TDRS

Weltraum TDRS is a lightweight ZeroMQ-based event hub.

A what?

TDRS allows distribution/publishing of events (basically messages) to a large amount of subscribers.

Okay, how does it work?

Every component (C) is connected to the TDRS service using a ZeroMQ ZMQ_SUB socket. Additionally, each component eventually connects to the TDRS service using a dedicated ZMQ_REQ socket. This connection allows each component to submit an event that gets broadcasted to all subscribed components, including itself. By its very nature, the publisher/subscriber-pattern does not allow for the subscribers to directly return a result to the component triggering the event. Therefor, this architecture expects components to react to each other using only events (instead of direct communication), pushing the whole infrastructure-design into a more micro-service-oriented direction.

Frequentely asked questions

Is there a client implementation?

Yes, check out the TDRS Node.js reference implementation.

Do I require to have Consul/ZooKeeper/you-name-it running, in order to use service discovery?

Nope, none of that.

Is it web scale?

Yes.

Can I haz a GIF?

Sure.

How can I build it?

$ autoreconf -i

$ ./configure

$ make

How can I run it?

Usage

Options::
	--help                    show this usage information
	--receiver-listen arg     set listener for receiver
	--publisher-listen arg    set listener for publisher
	--chain-link arg          add a chain link, specify one per link
	--discovery               enable auto discovery of chain links
	--discovery-interval arg  set the auto discovery interval (ms), default 1000
	--discovery-interface arg set the network interface to be used for auto
														discovery, e.g. eth0
	--discovery-port arg      set the UDP port to be used for auto discovery,
														default 5670
	--discovery-key arg       set the auto discovery key, default 'TDRS'

Single link

$ ./tdrs --receiver-listen "tcp://*:19890" --publisher-listen "tcp://*:19891"

Static multi-link

$ ./tdrs --receiver-listen "tcp://*:19790" --publisher-listen "tcp://*:19791" --chain-link "tcp://127.0.0.1:19891" --chain-link "tcp://127.0.0.1:19991"

$ ./tdrs --receiver-listen "tcp://*:19890" --publisher-listen "tcp://*:19891" --chain-link "tcp://127.0.0.1:19791" --chain-link "tcp://127.0.0.1:19991"

./tdrs --receiver-listen "tcp://*:19990" --publisher-listen "tcp://*:19991" --chain-link "tcp://127.0.0.1:19891" --chain-link "tcp://127.0.0.1:19791"

Dynamic multi-link

$ ./tdrs --receiver-listen "tcp://*:19790" --publisher-listen "tcp://*:19791" --discovery

$ ./tdrs --receiver-listen "tcp://*:19890" --publisher-listen "tcp://*:19891" --discovery

./tdrs --receiver-listen "tcp://*:19990" --publisher-listen "tcp://*:19991" --discovery

Docker

TDRS is available through the official Docker Hub. Docker usage is similar to command line usage. All available options are being translated to environment-variables:

docker run -it --name tdrs -e TDRS_RECEIVER_LISTEN="tcp://*:19790" -e TDRS_PUBLISHER_LISTEN="tcp://*:19791" -e TDRS_DISCOVERY=true weltraum/tdrs

What does TDRS stand for?

It stands for "Tracking and data relay satellite". We at Weltraum like to give our components names that sort of fit their function inside our infrastructure, from an astronautics point of view.