brew-graph.py

'''
	Generate a dot graph of all the packages installed
	through Homebrew. Requires pydot.

	Usage: python brew-graph.py <outfile.dot>
'''

import pydot
from subprocess import Popen, PIPE

def _brew(args):
	assert type(args) is list
	cmd = "brew %s" % ' '.join(args)
	p = Popen(cmd, shell=True, stdout=PIPE, stderr=PIPE)
	return p.stdout

def brew_lines(args):
	if type(args) is str:
		args = [args]
	return map(lambda l : l.rstrip('\n'), _brew(args).readlines())

def build_graph(verbose=False):
	def _build(node):
		# avoid nodes which have already been processed
		# or that represent packages which are not installed
		val = inst.get(node, -1)
		if val is 0: 
			inst[node] = 1
			for line in brew_lines(['deps', node]):
				# do not add edges to packages which are not installed
				if line not in inst:
					continue
				edge = pydot.Edge(node, line)
				graph.add_edge(edge)
				_build(line)
	graph = pydot.Dot(graph_type='digraph')
	packages = brew_lines('list')
	inst = dict.fromkeys(packages, 0)
	for p in inst:
		if verbose: print p
		_build(p)
	return graph

if __name__ == '__main__':
	import os, sys
	assert len(sys.argv) is 2
	outfile = sys.argv[1]
	assert not os.path.exists(outfile)
	dotGraph = build_graph(verbose=True)
	dotGraph.write(outfile)