecure by not verifying the server certificate dial
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your own connection. DialTLS will use the provided tls.Config when it
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encounters an amqps:// scheme and will dial a plain connection when it
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encounters an amqp:// scheme.
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SSL/TLS in RabbitMQ is documented here: http://www.rabbitmq.com/ssl.html
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*/
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package amqp
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