def start_node(i, dirname, extra_args=None, rpchost=None):
"""
Start a dobbscoind and return RPC connection to it
"""
datadir = os.path.join(dirname, "node"+str(i))
args = [ os.getenv("DOBBSCOIND", "dobbscoind"), "-datadir="+datadir, "-keypool=1", "-discover=0", "-rest" ]
if extra_args is not None: args.extend(extra_args)
dobbscoind_processes[i] = subprocess.Popen(args)
devnull = open("/dev/null", "w+")
subprocess.check_call([ os.getenv("DOBBSCOINCLI", "dobbscoin-cli"), "-datadir="+datadir] +
_rpchost_to_args(rpchost) +
["-rpcwait", "getblockcount"], stdout=devnull)
devnull.close()
url = "http://*****:*****@%s:%d" % (rpchost or '127.0.0.1', rpc_port(i))
proxy = AuthServiceProxy(url)
proxy.url = url # store URL on proxy for info
return proxy
