/usr/bin/walmgr3 is in skytools3-walmgr 3.2.6-5+b1.
This file is owned by root:root, with mode 0o755.
The actual contents of the file can be viewed below.
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"""WALShipping manager.
walmgr INI COMMAND [-n]
Master commands:
setup Configure PostgreSQL for WAL archiving
sync Copies in-progress WALs to slave
syncdaemon Daemon mode for regular syncing
stop Stop archiving - de-configure PostgreSQL
periodic Run periodic command if configured.
synch-standby Manage synchronous streaming replication.
Slave commands:
boot Stop playback, accept queries
pause Just wait, don't play WAL-s
continue Start playing WAL-s again
createslave Create streaming replication slave
Common commands:
init Create configuration files, set up ssh keys.
listbackups List backups.
backup Copies all master data to slave. Will keep backup history
if slave keep_backups is set. EXPERIMENTAL: If run on slave,
creates backup from in-recovery slave data.
restore [set][dst] Stop postmaster, move new data dir to right location and start
postmaster in playback mode. Optionally use [set] as the backupset
name to restore. In this case the directory is copied, not moved.
cleanup Cleanup any walmgr files after stop.
Internal commands:
xarchive archive one WAL file (master)
xrestore restore one WAL file (slave)
xlock Obtain backup lock (master)
xrelease Release backup lock (master)
xrotate Rotate backup sets, expire and archive oldest if necessary.
xpurgewals Remove WAL files not needed for backup (slave)
xpartialsync Append data to WAL file (slave)
"""
import os, sys, re, signal, time, traceback
import errno, glob, ConfigParser, shutil, subprocess
import pkgloader
pkgloader.require('skytools', '3.0')
import skytools
DEFAULT_PG_VERSION = "8.3"
XLOG_SEGMENT_SIZE = 16 * 1024**2
def usage(err):
if err > 0:
print >>sys.stderr, __doc__
else:
print __doc__
sys.exit(err)
def die(err,msg):
print >> sys.stderr, msg
sys.exit(err)
def yesno(prompt):
"""Ask a Yes/No question"""
while True:
sys.stderr.write(prompt + " ")
sys.stderr.flush()
answer = sys.stdin.readline()
if not answer:
return False
answer = answer.strip().lower()
if answer in ('yes','y'):
return True
if answer in ('no','n'):
return False
sys.stderr.write("Please answer yes or no.\n")
def copy_conf(src, dst):
"""Copy config file or symlink.
Does _not_ overwrite target.
"""
if os.path.isdir(dst):
dst = os.path.join(dst, os.path.basename(src))
if os.path.exists(dst):
return False
if os.path.islink(src):
linkdst = os.readlink(src)
os.symlink(linkdst, dst)
elif os.path.isfile(src):
shutil.copy2(src, dst)
else:
raise Exception("Unsupported file type: %s" % src)
return True
class WalChunk:
"""Represents a chunk of WAL used in record based shipping"""
def __init__(self,filename,pos=0,bytes=0):
self.filename = filename
self.pos = pos
self.bytes = bytes
self.start_time = time.time()
self.sync_count = 0
self.sync_time = 0.0
def __str__(self):
return "%s @ %d +%d" % (self.filename, self.pos, self.bytes)
class PgControlData:
"""Contents of pg_controldata"""
def __init__(self, bin_dir, data_dir, findRestartPoint):
"""Collect last checkpoint information from pg_controldata output"""
self.xlogid = None
self.xrecoff = None
self.timeline = None
self.wal_size = None
self.wal_name = None
self.cluster_state = None
self.is_shutdown = False
self.pg_version = 0
self.is_valid = False
try:
pg_controldata = os.path.join(bin_dir, "pg_controldata")
pipe = subprocess.Popen([ pg_controldata, data_dir ], stdout=subprocess.PIPE)
except OSError:
# don't complain if we cannot execute it
return
matches = 0
for line in pipe.stdout.readlines():
if findRestartPoint:
m = re.match("^Latest checkpoint's REDO location:\s+([0-9A-F]+)/([0-9A-F]+)", line)
else:
m = re.match("^Latest checkpoint location:\s+([0-9A-F]+)/([0-9A-F]+)", line)
if m:
matches += 1
self.xlogid = int(m.group(1), 16)
self.xrecoff = int(m.group(2), 16)
m = re.match("^Latest checkpoint's TimeLineID:\s+(\d+)", line)
if m:
matches += 1
self.timeline = int(m.group(1))
m = re.match("^Bytes per WAL segment:\s+(\d+)", line)
if m:
matches += 1
self.wal_size = int(m.group(1))
m = re.match("^pg_control version number:\s+(\d+)", line)
if m:
matches += 1
self.pg_version = int(m.group(1))
m = re.match("^Database cluster state:\s+(.*$)", line)
if m:
matches += 1
self.cluster_state = m.group(1)
self.is_shutdown = (self.cluster_state == "shut down")
# ran successfully and we got our needed matches
if pipe.wait() == 0 and matches == 5:
self.wal_name = "%08X%08X%08X" % \
(self.timeline, self.xlogid, self.xrecoff / self.wal_size)
self.is_valid = True
class BackupLabel:
"""Backup label contents"""
def __init__(self, backupdir):
"""Initialize a new BackupLabel from existing file"""
filename = os.path.join(backupdir, "backup_label")
self.first_wal = None
self.start_time = None
self.label_string = None
if not os.path.exists(filename):
return
for line in open(filename):
m = re.match('^START WAL LOCATION: [^\s]+ \(file ([0-9A-Z]+)\)$', line)
if m:
self.first_wal = m.group(1)
m = re.match('^START TIME:\s(.*)$', line)
if m:
self.start_time = m.group(1)
m = re.match('^LABEL: (.*)$', line)
if m:
self.label_string = m.group(1)
class Pgpass:
"""Manipulate pgpass contents"""
def __init__(self, passfile):
"""Load .pgpass contents"""
self.passfile = os.path.expanduser(passfile)
self.contents = []
if os.path.isfile(self.passfile):
self.contents = open(self.passfile).readlines()
def split_pgpass_line(selg, pgline):
"""Parses pgpass line, returns dict"""
try:
(host, port, db, user, pwd) = pgline.rstrip('\n\r').split(":")
return {'host': host, 'port': port, 'db': db, 'user': user, 'pwd': pwd}
except ValueError:
return None
def ensure_user(self, host, port, user, pwd):
"""Ensure that line for streaming replication exists in .pgpass"""
self.remove_user(host, port, user)
self.contents.insert(0, '%s:%s:%s:%s:%s\n' % (host, port, 'replication', user, pwd))
def remove_user(self, host, port, user):
"""Remove all matching lines from .pgpass"""
new_contents = []
found = False
for l in self.contents:
p = self.split_pgpass_line(l)
if p and p['host'] == host and p['port'] == port and p['user'] == user and p['db'] == 'replication':
found = True
continue
new_contents.append(l)
self.contents = new_contents
return found
def write(self):
"""Write contents back to file"""
f = open(self.passfile,'w')
os.chmod(self.passfile, 0600)
f.writelines(self.contents)
f.close()
class PostgresConfiguration:
"""Postgres configuration manipulation"""
def __init__(self, walmgr, cf_file):
"""load the configuration from master_config"""
self.walmgr = walmgr
self.log = walmgr.log
self.cf_file = cf_file
self.cf_buf = open(self.cf_file, "r").read()
def archive_mode(self):
"""Return value for specified parameter"""
# see if explicitly set
m = re.search("^\s*archive_mode\s*=\s*'?([a-zA-Z01]+)'?\s*#?.*$", self.cf_buf, re.M | re.I)
if m:
return m.group(1)
# also, it could be commented out as initdb leaves it
# it'd probably be best to check from the database ...
m = re.search("^#archive_mode\s*=.*$", self.cf_buf, re.M | re.I)
if m:
return "off"
return None
def synchronous_standby_names(self):
"""Return value for specified parameter"""
# see if explicitly set
m = re.search("^\s*synchronous_standby_names\s*=\s*'([^']*)'\s*#?.*$", self.cf_buf, re.M | re.I)
if m:
return m.group(1)
# also, it could be commented out as initdb leaves it
# it'd probably be best to check from the database ...
m = re.search("^#synchronous_standby_names\s*=.*$", self.cf_buf, re.M | re.I)
if m:
return ''
return None
def wal_level(self):
"""Return value for specified parameter"""
# see if explicitly set
m = re.search("^\s*wal_level\s*=\s*'?([a-z_]+)'?\s*#?.*$", self.cf_buf, re.M | re.I)
if m:
return m.group(1)
# also, it could be commented out as initdb leaves it
# it'd probably be best to check from the database ...
m = re.search("^#wal_level\s*=.*$", self.cf_buf, re.M | re.I)
if m:
return "minimal"
return None
def modify(self, cf_params):
"""Change the configuration parameters supplied in cf_params"""
for (param, value) in cf_params.iteritems():
r_active = re.compile("^\s*%s\s*=\s*([^\s#]*).*$" % param, re.M)
r_disabled = re.compile("^\s*#\s*%s\s*=.*$" % param, re.M)
cf_full = "%s = '%s'" % (param, value)
m = r_active.search(self.cf_buf)
if m:
old_val = m.group(1)
self.log.debug("found parameter %s with value %r", param, old_val)
self.cf_buf = "%s%s%s" % (self.cf_buf[:m.start()], cf_full, self.cf_buf[m.end():])
else:
m = r_disabled.search(self.cf_buf)
if m:
self.log.debug("found disabled parameter %s", param)
self.cf_buf = "%s\n%s%s" % (self.cf_buf[:m.end()], cf_full, self.cf_buf[m.end():])
else:
# not found, append to the end
self.log.debug("found no value")
self.cf_buf = "%s\n%s\n\n" % (self.cf_buf, cf_full)
def write(self):
"""Write the configuration back to file"""
cf_old = self.cf_file + ".old"
cf_new = self.cf_file + ".new"
if self.walmgr.not_really:
cf_new = "/tmp/postgresql.conf.new"
open(cf_new, "w").write(self.cf_buf)
self.log.info("Showing diff")
os.system("diff -u %s %s" % (self.cf_file, cf_new))
self.log.info("Done diff")
os.remove(cf_new)
return
# polite method does not work, as usually not enough perms for it
open(self.cf_file, "w").write(self.cf_buf)
def set_synchronous_standby_names(self,param_value):
"""Helper function to change synchronous_standby_names and signal postmaster"""
self.log.info("Changing synchronous_standby_names from %r to %r", self.synchronous_standby_names(), param_value)
cf_params = dict()
cf_params['synchronous_standby_names'] = param_value
self.modify(cf_params)
self.write()
data_dir=self.walmgr.cf.getfile("master_data")
self.log.info("Sending SIGHUP to postmaster")
self.walmgr.signal_postmaster(data_dir, signal.SIGHUP)
class WalMgr(skytools.DBScript):
def init_optparse(self, parser=None):
p = skytools.DBScript.init_optparse(self, parser)
p.set_usage(__doc__.strip())
p.add_option("-n", "--not-really", action="store_true", dest="not_really",
help = "Don't actually do anything.", default=False)
p.add_option("", "--init-master", action="store_true", dest="init_master",
help = "Initialize master walmgr.", default=False)
p.add_option("", "--slave", action="store", type="string", dest="slave",
help = "Slave host name.", default="")
p.add_option("", "--pgdata", action="store", type="string", dest="pgdata",
help = "Postgres data directory.", default="")
p.add_option("", "--config-dir", action="store", type="string", dest="config_dir",
help = "Configuration file location for --init-X commands.", default="~/conf")
p.add_option("", "--ssh-keygen", action="store_true", dest="ssh_keygen",
help = "master: generate SSH key pair if needed", default=False)
p.add_option("", "--ssh-add-key", action="store", dest="ssh_add_key",
help = "slave: add public key to authorized_hosts", default=False)
p.add_option("", "--ssh-remove-key", action="store", dest="ssh_remove_key",
help = "slave: remove master key from authorized_hosts", default=False)
p.add_option("", "--add-password", action="store", dest="add_password",
help = "slave: add password from file to .pgpass. Additional fields will be extracted from primary-conninfo", default=False)
p.add_option("", "--remove-password", action="store_true", dest="remove_password",
help = "slave: remove previously added line from .pgpass", default=False)
p.add_option("", "--primary-conninfo", action="store", dest="primary_conninfo", default=None,
help = "slave: connect string for streaming replication master")
p.add_option("", "--init-slave", action="store_true", dest="init_slave",
help = "Initialize slave walmgr.", default=False)
p.add_option("", "--synch-standby", action="store", dest="synchronous_standby_names", default=None,
help = "master: do the same thing as command synch-standby, but do not use INI file")
return p
def load_config(self):
"""override config load to allow operation without a config file"""
if len(self.args) < 1:
# no config file, generate default
# guess the job name from cmdline options
if self.options.init_master:
job_name = 'wal-master'
elif self.options.init_slave:
job_name = 'wal-slave'
else:
job_name = 'walmgr'
# common config settings
opt_dict = {
'use_skylog': '0',
'job_name': job_name,
}
# master configuration settings
master_opt_dict = {
'master_db': 'dbname=template1',
'completed_wals': '%%(slave)s:%%(walmgr_data)s/logs.complete',
'partial_wals': '%%(slave)s:%%(walmgr_data)s/logs.partial',
'full_backup': '%%(slave)s:%%(walmgr_data)s/data.master',
'config_backup': '%%(slave)s:%%(walmgr_data)s/config.backup',
'keep_symlinks': '1',
'compression': '0',
'walmgr_data': '~/walshipping',
'logfile': '~/log/%(job_name)s.log',
'pidfile': '~/pid/%(job_name)s.pid',
'use_skylog': '1',
}
# slave configuration settings
slave_opt_dict = {
'completed_wals': '%%(walmgr_data)s/logs.complete',
'partial_wals': '%%(walmgr_data)s/logs.partial',
'full_backup': '%%(walmgr_data)s/data.master',
'config_backup': '%%(walmgr_data)s/config.backup',
'walmgr_data': '~/walshipping',
'logfile': '~/log/%(job_name)s.log',
'pidfile': '~/pid/%(job_name)s.pid',
'use_skylog': '1',
}
if self.options.init_master:
opt_dict.update(master_opt_dict)
elif self.options.init_slave:
opt_dict.update(slave_opt_dict)
self.is_master = self.options.init_master
config = skytools.Config(self.service_name, None,
user_defs = opt_dict, override = self.cf_override)
else:
# default to regular config handling
config = skytools.DBScript.load_config(self)
self.is_master = config.has_option('master_data')
# create the log and pid files if needed
for cfk in [ "logfile", "pidfile" ]:
if config.has_option(cfk):
dirname = os.path.dirname(config.getfile(cfk))
if not os.path.isdir(dirname):
os.makedirs(dirname)
return config
def __init__(self, args):
skytools.DBScript.__init__(self, 'walmgr', args)
self.set_single_loop(1)
self.not_really = self.options.not_really
self.pg_backup = 0
self.walchunk = None
self.script = os.path.abspath(sys.argv[0])
if len(self.args) > 1:
# normal operations, cfgfile and command
self.cfgfile = self.args[0]
self.cmd = self.args[1]
self.args = self.args[2:]
else:
if self.options.init_master:
self.cmd = 'init_master'
elif self.options.init_slave:
self.cmd = 'init_slave'
elif self.options.synchronous_standby_names is not None:
self.cmd = "synch-standby"
else:
usage(1)
self.cfgfile = None
self.args = []
if self.cmd not in ('sync', 'syncdaemon'):
# don't let pidfile interfere with normal operations, but
# disallow concurrent syncing
self.pidfile = None
cmdtab = {
'init_master': self.walmgr_init_master,
'init_slave': self.walmgr_init_slave,
'setup': self.walmgr_setup,
'stop': self.master_stop,
'backup': self.run_backup,
'listbackups': self.list_backups,
'restore': self.restore_database,
'periodic': self.master_periodic,
'sync': self.master_sync,
'syncdaemon': self.master_syncdaemon,
'pause': self.slave_pause,
'continue': self.slave_continue,
'boot': self.slave_boot,
'createslave': self.slave_createslave,
'cleanup': self.walmgr_cleanup,
'synch-standby': self.master_synch_standby,
'xlock': self.slave_lock_backups_exit,
'xrelease': self.slave_resume_backups,
'xrotate': self.slave_rotate_backups,
'xpurgewals': self.slave_purge_wals,
'xarchive': self.master_xarchive,
'xrestore': self.xrestore,
'xpartialsync': self.slave_append_partial,
}
if not cmdtab.has_key(self.cmd):
usage(1)
self.work = cmdtab[self.cmd]
def assert_is_master(self, master_required):
if self.is_master != master_required:
self.log.warning("Action not available on current node.")
sys.exit(1)
def pg_start_backup(self, code):
q = "select pg_start_backup('FullBackup')"
self.log.info("Execute SQL: %s; [%s]", q, self.cf.get("master_db"))
if self.not_really:
self.pg_backup = 1
return
db = self.get_database("master_db")
db.cursor().execute(q)
db.commit()
self.close_database("master_db")
self.pg_backup = 1
def pg_stop_backup(self):
if not self.pg_backup:
return
q = "select pg_stop_backup()"
self.log.info("Execute SQL: %s; [%s]", q, self.cf.get("master_db"))
if self.not_really:
return
db = self.get_database("master_db")
db.cursor().execute(q)
db.commit()
self.close_database("master_db")
def signal_postmaster(self, data_dir, sgn):
pidfile = os.path.join(data_dir, "postmaster.pid")
if not os.path.isfile(pidfile):
self.log.info("postmaster is not running (pidfile not present)")
return False
buf = open(pidfile, "r").readline()
pid = int(buf.strip())
self.log.debug("Signal %d to process %d", sgn, pid)
if sgn == 0 or not self.not_really:
try:
os.kill(pid, sgn)
except OSError, ex:
if ex.errno == errno.ESRCH:
self.log.info("postmaster is not running (no process at indicated PID)")
return False
else:
raise
return True
def exec_rsync(self,args,die_on_error=False):
cmdline = [ "rsync", "-a", "--quiet" ]
if self.cf.getint("compression", 0) > 0:
cmdline.append("-z")
cmdline += args
cmd = "' '".join(cmdline)
self.log.debug("Execute rsync cmd: %r", cmd)
if self.not_really:
return 0
res = os.spawnvp(os.P_WAIT, cmdline[0], cmdline)
if res == 24:
self.log.info("Some files vanished, but thats OK")
res = 0
elif res != 0:
self.log.fatal("rsync exec failed, res=%d", res)
if die_on_error:
sys.exit(1)
return res
def exec_big_rsync(self, args):
if self.exec_rsync(args) != 0:
self.log.fatal("Big rsync failed")
self.pg_stop_backup()
sys.exit(1)
def rsync_log_directory(self, source_dir, dst_loc):
"""rsync a pg_log or pg_xlog directory - ignore most of the
directory contents, and pay attention to symlinks
"""
keep_symlinks = self.cf.getint("keep_symlinks", 1)
subdir = os.path.basename(source_dir)
if not os.path.exists(source_dir):
self.log.info("%s does not exist, skipping", subdir)
return
cmdline = []
# if this is a symlink, copy it's target first
if os.path.islink(source_dir) and keep_symlinks:
self.log.info('%s is a symlink, attempting to create link target', subdir)
# expand the link
link = os.readlink(source_dir)
if not link.startswith("/"):
link = os.path.join(os.getcwd(), link)
link_target = os.path.join(link, "")
slave_host = self.cf.get("slave")
remote_target = "%s:%s" % (slave_host, link_target)
options = [ "--include=archive_status", "--exclude=/**" ]
if self.exec_rsync( options + [ link_target, remote_target ]):
# unable to create the link target, just convert the links
# to directories in PGDATA
self.log.warning('Unable to create symlinked %s on target, copying', subdir)
cmdline += [ "--copy-unsafe-links" ]
cmdline += [ "--exclude=pg_log/*" ]
cmdline += [ "--exclude=pg_xlog/archive_status/*" ]
cmdline += [ "--include=pg_xlog/archive_status" ]
cmdline += [ "--exclude=pg_xlog/*" ]
self.exec_big_rsync(cmdline + [ source_dir, dst_loc ])
def exec_cmd(self, cmdline, allow_error=False):
cmd = "' '".join(cmdline)
self.log.debug("Execute cmd: %r", cmd)
if self.not_really:
return
process = subprocess.Popen(cmdline,stdout=subprocess.PIPE)
output = process.communicate()
res = process.returncode
if res != 0 and not allow_error:
self.log.fatal("exec failed, res=%d (%r)", res, cmdline)
sys.exit(1)
return (res,output[0])
def exec_system(self, cmdline):
self.log.debug("Execute cmd: %r", cmdline)
if self.not_really:
return 0
return os.WEXITSTATUS(os.system(cmdline))
def chdir(self, loc):
self.log.debug("chdir: %r", loc)
if self.not_really:
return
try:
os.chdir(loc)
except os.error:
self.log.fatal("CHDir failed")
self.pg_stop_backup()
sys.exit(1)
def parse_conninfo(self,conninfo):
"""Extract host,user and port from primary-conninfo"""
m = re.match("^.*\s*host\s*=\s*([^\s]+)\s*.*$", conninfo)
if m:
host = m.group(1)
else:
host = 'localhost'
m = re.match("^.*\s*user\s*=\s*([^\s]+)\s*.*$", conninfo)
if m:
user = m.group(1)
else:
user = os.environ['USER']
m = re.match("^.*\s*port\s*=\s*([^\s]+)\s*.*$", conninfo)
if m:
port = m.group(1)
else:
port = '5432'
m = re.match("^.*\s*sslmode\s*=\s*([^\s]+)\s*.*$", conninfo)
if m:
sslmode = m.group(1)
else:
sslmode = None
return host,port,user,sslmode
def get_last_complete(self):
"""Get the name of last xarchived segment."""
data_dir = self.cf.getfile("master_data")
fn = os.path.join(data_dir, ".walshipping.last")
try:
last = open(fn, "r").read().strip()
return last
except:
self.log.info("Failed to read %s", fn)
return None
def set_last_complete(self, last):
"""Set the name of last xarchived segment."""
data_dir = self.cf.getfile("master_data")
fn = os.path.join(data_dir, ".walshipping.last")
fn_tmp = fn + ".new"
try:
f = open(fn_tmp, "w")
f.write(last)
f.close()
os.rename(fn_tmp, fn)
except:
self.log.fatal("Cannot write to %s", fn)
def master_stop(self):
"""Deconfigure archiving, attempt to stop syncdaemon"""
data_dir = self.cf.getfile("master_data")
restart_cmd = self.cf.getfile("master_restart_cmd", "")
self.assert_is_master(True)
self.log.info("Disabling WAL archiving")
self.master_configure_archiving(False, restart_cmd)
# if we have a restart command, then use it, otherwise signal
if restart_cmd:
self.log.info("Restarting postmaster")
self.exec_system(restart_cmd)
else:
self.log.info("Sending SIGHUP to postmaster")
self.signal_postmaster(data_dir, signal.SIGHUP)
# stop any running syncdaemons
pidfile = self.cf.getfile("pidfile", "")
if os.path.exists(pidfile):
self.log.info('Pidfile %s exists, attempting to stop syncdaemon.', pidfile)
self.exec_cmd([self.script, self.cfgfile, "syncdaemon", "-s"])
self.log.info("Done")
def walmgr_cleanup(self):
"""
Clean up any walmgr files on slave and master.
"""
if not self.is_master:
# remove walshipping directory
dirname = self.cf.getfile("walmgr_data")
self.log.info("Removing walmgr data directory: %s", dirname)
if not self.not_really:
shutil.rmtree(dirname)
# remove backup 8.3/main.X directories
backups = glob.glob(self.cf.getfile("slave_data") + ".[0-9]")
for dirname in backups:
self.log.info("Removing backup main directory: %s", dirname)
if not self.not_really:
shutil.rmtree(dirname)
ssh_dir = os.path.expanduser("~/.ssh")
auth_file = os.path.join(ssh_dir, "authorized_keys")
if self.options.ssh_remove_key and os.path.isfile(auth_file):
# remove master key from ssh authorized keys, simple substring match should do
keys = ""
for key in open(auth_file):
if not self.options.ssh_remove_key in key:
keys += key
else:
self.log.info("Removed %s from %s", self.options.ssh_remove_key, auth_file)
self.log.info("Overwriting authorized_keys file")
if not self.not_really:
tmpfile = auth_file + ".walmgr.tmp"
f = open(tmpfile, "w")
f.write(keys)
f.close()
os.rename(tmpfile, auth_file)
else:
self.log.debug("authorized_keys:\n%s", keys)
# remove password from .pgpass
primary_conninfo = self.cf.get("primary_conninfo", "")
if self.options.remove_password and primary_conninfo and not self.not_really:
pg = Pgpass('~/.pgpass')
host, port, user, _ = self.parse_conninfo(primary_conninfo)
if pg.remove_user(host, port, user):
self.log.info("Removing line from .pgpass")
pg.write()
# get rid of the configuration file, both master and slave
self.log.info("Removing config file: %s", self.cfgfile)
if not self.not_really:
os.remove(self.cfgfile)
def master_synch_standby(self):
"""Manage synchronous_standby_names parameter"""
if self.options.synchronous_standby_names is None:
if len(self.args) < 1:
die(1, "usage: synch-standby SYNCHRONOUS_STANDBY_NAMES")
names = self.args[0]
self.assert_is_master(True)
else:
# as synchronous_standby_names is available since 9.1
# we can override DEFAULT_PG_VERSION
global DEFAULT_PG_VERSION
DEFAULT_PG_VERSION = "9.1"
self.guess_locations()
self.override_cf_option('master_config', self.postgres_conf)
self.override_cf_option('master_data', self.pgdata)
self.override_cf_option('master_db', 'dbname=template1')
names = self.options.synchronous_standby_names
cf = PostgresConfiguration(self, self.cf.getfile("master_config"))
# list of slaves
db = self.get_database("master_db")
cur = db.cursor()
cur.execute("select application_name from pg_stat_replication")
slave_names = [slave[0] for slave in cur.fetchall()]
self.close_database("master_db")
if names.strip() == "":
if not self.not_really:
cf.set_synchronous_standby_names("")
return
if names.strip() == "*":
if slave_names:
if not self.not_really:
cf.set_synchronous_standby_names(names)
return
else:
die(1,"At least one slave must be available when enabling synchronous mode")
# ensure that at least one slave is available from new parameter value
slave_found = None
for new_synch_slave in re.findall(r"[^\s,]+",names):
if new_synch_slave not in slave_names:
self.log.warning("No slave available with name %s", new_synch_slave)
else:
slave_found = True
break
if not slave_found:
die(1,"At least one slave must be available from new list when enabling synchronous mode")
elif not self.not_really:
cf.set_synchronous_standby_names(names)
def master_configure_archiving(self, enable_archiving, can_restart):
"""Turn the archiving on or off"""
cf = PostgresConfiguration(self, self.cf.getfile("master_config"))
curr_archive_mode = cf.archive_mode()
curr_wal_level = cf.wal_level()
need_restart_warning = False
if enable_archiving:
# enable archiving
cf_file = os.path.abspath(self.cf.filename)
xarchive = "%s %s %s" % (self.script, cf_file, "xarchive %p %f")
cf_params = { "archive_command": xarchive }
if curr_archive_mode is not None:
# archive mode specified in config, turn it on
self.log.debug("found 'archive_mode' in config -- enabling it")
cf_params["archive_mode"] = "on"
if curr_archive_mode.lower() not in ('1', 'on', 'true') and not can_restart:
need_restart_warning = True
if curr_wal_level is not None and curr_wal_level != 'hot_standby':
# wal level set in config, enable it
wal_level = self.cf.getboolean("hot_standby", False) and "hot_standby" or "archive"
self.log.debug("found 'wal_level' in config -- setting to '%s'", wal_level)
cf_params["wal_level"] = wal_level
if curr_wal_level not in ("archive", "hot_standby") and not can_restart:
need_restart_warning = True
if need_restart_warning:
self.log.warning("database must be restarted to enable archiving")
else:
# disable archiving
cf_params = dict()
if can_restart:
# can restart, disable archive mode and set wal_level to minimal
cf_params['archive_command'] = ''
if curr_archive_mode:
cf_params['archive_mode'] = 'off'
if curr_wal_level:
cf_params['wal_level'] = 'minimal'
cf_params['max_wal_senders'] = '0'
else:
# not possible to change archive_mode or wal_level (requires restart),
# so we just set the archive_command to /bin/true to avoid WAL pileup.
self.log.info("database must be restarted to disable archiving")
self.log.info("Setting archive_command to /bin/true to avoid WAL pileup")
cf_params['archive_command'] = '/bin/true'
# disable synchronous standbys, note that presently we don't care
# if there is more than one standby.
if cf.synchronous_standby_names():
cf_params['synchronous_standby_names'] = ''
self.log.debug("modifying configuration: %s", cf_params)
cf.modify(cf_params)
cf.write()
def slave_deconfigure_archiving(self, cf_file):
"""Disable archiving for the slave. This is done by setting
archive_command to a trivial command, so that archiving can be
re-enabled without restarting postgres. Needed when slave is
booted with postgresql.conf from master."""
self.log.debug("Disable archiving in %s", cf_file)
cf = PostgresConfiguration(self, cf_file)
cf_params = { "archive_command": "/bin/true" }
self.log.debug("modifying configuration: %s", cf_params)
cf.modify(cf_params)
cf.write()
def remote_mkdir(self, remdir):
tmp = remdir.split(":", 1)
if len(tmp) < 1:
raise Exception("cannot find pathname")
elif len(tmp) < 2:
self.exec_cmd([ "mkdir", "-p", tmp[0] ])
else:
host, path = tmp
cmdline = ["ssh", "-nT", host, "mkdir", "-p", path]
self.exec_cmd(cmdline)
def remote_walmgr(self, command, stdin_disabled = True, allow_error=False):
"""Pass a command to slave WalManager"""
sshopt = "-T"
if stdin_disabled:
sshopt += "n"
slave_config = self.cf.getfile("slave_config")
if not slave_config:
raise Exception("slave_config not specified in %s" % self.cfgfile)
slave_host = self.cf.get("slave")
cmdline = [ "ssh", sshopt, "-o", "Batchmode=yes", "-o", "StrictHostKeyChecking=no",
slave_host, self.script, slave_config, command ]
if self.not_really:
cmdline += ["--not-really"]
return self.exec_cmd(cmdline, allow_error)
def remote_xlock(self):
"""
Obtain the backup lock to ensure that several backups are not
run in parralel. If someone already has the lock we check if
this is from a previous (failed) backup. If that is the case,
the lock is released and re-obtained.
"""
xlock_cmd = "xlock %d" % os.getpid()
ret = self.remote_walmgr(xlock_cmd, allow_error=True)
if ret[0] != 0:
# lock failed.
try:
lock_pid = int(ret[1])
except ValueError:
self.log.fatal("Invalid pid in backup lock")
sys.exit(1)
try:
os.kill(lock_pid, 0)
self.log.fatal("Backup lock already taken")
sys.exit(1)
except OSError:
# no process, carry on
self.remote_walmgr("xrelease")
self.remote_walmgr(xlock_cmd)
def override_cf_option(self, option, value):
"""Set a configuration option, if it is unset"""
if not self.cf.has_option(option):
self.cf.cf.set('walmgr', option, value)
def guess_locations(self):
"""
Guess PGDATA and configuration file locations.
"""
# find the PGDATA directory
if self.options.pgdata:
self.pgdata = self.options.pgdata
elif 'PGDATA' in os.environ:
self.pgdata = os.environ['PGDATA']
else:
self.pgdata = "~/%s/main" % DEFAULT_PG_VERSION
self.pgdata = os.path.expanduser(self.pgdata)
if not os.path.isdir(self.pgdata):
die(1, 'Postgres data directory not found: %s' % self.pgdata)
postmaster_opts = os.path.join(self.pgdata, 'postmaster.opts')
self.postgres_bin = ""
self.postgres_conf = ""
if os.path.exists(postmaster_opts):
# postmaster_opts exists, attempt to guess various paths
# get unquoted args from opts file
cmdline = [ k.strip('"') for k in open(postmaster_opts).read().split() ]
if cmdline:
self.postgres_bin = os.path.dirname(cmdline[0])
cmdline = cmdline[1:]
for item in cmdline:
if item.startswith("config_file="):
self.postgres_conf = item.split("=")[1]
if not self.postgres_conf:
self.postgres_conf = os.path.join(self.pgdata, "postgresql.conf")
else:
# no postmaster opts, resort to guessing
self.log.info('postmaster.opts not found, resorting to guesses')
# use the directory of first postgres executable from path
for path in os.environ['PATH'].split(os.pathsep):
path = os.path.expanduser(path)
exe = os.path.join(path, "postgres")
if os.path.isfile(exe):
self.postgres_bin = path
break
else:
# not found, use Debian default
self.postgres_bin = "/usr/lib/postgresql/%s/bin" % DEFAULT_PG_VERSION
if os.path.exists(self.pgdata):
self.postgres_conf = os.path.join(self.pgdata, "postgresql.conf")
else:
self.postgres_conf = "/etc/postgresql/%s/main/postgresql.conf" % DEFAULT_PG_VERSION
if not os.path.isdir(self.postgres_bin):
die(1, "Postgres bin directory not found.")
if not os.path.isfile(self.postgres_conf):
if not self.options.init_slave:
# postgres_conf is required for master
die(1, "Configuration file not found: %s" % self.postgres_conf)
# Attempt to guess the init.d script name
script_suffixes = [ "9.1", "9.0", "8.4", "8.3", "8.2", "8.1", "8.0" ]
self.initd_script = "/etc/init.d/postgresql"
if not os.path.exists(self.initd_script):
for suffix in script_suffixes:
try_file = "%s-%s" % (self.initd_script, suffix)
if os.path.exists(try_file):
self.initd_script = try_file
break
else:
self.initd_script = "%s -m fast -D %s" % \
(os.path.join(self.postgres_bin, "pg_ctl"), os.path.abspath(self.pgdata))
def write_walmgr_config(self, config_data):
cf_name = os.path.join(os.path.expanduser(self.options.config_dir),
self.cf.get("job_name") + ".ini")
dirname = os.path.dirname(cf_name)
if not os.path.isdir(dirname):
self.log.info('Creating config directory: %s', dirname)
os.makedirs(dirname)
self.log.info('Writing configuration file: %s', cf_name)
self.log.debug("config data:\n%s", config_data)
if not self.not_really:
cf = open(cf_name, "w")
cf.write(config_data)
cf.close()
def walmgr_init_master(self):
"""
Initialize configuration file, generate SSH key pair if needed.
"""
self.guess_locations()
if not self.options.slave:
die(1, 'Specify slave host name with "--slave" option.')
self.override_cf_option('master_bin', self.postgres_bin)
self.override_cf_option('master_config', self.postgres_conf)
self.override_cf_option('master_data', self.pgdata)
# assume that slave config is in the same location as master's
# can override with --set slave_config=
slave_walmgr_dir = os.path.abspath(os.path.expanduser(self.options.config_dir))
self.override_cf_option('slave_config', os.path.join(slave_walmgr_dir, "wal-slave.ini"))
master_config = """[walmgr]
job_name = %(job_name)s
logfile = %(logfile)s
pidfile = %(pidfile)s
use_skylog = 1
master_db = %(master_db)s
master_data = %(master_data)s
master_config = %(master_config)s
master_bin = %(master_bin)s
slave = %(slave)s
slave_config = %(slave_config)s
walmgr_data = %(walmgr_data)s
completed_wals = %(completed_wals)s
partial_wals = %(partial_wals)s
full_backup = %(full_backup)s
config_backup = %(config_backup)s
keep_symlinks = %(keep_symlinks)s
compression = %(compression)s
"""
try:
opt_dict = dict([(k, self.cf.get(k)) for k in self.cf.options()])
opt_dict['slave'] = self.options.slave
master_config = master_config % opt_dict
except KeyError, e:
die(1, 'Required setting missing: %s' % e)
self.write_walmgr_config(master_config)
# generate SSH key pair if requested
if self.options.ssh_keygen:
keyfile = os.path.expanduser("~/.ssh/id_dsa")
if os.path.isfile(keyfile):
self.log.info("SSH key %s already exists, skipping", keyfile)
else:
self.log.info("Generating ssh key: %s", keyfile)
cmdline = ["ssh-keygen", "-t", "dsa", "-N", "", "-q", "-f", keyfile ]
self.log.debug(' '.join(cmdline))
if not self.not_really:
subprocess.call(cmdline)
key = open(keyfile + ".pub").read().strip()
self.log.info("public key: %s", key)
def walmgr_init_slave(self):
"""
Initialize configuration file, move SSH pubkey into place.
"""
self.guess_locations()
self.override_cf_option('slave_bin', self.postgres_bin)
self.override_cf_option('slave_data', self.pgdata)
self.override_cf_option('slave_config_dir', os.path.dirname(self.postgres_conf))
if self.initd_script:
self.override_cf_option('slave_start_cmd', "%s start" % self.initd_script)
self.override_cf_option('slave_stop_cmd', "%s stop" % self.initd_script)
slave_config = """[walmgr]
job_name = %(job_name)s
logfile = %(logfile)s
use_skylog = %(use_skylog)s
slave_data = %(slave_data)s
slave_bin = %(slave_bin)s
slave_stop_cmd = %(slave_stop_cmd)s
slave_start_cmd = %(slave_start_cmd)s
slave_config_dir = %(slave_config_dir)s
walmgr_data = %(walmgr_data)s
completed_wals = %(completed_wals)s
partial_wals = %(partial_wals)s
full_backup = %(full_backup)s
config_backup = %(config_backup)s
"""
if self.options.primary_conninfo:
self.override_cf_option('primary_conninfo', self.options.primary_conninfo)
slave_config += """
primary_conninfo = %(primary_conninfo)s
"""
try:
opt_dict = dict([(k, self.cf.get(k)) for k in self.cf.options()])
slave_config = slave_config % opt_dict
except KeyError, e:
die(1, 'Required setting missing: %s' % e)
self.write_walmgr_config(slave_config)
if self.options.ssh_add_key:
# add the named public key to authorized hosts
ssh_dir = os.path.expanduser("~/.ssh")
auth_file = os.path.join(ssh_dir, "authorized_keys")
if not os.path.isdir(ssh_dir):
self.log.info("Creating directory: %s", ssh_dir)
if not self.not_really:
os.mkdir(ssh_dir)
self.log.debug("Reading public key from %s", self.options.ssh_add_key)
master_pubkey = open(self.options.ssh_add_key).read()
key_present = False
if os.path.isfile(auth_file):
for key in open(auth_file):
if key == master_pubkey:
self.log.info("Key already present in %s, skipping", auth_file)
key_present = True
if not key_present:
self.log.info("Adding %s to %s", self.options.ssh_add_key, auth_file)
if not self.not_really:
af = open(auth_file, "a")
af.write(master_pubkey)
af.close()
if self.options.add_password and self.options.primary_conninfo:
# add password to pgpass
self.log.debug("Reading password from file %s", self.options.add_password)
pwd = open(self.options.add_password).readline().rstrip('\n\r')
pg = Pgpass('~/.pgpass')
host, port, user, _ = self.parse_conninfo(self.options.primary_conninfo)
pg.ensure_user(host, port, user, pwd)
pg.write()
self.log.info("Added password from %s to .pgpass", self.options.add_password)
def walmgr_setup(self):
if self.is_master:
self.log.info("Configuring WAL archiving")
data_dir = self.cf.getfile("master_data")
restart_cmd = self.cf.getfile("master_restart_cmd", "")
self.master_configure_archiving(True, restart_cmd)
# if we have a restart command, then use it, otherwise signal
if restart_cmd:
self.log.info("Restarting postmaster")
self.exec_system(restart_cmd)
else:
self.log.info("Sending SIGHUP to postmaster")
self.signal_postmaster(data_dir, signal.SIGHUP)
# ask slave to init
self.remote_walmgr("setup")
self.log.info("Done")
else:
# create slave directory structure
def mkdirs(dir):
if not os.path.exists(dir):
self.log.debug("Creating directory %s", dir)
if not self.not_really:
os.makedirs(dir)
mkdirs(self.cf.getfile("completed_wals"))
mkdirs(self.cf.getfile("partial_wals"))
mkdirs(self.cf.getfile("full_backup"))
cf_backup = self.cf.getfile("config_backup", "")
if cf_backup:
mkdirs(cf_backup)
def master_periodic(self):
"""
Run periodic command on master node.
We keep time using .walshipping.last file, so this has to be run before
set_last_complete()
"""
self.assert_is_master(True)
try:
command_interval = self.cf.getint("command_interval", 0)
periodic_command = self.cf.get("periodic_command", "")
if periodic_command:
check_file = os.path.join(self.cf.getfile("master_data"), ".walshipping.periodic")
elapsed = 0
if os.path.isfile(check_file):
elapsed = time.time() - os.stat(check_file).st_mtime
self.log.info("Running periodic command: %s", periodic_command)
if not elapsed or elapsed > command_interval:
if not self.not_really:
rc = os.WEXITSTATUS(self.exec_system(periodic_command))
if rc != 0:
self.log.error("Periodic command exited with status %d", rc)
# dont update timestamp - try again next time
else:
open(check_file,"w").write("1")
else:
self.log.debug("%d seconds elapsed, not enough to run periodic.", elapsed)
except Exception, det:
self.log.error("Failed to run periodic command: %s", det)
def master_backup(self):
"""
Copy master data directory to slave.
1. Obtain backup lock on slave.
2. Rotate backups on slave
3. Perform backup as usual
4. Purge unneeded WAL-s from slave
5. Release backup lock
"""
self.remote_xlock()
errors = False
try:
self.pg_start_backup("FullBackup")
self.remote_walmgr("xrotate")
data_dir = self.cf.getfile("master_data")
dst_loc = self.cf.getfile("full_backup")
if dst_loc[-1] != "/":
dst_loc += "/"
master_spc_dir = os.path.join(data_dir, "pg_tblspc")
slave_spc_dir = dst_loc + "tmpspc"
# copy data
self.chdir(data_dir)
cmdline = [
"--delete",
"--exclude", ".*",
"--exclude", "*.pid",
"--exclude", "*.opts",
"--exclude", "*.conf",
"--exclude", "pg_xlog",
"--exclude", "pg_tblspc",
"--exclude", "pg_log",
"--exclude", "base/pgsql_tmp",
"--copy-unsafe-links",
".", dst_loc]
self.exec_big_rsync(cmdline)
# copy tblspc first, to test
if os.path.isdir(master_spc_dir):
self.log.info("Checking tablespaces")
list = os.listdir(master_spc_dir)
if len(list) > 0:
self.remote_mkdir(slave_spc_dir)
for tblspc in list:
if tblspc[0] == ".":
continue
tfn = os.path.join(master_spc_dir, tblspc)
if not os.path.islink(tfn):
self.log.info("Suspicious pg_tblspc entry: %s", tblspc)
continue
spc_path = os.path.realpath(tfn)
self.log.info("Got tablespace %s: %s", tblspc, spc_path)
dstfn = slave_spc_dir + "/" + tblspc
try:
os.chdir(spc_path)
except Exception, det:
self.log.warning("Broken link: %s", det)
continue
cmdline = [ "--delete", "--exclude", ".*", "--copy-unsafe-links", ".", dstfn]
self.exec_big_rsync(cmdline)
# copy the pg_log and pg_xlog directories, these may be
# symlinked to nonstandard location, so pay attention
self.rsync_log_directory(os.path.join(data_dir, "pg_log"), dst_loc)
self.rsync_log_directory(os.path.join(data_dir, "pg_xlog"), dst_loc)
# copy config files
conf_dst_loc = self.cf.getfile("config_backup", "")
if conf_dst_loc:
master_conf_dir = os.path.dirname(self.cf.getfile("master_config"))
self.log.info("Backup conf files from %s", master_conf_dir)
self.chdir(master_conf_dir)
cmdline = [
"--include", "*.conf",
"--exclude", "*",
".", conf_dst_loc]
self.exec_big_rsync(cmdline)
self.remote_walmgr("xpurgewals")
except Exception, e:
self.log.error(e)
errors = True
finally:
try:
self.pg_stop_backup()
except:
pass
try:
self.remote_walmgr("xrelease")
except:
pass
if not errors:
self.log.info("Full backup successful")
else:
self.log.error("Full backup failed.")
def slave_backup(self):
"""
Create backup on slave host.
1. Obtain backup lock
2. Pause WAL apply
3. Wait for WAL apply to complete (look at PROGRESS file)
4. Rotate old backups
5. Copy data directory to data.master
6. Create backup label and history file.
7. Purge unneeded WAL-s
8. Resume WAL apply
9. Release backup lock
"""
self.assert_is_master(False)
if self.slave_lock_backups() != 0:
self.log.error("Cannot obtain backup lock.")
sys.exit(1)
try:
self.slave_pause(waitcomplete=1)
try:
self.slave_rotate_backups()
src = self.cf.getfile("slave_data")
dst = self.cf.getfile("full_backup")
start_time = time.localtime()
cmdline = ["cp", "-a", src, dst ]
self.log.info("Executing %s", " ".join(cmdline))
if not self.not_really:
self.exec_cmd(cmdline)
stop_time = time.localtime()
# Obtain the last restart point information
ctl = PgControlData(self.cf.getfile("slave_bin", ""), dst, True)
# TODO: The newly created backup directory probably still contains
# backup_label.old and recovery.conf files. Remove these.
if not ctl.is_valid:
self.log.warning("Unable to determine last restart point, backup_label not created.")
else:
# Write backup label and history file
backup_label = \
"""START WAL LOCATION: %(xlogid)X/%(xrecoff)X (file %(wal_name)s)
CHECKPOINT LOCATION: %(xlogid)X/%(xrecoff)X
START TIME: %(start_time)s
LABEL: SlaveBackup"
"""
backup_history = \
"""START WAL LOCATION: %(xlogid)X/%(xrecoff)X (file %(wal_name)s)
STOP WAL LOCATION: %(xlogid)X/%(xrecoff)X (file %(wal_name)s)
CHECKPOINT LOCATION: %(xlogid)X/%(xrecoff)X
START TIME: %(start_time)s
LABEL: SlaveBackup"
STOP TIME: %(stop_time)s
"""
label_params = {
"xlogid": ctl.xlogid,
"xrecoff": ctl.xrecoff,
"wal_name": ctl.wal_name,
"start_time": time.strftime("%Y-%m-%d %H:%M:%S %Z", start_time),
"stop_time": time.strftime("%Y-%m-%d %H:%M:%S %Z", stop_time),
}
# Write the label
filename = os.path.join(dst, "backup_label")
if self.not_really:
self.log.info("Writing backup label to %s", filename)
else:
lf = open(filename, "w")
lf.write(backup_label % label_params)
lf.close()
# Now the history
histfile = "%s.%08X.backup" % (ctl.wal_name, ctl.xrecoff % ctl.wal_size)
completed_wals = self.cf.getfile("completed_wals")
filename = os.path.join(completed_wals, histfile)
if os.path.exists(filename):
self.log.warning("%s: already exists, refusing to overwrite.", filename)
else:
if self.not_really:
self.log.info("Writing backup history to %s", filename)
else:
lf = open(filename, "w")
lf.write(backup_history % label_params)
lf.close()
self.slave_purge_wals()
finally:
self.slave_continue()
finally:
self.slave_resume_backups()
def run_backup(self):
if self.is_master:
self.master_backup()
else:
self.slave_backup()
def master_xarchive(self):
"""Copy a complete WAL segment to slave."""
self.assert_is_master(True)
if len(self.args) < 2:
die(1, "usage: xarchive srcpath srcname")
srcpath = self.args[0]
srcname = self.args[1]
start_time = time.time()
self.log.debug("%s: start copy", srcname)
self.master_periodic()
dst_loc = self.cf.getfile("completed_wals")
if dst_loc[-1] != "/":
dst_loc += "/"
# copy data
self.exec_rsync([ srcpath, dst_loc ], True)
# sync the buffers to disk - this is should reduce the chance
# of WAL file corruption in case the slave crashes.
slave = self.cf.get("slave")
cmdline = ["ssh", "-nT", slave, "sync" ]
self.exec_cmd(cmdline)
# slave has the file now, set markers
self.set_last_complete(srcname)
self.log.debug("%s: done", srcname)
end_time = time.time()
self.stat_add('count', 1)
self.stat_add('duration', end_time - start_time)
self.send_stats()
def slave_append_partial(self):
"""
Read 'bytes' worth of data from stdin, append to the partial log file
starting from 'offset'. On error it is assumed that master restarts
from zero.
The resulting file is always padded to XLOG_SEGMENT_SIZE bytes to
simplify recovery.
"""
def fail(message):
self.log.error("Slave: %s: %s", filename, message)
sys.exit(1)
self.assert_is_master(False)
if len(self.args) < 3:
die(1, "usage: xpartialsync <filename> <offset> <bytes>")
filename = self.args[0]
offset = int(self.args[1])
bytes = int(self.args[2])
data = sys.stdin.read(bytes)
if len(data) != bytes:
fail("not enough data, expected %d, got %d" % (bytes, len(data)))
chunk = WalChunk(filename, offset, bytes)
self.log.debug("Slave: adding to %s", chunk)
name = os.path.join(self.cf.getfile("partial_wals"), filename)
if self.not_really:
self.log.info("Adding to partial: %s", name)
return
try:
xlog = open(name, (offset == 0) and "w+" or "r+")
except:
fail("unable to open partial WAL: %s" % name)
xlog.seek(offset)
xlog.write(data)
# padd the file to 16MB boundary, use sparse files
padsize = XLOG_SEGMENT_SIZE - xlog.tell()
if padsize > 0:
xlog.seek(XLOG_SEGMENT_SIZE-1)
xlog.write('\0')
xlog.close()
def master_send_partial(self, xlog_dir, chunk, daemon_mode):
"""
Send the partial log chunk to slave. Use SSH with input redirection for the copy,
consider other options if the overhead becomes visible.
"""
try:
xlog = open(os.path.join(xlog_dir, chunk.filename))
except IOError, det:
self.log.warning("Cannot access file %s", chunk.filename)
return
xlog.seek(chunk.pos)
# Fork the sync process
childpid = os.fork()
syncstart = time.time()
if childpid == 0:
os.dup2(xlog.fileno(), sys.stdin.fileno())
try:
self.remote_walmgr("xpartialsync %s %d %d" % (chunk.filename, chunk.pos, chunk.bytes), False)
except:
os._exit(1)
os._exit(0)
chunk.sync_time += (time.time() - syncstart)
status = os.waitpid(childpid, 0)
rc = os.WEXITSTATUS(status[1])
if rc == 0:
log = daemon_mode and self.log.debug or self.log.info
log("sent to slave: %s" % chunk)
chunk.pos += chunk.bytes
chunk.sync_count += 1
else:
# Start from zero after an error
chunk.pos = 0
self.log.error("xpartialsync exited with status %d, restarting from zero.", rc)
time.sleep(5)
def master_syncdaemon(self):
self.assert_is_master(True)
self.set_single_loop(0)
self.master_sync(True)
def master_sync(self, daemon_mode=False):
"""
Copy partial WAL segments to slave.
On 8.2 set use_xlog_functions=1 in config file - this enables record based
walshipping. On 8.0 the only option is to sync files.
If daemon_mode is specified it never switches from record based shipping to
file based shipping.
"""
self.assert_is_master(True)
use_xlog_functions = self.cf.getint("use_xlog_functions", False)
data_dir = self.cf.getfile("master_data")
xlog_dir = os.path.join(data_dir, "pg_xlog")
master_bin = self.cf.getfile("master_bin", "")
dst_loc = os.path.join(self.cf.getfile("partial_wals"), "")
db = None
if use_xlog_functions:
try:
db = self.get_database("master_db", autocommit=1)
except:
self.log.warning("Database unavailable, record based log shipping not possible.")
if daemon_mode:
return
if db:
cur = db.cursor()
cur.execute("select file_name, file_offset from pg_xlogfile_name_offset(pg_current_xlog_location())")
(file_name, file_offs) = cur.fetchone()
if not self.walchunk or self.walchunk.filename != file_name:
# Switched to new WAL segment. Don't bother to copy the last bits - it
# will be obsoleted by the archive_command.
if self.walchunk and self.walchunk.sync_count > 0:
self.log.info("Switched in %d seconds, %f sec in %d interim syncs, avg %f",
time.time() - self.walchunk.start_time,
self.walchunk.sync_time,
self.walchunk.sync_count,
self.walchunk.sync_time / self.walchunk.sync_count)
self.walchunk = WalChunk(file_name, 0, file_offs)
else:
self.walchunk.bytes = file_offs - self.walchunk.pos
if self.walchunk.bytes > 0:
self.master_send_partial(xlog_dir, self.walchunk, daemon_mode)
else:
files = os.listdir(xlog_dir)
files.sort()
last = self.get_last_complete()
if last:
self.log.info("%s: last complete", last)
else:
self.log.info("last complete not found, copying all")
# obtain the last checkpoint wal name, this can be used for
# limiting the amount of WAL files to copy if the database
# has been cleanly shut down
ctl = PgControlData(master_bin, data_dir, False)
checkpoint_wal = None
if ctl.is_valid:
if not ctl.is_shutdown:
# cannot rely on the checkpoint wal, should use some other method
self.log.info("Database state is not 'shut down', copying all")
else:
# ok, the database is shut down, we can use last checkpoint wal
checkpoint_wal = ctl.wal_name
self.log.info("last checkpoint wal: %s", checkpoint_wal)
else:
self.log.info("Unable to obtain control file information, copying all")
for fn in files:
# check if interesting file
if len(fn) < 10:
continue
if fn[0] < "0" or fn[0] > '9':
continue
if fn.find(".") > 0:
continue
# check if too old
if last:
dot = last.find(".")
if dot > 0:
xlast = last[:dot]
if fn < xlast:
continue
else:
if fn <= last:
continue
# check if too new
if checkpoint_wal and fn > checkpoint_wal:
continue
# got interesting WAL
xlog = os.path.join(xlog_dir, fn)
# copy data
self.log.info('Syncing %s', xlog)
if self.exec_rsync([xlog, dst_loc], not daemon_mode) != 0:
self.log.error('Cannot sync %s', xlog)
break
else:
self.log.info("Partial copy done")
def xrestore(self):
if len(self.args) < 2:
die(1, "usage: xrestore srcname dstpath [last restartpoint wal]")
srcname = self.args[0]
dstpath = self.args[1]
lstname = None
if len(self.args) > 2:
lstname = self.args[2]
if self.is_master:
self.master_xrestore(srcname, dstpath)
else:
self.slave_xrestore_unsafe(srcname, dstpath, os.getppid(), lstname)
def slave_xrestore(self, srcname, dstpath):
loop = 1
ppid = os.getppid()
while loop:
try:
self.slave_xrestore_unsafe(srcname, dstpath, ppid)
loop = 0
except SystemExit, d:
sys.exit(1)
except Exception, d:
exc, msg, tb = sys.exc_info()
self.log.fatal("xrestore %s crashed: %s: '%s' (%s: %r)",
srcname, exc, str(msg).rstrip(),
tb, traceback.format_tb(tb))
del tb
time.sleep(10)
self.log.info("Re-exec: %r", sys.argv)
os.execv(sys.argv[0], sys.argv)
def master_xrestore(self, srcname, dstpath):
"""
Restore the xlog file from slave.
"""
paths = [ self.cf.getfile("completed_wals"), self.cf.getfile("partial_wals") ]
self.log.info("Restore %s to %s", srcname, dstpath)
for src in paths:
self.log.debug("Looking in %s", src)
srcfile = os.path.join(src, srcname)
if self.exec_rsync([srcfile, dstpath]) == 0:
return
self.log.warning("Could not restore file %s", srcname)
def is_parent_alive(self, parent_pid):
if os.getppid() != parent_pid or parent_pid <= 1:
return False
return True
def slave_xrestore_unsafe(self, srcname, dstpath, parent_pid, lstname = None):
srcdir = self.cf.getfile("completed_wals")
partdir = self.cf.getfile("partial_wals")
pausefile = os.path.join(srcdir, "PAUSE")
stopfile = os.path.join(srcdir, "STOP")
prgrfile = os.path.join(srcdir, "PROGRESS")
prxlogfile = os.path.join(srcdir,"PG_RECEIVEXLOG")
srcfile = os.path.join(srcdir, srcname)
partfile = os.path.join(partdir, srcname)
# if we are using streaming replication, exit immediately
# if the srcfile is not here yet
primary_conninfo = self.cf.get("primary_conninfo", "")
if primary_conninfo and not os.path.isfile(srcfile):
self.log.info("%s: not found (ignored)", srcname)
# remove PG_RECEIVEXLOG file if it's present
if os.path.isfile(prxlogfile) and not srcname.endswith('.history'):
os.remove(prxlogfile)
sys.exit(1)
# assume that postgres has processed the WAL file and is
# asking for next - hence work not in progress anymore
if os.path.isfile(prgrfile):
os.remove(prgrfile)
# loop until srcfile or stopfile appears
while 1:
if os.path.isfile(pausefile):
self.log.info("pause requested, sleeping")
time.sleep(20)
continue
if os.path.isfile(srcfile):
self.log.info("%s: Found", srcname)
break
# ignore .history files
unused, ext = os.path.splitext(srcname)
if ext == ".history":
self.log.info("%s: not found, ignoring", srcname)
sys.exit(1)
# if stopping, include also partial wals
if os.path.isfile(stopfile):
if os.path.isfile(partfile):
self.log.info("%s: found partial", srcname)
srcfile = partfile
break
else:
self.log.info("%s: not found, stopping", srcname)
sys.exit(1)
# nothing to do, just in case check if parent is alive
if not self.is_parent_alive(parent_pid):
self.log.warning("Parent dead, quitting")
sys.exit(1)
# nothing to do, sleep
self.log.debug("%s: not found, sleeping", srcname)
time.sleep(1)
# got one, copy it
cmdline = ["cp", srcfile, dstpath]
self.exec_cmd(cmdline)
if self.cf.getint("keep_backups", 0) == 0:
# cleanup only if we don't keep backup history, keep the files needed
# to roll forward from last restart point. If the restart point is not
# handed to us (i.e 8.3 or later), then calculate it ourselves.
# Note that historic WAL files are removed during backup rotation
if lstname == None:
lstname = self.last_restart_point(srcname)
self.log.debug("calculated restart point: %s", lstname)
else:
self.log.debug("using supplied restart point: %s", lstname)
self.log.debug("%s: copy done, cleanup", srcname)
self.slave_cleanup(lstname)
# create a PROGRESS file to notify that postgres is processing the WAL
open(prgrfile, "w").write("1")
# it would be nice to have apply time too
self.stat_add('count', 1)
self.send_stats()
def restore_database(self, restore_config=True):
"""Restore the database from backup
If setname is specified, the contents of that backup set directory are
restored instead of "full_backup". Also copy is used instead of rename to
restore the directory (unless a pg_xlog directory has been specified).
Restore to altdst if specified. Complain if it exists.
"""
setname = len(self.args) > 0 and self.args[0] or None
altdst = len(self.args) > 1 and self.args[1] or None
if not self.is_master:
data_dir = self.cf.getfile("slave_data")
stop_cmd = self.cf.getfile("slave_stop_cmd", "")
start_cmd = self.cf.getfile("slave_start_cmd")
pidfile = os.path.join(data_dir, "postmaster.pid")
else:
if not setname or not altdst:
die(1, "Source and target directories must be specified if running on master node.")
data_dir = altdst
stop_cmd = None
pidfile = None
if setname:
full_dir = os.path.join(self.cf.getfile("walmgr_data"), setname)
else:
full_dir = self.cf.getfile("full_backup")
# stop postmaster if ordered
if stop_cmd and os.path.isfile(pidfile):
self.log.info("Stopping postmaster: %s", stop_cmd)
self.exec_system(stop_cmd)
time.sleep(3)
# is it dead?
if pidfile and os.path.isfile(pidfile):
self.log.info("Pidfile exists, checking if process is running.")
if self.signal_postmaster(data_dir, 0):
self.log.fatal("Postmaster still running. Cannot continue.")
sys.exit(1)
# find name for data backup
i = 0
while 1:
bak = "%s.%d" % (data_dir.rstrip("/"), i)
if not os.path.isdir(bak):
break
i += 1
if self.is_master:
print >>sys.stderr, "About to restore to directory %s. The postgres cluster should be shut down." % data_dir
if not yesno("Is postgres shut down on %s ?" % data_dir):
die(1, "Shut it down and try again.")
if not self.is_master:
createbackup = True
elif os.path.isdir(data_dir):
createbackup = yesno("Create backup of %s?" % data_dir)
else:
# nothing to back up
createbackup = False
# see if we have to make a backup of the data directory
backup_datadir = self.cf.getboolean('backup_datadir', True)
if os.path.isdir(data_dir) and not backup_datadir:
self.log.warning('backup_datadir is disabled, deleting old data dir')
shutil.rmtree(data_dir)
if not setname and os.path.isdir(data_dir) and backup_datadir:
# compatibility mode - restore without a set name and data directory exists
self.log.info("Data directory already exists, moving it out of the way.")
createbackup = True
# move old data away
if createbackup and os.path.isdir(data_dir):
self.log.info("Move %s to %s", data_dir, bak)
if not self.not_really:
os.rename(data_dir, bak)
# move new data, copy if setname specified
self.log.info("%s %s to %s", setname and "Copy" or "Move", full_dir, data_dir)
if self.cf.getfile('slave_pg_xlog', ''):
link_xlog_dir = True
exclude_pg_xlog = '--exclude=pg_xlog'
else:
link_xlog_dir = False
exclude_pg_xlog = ''
if not self.not_really:
if not setname and not link_xlog_dir:
os.rename(full_dir, data_dir)
else:
rsync_args=["--delete", "--no-relative", "--exclude=pg_xlog/*"]
if exclude_pg_xlog:
rsync_args.append(exclude_pg_xlog)
rsync_args += [os.path.join(full_dir, ""), data_dir]
self.exec_rsync(rsync_args, True)
if link_xlog_dir:
os.symlink(self.cf.getfile('slave_pg_xlog'), "%s/pg_xlog" % data_dir)
if (self.is_master and createbackup and os.path.isdir(bak)):
# restore original xlog files to data_dir/pg_xlog
# symlinked directories are dereferenced
self.exec_cmd(["cp", "-rL", "%s/pg_xlog/" % full_dir, "%s/pg_xlog" % data_dir ])
else:
# create an archive_status directory
xlog_dir = os.path.join(data_dir, "pg_xlog")
archive_path = os.path.join(xlog_dir, "archive_status")
if not os.path.exists(archive_path):
os.mkdir(archive_path, 0700)
else:
data_dir = full_dir
# copy configuration files to rotated backup directory
if createbackup and os.path.isdir(bak):
for cf in ('postgresql.conf', 'pg_hba.conf', 'pg_ident.conf'):
cfsrc = os.path.join(bak, cf)
cfdst = os.path.join(data_dir, cf)
if os.path.exists(cfdst):
self.log.info("Already exists: %s", cfdst)
elif os.path.exists(cfsrc):
self.log.debug("Copy %s to %s", cfsrc, cfdst)
if not self.not_really:
copy_conf(cfsrc, cfdst)
# re-link tablespaces
spc_dir = os.path.join(data_dir, "pg_tblspc")
tmp_dir = os.path.join(data_dir, "tmpspc")
if not os.path.isdir(spc_dir):
# 8.3 requires its existence
os.mkdir(spc_dir)
if os.path.isdir(tmp_dir):
self.log.info("Linking tablespaces to temporary location")
# don't look into spc_dir, thus allowing
# user to move them before. re-link only those
# that are still in tmp_dir
list = os.listdir(tmp_dir)
list.sort()
for d in list:
if d[0] == ".":
continue
link_loc = os.path.abspath(os.path.join(spc_dir, d))
link_dst = os.path.abspath(os.path.join(tmp_dir, d))
self.log.info("Linking tablespace %s to %s", d, link_dst)
if not self.not_really:
if os.path.islink(link_loc):
os.remove(link_loc)
os.symlink(link_dst, link_loc)
# write recovery.conf
rconf = os.path.join(data_dir, "recovery.conf")
cf_file = os.path.abspath(self.cf.filename)
# determine if we can use %r in restore_command
ctl = PgControlData(self.cf.getfile("slave_bin", ""), data_dir, True)
if ctl.pg_version > 830:
self.log.debug('pg_version is %s, adding %%r to restore command', ctl.pg_version)
restore_command = 'xrestore %f "%p" %r'
else:
if not ctl.is_valid:
self.log.warning('unable to run pg_controldata, assuming pre 8.3 environment')
else:
self.log.debug('using pg_controldata to determine restart points')
restore_command = 'xrestore %f "%p"'
conf = "restore_command = '%s %s %s'\n" % (self.script, cf_file, restore_command)
# do we have streaming replication (hot standby)
primary_conninfo = self.cf.get("primary_conninfo", "")
if primary_conninfo:
conf += "standby_mode = 'on'\n"
conf += "trigger_file = '%s'\n" % os.path.join(self.cf.getfile("completed_wals"), "STOP")
conf += "primary_conninfo = '%s'\n" % primary_conninfo
conf += "archive_cleanup_command = '%s %s %%r'\n" % \
(os.path.join(self.cf.getfile("slave_bin"), "pg_archivecleanup"),
self.cf.getfile("completed_wals"))
self.log.info("Write %s", rconf)
if self.not_really:
print conf
else:
f = open(rconf, "w")
f.write(conf)
f.close()
# remove stopfile on slave
if not self.is_master:
stopfile = os.path.join(self.cf.getfile("completed_wals"), "STOP")
if os.path.isfile(stopfile):
self.log.info("Removing stopfile: %s", stopfile)
if not self.not_really:
os.remove(stopfile)
# attempt to restore configuration. Note that we cannot
# postpone this to boot time, as the configuration is needed
# to start postmaster.
if restore_config:
self.slave_restore_config()
# run database in recovery mode
self.log.info("Starting postmaster: %s", start_cmd)
self.exec_system(start_cmd)
else:
self.log.info("Data files restored, recovery.conf created.")
self.log.info("postgresql.conf and additional WAL files may need to be restored manually.")
def slave_restore_config(self):
"""Restore the configuration files if target directory specified."""
self.assert_is_master(False)
cf_source_dir = self.cf.getfile("config_backup", "")
cf_target_dir = self.cf.getfile("slave_config_dir", "")
if not cf_source_dir:
self.log.info("Configuration backup location not specified.")
return
if not cf_target_dir:
self.log.info("Configuration directory not specified, config files not restored.")
return
if not os.path.exists(cf_target_dir):
self.log.warning("Configuration directory does not exist: %s", cf_target_dir)
return
self.log.info("Restoring configuration files")
for cf in ('postgresql.conf', 'pg_hba.conf', 'pg_ident.conf'):
cfsrc = os.path.join(cf_source_dir, cf)
cfdst = os.path.join(cf_target_dir, cf)
if not os.path.isfile(cfsrc):
self.log.warning("Missing configuration file backup: %s", cf)
continue
self.log.debug("Copy %s to %s", cfsrc, cfdst)
if not self.not_really:
copy_conf(cfsrc, cfdst)
if cf == 'postgresql.conf':
self.slave_deconfigure_archiving(cfdst)
def slave_boot(self):
self.assert_is_master(False)
srcdir = self.cf.getfile("completed_wals")
datadir = self.cf.getfile("slave_data")
stopfile = os.path.join(srcdir, "STOP")
if self.not_really:
self.log.info("Writing STOP file: %s", stopfile)
else:
open(stopfile, "w").write("1")
self.log.info("Stopping recovery mode")
def slave_createslave(self):
self.assert_is_master(False)
errors = False
xlog_dir = self.cf.getfile("completed_wals")
full_dir = self.cf.getfile("full_backup")
prxloglock = os.path.join(xlog_dir,"PG_RECEIVEXLOG")
pg_receivexlog = os.path.join(self.cf.getfile("slave_bin"), "pg_receivexlog")
pg_basebackup = os.path.join(self.cf.getfile("slave_bin"), "pg_basebackup")
# check if pg_receivexlog is available
if not os.access(pg_receivexlog, os.X_OK):
die(1, "pg_receivexlog not available")
# check if pg_receivexlog is already running
if os.path.isfile(prxloglock):
pidstring = open(prxloglock,"r").read()
try:
pid =int(pidstring)
try:
os.kill(pid, 0)
except OSError, e:
if e.errno == errno.EPERM:
self.log.fatal("Found pg_receivexlog lock file %s, pid %d in use", prxloglock, pid)
sys.exit(1)
elif e.errno == errno.ESRCH:
self.log.info("Ignoring stale pg_receivexlog lock file")
if not self.not_really:
os.remove(prxloglock)
else:
self.log.fatal("pg_receivexlog is already running in %s, pid %d", xlog_dir, pid)
sys.exit(1)
except ValueError:
self.log.fatal("pg_receivexlog lock file %s does not contain a pid: %s", prxloglock, pidstring)
sys.exit(1)
# create directories
self.walmgr_setup()
# ensure that backup destination is 0700
if not self.not_really:
os.chmod(full_dir,0700)
self.args = [str(os.getpid())]
if self.slave_lock_backups() != 0:
self.log.fatal("Cannot obtain backup lock.")
sys.exit(1)
# get host and user from primary_conninfo
primary_conninfo = self.cf.get("primary_conninfo", "")
if not primary_conninfo:
die(1, "primary_conninfo missing")
host, port, user, sslmode = self.parse_conninfo(primary_conninfo)
# change sslmode for pg_receivexlog and pg_basebackup
envssl=None
if sslmode:
envssl={"PGSSLMODE": sslmode}
try:
# determine postgres version, we cannot use pg_control version number since
# 9.0 and 9.1 are using the same number in controlfile
pg_ver = ""
try:
cmdline = [os.path.join(self.cf.getfile("slave_bin"), "postgres"),'-V']
process = subprocess.Popen(cmdline, stdout=subprocess.PIPE)
output = process.communicate()
pg_ver = output[0].split()[2]
self.log.debug("PostgreSQL version: %s" % pg_ver)
except:
pass
# create pg_receivexlog process
cmdline = [pg_receivexlog,'-D', xlog_dir, '-h', host, '-U', user, '-p', port, '-w']
self.log.info("Starting pg_receivexlog")
if not self.not_really:
p_rxlog = subprocess.Popen(cmdline,env=envssl)
# create pg_receivexlog lock file
open(prxloglock, "w").write(str(p_rxlog.pid))
# leave error checking for pg_basebackup
# if pg_basebackup command fails then pg_receivexlog is not working either
# start backup
self.log.info("Starting pg_basebackup")
cmdline = [pg_basebackup, '-D', full_dir, '-h', host, '-U', user, '-p', port, '-w']
if not self.not_really:
p_basebackup = subprocess.Popen(cmdline, stdout=subprocess.PIPE, stderr=subprocess.PIPE, env=envssl)
output = p_basebackup.communicate()
res = p_basebackup.returncode
if res != 0:
raise Exception("exec failed, res=%d (%r), %s" % (res, cmdline, output[1]))
# fix skipped ssl symlinks (only relevant for 9.1)
if pg_ver.startswith('9.1.'):
for line in output[1].splitlines():
m = re.match('WARNING: skipping special file "\./server\.(crt|key)"', line)
if m:
# create symlinks
if m.group(1) == 'crt':
os.symlink('/etc/ssl/certs/ssl-cert-snakeoil.pem',
os.path.join(full_dir,'server.crt'))
elif m.group(1) == 'key':
os.symlink('/etc/ssl/private/ssl-cert-snakeoil.key',
os.path.join(full_dir,'server.key'))
self.log.info("pg_basebackup finished successfully")
# restore
self.args = []
self.restore_database(False)
# wait for recovery
while os.path.isfile(prxloglock) and not self.not_really:
time.sleep(5)
except Exception, e:
self.log.error(e)
errors = True
finally:
# stop pg_receivexlog
try:
if not self.not_really:
os.kill(p_rxlog.pid, signal.SIGTERM)
self.log.info("pg_receivelog stopped")
except Exception, det:
self.log.warning("Failed to stop pg_receivexlog: %s", det)
# cleanup
if os.path.isfile(prxloglock):
os.remove(prxloglock)
if not self.not_really:
for f in os.listdir(xlog_dir):
if f.endswith('.partial'):
self.log.debug("Removing %s", os.path.join(xlog_dir,f))
os.remove(os.path.join(xlog_dir,f))
if not self.not_really and os.path.isdir(full_dir):
shutil.rmtree(full_dir)
self.slave_resume_backups()
if not errors:
self.log.info("Streaming replication standby created successfully")
else:
self.log.error("Failed to create streaming replication standby")
sys.exit(1)
def slave_pause(self, waitcomplete=0):
"""Pause the WAL apply, wait until last file applied if needed"""
self.assert_is_master(False)
srcdir = self.cf.getfile("completed_wals")
pausefile = os.path.join(srcdir, "PAUSE")
if not self.not_really:
open(pausefile, "w").write("1")
else:
self.log.info("Writing PAUSE file: %s", pausefile)
self.log.info("Pausing recovery mode")
# wait for log apply to complete
if waitcomplete:
prgrfile = os.path.join(srcdir, "PROGRESS")
stopfile = os.path.join(srcdir, "STOP")
if os.path.isfile(stopfile):
self.log.warning("Recovery is stopped, backup is invalid if the database is open.")
return
while os.path.isfile(prgrfile):
self.log.info("Waiting for WAL processing to complete ...")
if self.not_really:
return
time.sleep(1)
def slave_continue(self):
self.assert_is_master(False)
srcdir = self.cf.getfile("completed_wals")
pausefile = os.path.join(srcdir, "PAUSE")
if os.path.isfile(pausefile):
if not self.not_really:
os.remove(pausefile)
self.log.info("Continuing with recovery")
else:
self.log.info("Recovery not paused?")
def slave_lock_backups_exit(self):
"""Exit with lock acquired status"""
self.assert_is_master(False)
sys.exit(self.slave_lock_backups())
def slave_lock_backups(self):
"""Create lock file to deny other concurrent backups"""
srcdir = self.cf.getfile("completed_wals")
lockfile = os.path.join(srcdir, "BACKUPLOCK")
if os.path.isfile(lockfile):
self.log.warning("Somebody already has the backup lock.")
lockfilehandle = open(lockfile,"r")
pidstring = lockfilehandle.read();
try:
pid = int(pidstring)
print("%d" % pid)
except ValueError:
self.log.error("lock file does not contain a pid: %s", pidstring)
return 1
if not self.not_really:
f = open(lockfile, "w")
if len(self.args) > 0:
f.write(self.args[0])
f.close()
self.log.info("Backup lock obtained.")
return 0
def slave_resume_backups(self):
"""Remove backup lock file, allow other backups to run"""
self.assert_is_master(False)
srcdir = self.cf.getfile("completed_wals")
lockfile = os.path.join(srcdir, "BACKUPLOCK")
if os.path.isfile(lockfile):
if not self.not_really:
os.remove(lockfile)
self.log.info("Backup lock released.")
else:
self.log.info("Backup lock not held.")
def list_backups(self):
"""List available backups. On master this just calls slave listbackups via SSH"""
if self.is_master:
self.remote_walmgr("listbackups")
else:
backups = self.get_backup_list(self.cf.getfile("full_backup"))
if backups:
print "\nList of backups:\n"
print "%-15s %-24s %-11s %-24s" % \
("Backup set", "Timestamp", "Label", "First WAL")
print "%s %s %s %s" % (15*'-', 24*'-', 11*'-',24*'-')
for backup in backups:
lbl = BackupLabel(backup)
print "%-15s %-24.24s %-11.11s %-24s" % \
(os.path.basename(backup), lbl.start_time,
lbl.label_string, lbl.first_wal)
print
else:
print "\nNo backups found.\n"
def get_first_walname(self,backupdir):
"""Returns the name of the first needed WAL segment for backupset"""
label = BackupLabel(backupdir)
if not label.first_wal:
self.log.error("WAL name not found at %s", backupdir)
return None
return label.first_wal
def last_restart_point(self,walname):
"""
Determine the WAL file of the last restart point (recovery checkpoint).
For 8.3 this could be done with %r parameter to restore_command, for 8.2
we need to consult control file (parse pg_controldata output).
"""
slave_data = self.cf.getfile("slave_data")
backup_label = os.path.join(slave_data, "backup_label")
if os.path.exists(backup_label):
# Label file still exists, use it for determining the restart point
lbl = BackupLabel(slave_data)
self.log.debug("Last restart point from backup_label: %s", lbl.first_wal)
return lbl.first_wal
ctl = PgControlData(self.cf.getfile("slave_bin", ""), ".", True)
if not ctl.is_valid:
# No restart point information, use the given wal name
self.log.warning("Unable to determine last restart point")
return walname
self.log.debug("Last restart point: %s", ctl.wal_name)
return ctl.wal_name
def order_backupdirs(self,prefix,a,b):
"""Compare the backup directory indexes numerically"""
prefix = os.path.abspath(prefix)
a_indx = a[len(prefix)+1:]
if not a_indx:
a_indx = -1
b_indx = b[len(prefix)+1:]
if not b_indx:
b_indx = -1
return cmp(int(a_indx), int(b_indx))
def get_backup_list(self,dst_loc):
"""Return the list of backup directories"""
dirlist = glob.glob(os.path.abspath(dst_loc) + "*")
dirlist.sort(lambda x,y: self.order_backupdirs(dst_loc, x,y))
backupdirs = [ dir for dir in dirlist
if os.path.isdir(dir) and os.path.isfile(os.path.join(dir, "backup_label"))
or os.path.isfile(os.path.join(dir, "backup_label.old"))]
return backupdirs
def slave_purge_wals(self):
"""
Remove WAL files not needed for recovery
"""
self.assert_is_master(False)
backups = self.get_backup_list(self.cf.getfile("full_backup"))
if backups:
lastwal = self.get_first_walname(backups[-1])
if lastwal:
self.log.info("First useful WAL file is: %s", lastwal)
self.slave_cleanup(lastwal)
else:
self.log.debug("No WAL-s to clean up.")
def slave_rotate_backups(self):
"""
Rotate backups by increasing backup directory suffixes. Note that since
we also have to make room for next backup, we actually have
keep_backups - 1 backups available after this.
Unneeded WAL files are not removed here, handled by xpurgewals command instead.
"""
self.assert_is_master(False)
dst_loc = self.cf.getfile("full_backup")
maxbackups = self.cf.getint("keep_backups", 0)
archive_command = self.cf.get("archive_command", "")
backupdirs = self.get_backup_list(dst_loc)
if not backupdirs or maxbackups < 1:
self.log.debug("Nothing to rotate")
# remove expired backups
while len(backupdirs) >= maxbackups and len(backupdirs) > 0:
last = backupdirs.pop()
# if archive_command is set, run it before removing the directory
# Resume only if archive command succeeds.
if archive_command:
cmdline = archive_command.replace("$BACKUPDIR", last)
self.log.info("Executing archive_command: %s", cmdline)
rc = self.exec_system(cmdline)
if rc != 0:
self.log.error("Backup archiving returned %d, exiting!", rc)
sys.exit(1)
self.log.info("Removing expired backup directory: %s", last)
if self.not_really:
continue
cmdline = [ "rm", "-r", last ]
self.exec_cmd(cmdline)
# bump the suffixes if base directory exists
if os.path.isdir(dst_loc):
backupdirs.sort(lambda x,y: self.order_backupdirs(dst_loc, y,x))
for dir in backupdirs:
(name, index) = os.path.splitext(dir)
if not re.match('\.[0-9]+$', index):
name = name + index
index = 0
else:
index = int(index[1:])+1
self.log.debug("Rename %s to %s.%s", dir, name, index)
if self.not_really:
continue
os.rename(dir, "%s.%s" % (name,index))
def slave_cleanup(self, last_applied):
completed_wals = self.cf.getfile("completed_wals")
partial_wals = self.cf.getfile("partial_wals")
self.log.debug("cleaning completed wals before %s", last_applied)
self.del_wals(completed_wals, last_applied)
if os.path.isdir(partial_wals):
self.log.debug("cleaning partial wals before %s", last_applied)
self.del_wals(partial_wals, last_applied)
else:
self.log.warning("partial_wals dir does not exist: %s", partial_wals)
self.log.debug("cleaning done")
def del_wals(self, path, last):
dot = last.find(".")
if dot > 0:
last = last[:dot]
list = os.listdir(path)
list.sort()
cur_last = None
n = len(list)
for i in range(n):
fname = list[i]
full = os.path.join(path, fname)
if fname[0] < "0" or fname[0] > "9":
continue
if not fname.startswith(last[0:8]):
# only look at WAL segments in a same timeline
continue
ok_del = 0
if fname < last:
self.log.debug("deleting %s", full)
if not self.not_really:
try:
os.remove(full)
except:
# don't report the errors if the file has been already removed
# happens due to conflicts with pg_archivecleanup for instance.
pass
cur_last = fname
return cur_last
if __name__ == "__main__":
script = WalMgr(sys.argv[1:])
script.start()
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