def establish_user_defined_connection(instance, conn, clusters):
""" connect the database and get all necessary options like pid and work_directory
we use port, host and socket_directory, prefering socket over TCP connections
"""
pgcon = None
# establish a new connection
try:
pgcon = psycopg2.connect(**conn)
except Exception as e:
logger.error('failed to establish connection to {0} via {1}'.format(
instance, conn))
logger.error('PostgreSQL exception: {0}'.format(e))
return None
# get the database version from the pgcon properties
dbver = dbversion_as_float(pgcon)
cur = pgcon.cursor()
cur.execute('show data_directory')
work_directory = cur.fetchone()[0]
cur.close()
pgcon.commit()
# now, when we have the work directory, acquire the pid of the postmaster.
pid = read_postmaster_pid(work_directory, instance)
if pid is None:
logger.error(
'failed to read pid of the postmaster on {0}'.format(conn))
return None
# check that we don't have the same pid already in the accumulated results.
# for instance, a user may specify 2 different set of connection options for
# the same database (one for the unix_socket_directory and another for the host)
pids = [opt['pid'] for opt in clusters if 'pid' in opt]
if pid in pids:
duplicate_instance = [
opt['name'] for opt in clusters
if 'pid' in opt and opt.get('pid', 0) == pid
][0]
logger.error('duplicate connection options detected for databases '
'{0} and {1}, same pid {2}, skipping {0}'.format(
instance, duplicate_instance, pid))
pgcon.close()
return True
# now we have all components to create a cluster descriptor
desc = make_cluster_desc(name=instance,
version=dbver,
workdir=work_directory,
pid=pid,
pgcon=pgcon,
conn=conn)
clusters.append(desc)
return True
def refresh(self):
""" Reads data from /proc and PostgreSQL stats """
result = []
# fetch up-to-date list of subprocess PIDs
self.get_subprocesses_pid()
try:
if not self.pgcon:
# if we've lost the connection, try to reconnect and
# re-initialize all connection invariants
self.pgcon, self.postmaster_pid = self.reconnect()
self.connection_pid = self.pgcon.get_backend_pid()
self.max_connections = self._get_max_connections()
self.dbver = dbversion_as_float(self.pgcon)
self.server_version = self.pgcon.get_parameter_status(
'server_version')
stat_data = self._read_pg_stat_activity()
except psycopg2.OperationalError as e:
logger.info("failed to query the server: {}".format(e))
if self.pgcon and not self.pgcon.closed:
self.pgcon.close()
self.pgcon = None
self._do_refresh([])
return
logger.info("new refresh round")
for pid in self.pids:
if pid == self.connection_pid:
continue
is_backend = pid in stat_data
is_active = is_backend and (stat_data[pid]['query'] != 'idle'
or pid in self.always_track_pids)
result_row = {}
# for each pid, get hash row from /proc/
proc_data = self._read_proc(pid, is_backend, is_active)
if proc_data:
result_row.update(proc_data)
if stat_data and pid in stat_data:
# ditto for the pg_stat_activity
result_row.update(stat_data[pid])
# result is not empty - add it to the list of current rows
if result_row:
result.append(result_row)
# and refresh the rows with this data
self._do_refresh(result)
def refresh(self):
""" Reads data from /proc and PostgreSQL stats """
result = []
# fetch up-to-date list of subprocess PIDs
self.get_subprocesses_pid()
try:
if not self.pgcon:
# if we've lost the connection, try to reconnect and
# re-initialize all connection invariants
self.pgcon, self.postmaster_pid = self.reconnect()
self.connection_pid = self.pgcon.get_backend_pid()
self.max_connections = self._get_max_connections()
self.dbver = dbversion_as_float(self.pgcon)
self.server_version = self.pgcon.get_parameter_status('server_version')
stat_data = self._read_pg_stat_activity()
except psycopg2.OperationalError as e:
logger.info("failed to query the server: {}".format(e))
if self.pgcon and not self.pgcon.closed:
self.pgcon.close()
self.pgcon = None
self._do_refresh([])
return
logger.info("new refresh round")
for pid in self.pids:
if pid == self.connection_pid:
continue
is_backend = pid in stat_data
is_active = is_backend and (stat_data[pid]['query'] != 'idle' or pid in self.always_track_pids)
result_row = {}
# for each pid, get hash row from /proc/
proc_data = self._read_proc(pid, is_backend, is_active)
if proc_data:
result_row.update(proc_data)
if stat_data and pid in stat_data:
# ditto for the pg_stat_activity
result_row.update(stat_data[pid])
# result is not empty - add it to the list of current rows
if result_row:
result.append(result_row)
# and refresh the rows with this data
self._do_refresh(result)
def establish_user_defined_connection(instance, conn, clusters):
""" connect the database and get all necessary options like pid and work_directory
we use port, host and socket_directory, prefering socket over TCP connections
"""
# establish a new connection
try:
pgcon = psycopg2.connect(**conn)
except Exception as e:
logger.error('failed to establish connection to {0} via {1}'.format(instance, conn))
logger.error('PostgreSQL exception: {0}'.format(e))
return None
# get the database version from the pgcon properties
dbver = dbversion_as_float(pgcon)
cur = pgcon.cursor()
cur.execute('show data_directory')
work_directory = cur.fetchone()[0]
cur.close()
pgcon.commit()
# now, when we have the work directory, acquire the pid of the postmaster.
pid = read_postmaster_pid(work_directory, instance)
if pid is None:
logger.error('failed to read pid of the postmaster on {0}'.format(conn))
return None
# check that we don't have the same pid already in the accumulated results.
# for instance, a user may specify 2 different set of connection options for
# the same database (one for the unix_socket_directory and another for the host)
pids = [opt['pid'] for opt in clusters if 'pid' in opt]
if pid in pids:
duplicate_instance = [opt['name'] for opt in clusters if 'pid' in opt and opt.get('pid', 0) == pid][0]
logger.error('duplicate connection options detected for databases '
'{0} and {1}, same pid {2}, skipping {0}'.format(instance, duplicate_instance, pid))
pgcon.close()
return True
# now we have all components to create a cluster descriptor
desc = make_cluster_desc(name=instance, version=dbver, workdir=work_directory,
pid=pid, pgcon=pgcon, conn=conn)
clusters.append(desc)
return True