Overview

• Use goph to SSH into a Cisco BGP router, run show ip bgp 4.2.2.2 bestpath, and parse fields from the IPv4 BGP bestpath entry similar to the one shown below:

BGP routing table entry for 4.0.0.0/9, version 154410995
Paths: (21 available, best #7, table default)
  Not advertised to any peer
  Refresh Epoch 1
  3356
    4.68.4.46 from 4.68.4.46 (4.69.184.201)
      Origin IGP, metric 0, localpref 100, valid, external, atomic-aggregate, best
      Community: 3356:0 3356:3 3356:100 3356:123 3356:575 3356:2012
      path 7F2C230B7E50 RPKI State not found
      rx pathid: 0, tx pathid: 0x0

• In this case, you can ssh into the router as rviews with no password, and thus the reason for using goph.Password(""):

// route-views username 'rviews' with no password
client, err := goph.New("rviews", "route-views.routeviews.org", goph.Password(""))
if err != nil {
        logoru.Critical(err.Error())
}
defer client.Close()

• This is only an example. If you only want bgp bestpath for an IP, you don't really need to use goph, you can get the same information simpler by using iptoasn.

Build and Usage

• Run make all
• Run ./routeviews_go

routeviews_go will ssh into the router, parse output with gotextfsm, and dump the dictionary of parsed values to stdout.

$ ./routeviews_go
2023-10-07 15:56:37.920 |  INFO    | map[bgpAsPath:3356 bgpIpv4NextHop:4.68.4.46 bgpIpv4Prefix:4.0.0.0 bgpPrefixLength:9 bgpTableVersion:154410995]

$

Dependencies

• goph
• gotextfsm
• logoru

FAQ

• Q: Why not use go-ansible? A: This repo is simpler for my use-case.
• Q: Is goph faster than python Ansible? A: I think it's debatable; most of the run-time is waiting on ssh / route-views itself, and that is a significant portion of either runtime. That said, I like the portability of the Go runtime-build-system more than python / ansible; Go builds static-linked binaries for the CPU target.
• Q: Is goph a replacement for go-expect? A: Not at this time.