About the Message Broker Dummy module

About the module

The sub-module "Message Broker Dummy" processes all messages in a synchronous way, allowing you to test and debug your code without setting up an external message broker.

It does so by simulating the routing features of a real message broker. We have implemented a big subset of the AMQP standard, which allows you to execute the most commonly needed routing methods.

Not implemented AMQP features

The AMQP standard is complex and we are not able to implement every detail, so we have discarded some of the not so common features:

• headers Exchange not supported
• routing keys with hashes not at the beginning and not at the end are not supported (would require complex pattern matching algorithms)
• auto-ack mode is not supported, every message must be acked
• most headers and configuration attributes are ignored, because they are of limited use in the simulation (i.e. durable, auto_delete, no_wait, etc)

Especially keep in mind the limitation regarding the routing keys. It is not impossible to implement this, but you are often able to find an alternative routing key without a hash in the middle of the pattern.

Limitations of this approach

This approach has natural limitations, because the only messages that we can process are the ones that are sent within our system. If you want to test the interaction between drupal installations or multiple systems written in different languages you can't avoid a full message broker installation.