There must be a more idiomatic way

sample.py

        for container in containers:
            p1 = re.compile('.*?kinto_read-only_(\d)$')
            p2 = re.compile('.*?kinto_master_(\d)$')
            print container['Names']
            if container['Names']:
                for name in container['Names']:
                    if p1.match(name):
                        ports = container['Ports']
                        for port in ports:
                            self.read_only['ip'] = port['IP']
                            self.read_only['port'] = port['PrivatePort']
                    if p2.match(name):
                        ports = container['Ports']
                        for port in ports:
                            self.master['ip'] = port['IP']
                            self.master['port'] = port['PrivatePort']

nitpick: I would not use list comprehensions to filter out things, because it means you are looping over the whole list at most twice -- which is suboptimal