README.md

Say in kubernetes/kubernetes, you need to see how we drag in rsc.io/pdf

python ~/bin/gomod_graph.py -p rsc.io/pdf > filename.dot
dot -Tsvg filename.dot -o filename.svg

if you are not interested in the version numbers

python ~/bin/gomod_graph.py -p rsc.io/pdf --skip > filename.dot
dot -Tsvg filename.dot -o filename.svg

gomod_graph.py

#!/usr/bin/python

import argparse
import atexit
import logging
import subprocess
from copy import deepcopy


def get_dependencies():
    dependson = {}
    usedby = {}
    f = subprocess.Popen('go mod graph', stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
    (stdout, stderr) = f.communicate()
    if stderr:
        logging.fatal(stderr)
    for line in stdout.splitlines():
        key, value = line.decode().split(' ')
        key = key.split('@')[0]
        value = value.split('@')[0]
        dependson.setdefault(key, set()).add(value)
        usedby.setdefault(value, set()).add(key)
    return usedby, dependson


def get_all_parents(dep, visited, usedby):
    visited.add(dep)
    if dep not in usedby:
        return set()
    array = usedby[dep].copy()
    for item in array.copy():
        if item not in visited:
            array |= get_all_parents(item, visited, usedby)
    return array


def draw_diagraph(items, skip):
    f = subprocess.Popen('go mod graph', stdout=subprocess.PIPE, stderr=subprocess.PIPE, shell=True)
    (stdout, stderr) = f.communicate()
    if stderr:
        logging.fatal(stderr)
    print("digraph G {")
    print("rankdir=LR;")
    for line in stdout.splitlines():
        key, value = line.decode().split(' ')

        if skip:
            key = key.split('@')[0]
            value = value.split('@')[0]

        found_key = False
        found_value = False
        for item in items:
            if key.startswith(item):
                found_key = True
            if value.startswith(item):
                found_value = True
        if found_key and found_value:
            print("\"%s\" -> \"%s\"" % (key, value))
    print("}")


chains = {}


def print_chains():
    longest = max(chains.keys())
    print("Longest chain is:", longest)
    print("%r" % chains[longest])


def visit_node(dep, parents, dependson):
    parents.append(dep)
    if dep in dependson:
        for item in dependson[dep]:
            if item not in parents:
                visit_node(item, deepcopy(parents), dependson)
            else:
                chains.setdefault(len(parents), list()).append(parents)
    else:
        chains.setdefault(len(parents), list()).append(parents)


def main():
    parser = argparse.ArgumentParser()
    parser.add_argument('-p', '--package', required=True)
    parser.add_argument('-s', '--skip', action='store_true')
    parser.add_argument('-d', '--depth', action='store_true')
    args = parser.parse_args()

    usedby, dependson = get_dependencies()
    if args.depth:
        atexit.register(print_chains)
        visit_node(args.package, [], dependson)
        print_chains()
    else:
        parents = get_all_parents(args.package, set(), usedby)
        draw_diagraph(parents | {args.package}, args.skip)


if __name__ == "__main__":
    main()