Example #1
0
  def __init__(self, hosts, timeout):
    self.hosts = [ (server, instance) for (server, port, instance) in hosts ]
    self.ports = dict( ((server, instance), port) for (server, port, instance) in hosts )
    self.timeout = float(timeout)
    servers = set([server for (server, port, instance) in hosts])
    if len(servers) < settings.REPLICATION_FACTOR:
      raise Exception("REPLICATION_FACTOR=%d cannot exceed servers=%d" % (settings.REPLICATION_FACTOR, len(servers)))

    self.hash_ring = ConsistentHashRing(self.hosts)
    self.keyfunc = load_keyfunc()
    self.connections = {}
    self.last_failure = {}
    # Create a connection pool for each host
    for host in self.hosts:
      self.connections[host] = set()
Example #2
0
    def __init__(self, hosts, timeout):
        self.hosts = [ (server, instance) for (server, port, instance) in hosts ]
        self.ports = dict( ((server, instance), port) for (server, port, instance) in hosts )
        self.timeout = float(timeout)
        servers = set([server for (server, port, instance) in hosts])
        # TODO boring
        #if len(servers) < settings.REPLICATION_FACTOR:
            #raise Exception("REPLICATION_FACTOR=%d cannot exceed servers=%d" % (settings.REPLICATION_FACTOR, len(servers)))

        self.hash_ring = ConsistentHashRing(self.hosts)
        self.keyfunc = load_keyfunc()
        self.connections = {}
        self.last_failure = {}
        # Create a connection pool for each host
        for host in self.hosts:
            self.connections[host] = set()
Example #3
0
class CarbonLinkPool:
    def __init__(self, hosts, timeout):
        self.hosts = [ (server, instance) for (server, port, instance) in hosts ]
        self.ports = dict( ((server, instance), port) for (server, port, instance) in hosts )
        self.timeout = float(timeout)
        servers = set([server for (server, port, instance) in hosts])
        # TODO boring
        #if len(servers) < settings.REPLICATION_FACTOR:
            #raise Exception("REPLICATION_FACTOR=%d cannot exceed servers=%d" % (settings.REPLICATION_FACTOR, len(servers)))

        self.hash_ring = ConsistentHashRing(self.hosts)
        self.keyfunc = load_keyfunc()
        self.connections = {}
        self.last_failure = {}
        # Create a connection pool for each host
        for host in self.hosts:
            self.connections[host] = set()

    def select_host(self, metric):
        "Returns the carbon host that has data for the given metric"
        key = self.keyfunc(metric)
        nodes = []
        servers = set()
        for node in self.hash_ring.get_nodes(key):
            (server, instance) = node
            if server in servers:
                continue
            servers.add(server)
            nodes.append(node)
            if len(servers) >= settings.REPLICATION_FACTOR:
                break

        available = [ n for n in nodes if self.is_available(n) ]
        return random.choice(available or nodes)

    def is_available(self, host):
        now = time.time()
        last_fail = self.last_failure.get(host, 0)
        return (now - last_fail) < settings.CARBONLINK_RETRY_DELAY

    def get_connection(self, host):
        # First try to take one out of the pool for this host
        (server, instance) = host
        port = self.ports[host]
        connectionPool = self.connections[host]
        try:
            return connectionPool.pop()
        except KeyError:
            pass #nothing left in the pool, gotta make a new connection

        log.cache("CarbonLink creating a new socket for %s" % str(host))
        connection = socket.socket()
        connection.settimeout(self.timeout)
        try:
            connection.connect( (server, port) )
        except:
            self.last_failure[host] = time.time()
            raise
        else:
            connection.setsockopt( socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1 )
            return connection

    def query(self, metric):
        request = dict(type='cache-query', metric=metric)
        results = self.send_request(request)
        log.cache("CarbonLink cache-query request for %s returned %d datapoints" % (metric, len(results['datapoints'])))
        return results['datapoints']

    def get_metadata(self, metric, key):
        request = dict(type='get-metadata', metric=metric, key=key)
        results = self.send_request(request)
        log.cache("CarbonLink get-metadata request received for %s:%s" % (metric, key))
        return results['value']

    def set_metadata(self, metric, key, value):
        request = dict(type='set-metadata', metric=metric, key=key, value=value)
        results = self.send_request(request)
        log.cache("CarbonLink set-metadata request received for %s:%s" % (metric, key))
        return results

    def send_request(self, request):
        metric = request['metric']
        serialized_request = pickle.dumps(request, protocol=-1)
        len_prefix = struct.pack("!L", len(serialized_request))
        request_packet = len_prefix + serialized_request

        host = self.select_host(metric)
        conn = self.get_connection(host)
        log.cache("CarbonLink sending request for %s to %s" % (metric, str(host)))
        try:
            conn.sendall(request_packet)
            result = self.recv_response(conn)
        except:
            self.last_failure[host] = time.time()
            raise
        else:
            self.connections[host].add(conn)
            if 'error' in result:
                log.cache("Error getting data from cache: %s" % result['error'])
                raise CarbonLinkRequestError(result['error'])
            else:
                return result

    def recv_response(self, conn):
        len_prefix = recv_exactly(conn, 4)
        body_size = struct.unpack("!L", len_prefix)[0]
        body = recv_exactly(conn, body_size)
        return unpickle.loads(body)
Example #4
0
class CarbonLinkPool:
  def __init__(self, hosts, timeout):
    self.hosts = [ (server, instance) for (server, port, instance) in hosts ]
    self.ports = dict( ((server, instance), port) for (server, port, instance) in hosts )
    self.timeout = float(timeout)
    servers = set([server for (server, port, instance) in hosts])
    if len(servers) < settings.REPLICATION_FACTOR:
      raise Exception("REPLICATION_FACTOR=%d cannot exceed servers=%d" % (settings.REPLICATION_FACTOR, len(servers)))

    self.hash_ring = ConsistentHashRing(self.hosts)
    self.keyfunc = load_keyfunc()
    self.connections = {}
    self.last_failure = {}
    # Create a connection pool for each host
    for host in self.hosts:
      self.connections[host] = set()

  def select_host(self, metric):
    "Returns the carbon host that has data for the given metric"
    key = self.keyfunc(metric)
    nodes = []
    servers = set()
    for node in self.hash_ring.get_nodes(key):
      (server, instance) = node
      if server in servers:
        continue
      servers.add(server)
      nodes.append(node)
      if len(servers) >= settings.REPLICATION_FACTOR:
        break

    available = [ n for n in nodes if self.is_available(n) ]
    return random.choice(available or nodes)

  def is_available(self, host):
    now = time.time()
    last_fail = self.last_failure.get(host, 0)
    return (now - last_fail) < settings.CARBONLINK_RETRY_DELAY

  def get_connection(self, host):
    # First try to take one out of the pool for this host
    (server, instance) = host
    port = self.ports[host]
    connectionPool = self.connections[host]
    try:
      return connectionPool.pop()
    except KeyError:
      pass #nothing left in the pool, gotta make a new connection

    log.cache("CarbonLink creating a new socket for %s" % str(host))
    connection = socket.socket()
    connection.settimeout(self.timeout)
    try:
      connection.connect( (server, port) )
    except:
      self.last_failure[host] = time.time()
      raise
    else:
      connection.setsockopt( socket.SOL_SOCKET, socket.SO_KEEPALIVE, 1 )
      return connection

  def query(self, metric):
    request = dict(type='cache-query', metric=metric)
    results = self.send_request(request)
    log.cache("CarbonLink cache-query request for %s returned %d datapoints" % (metric, len(results['datapoints'])))
    return results['datapoints']

  def get_metadata(self, metric, key):
    request = dict(type='get-metadata', metric=metric, key=key)
    results = self.send_request(request)
    log.cache("CarbonLink get-metadata request received for %s:%s" % (metric, key))
    return results['value']

  def set_metadata(self, metric, key, value):
    request = dict(type='set-metadata', metric=metric, key=key, value=value)
    results = self.send_request(request)
    log.cache("CarbonLink set-metadata request received for %s:%s" % (metric, key))
    return results

  def send_request(self, request):
    metric = request['metric']
    serialized_request = pickle.dumps(request, protocol=-1)
    len_prefix = struct.pack("!L", len(serialized_request))
    request_packet = len_prefix + serialized_request

    host = self.select_host(metric)
    conn = self.get_connection(host)
    log.cache("CarbonLink sending request for %s to %s" % (metric, str(host)))
    try:
      conn.sendall(request_packet)
      result = self.recv_response(conn)
    except:
      self.last_failure[host] = time.time()
      raise
    else:
      self.connections[host].add(conn)
      if 'error' in result:
        log.cache("Error getting data from cache: %s" % result['error'])
        raise CarbonLinkRequestError(result['error'])
      else:
        return result

  def recv_response(self, conn):
    len_prefix = recv_exactly(conn, 4)
    body_size = struct.unpack("!L", len_prefix)[0]
    body = recv_exactly(conn, body_size)
    return unpickle.loads(body)