Hello Awesome Kamailio Community,
We are writing on behalf of 2600hz, where we have been using Kamailio for some time now
and are very pleased with our results! So, seems time to commit something back, dontchya
think?
We would like to present to you a new module, to hopefully be included in master. We
call it db_kazoo (although a new name is fine too).
db_kazoo is a general purpose AMQP connector (connects to our rabbitmq-server). It exposes
publish/consume capabilities into Kamailio. Why is this amazing, you ask? Well even if you
didn’t ask, we will explain…
From a high-level, the purpose of the module might be
for things like:
- Integrate to an AMQP application to make real-time routing
decisions (instead of using, say, a SQL database)
- Provide a real-time integration into your program, instead of your database, so you can
overlay additional logic in your preferred language while also utilizing a message bus
- Utilize messaging to have a distributed messaging layer, such that machines processing
requests/responses/events can go up/down or share the workload and your Kamailio node will
still be happy
With this module, someone can:
1 - publish json payloads to rabbitmq
2 - publish json payloads to rabbitmq and wait for correlated response message
3 - subscribe to an exchange with a routing key
The module works with a main forked process that does the communication with rabbitmq for
issuing publishes, waiting for replies and consuming messages. When it consumes a message
it defers the process to a worker process so that it doesn't block this main process.
The worker process issues an event-route where we can act on the received payload. The
name of the event-route is composed by values extracted from the payload.
Consumed messages have the option of being acknowledge in two ways:
1 - immediately when received
2 - after processing by the worker
One unique feature of our implementation revolves around failover of the message bus
itself. In our design, the module supports multiple RabbitMQ servers and will fallback
from one to the next in a list of RabbitMQ servers if the connection fails to the current
connected server. When using acknowledge in db_kazoo with clustering in RabbitMQ, we have
simulated and experienced full reconnects while in the middle of processing pending
messages. In this way, when we get disconnected from one server we proved that, even at
high speeds, we are able to connect to the next in the list and continue interacting with
our application.
We have run a variety of sipp load tests on this module and believe it is ready for prime
time. We monitored memory, response accuracy and overall stability and it seemed OK. But
we would, of course, love for others to help us find what we have missed, or contribute
more features, or overall just use the work we slaved over for so many hours. Or just make
comments and suggestions!
If nothing else, we hope we’ve provided something useful to the Kamailio community, as you
all have provided useful items to us.
Thanks to everyone for all the work on Kamailio and related products.
Look forward to hearing from you all.
This is our first formal / large contribution to Kamailio so if we’ve done something wrong
process, code or otherwise please let us know!