Cheat Sheet for configuring Exchange Options

Configuring Exchange Options

The C++ Broker M4 or later supports the following additional Exchange options in addition to the standard AMQP define options

• Exchange Level Message sequencing

Exchange Level Message sequencing

This feature can be used to place a sequence number into each message's headers, based on the order they pass through an exchange. The sequencing starts at 0 and then wraps in an AMQP int64 type.

The field name used is "qpid.msg_sequence"

To use this feature an exchange needs to be declared specifying this option in the declare

....
    FieldTable args;
    args.setInt("qpid.msg_sequence",1);

...
    // now declare the exchange
    session.exchangeDeclare(arg::exchange="direct", arg::arguments=args);

Then each message passing through that exchange will be numbers in the application headers.

    unit64_t seqNo;
    //after message transfer
    seqNo = message.getHeaders().getAsInt64("qpid.msg_sequence");