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# Source code for postgresql.cluster

    ##
    # .cluster - PostgreSQL cluster management
    ##
    """
    Create, control, and destroy PostgreSQL clusters.

    postgresql.cluster provides a programmer's interface to controlling a PostgreSQL
    cluster. It provides direct access to proper signalling interfaces.
    """
    import sys
    import os
    import errno
    import time
    import subprocess as sp
    from tempfile import NamedTemporaryFile

    from . import api as pg_api
    from . import configfile
    from . import installation as pg_inn
    from . import exceptions as pg_exc
    from . import driver as pg_driver
    from .encodings.aliases import get_python_name
    from .python.os import close_fds

    if sys.platform in ('win32', 'win64'):
    	from .port import signal1_msw as signal
    	pg_kill = signal.kill
    	def namedtemp(encoding):
    		return NamedTemporaryFile(delete = False, mode = 'w', encoding=encoding)
    else:
    	import signal
    	pg_kill = os.kill
    	def namedtemp(encoding):
    		return NamedTemporaryFile(mode = 'w', encoding=encoding)

    class ClusterError(pg_exc.Error):
    	"""
    	General cluster error.
    	"""
    	code = '-C000'
    	source = 'CLUSTER'
    class ClusterInitializationError(ClusterError):
    	"General cluster initialization failure"
    	code = '-Cini'
    class InitDBError(ClusterInitializationError):
    	"A non-zero result was returned by the initdb command"
    	code = '-Cidb'
    class ClusterStartupError(ClusterError):
    	"Cluster startup failed"
    	code = '-Cbot'
    class ClusterNotRunningError(ClusterError):
    	"Cluster is not running"
    	code = '-Cdwn'
    class ClusterTimeoutError(ClusterError):
    	"Cluster operation timed out"
    	code = '-Cout'

    class ClusterWarning(pg_exc.Warning):
    	"Warning issued by cluster operations"
    	code = '-Cwrn'
    	source = 'CLUSTER'

    DEFAULT_CLUSTER_ENCODING = 'utf-8'
    DEFAULT_CONFIG_FILENAME = 'postgresql.conf'
    DEFAULT_HBA_FILENAME = 'pg_hba.conf'
    DEFAULT_PID_FILENAME = 'postmaster.pid'

    initdb_option_map = {
    	'encoding' : '-E',
    	'authentication' : '-A',
    	'user' : '-U',
    	# pwprompt is not supported.
    	# interactive use should be implemented by the application
    	# calling Cluster.init()
    }

    class Cluster(pg_api.Cluster):
    	"""
    	Interface to a PostgreSQL cluster.

    	Provides mechanisms to start, stop, restart, kill, drop, and initalize a
    	cluster(data directory).

    	Cluster does not strive to be consistent with ``pg_ctl``. This is considered
    	to be a base class for managing a cluster, and is intended to be extended to
    	accommodate for a particular purpose.
    	"""
    	driver = pg_driver.default
    	installation = None
    	data_directory = None
    	DEFAULT_CLUSTER_ENCODING = DEFAULT_CLUSTER_ENCODING
    	DEFAULT_CONFIG_FILENAME = DEFAULT_CONFIG_FILENAME
    	DEFAULT_PID_FILENAME = DEFAULT_PID_FILENAME
    	DEFAULT_HBA_FILENAME = DEFAULT_HBA_FILENAME

    	@property
    	def state(self):
    		if self.running():
    			return 'running'
    		if not os.path.exists(self.data_directory):
    			return 'void'
    		return 'stopped'

    	def _e_metas(self):
    		state = self.state
    		yield (None, '[' + state + ']')
    		if state == 'running':
    			yield ('pid', self.state)

    	@property
    	def daemon_path(self):
    		"""
    		Path to the executable to use to startup the cluster.
    		"""
    		return self.installation.postmaster or self.installation.postgres

    	def get_pid_from_file(self):
    		"""
    		The current pid from the postmaster.pid file.
    		"""
    		try:
    			path = os.path.join(self.data_directory, self.DEFAULT_PID_FILENAME)
    			with open(path) as f:
    				return int(f.readline())
    		except IOError as e:
    			if e.errno in (errno.EIO, errno.ENOENT):
    				return None

    	@property
    	def pid(self):
    		"""
    		If we have the subprocess, use the pid on the object.
    		"""
    		pid = self.get_pid_from_file()
    		if pid is None:
    			d = self.daemon_process
    			if d is not None:
    				return d.pid
    		return pid

    	@property
    	def settings(self):
    		if not hasattr(self, '_settings'):
    			self._settings = configfile.ConfigFile(self.pgsql_dot_conf)
    		return self._settings

    	@property
    	def hba_file(self, join = os.path.join):
    		"""
    		The path to the HBA file of the cluster.
    		"""
    		return self.settings.get(
    			'hba_file',
    			join(self.data_directory, self.DEFAULT_HBA_FILENAME)
    		)

    	def __init__(self,
    		installation : "installation object",
    		data_directory : "path to the data directory",
    	):
    		self.installation = installation
    		self.data_directory = os.path.abspath(data_directory)
    		self.pgsql_dot_conf = os.path.join(
    			self.data_directory,
    			self.DEFAULT_CONFIG_FILENAME
    		)
    		self.daemon_process = None
    		self.daemon_command = None

    	def __repr__(self, format = "{mod}.{name}({ins!r}, {dir!r})".format):
    		return format(
    			type(self).__module__,
    			type(self).__name__,
    			self.installation,
    			self.data_directory,
    		)

    	def __enter__(self):
    		"""
    		Start the cluster and wait for it to startup.
    		"""
    		self.start()
    		self.wait_until_started()
    		return self

    	def __exit__(self, typ, val, tb):
    		"""
    		Stop the cluster and wait for it to shutdown.
    		"""
    		self.stop()
    		self.wait_until_stopped()

    	def init(self,
    		password : \
    			"Password to assign to the " \
    			"cluster's superuser(`user` keyword)." = None,
    		**kw
    	):
    		"""
    		Create the cluster at the given `data_directory` using the
    		provided keyword parameters as options to the command.

    		`command_option_map` provides the mapping of keyword arguments
    		to command options.
    		"""
    		initdb = self.installation.initdb
    		if initdb is None:
    			initdb = (self.installation.pg_ctl, 'initdb',)
    		else:
    			initdb = (initdb,)

    		if None in initdb:
    			raise ClusterInitializationError(
    				"unable to find executable for cluster initialization",
    				details = {
    					'detail' : "The installation does not have 'initdb' or 'pg_ctl'.",
    				},
    				creator = self
    			)
    		# Transform keyword options into command options for the executable.

    		# A default is used rather than looking at the environment to, well,
    		# avoid looking at the environment.
    		kw.setdefault('encoding', self.DEFAULT_CLUSTER_ENCODING)
    		opts = []
    		for x in kw:
    			if x in ('logfile', 'extra_arguments'):
    				continue
    			if x not in initdb_option_map:
    				raise TypeError("got an unexpected keyword argument %r" %(x,))
    			opts.append(initdb_option_map[x])
    			opts.append(kw[x])
    		logfile = kw.get('logfile') or sp.PIPE
    		extra_args = tuple([
    			str(x) for x in kw.get('extra_arguments', ())
    		])

    		supw_file = ()
    		supw_tmp = None
    		p = None
    		try:
    			if password is not None:
    				# got a superuserpass, store it in a tempfile for initdb
    				supw_tmp = namedtemp(encoding = get_python_name(kw['encoding']))
    				supw_tmp.write(password)
    				supw_tmp.flush()
    				supw_file = ('--pwfile=' + supw_tmp.name,)

    			cmd = initdb + ('-D', self.data_directory) \
    				+ tuple(opts) \
    				+ supw_file \
    				+ extra_args

    			p = sp.Popen(
    				cmd,
    				close_fds = close_fds,
    				bufsize = 1024 * 5, # not expecting this to ever be filled.
    				stdin = sp.PIPE,
    				stdout = logfile,
    				# stderr is used to identify a reasonable error message.
    				stderr = sp.PIPE,
    			)
    			# stdin is not used; it is not desirable for initdb to be attached.
    			p.stdin.close()

    			while True:
    				try:
    					rc = p.wait()
    					break
    				except OSError as e:
    					if e.errno != errno.EINTR:
    						raise
    				finally:
    					if p.stdout is not None:
    						p.stdout.close()

    			if rc != 0:
    				# initdb returned non-zero, pickup stderr and attach to exception.

    				r = p.stderr.read().strip()
    				try:
    					msg = r.decode('utf-8')
    				except UnicodeDecodeError:
    					# split up the lines, and use rep.
    					msg = os.linesep.join([
    						repr(x)[2:-1] for x in r.splitlines()
    					])
    				raise InitDBError(
    					"initdb exited with non-zero status",
    					details = {
    						'command': cmd,
    						'stderr': msg,
    						'stdout': msg,
    					},
    					creator = self
    				)
    		finally:
    			if p is not None:
    				for x in (p.stderr, p.stdin, p.stdout):
    					if x is not None:
    						x.close()

    			if supw_tmp is not None:
    				n = supw_tmp.name
    				supw_tmp.close()
    				# XXX: win32 compensation.
    				if os.path.exists(n):
    					os.unlink(n)

    	def drop(self):
    		"""
    		Stop the cluster and remove it from the filesystem
    		"""
    		if self.running():
    			self.shutdown()
    			try:
    				self.wait_until_stopped()
    			except ClusterTimeoutError:
    				self.kill()
    				try:
    					self.wait_until_stopped()
    				except ClusterTimeoutError:
    					ClusterWarning(
    						'cluster failed to shutdown after kill',
    						details = {'hint' : 'Shared memory may have been leaked.'},
    						creator = self
    					).emit()
    		# Really, using rm -rf would be the best, but use this for portability.
    		for root, dirs, files in os.walk(self.data_directory, topdown = False):
    			for name in files:
    				os.remove(os.path.join(root, name))
    			for name in dirs:
    				os.rmdir(os.path.join(root, name))
    		os.rmdir(self.data_directory)

    	def start(self,
    		logfile : "Where to send stderr" = None,
    		settings : "Mapping of runtime parameters" = None
    	):
    		"""
    		Start the cluster.
    		"""
    		if self.running():
    			return
    		cmd = (self.daemon_path, '-D', self.data_directory)
    		if settings is not None:
    			for k,v in dict(settings).items():
    				cmd.append('--{k}={v}'.format(k=k,v=v))

    		p = sp.Popen(
    			cmd,
    			close_fds = close_fds,
    			bufsize = 1024,
    			# send everything to logfile
    			stdout = sp.PIPE if logfile is None else logfile,
    			stderr = sp.STDOUT,
    			stdin = sp.PIPE,
    		)
    		if logfile is None:
    			p.stdout.close()
    		p.stdin.close()
    		self.daemon_process = p
    		self.daemon_command = cmd

    	def restart(self, logfile = None, settings = None, timeout = 10):
    		"""
    		Restart the cluster gracefully.

    		This provides a higher level interface to stopping then starting the
    		cluster. It will perform the wait operations and block until the
    		restart is complete.

    		If waiting is not desired, .start() and .stop() should be used directly.
    		"""
    		if self.running():
    			self.stop()
    			self.wait_until_stopped(timeout = timeout)
    		if self.running():
    			raise ClusterError(
    				"failed to shutdown cluster",
    				creator = self
    			)
    		self.start(logfile = logfile, settings = settings)
    		self.wait_until_started(timeout = timeout)

    	def reload(self):
    		"""
    		Signal the cluster to reload its configuration file.
    		"""
    		pid = self.pid
    		if pid is not None:
    			try:
    				pg_kill(pid, signal.SIGHUP)
    			except OSError as e:
    				if e.errno != errno.ESRCH:
    					raise

    	def stop(self):
    		"""
    		Stop the cluster gracefully waiting for clients to disconnect(SIGTERM).
    		"""
    		pid = self.pid
    		if pid is not None:
    			try:
    				pg_kill(pid, signal.SIGTERM)
    			except OSError as e:
    				if e.errno != errno.ESRCH:
    					raise

    	def shutdown(self):
    		"""
    		Shutdown the cluster as soon as possible, disconnecting clients.
    		"""
    		pid = self.pid
    		if pid is not None:
    			try:
    				pg_kill(pid, signal.SIGINT)
    			except OSError as e:
    				if e.errno != errno.ESRCH:
    					raise

    	def kill(self):
    		"""
    		Stop the cluster immediately(SIGKILL).

    		Does *not* wait for shutdown.
    		"""
    		pid = self.pid
    		if pid is not None:
    			try:
    				pg_kill(pid, signal.SIGKILL)
    			except OSError as e:
    				if e.errno != errno.ESRCH:
    					raise
    				# already dead, so it would seem.

    	def initialized(self):
    		"""
    		Whether or not the data directory *appears* to be a valid cluster.
    		"""
    		if os.path.isdir(self.data_directory) and \
    		os.path.exists(self.pgsql_dot_conf) and \
    		os.path.isdir(os.path.join(self.data_directory, 'base')):
    			return True
    		return False

    	def running(self):
    		"""
    		Whether or not the postmaster is running.

    		This does *not* mean the cluster is accepting connections.
    		"""
    		if self.daemon_process is not None:
    			r = self.daemon_process.poll()
    			if r is not None:
    				pid = self.get_pid_from_file()
    				if pid is not None:
    					# daemon process does not exist, but there's a pidfile.
    					self.daemon_process = None
    					return self.running()
    				return False
    			else:
    				return True
    		else:
    			pid = self.get_pid_from_file()
    			if pid is None:
    				return False
    			try:
    				pg_kill(pid, signal.SIG_DFL)
    			except OSError as e:
    				if e.errno != errno.ESRCH:
    					raise
    				return False
    			return True

    	def connector(self, **kw):
    		"""
    		Create a postgresql.driver connector based on the given keywords and
    		listen_addresses and port configuration in settings.
    		"""
    		host, port = self.address()
    		return self.driver.fit(
    			host = host or 'localhost',
    			port = port or 5432,
    			**kw
    		)

    	def connection(self, **kw):
    		"""
    		Create a connection object to the cluster, but do not connect.
    		"""
    		return self.connector(**kw)()

    	def connect(self, **kw):
    		"""
    		Create an established connection from the connector.

    		Cluster must be running.
    		"""
    		if not self.running():
    			raise ClusterNotRunningError(
    				"cannot connect if cluster is not running",
    				creator = self
    			)
    		x = self.connection(**kw)
    		x.connect()
    		return x

    	def address(self):
    		"""
    		Get the host-port pair from the configuration.
    		"""
    		d = self.settings.getset((
    			'listen_addresses', 'port',
    		))
    		if d.get('listen_addresses') is not None:
    			# Prefer localhost over other addresses.
    			# More likely to get a successful connection.
    			addrs = d.get('listen_addresses').lower().split(',')
    			if 'localhost' in addrs or '*' in addrs:
    				host = 'localhost'
    			elif '127.0.0.1' in addrs:
    				host = '127.0.0.1'
    			elif '::1' in addrs:
    				host = '::1'
    			else:
    				host = addrs[0]
    		else:
    			host = None
    		return (host, d.get('port'))

    	def ready_for_connections(self):
    		"""
    		If the daemon is running, and is not in startup mode.

    		This only works for clusters configured for TCP/IP connections.
    		"""
    		if not self.running():
    			return False
    		e = None
    		host, port = self.address()
    		connection = self.driver.fit(
    			user = ' -*- ping -*- ',
    			host = host, port = port,
    			database = 'template1',
    			sslmode = 'disable',
    		)()
    		try:
    			connection.connect()
    		except pg_exc.ClientCannotConnectError as err:
    			for attempt in err.database.failures:
    				x = attempt.error
    				if self.installation.version_info[:2] < (8,1):
    					if isinstance(x, (
    						pg_exc.UndefinedObjectError,
    						pg_exc.AuthenticationSpecificationError,
    					)):
    						# undefined user.. whatever...
    						return True
    				else:
    					if isinstance(x, pg_exc.AuthenticationSpecificationError):
    						return True
    				# configuration file error. ya, that's probably not going to change.
    				if isinstance(x, (pg_exc.CFError, pg_exc.ProtocolError)):
    					raise x
    				if isinstance(x, pg_exc.ServerNotReadyError):
    					e = x
    					break
    			else:
    				e = err
    		# the else true means we successfully connected with those
    		# credentials... strange, but true..
    		return e if e is not None else True

    	def wait_until_started(self,
    		timeout : "how long to wait before throwing a timeout exception" = 10,
    		delay : "how long to sleep before re-testing" = 0.05,
    	):
    		"""
    		After the `start` method is used, this can be ran in order to block
    		until the cluster is ready for use.

    		This method loops until `ready_for_connections` returns `True` in
    		order to make sure that the cluster is actually up.
    		"""
    		start = time.time()
    		checkpoint = start
    		while True:
    			if not self.running():
    				if self.daemon_process is not None:
    					r = self.daemon_process.returncode
    					if r is not None:
    						raise ClusterStartupError(
    							"postgres daemon terminated",
    							details = {
    								'RESULT' : r,
    								'COMMAND' : self.daemon_command,
    							},
    							creator = self
    						)
    				else:
    					raise ClusterNotRunningError(
    						"postgres daemon has not been started",
    						creator = self
    					)
    			r = self.ready_for_connections()

    			checkpoint = time.time()
    			if r is True:
    				break

    			if checkpoint - start >= timeout:
    				# timeout was reached, but raise ServerNotReadyError
    				# to signal to the user that it was *not* due to some unknown
    				# condition, rather it's *still* starting up.
    				if r is not None and isinstance(r, pg_exc.ServerNotReadyError):
    					raise r
    				e = ClusterTimeoutError(
    					'timeout on startup',
    					creator = self
    				)
    				if r not in (True,False):
    					raise e from r
    				raise e
    			time.sleep(delay)

    	def wait_until_stopped(self,
    		timeout : "how long to wait before throwing a timeout exception" = 10,
    		delay : "how long to sleep before re-testing" = 0.05
    	):
    		"""
    		After the `stop` method is used, this can be ran in order to block until
    		the cluster is shutdown.

    		Additionally, catching `ClusterTimeoutError` exceptions would be a
    		starting point for making decisions about whether or not to issue a kill
    		to the daemon.
    		"""
    		start = time.time()
    		while self.running() is True:
    			# pickup the exit code.
    			if self.daemon_process is not None:
    				self.last_exit_code = self.daemon_process.poll()
    			else:
    				self.last_exit_code = pg_kill(self.get_pid_from_file(), 0)
    			if time.time() - start >= timeout:
    				raise ClusterTimeoutError(
    					'timeout on shutdown',
    					creator = self,
    				)
    			time.sleep(delay)
    ##
    # vim: ts=3:sw=3:noet:

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