Middleware for Rabbus and RabbitMQ to reject old messages.
The gist of how this works:
When a message is published through Rabbus with this middleware, a sequence header is attached. The sequence is automatically incremented for each message that is sent.
On the consumer side of things, the middleware reads the sequence of each message that comes in. If the sequence number of the message is the one that is expected, or one in the future ( a higher sequence number) it allows the message to continue through the other middleware / processing. If the sequence number is old, it rejects the message, dropping it from RabbitMQ entirely.
Due to the nature of this plug rejecting out of sequence / old messages, you should have a dead letter exchange configured for your queue.
To use Rabbus-Sequence, you need Rabbus
in your system already. Then you need to create an instance of
Sequence.Consumer for each end of
For a message producer:
var Sequence = ;var pub = ;var pubSequence =key: "id";pub;
For a message consumer:
var Sequence = ;var sub = ;var subSequence =key: "id";sub;
Note the use of a
key in the options for the Sequence
objects. This tells the sequence which to track a sequence
for each unique value found in this field on the messages.
For example, if you have two messages that are sent with
id field, and the
key set to
id, these messages
will use the same sequence.
id: "1234"foo: "bar"id: "1234"foo: "baz quux"
This will produce a sequence 1 and 2 for the two messages.
When a new
id value is encountered, a new sequence is
produced, starting at a value of 1.
Rabbus and Rabbus-Sequence are Copyright ©2015 Muted Solutions, LLC. All Rights Reserved.
Distributed under the MIT license.