Router to Router Links

Hi everyone! Happy new year and all the best for 2022!

Just a quick question around router-to-router links, and if I’m actually doing things right, as I decided to check out Crossbar over my leave period during December. I already use Autobahn (JS) for some of my web stuff, but would like to consider using Crossbar as my router.

Firstly, can router-to-router links support wildcard topics? I’ve managed to get two routers linked using a ‘rawsocket’ connection over TCP with a ‘cbor’ serializer. Authentication is using ‘cryptosign’ keys, and appears to be working. When trying to subscribe to a set of topics on my client using a wildcard pattern, I’m presented with an error that the syntax or format of the topic isn’t correct (I’m seeing this on the remote router). It works fine though in a standalone configuration. I’m using ‘prefix’ in the ‘match’ field with nothing present in the ‘uri’ field for the ‘router2router’ role.

Secondly, has anyone experienced duplicate messages or topics being sent over a router-to-router connection? Obviously, this isn’t ideal, as it’ll trigger a few false calls which can cause some chaos later down the line. Maybe I’m doing something wrong?

I’m using the latest Docker image. When booting up Crossbar, the version appears to be v20.12.3. I’m using Ubuntu 21.10 as my underlying host OS.

Any feedback would be greatly appreciated.

Hi, happy new year to you too!

First of all, it’s great to get user feedback and first testing of router-to-router links! The feature is alpha, but the core functionality is working, and it is a prio-1 area of work to shake out bugs and gaps now.

Also, I guess you have used manually configured router-to-router links in your testing? This works (technically), and is good for testing and such, but we actually have now fully open-sourced the automatic management of router-to-router links eg for clusters (scale-out and HA) via master nodes as well!

Unfortunately, the docs are scarce, there will be bugs, and it’s non-trivial to figure out what’s going on when stuff runs wrong.

Anyways, it’s alpha, but rgd your concrete questions:

  1. wildcard topics with router-to-router links: right now, only fully qualified topics and procedures (exact subs/regs) are tested, but we want to support and test-cover wildcard and prefix subs/regs! if you care, pls file an issue on the Crossbar.io repo

  2. dup messages on router-to-router links: if you have more than 2 nodes in a network, it matters if you setup links in both directions between nodes, and also the flags register/subscribe local/remote on those links. if you post your node configs of all involved nodes, I can have a look

  3. Docker image: the current version is v21.11.1. Try:

docker run --rm crossbario/crossbar:cpy-slim-amd64-21.11.1 version

https://hub.docker.com/layers/crossbario/crossbar/cpy-slim-amd64-21.11.1/images/sha256-1554b86d0537042e872cba045335f27ae0a76bbd88b5dbf99c59481f8e1a5fb7?context=repo


Hope this helps … somewhat - thanks for testing and your feedback!

Cheers,
/Tobias

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The solution I was looking for is very specifically mentioned here. Wasn’t really expecting to find it. Thanks Wesley for asking and thanks Oberstet for clearing out my querry.