gistfile1.py

projects = {'ProjectA' : {'deps' : ['ProjectB']},
            'ProjectB' : {'deps' : None},
            'ProjectC' : {'deps' : ['ProjectA']}}
cont = 0


def deploy(name, desc):
    """
    Detects the order of deploy for projects in a dict.
    Each dic entry is the name of Projet : {desc}, where desc is a dict containing:
    deps : Name of projects it depends on.
    description: optional description
    """
    global cont
    if 'deployed' in desc:
        return
    if not desc['deps']:
        cont += 1
        desc['deployed'] = cont
    else:
        for dep in desc['deps']:
            if projects[dep]['deps'] and name in projects[dep]['deps']:
                raise Exception('Cyclic reference between %s to %s' % (name, dep))
            deploy(dep, projects[dep])
        cont += 1
        desc['deployed'] = cont

if __name__ == '__main__':
    for k,v in projects.iteritems():
        deploy(k,v)
    print 'The deploy order is: ', sorted(projects.keys(), key = lambda k: projects[k]['deployed'])