1 # The source code is from following Python documentation: 2 # https://docs.python.org/2/howto/logging-cookbook.html#network-logging 3 4 # Classes in this file are used to create a simple TCP socket-based logging 5 # receiver. The receiver listens to default logging port (9020) and save log to 6 # any given log configuration, e.g., a local file. Once the receiver is running, 7 # client can add a logging handler to write log to the receiver with following 8 # sample code: 9 # socketHandler = logging.handlers.SocketHandler('localhost', 10 # logging.handlers.DEFAULT_TCP_LOGGING_PORT) 11 # logging.getLogger().addHandler(socketHandler) 12 13 import ctypes 14 import pickle 15 import logging 16 import multiprocessing 17 import select 18 import SocketServer 19 import struct 20 import time 21 22 import common 23 from autotest_lib.client.common_lib import utils 24 25 class LogRecordStreamHandler(SocketServer.StreamRequestHandler): 26 """Handler for a streaming logging request. 27 28 This basically logs the record using whatever logging policy is 29 configured locally. 30 """ 31 32 def handle(self): 33 """ 34 Handle multiple requests - each expected to be a 4-byte length, 35 followed by the LogRecord in pickle format. Logs the record 36 according to whatever policy is configured locally. 37 """ 38 while True: 39 chunk = self.connection.recv(4) 40 if len(chunk) < 4: 41 return 42 slen = struct.unpack('>L', chunk)[0] 43 chunk = self.connection.recv(slen) 44 while len(chunk) < slen: 45 chunk = chunk + self.connection.recv(slen - len(chunk)) 46 obj = self.unpickle(chunk) 47 record = logging.makeLogRecord(obj) 48 self.handle_log_record(record) 49 50 51 def unpickle(self, data): 52 """Unpickle data received. 53 54 @param data: Received data. 55 @returns: unpickled data. 56 """ 57 return pickle.loads(data) 58 59 60 def handle_log_record(self, record): 61 """Process log record. 62 63 @param record: log record. 64 """ 65 # if a name is specified, we use the named logger rather than the one 66 # implied by the record. 67 if self.server.logname is not None: 68 name = self.server.logname 69 else: 70 name = record.name 71 logger = logging.getLogger(name) 72 # N.B. EVERY record gets logged. This is because Logger.handle 73 # is normally called AFTER logger-level filtering. If you want 74 # to do filtering, do it at the client end to save wasting 75 # cycles and network bandwidth! 76 logger.handle(record) 77 78 79 class LogRecordSocketReceiver(SocketServer.ThreadingTCPServer): 80 """Simple TCP socket-based logging receiver. 81 """ 82 83 allow_reuse_address = 1 84 85 def __init__(self, host='localhost', port=None, 86 handler=LogRecordStreamHandler): 87 if not port: 88 port = utils.get_unused_port() 89 SocketServer.ThreadingTCPServer.__init__(self, (host, port), handler) 90 self.abort = 0 91 self.timeout = 1 92 self.logname = None 93 self.port = port 94 95 96 def serve_until_stopped(self): 97 """Run the socket receiver until aborted.""" 98 print 'Log Record Socket Receiver is started.' 99 abort = 0 100 while not abort: 101 rd, wr, ex = select.select([self.socket.fileno()], [], [], 102 self.timeout) 103 if rd: 104 self.handle_request() 105 abort = self.abort 106 print 'Log Record Socket Receiver is stopped.' 107 108 109 class LogSocketServer: 110 """A wrapper class to start and stop a TCP server for logging.""" 111 112 process = None 113 port = None 114 115 @staticmethod 116 def start(**kwargs): 117 """Start Log Record Socket Receiver in a new process. 118 119 @param kwargs: log configuration, e.g., format, filename. 120 121 @raise Exception: if TCP server is already running. 122 """ 123 if LogSocketServer.process: 124 raise Exception('Log Record Socket Receiver is already running.') 125 server_started = multiprocessing.Value(ctypes.c_bool, False) 126 port = multiprocessing.Value(ctypes.c_int, 0) 127 LogSocketServer.process = multiprocessing.Process( 128 target=LogSocketServer._start_server, 129 args=(server_started, port), 130 kwargs=kwargs) 131 LogSocketServer.process.start() 132 while not server_started.value: 133 time.sleep(0.1) 134 LogSocketServer.port = port.value 135 print 'Log Record Socket Server is started at port %d.' % port.value 136 137 138 @staticmethod 139 def _start_server(server_started, port, **kwargs): 140 """Start the TCP server to receive log. 141 142 @param server_started: True if socket log server is started. 143 @param port: Port used by socket log server. 144 @param kwargs: log configuration, e.g., format, filename. 145 """ 146 # Clear all existing log handlers. 147 logging.getLogger().handlers = [] 148 if not kwargs: 149 logging.basicConfig( 150 format='%(asctime)s - %(levelname)s - %(message)s') 151 else: 152 logging.basicConfig(**kwargs) 153 154 tcp_server = LogRecordSocketReceiver() 155 print('Starting TCP server...') 156 server_started.value = True 157 port.value = tcp_server.port 158 tcp_server.serve_until_stopped() 159 160 161 @staticmethod 162 def stop(): 163 """Stop Log Record Socket Receiver. 164 """ 165 if LogSocketServer.process: 166 LogSocketServer.process.terminate() 167 LogSocketServer.process = None 168 LogSocketServer.port = None 169
