Tooltron

"""

Outputs a graphviz dot file of the dependencies.

"""

from optparse import make_option

import re

import textwrap

from django.core.management.base import BaseCommand

from django.core.management.color import no_style

from south.migration import Migrations, all_migrations

class Command(BaseCommand):

    help = "Outputs a GraphViz dot file of all migration dependencies to stdout."

    def handle(self, **options):

        # Resolve dependencies

        Migrations.calculate_dependencies()

        colors = [ 'crimson', 'darkgreen', 'darkgoldenrod', 'navy',

                'brown', 'darkorange', 'aquamarine' , 'blueviolet' ]

        color_index = 0

        wrapper = textwrap.TextWrapper(width=40)

        print "digraph G {"

        # Group each app in a subgraph

        for migrations in all_migrations():

            print "  subgraph %s {" % migrations.app_label()

            print "    node [color=%s];" % colors[color_index]

            for migration in migrations:

                # Munge the label - text wrap and change _ to spaces

                label = "%s - %s" % (

                        migration.app_label(), migration.name())

                label = re.sub(r"_+", " ", label)

                label=  "\\n".join(wrapper.wrap(label))

                print '    "%s.%s" [label="%s"];' % (

                        migration.app_label(), migration.name(), label)

            print "  }"

            color_index = (color_index + 1) % len(colors)

        # For every migration, print its links.

        for migrations in all_migrations():

            for migration in migrations:

                for other in migration.dependencies:

                    # Added weight tends to keep migrations from the same app

                    # in vertical alignment

                    attrs = "[weight=2.0]"

                    # But the more interesting edges are those between apps

                    if other.app_label() != migration.app_label():

                        attrs = "[style=bold]"

                    print '  "%s.%s" -> "%s.%s" %s;' % (

                        other.app_label(), other.name(),

                        migration.app_label(), migration.name(),

                        attrs

                    )

        print "}";