Exemplo n.º 1
0
def learner(db):
    while True:
        command = (yield)
        try:
            if command["action"] == "put":
                log_info("setting db['%s'] to %s" % (command["key"], command["value"]))
                db[command["key"]] = command["value"]
            elif command["action"] == "incr":
                db[command["key"]] = str(int(db[command["key"]]) + 1)
                log_info("incrementing db['%s']" % command["key"])
            elif command["action"] == "get":
                # TODO only needs to execute on one
                log_fail("db['%s'] is %s" % (command["key"], db[command["key"]]))
        except KeyError:
            log_fail("key %s is not in db" % command["key"])
Exemplo n.º 2
0
def learner(db):
    while True:
        command = (yield)
        try:
            if command['action'] == 'put':
                log_info("setting db['%s'] to %s" %
                         (command['key'], command['value']))
                db[command['key']] = command['value']
            elif command['action'] == 'incr':
                db[command['key']] = str(int(db[command['key']]) + 1)
                log_info("incrementing db['%s']" % command['key'])
            elif command['action'] == 'get':
                #TODO only needs to execute on one
                log_fail("db['%s'] is %s" %
                         (command['key'], db[command['key']]))
        except KeyError:
            log_fail("key %s is not in db" % command['key'])
Exemplo n.º 3
0
def client(request):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    proposer = servers[1]
    s_request = request.split()
    if s_request[0] == 'get':
        request = {'action': 'get',
                   'key': s_request[1]}
    elif s_request[0] == 'incr':
        request = {'action': 'incr',
                   'key': s_request[1]}
    elif s_request[0] == 'put':
        request = {'action': 'put',
                   'key': s_request[1],
                   'value': s_request[2]}
    else:
        log_fail("bad command: %s" % request)
        sys.exit(-1)
    request_msg = json.dumps({'request':request, 'protocol':'paxos'})
    sock.sendto(request_msg, proposer)
Exemplo n.º 4
0
        # get_name_route:     		get_user_by_name
        # delete_id_route:    		delete_user_by_id
        # delete_name_route:  		delete_user_by_name
        # delete_activity_route:	delete_activity_by_activity_id

        duplicated_flag = 0  #The duplicated_flag is used to skip the if loops for duplicated operation
        for msgID in msgIDList:  #This part of code tests for duplicates, if the msg_id is in the dictonary, skip if loops and send back original response
            if msgID == request['msg_id']:
                log_warning("REPLICATED msg_in: " + request['msg_id'])
                qout.write(msgIDList[msgID])
                duplicated_flag = 1
                break

        if duplicated_flag == 1: continue
        if request['method'] == None:
            log_fail("INVALID METHOD ID " + request['msg_id'])
            continue

        #print opnum of the request
        log_back("###### EXPECTED OP# : " + str(nextTopNum))
        log_back("!!!!!! REQUEST OP# : " + str(request['opnum']))

        msg_out = Message()  #creating empty message object for msg_out
        key = request['msg_id']  #assigning msg_id to key
        #print "line 413", key
        method = request['method']
        if method == constants.METHOD_POST_USER:
            rqresult = create_user(table, request)
            #rqresult['backend'] = args.suffix
            write_out_msg(rqresult)
            log_back("#####	created user    #####\n")
Exemplo n.º 5
0
def paxos(learner):
    state = 'waiting'
    hnum = 0
    nreceives = 0
    client = None
    request_q = deque()
    current_i = None

    while True:
        if len(request_q) > 0 and state == 'waiting':
            # adds fifo semantics to system
            data, sock, addr = request_q.popleft()
        else:
            data, sock, addr = (yield)

        if 'request' in data:
            if state != 'waiting':
                request_q.append((data, sock, addr))
                log_warn('queue contains %s elements' % len(request_q))
                continue
            # we have been chosen as the proposer
            # we need to check with all acceptors
            log_verbose('coordinator received request, preparing %s' %
                        str(data))
            client = addr
            state = 'preparing'
            nreceives = 0
            current_i = hnum + 1
            prep_msg = json.dumps({
                'protocol': 'paxos',
                'prepare': data['request'],
                'i': hnum + 1
            })
            bcast(sock, prep_msg)
        elif state == 'preparing':
            if 'promise' in data and data['i'] == current_i:
                nreceives += 1
                if nreceives > (len(servers) / 2):
                    log_verbose('got more than n/2 promises, moving on')
                    state = 'accepting'
                    nreceives = 0
                    accept_msg = json.dumps({
                        'protocol': 'paxos',
                        'accept': data['promise'],
                        'i': hnum
                    })
                    bcast(sock, accept_msg)
            elif 'nack' in data and data['i'] != current_i:
                log_warn('caught (and ignored) old nack: %s\tcurrent i: %s' %
                         (data['i'], current_i))
            elif 'nack' in data and data['i'] == current_i:
                log_warn('falling back to waiting state from preparing')
                log_fail('nack id: %s\thnum: %s' % (data['i'], hnum))
                state = 'waiting'
                nreceives = 0
        elif state == 'accepting':
            if 'accepted' in data and data['i'] == current_i:
                nreceives += 1
                if nreceives > (len(servers) / 2):
                    log_verbose('successfully got more than n/2 accepts')
                    success_msg = json.dumps({
                        'protocol': 'paxos',
                        'success': True
                    })
                    sock.sendto(success_msg, client)
                    state = 'waiting'
                    nreceives = 0
                    current_i = None
                    client = None
            elif 'nack' in data and data['i'] != current_i:
                log_warn('caught (and ignored) old nack: %s\tcurrent i: %s' %
                         (data['i'], current_i))
            elif 'nack' in data and data['i'] == current_i:
                log_warn('falling back to waiting state from accepting')
                log_fail('possible inconsistency')
                log_fail('nack id: %s\thnum: %s' % (data['i'], hnum))
                state = 'waiting'
                nreceives = 0

        if 'prepare' in data:
            if data['i'] > hnum:
                hnum = data['i']
                response = json.dumps({
                    'protocol': 'paxos',
                    'promise': data['prepare'],
                    'i': data['i']
                })
            else:
                log_warn('got prepare for number less than hnum')
                response = json.dumps({'protocol': 'paxos', 'nack': data['i']})
            sock.sendto(response, addr)
        elif 'accept' in data:
            if data['i'] == hnum:
                learner.send(data['accept'])
                response = json.dumps({
                    'protocol': 'paxos',
                    'accepted': data['accept'],
                    'i': hnum
                })
            else:
                log_warn('got accept for number other than hnum')
                log_fail('possible inconsistency')
                response = json.dumps({'protocol': 'paxos', 'nack': data['i']})
            sock.sendto(response, addr)
Exemplo n.º 6
0
def paxos(learner):
    state = "waiting"
    hnum = 0
    nreceives = 0
    client = None
    request_q = deque()
    current_i = None

    while True:
        if len(request_q) > 0 and state == "waiting":
            # adds fifo semantics to system
            data, sock, addr = request_q.popleft()
        else:
            data, sock, addr = (yield)

        if "request" in data:
            if state != "waiting":
                request_q.append((data, sock, addr))
                log_warn("queue contains %s elements" % len(request_q))
                continue
            # we have been chosen as the proposer
            # we need to check with all acceptors
            log_verbose("coordinator received request, preparing %s" % str(data))
            client = addr
            state = "preparing"
            nreceives = 0
            current_i = hnum + 1
            prep_msg = json.dumps({"protocol": "paxos", "prepare": data["request"], "i": hnum + 1})
            bcast(sock, prep_msg)
        elif state == "preparing":
            if "promise" in data and data["i"] == current_i:
                nreceives += 1
                if nreceives > (len(servers) / 2):
                    log_verbose("got more than n/2 promises, moving on")
                    state = "accepting"
                    nreceives = 0
                    accept_msg = json.dumps({"protocol": "paxos", "accept": data["promise"], "i": hnum})
                    bcast(sock, accept_msg)
            elif "nack" in data and data["i"] != current_i:
                log_warn("caught (and ignored) old nack: %s\tcurrent i: %s" % (data["i"], current_i))
            elif "nack" in data and data["i"] == current_i:
                log_warn("falling back to waiting state from preparing")
                log_fail("nack id: %s\thnum: %s" % (data["i"], hnum))
                state = "waiting"
                nreceives = 0
        elif state == "accepting":
            if "accepted" in data and data["i"] == current_i:
                nreceives += 1
                if nreceives > (len(servers) / 2):
                    log_verbose("successfully got more than n/2 accepts")
                    success_msg = json.dumps({"protocol": "paxos", "success": True})
                    sock.sendto(success_msg, client)
                    state = "waiting"
                    nreceives = 0
                    current_i = None
                    client = None
            elif "nack" in data and data["i"] != current_i:
                log_warn("caught (and ignored) old nack: %s\tcurrent i: %s" % (data["i"], current_i))
            elif "nack" in data and data["i"] == current_i:
                log_warn("falling back to waiting state from accepting")
                log_fail("possible inconsistency")
                log_fail("nack id: %s\thnum: %s" % (data["i"], hnum))
                state = "waiting"
                nreceives = 0

        if "prepare" in data:
            if data["i"] > hnum:
                hnum = data["i"]
                response = json.dumps({"protocol": "paxos", "promise": data["prepare"], "i": data["i"]})
            else:
                log_warn("got prepare for number less than hnum")
                response = json.dumps({"protocol": "paxos", "nack": data["i"]})
            sock.sendto(response, addr)
        elif "accept" in data:
            if data["i"] == hnum:
                learner.send(data["accept"])
                response = json.dumps({"protocol": "paxos", "accepted": data["accept"], "i": hnum})
            else:
                log_warn("got accept for number other than hnum")
                log_fail("possible inconsistency")
                response = json.dumps({"protocol": "paxos", "nack": data["i"]})
            sock.sendto(response, addr)