netmap-graphviz.py

#!/usr/bin/env python3
import glob
import re
import xml.etree.ElementTree as et
# import json
# from datetime import datetime
# from collections import namedtuple
from collections import defaultdict
from itertools import combinations
from pathlib import Path
import subprocess

SCALE = 1/400.0
GV_EPSILON = 0.000001

def main():

    # Load router configuration
    configs = load_configs()

    # Extract router pairs
    links = defaultdict(set) # cid => set(r1, r2)
    metrics = defaultdict(set) # cid => set(metric1, metric2)
    for rtr_name, config in configs.items():
        print(rtr_name)
        for iface in config.findall('.//interface'):
            desc = iface.findtext('./description', default="")
            name = iface.findtext('./name', default="")

            # Get Circuit ID
            m = re.match(r'^BACKBONE: .* I2-.*-(\d+)$', desc)
            if not m:
                continue
            cid = m.group(1)

            # Get metric
            isis_metric = config.findtext(f'.//interface[name="{name}.4079"]/level[name="2"]/metric', None)

            # Router is connected to CID
            links[cid].add(rtr_name)
            if isis_metric is not None:
                metrics[cid].add(int(isis_metric))

    dot = generate_graph(links, metrics)
    print(dot)

    # Run through graphviz
    ps = subprocess.Popen(
        f"docker run -i --rm nshine/dot neato -Tpng -Gepsilon={GV_EPSILON}".split(" "),
        stdout=subprocess.PIPE,
        stdin=subprocess.PIPE
    )
    ps.stdin.write(dot.encode("utf-8"))
    ps.stdin.close()
    png = ps.stdout.read()
    Path("netmap-graphviz.png").write_bytes(png)

def generate_graph(links, metrics):
    # Generate graph
    rv = []
    rv.extend([
        "graph G {",
        # " orientation = landscape;",
        " overlap = false;",
        " splines = true;",
        " node [shape=box; fontname=\"helvetica\"];",
        " edge [fontname=\"helvetica\"];",
    ])

    for cid, node_sets in links.items():
        if len(node_sets) < 2:
            print(f"Didn't find two nodes for CID {cid}. Nodes: {node_sets}")
        for (a,b) in combinations(node_sets, 2):
            m = max(metrics[cid], default=1) * SCALE
            rv.append(f" \"{a}\" -- \"{b}\" [len={m}];")

    rv.append("}")
    return "\n".join(rv)

def load_configs():
    rv = {}
    for config_file in glob.glob("../internet2-configs/rtsw/xml/*.xml"):
        # print("parsing file {}".format(config_file))
        try:
            rtr_config = et.parse(config_file)
            rtr_name = extract_hostname(rtr_config)
            rv[rtr_name] = rtr_config
        except et.ParseError:
            pass
    return rv


RE_HOSTNAME_CLEANUP = re.compile(r'-re\d', re.IGNORECASE)
def extract_hostname(config_root):
    """Return the sanitized router hostname"""
    rtr_name = config_root.findtext('.//system/host-name')
    rtr_name = RE_HOSTNAME_CLEANUP.sub('', rtr_name)
    return rtr_name


SKIP_IF_NAMES = set(["all", "fxp0.0", "dsc", "dsc.0"])


# Main program
if __name__ == "__main__":
    main()