[FR] Update the parser to use FRRouting JSON as data-source instead of screen-scraping

[netravnen]

Disclaimer: duplicate of thatmattlove/hyperglass-frr/issues/1

FRRouting support for getting a Command Line Interface command output in JSON format is getting better and better over time.

E.g. for hyperglass-frr is show bgp [ ipv4 | ipv6 ] unicast [ prefix | route ] json

Will avoid screen-scraping and well-known data-format is used as data-source when querying FRRouting for information.

---

frrouting-A# show bgp ipv4 unicast 172.20.230.0/25
BGP routing table entry for 172.20.230.0/25
Paths: (1 available, best #1, table default)
  Local
    0.0.0.0 from 0.0.0.0 (192.0.2.10)
      Origin IGP, metric 0, localpref 0, weight 32768, valid, sourced, local, bestpath-from-AS Local, best (First path received)
      Community: graceful-shutdown
      AddPath ID: RX 0, TX-All 2 TX-Best-Per-AS 0
      Advertised to: 192.0.2.11
      Last update: Sat Feb 22 03:43:28 2020

---

frrouting-A# show bgp ipv4 unicast 172.20.230.0/25 json 
{
  "prefix":"172.20.230.0\/25",
  "paths":[
    {
      "aspath":{
        "string":"Local",
        "segments":[
        ],
        "length":0
      },
      "origin":"IGP",
      "med":0,
      "metric":0,
      "localpref":0,
      "weight":32768,
      "valid":true,
      "sourced":true,
      "local":true,
      "bestpath":{
        "bestpathFromAs":0,
        "overall":true,
        "selectionReason":"First path received"
      },
      "community":{
        "string":"graceful-shutdown",
        "list":[
          "gracefulShutdown"
        ]
      },
      "addpathRxId":0,
      "addpathTxId":2,
      "addpathTxIdAll":2,
      "addpathTxIdBestPerAS":0,
      "advertisedTo":{
        "192.0.2.11":{
          "hostname":"frrouting-B"
        }
      },
      "lastUpdate":{
        "epoch":1582343008,
        "string":"Sat Feb 22 03:43:28 2020\n"
      },
      "nexthops":[
        {
          "ip":"0.0.0.0",
          "afi":"ipv4",
          "metric":0,
          "accessible":true,
          "used":true
        }
      ],
      "peer":{
        "peerId":"0.0.0.0",
        "routerId":"192.0.2.10"
      }
    }
  ]
}

---

frrouting-A# find json 
<snip>
  (view)  show [ip] bgp <view|vrf> all [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]] [json]
  (view)  show [ip] bgp [<ipv4|ipv6> [unicast]] neighbors <A.B.C.D|X:X::X:X|WORD> received prefix-filter [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn>]] route-leak  [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]]          [cidr-only          |dampening <flap-statistics|dampened-paths>          |community [AA:NN|local-AS|no-advertise|no-export          ]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]] neighbors <A.B.C.D|X:X::X:X|WORD> <advertised-routes|received-routes|filtered-routes> [route-map WORD] [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]] neighbors <A.B.C.D|X:X::X:X|WORD> <flap-statistics|dampened-routes|routes> [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]] large-community [<AA:BB:CC> [exact-match]] [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]] large-community-list <(1-500)|WORD> [exact-match] [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]] summary [failed] [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> [<unicast|multicast|vpn|labeled-unicast|flowspec>]]<A.B.C.D|A.B.C.D/M|X:X::X:X|X:X::X:X/M> [<bestpath|multipath>] [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6> flowspec] detail [json]
  (view)  show [ip] bgp [<view|vrf> VIEWVRFNAME] [<ipv4|ipv6>] neighbors [<A.B.C.D|X:X::X:X|WORD>] [json]
</snip>

[thatmattlove]

Hello,

My plan is to do this ASAP, but I have not yet built any UI components to handled structured data output, so doing this now would just print a big JSON blob to the screen, which would be less readable than the CLI output. I’ve put off writing said UI components until I can at least get structured data out of Cisco IOS, IOS-XR, and JunOS as those are the most widely used platforms.

I’m finally almost ready to release v1.0.0-beta.1 of hyperglass, so this shouldn’t be too far behind.

[thatmattlove]

Hi there,

Really sorry for not responding to this sooner.

Starting in hyperglass v1.0.0-beta.76, I've started deprecating hyperglass-agent. Moving forward, FRR & BIRD can be interacted with in the same manner as any other device, i.e. via SSH. See here for details/caveats). Everything will still work as-is for now, but I'd encourage you to try moving to frr_ssh/bird_ssh as the nos (and of course, let me know of any problems via a new hyperglass issue).

I'm going to go ahead and close this issue out.

Thanks,
Matt