Products.ZenUtils.ZenDaemon

48 """ 49 Base class for creating daemons 50 """ 51 52 pidfile = None 53

54 - def __init__(self, noopts=0, keeproot=False):

55 """ 56 Initializer that takes care of basic daemon options. 57 Creates a PID file. 58 """ 59 super(ZenDaemon, self).__init__(noopts) 60 self.pidfile = None 61 self.keeproot=keeproot 62 self.reporter = None 63 self.fqdn = socket.getfqdn() 64 from twisted.internet import reactor 65 reactor.addSystemEventTrigger('before', 'shutdown', self.sigTerm) 66 if not noopts: 67 if self.options.daemon: 68 self.changeUser() 69 self.becomeDaemon() 70 if self.options.daemon or self.options.watchdogPath: 71 try: 72 self.writePidFile() 73 except OSError: 74 msg= "ERROR: unable to open PID file %s" % \ 75 (self.pidfile or '(unknown)') 76 raise SystemExit(msg) 77 78 if self.options.watchdog and not self.options.watchdogPath: 79 self.becomeWatchdog()

80

81 - def openPrivilegedPort(self, *address):

82 """Execute under zensocket, providing the args to zensocket""" 83 zensocket = binPath('zensocket') 84 cmd = [zensocket, zensocket] + list(address) + ['--'] + \ 85 [sys.executable] + sys.argv + \ 86 ['--useFileDescriptor=$privilegedSocket'] 87 os.execlp(*cmd)

88 89

90 - def writePidFile(self):

91 """ 92 Write the PID file to disk 93 """ 94 myname = sys.argv[0].split(os.sep)[-1] 95 if myname.endswith('.py'): myname = myname[:-3] 96 monitor = getattr(self.options, 'monitor', 'localhost') 97 myname = "%s-%s.pid" % (myname, monitor) 98 if self.options.watchdog and not self.options.watchdogPath: 99 self.pidfile = zenPath("var", 'watchdog-%s' % myname) 100 else: 101 self.pidfile = zenPath("var", myname) 102 fp = open(self.pidfile, 'w') 103 fp.write(str(os.getpid())) 104 fp.close()

105

106 - def setupLogging(self):

107 """ 108 Create formating for log entries and set default log level 109 """ 110 111 # Setup python logging module 112 rlog = logging.getLogger() 113 rlog.setLevel(logging.WARN) 114 if hasattr(self, 'mname'): mname = self.mname 115 else: mname = self.__class__.__name__ 116 self.log = logging.getLogger("zen."+ mname) 117 zlog = logging.getLogger("zen") 118 zlog.setLevel(self.options.logseverity) 119 if self.options.watchdogPath or \ 120 self.options.daemon: 121 logdir = self.checkLogpath() 122 if not logdir: 123 logdir = zenPath("log") 124 logfile = os.path.join(logdir, mname.lower()+".log") 125 maxBytes = self.options.maxLogKiloBytes * 1024 126 backupCount = self.options.maxBackupLogs 127 h = logging.handlers.RotatingFileHandler(filename=logfile, maxBytes=maxBytes, backupCount=backupCount) 128 h.setFormatter(logging.Formatter( 129 "%(asctime)s %(levelname)s %(name)s: %(message)s")) 130 rlog.addHandler(h) 131 else: 132 logging.basicConfig() 133 if self.options.weblog: 134 [ h.setFormatter(HtmlFormatter()) for h in rlog.handlers ] 135 else: 136 f = logging.Formatter("%(asctime)s %(levelname)s %(name)s: %(message)s") 137 [ h.setFormatter(f) for h in rlog.handlers ] 138 139 # Allow the user to dynamically lower and raise the logging 140 # level without restarts. 141 import signal 142 try: 143 signal.signal(signal.SIGUSR1, self.sighandler_USR1) 144 except ValueError: 145 # If we get called multiple times, this will generate an exception: 146 # ValueError: signal only works in main thread 147 # Ignore it as we've already set up the signal handler. 148 pass

149

150 - def sighandler_USR1(self, signum, frame):

151 """ 152 Switch to debug level if signaled by the user, and to 153 default when signaled again. 154 """ 155 log = logging.getLogger('zen') 156 currentLevel = log.getEffectiveLevel() 157 if currentLevel == logging.DEBUG: 158 log.setLevel(self.options.logseverity) 159 log.info("Restoring logging level back to %s (%d)", 160 logging.getLevelName(self.options.logseverity) or "unknown", 161 self.options.logseverity) 162 # Stop twisted logging 163 if hasattr(self, 'mname'): mname = self.mname 164 else: mname = self.__class__.__name__ 165 observer = twisted_log.PythonLoggingObserver(loggerName="zen."+ mname) 166 observer.stop() 167 else: 168 log.setLevel(logging.DEBUG) 169 log.info("Setting logging level to DEBUG") 170 171 # Setup twisted logging 172 if hasattr(self, 'mname'): mname = self.mname 173 else: mname = self.__class__.__name__ 174 observer = twisted_log.PythonLoggingObserver(loggerName="zen."+ mname) 175 observer.start()

176 177

178 - def changeUser(self):

179 """ 180 Switch identity to the appropriate Unix user 181 """ 182 if not self.keeproot: 183 try: 184 cname = pwd.getpwuid(os.getuid())[0] 185 pwrec = pwd.getpwnam(self.options.uid) 186 os.setuid(pwrec.pw_uid) 187 os.environ['HOME'] = pwrec.pw_dir 188 except (KeyError, OSError): 189 print >>sys.stderr, "WARN: user:%s not found running as:%s"%( 190 self.options.uid,cname)

191 192

193 - def becomeDaemon(self):

194 """Code below comes from the excellent recipe by Chad J. Schroeder. 195 """ 196 try: 197 pid = os.fork() 198 except OSError, e: 199 raise Exception( "%s [%d]" % (e.strerror, e.errno) ) 200 201 if (pid == 0): # The first child. 202 os.setsid() 203 try: 204 pid = os.fork() # Fork a second child. 205 except OSError, e: 206 raise Exception( "%s [%d]" % (e.strerror, e.errno) ) 207 208 if (pid == 0): # The second child. 209 os.chdir(WORKDIR) 210 os.umask(UMASK) 211 else: 212 os._exit(0) # Exit parent (the first child) of the second child. 213 else: 214 os._exit(0) # Exit parent of the first child. 215 216 # Iterate through and close all stdin/out/err 217 for fd in range(0, MAXFD): 218 try: 219 os.close(fd) 220 except OSError: # ERROR, fd wasn't open to begin with (ignored) 221 pass 222 223 os.open(REDIRECT_TO, os.O_RDWR) # standard input (0) 224 # Duplicate standard input to standard output and standard error. 225 os.dup2(0, 1) # standard output (1) 226 os.dup2(0, 2) # standard error (2)

227 228

229 - def sigTerm(self, signum=None, frame=None):

230 """ 231 Signal handler for the SIGTERM signal. 232 """ 233 # This probably won't be called when running as daemon. 234 # See ticket #1757 235 from Products.ZenUtils.Utils import unused 236 unused(signum, frame) 237 stop = getattr(self, "stop", None) 238 if callable(stop): stop() 239 if self.pidfile and os.path.exists(self.pidfile): 240 self.log.info("Deleting PID file %s ...", self.pidfile) 241 os.remove(self.pidfile) 242 self.log.info('Daemon %s shutting down' % self.__class__.__name__) 243 raise SystemExit

244 245

246 - def watchdogCycleTime(self):

247 """ 248 Return our cycle time (in minutes) 249 250 @return: cycle time 251 @rtype: integer 252 """ 253 # time between child reports: default to 2x the default cycle time 254 default = 1200 255 cycleTime = getattr(self.options, 'cycleTime', default) 256 if not cycleTime: 257 cycleTime = default 258 return cycleTime

259

260 - def watchdogStartTimeout(self):

261 """ 262 Return our watchdog start timeout (in minutes) 263 264 @return: start timeout 265 @rtype: integer 266 """ 267 # Default start timeout should be cycle time plus a couple of minutes 268 default = self.watchdogCycleTime() + 120 269 startTimeout = getattr(self.options, 'starttimeout', default) 270 if not startTimeout: 271 startTimeout = default 272 return startTimeout

273 274

275 - def watchdogMaxRestartTime(self):

276 """ 277 Return our watchdog max restart time (in minutes) 278 279 @return: maximum restart time 280 @rtype: integer 281 """ 282 default = 600 283 maxTime = getattr(self.options, 'maxRestartTime', default) 284 if not maxTime: 285 maxTime = default 286 return default

287 288

289 - def becomeWatchdog(self):

290 """ 291 Watch the specified daemon and restart it if necessary. 292 """ 293 from Products.ZenUtils.Watchdog import Watcher, log 294 log.setLevel(self.options.logseverity) 295 cmd = sys.argv[:] 296 if '--watchdog' in cmd: 297 cmd.remove('--watchdog') 298 if '--daemon' in cmd: 299 cmd.remove('--daemon') 300 301 socketPath = '%s/.%s-watchdog-%d' % ( 302 zenPath('var'), self.__class__.__name__, os.getpid()) 303 304 cycleTime = self.watchdogCycleTime() 305 startTimeout = self.watchdogStartTimeout() 306 maxTime = self.watchdogMaxRestartTime() 307 self.log.debug("Watchdog cycleTime=%d startTimeout=%d maxTime=%d", 308 cycleTime, startTimeout, maxTime) 309 310 watchdog = Watcher(socketPath, 311 cmd, 312 startTimeout, 313 cycleTime, 314 maxTime) 315 watchdog.run() 316 sys.exit(0)

317

318 - def niceDoggie(self, timeout):

319 # defer creation of the reporter until we know we're not going 320 # through zensocket or other startup that results in closing 321 # this socket 322 if not self.reporter and self.options.watchdogPath: 323 from Watchdog import Reporter 324 self.reporter = Reporter(self.options.watchdogPath) 325 if self.reporter: 326 self.reporter.niceDoggie(timeout)

327

328 - def buildOptions(self):

329 """ 330 Standard set of command-line options. 331 """ 332 CmdBase.buildOptions(self) 333 self.parser.add_option('--uid',dest='uid',default="zenoss", 334 help='User to become when running default:zenoss') 335 self.parser.add_option('-c', '--cycle',dest='cycle', 336 action="store_true", default=False, 337 help="Cycle continuously on cycleInterval from Zope") 338 self.parser.add_option('-D', '--daemon', default=False, 339 dest='daemon',action="store_true", 340 help="Launch into the background") 341 self.parser.add_option('--weblog', default=False, 342 dest='weblog',action="store_true", 343 help="output log info in HTML table format") 344 self.parser.add_option('--watchdog', default=False, 345 dest='watchdog', action="store_true", 346 help="Run under a supervisor which will restart it") 347 self.parser.add_option('--watchdogPath', default=None, 348 dest='watchdogPath', 349 help="The path to the watchdog reporting socket") 350 self.parser.add_option('--starttimeout', 351 dest='starttimeout', 352 type="int", 353 help="Wait seconds for initial heartbeat")

Source Code for Module Products.ZenUtils.ZenDaemon