On 2026-06-04 01:59, Saku Ytti via NANOG wrote:
It boggles my mind that someone goes 'I'm going to write this very
complex daemon' and then they proceed to write monolithic tightly
coupled CLI+daemon+logic.
You may not think of them like Internet APIs, but there is a kind of
tightly bound library access to FRR:
https://docs.frrouting.org/projects/dev-guide/en/latest/library.html
FRR does have some hooks for customization. It also has a Lua scripting
interface:
https://docs.frrouting.org/projects/dev-guide/en/latest/scripting.html
There is an ability to add your own callback hooks, command line
additions, ... and other stuff.
Link State API
https://docs.frrouting.org/projects/dev-guide/en/latest/link-state.html
Northbound API
https://docs.frrouting.org/projects/dev-guide/en/latest/northbound/northbound.html
Zebra Neighbor API
https://docs.frrouting.org/projects/dev-guide/en/latest/zebra-neigh-api.html
Mind you, all this access probably requires you have the FRR source code
open, but given the complexity of the daemons and networking in general,
this access is probably as close to API as possible.
So we have a huge collection of BGP implementations, as mentioned just
here, frr, gobgp, bird, rustybgp, openbgp, exabgp and many many
others. But we don't really have any BGP library approaching a similar
maturity level. While to me it seems it should have been an obvious
win for any project, to start day1 with decoupled library, cli and
daemon as separate libraries, i see it reducing work day1 due to
forcing more maintainability in design.
Then instead of using low performance, lacking or non-existing APIs in
your automation, you could write your own BGP worker using the library
to have superior flexibility and performance, and exactly the
behaviour you want. Many things you cannot do at all, because you
don't have a library, like fuzzing, the daemon won't allow you to do
wrong/bad things.
https://docs.frrouting.org/projects/dev-guide/en/latest/fuzzing.html
So please, the next person planning to write BGP or whatever project
they're thinking of, separate the logic and daemon. Thank you.
I'm not an FRR developer, just a satisfied user with a programming bent.
Raymond Burkholder
https://blog.raymond.burkholder.net/
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