/
disc_cassdb.py
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/
disc_cassdb.py
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#
# Copyright (c) 2013 Juniper Networks, Inc. All rights reserved.
#
import re
import json
import time
import gevent
import disc_consts
import disc_exceptions
from datetime import datetime
from gevent.coros import BoundedSemaphore
import pycassa
import pycassa.util
from pycassa.system_manager import *
from pycassa.util import *
from pycassa.types import *
from sandesh_common.vns.constants import DISCOVERY_SERVER_KEYSPACE_NAME, \
CASSANDRA_DEFAULT_GC_GRACE_SECONDS
class DiscoveryCassandraClient(object):
_DISCOVERY_KEYSPACE_NAME = DISCOVERY_SERVER_KEYSPACE_NAME
_DISCOVERY_CF_NAME = 'discovery'
@classmethod
def get_db_info(cls):
db_info = [(cls._DISCOVERY_KEYSPACE_NAME, [cls._DISCOVERY_CF_NAME])]
return db_info
# end get_db_info
def __init__(self, module, cass_srv_list, reset_config=False,
max_retries=5, timeout=5):
self._disco_cf_name = 'discovery'
self._keyspace_name = 'DISCOVERY_SERVER'
self._reset_config = reset_config
self._cassandra_init(cass_srv_list, max_retries, timeout)
self._debug = {
}
#end __init__
# Helper routines for cassandra
def _cassandra_init(self, server_list, max_retries, timeout):
# column name <table-name>, <id1>, <id2>
disco_cf_info = (self._disco_cf_name,
CompositeType(AsciiType(), UTF8Type(), UTF8Type()), AsciiType())
# 1. Ensure keyspace and schema/CFs exist
self._cassandra_ensure_keyspace(server_list, self._keyspace_name,
[disco_cf_info])
pool = pycassa.ConnectionPool(self._keyspace_name,
server_list, max_overflow=-1,
use_threadlocal=True, prefill=True,
pool_size=100, pool_timeout=120,
max_retries=max_retries, timeout=timeout)
rd_consistency = pycassa.cassandra.ttypes.ConsistencyLevel.ONE
wr_consistency = pycassa.cassandra.ttypes.ConsistencyLevel.ONE
self._disco_cf = pycassa.ColumnFamily(pool, self._disco_cf_name,
read_consistency_level = rd_consistency,
write_consistency_level = wr_consistency)
#end _cassandra_init
def _cassandra_ensure_keyspace(self, server_list,
keyspace_name, cf_info_list):
# Retry till cassandra is up
server_idx = 0
num_dbnodes = len(server_list)
connected = False
while not connected:
try:
cass_server = server_list[server_idx]
sys_mgr = SystemManager(cass_server)
connected = True
except Exception as e:
# TODO do only for thrift.transport.TTransport.TTransportException
server_idx = (server_idx + 1) % num_dbnodes
time.sleep(3)
if self._reset_config:
try:
sys_mgr.drop_keyspace(keyspace_name)
except pycassa.cassandra.ttypes.InvalidRequestException as e:
# TODO verify only EEXISTS
print "Warning! " + str(e)
try:
# TODO replication_factor adjust?
sys_mgr.create_keyspace(keyspace_name, SIMPLE_STRATEGY,
{'replication_factor': str(num_dbnodes)})
except pycassa.cassandra.ttypes.InvalidRequestException as e:
# TODO verify only EEXISTS
print "Warning! " + str(e)
for cf_info in cf_info_list:
try:
(cf_name, comparator_type, validator_type) = cf_info
sys_mgr.create_column_family(keyspace_name, cf_name,
comparator_type = comparator_type, default_validation_class = validator_type)
sys_mgr.alter_column_family(keyspace_name, cf_name,
gc_grace_seconds=CASSANDRA_DEFAULT_GC_GRACE_SECONDS)
except pycassa.cassandra.ttypes.InvalidRequestException as e:
# TODO verify only EEXISTS
print "Warning! " + str(e)
#end _cassandra_ensure_keyspace
def get_debug_stats(self):
return self._debug
# end
"""
various column names
('client', client_id, 'client-entry')
('subscriber', service_id, client_id)
('subscription', client_id, service_id)
('service', service_id, 'service-entry')
"""
# decorator to catch connectivity error
def cass_error_handler(func):
def error_handler(*args, **kwargs):
try:
return func(*args,**kwargs)
except (pycassa.pool.AllServersUnavailable,
pycassa.pool.MaximumRetryException):
raise disc_exceptions.ServiceUnavailable()
except Exception as e:
raise
return error_handler
# return all publisher entries
@cass_error_handler
def service_entries(self, service_type = None):
col_name = ('service',)
try:
data = self._disco_cf.get_range(column_start = col_name, column_finish = col_name)
for service_type, services in data:
for col_name in services:
col_value = services[col_name]
entry = json.loads(col_value)
col_name = ('subscriber', entry['service_id'],)
entry['in_use'] = self._disco_cf.get_count(service_type,
column_start = col_name, column_finish = col_name)
yield(entry)
except pycassa.pool.AllServersUnavailable:
raise disc_exceptions.ServiceUnavailable()
#raise StopIteration
# return all clients
def subscriber_entries(self):
col_name = ('client',)
data = self._disco_cf.get_range(column_start = col_name, column_finish = col_name)
for service_type, clients in data:
for col_name in clients:
(foo, client_id, service_id) = col_name
# skip pure client entry
if service_id == disc_consts.CLIENT_TAG:
continue
yield((client_id, service_type))
# end
# return all subscriptions
@cass_error_handler
def get_all_clients(self, service_type=None, service_id=None):
r = []
entry_format_subscriber = False
if service_type and service_id:
# ('subscriber', service_id, client_id)
col_name = ('subscriber', service_id,)
try:
clients = self._disco_cf.get(service_type, column_start = col_name,
column_finish = col_name, column_count = disc_consts.MAX_COL)
except pycassa.NotFoundException:
return None
data = [(service_type, dict(clients))]
entry_format_subscriber = True
elif service_type:
col_name = ('client', )
try:
clients = self._disco_cf.get(service_type, column_start = col_name,
column_finish = col_name, column_count = disc_consts.MAX_COL)
except pycassa.NotFoundException:
return None
data = [(service_type, dict(clients))]
else:
col_name = ('client', )
try:
data = self._disco_cf.get_range(column_start=col_name, column_finish=col_name)
except pycassa.NotFoundException:
return None
for service_type, clients in data:
rr = []
for col_name in clients:
if entry_format_subscriber:
(foo, service_id, client_id) = col_name
else:
(foo, client_id, service_id) = col_name
# skip pure client entry
if service_id == disc_consts.CLIENT_TAG:
continue
entry_str = clients[col_name]
entry = json.loads(entry_str)
rr.append((service_type, client_id, service_id,
entry['mtime'], entry['ttl']))
# sort by modification time
# rr = sorted(rr, key=lambda entry: entry[3])
r.extend(rr)
return r
# end get_all_clients
# update publisher entry
@cass_error_handler
def update_service(self, service_type, service_id, entry):
self.insert_service(service_type, service_id, entry)
# end
@cass_error_handler
def insert_service(self, service_type, service_id, entry):
col_name = ('service', service_id, 'service-entry')
self._disco_cf.insert(service_type, {col_name : json.dumps(entry)})
# end insert_service
# forget service and subscribers
@cass_error_handler
def delete_service(self, entry):
col_name = ('service', entry['service_id'], 'service-entry')
self._disco_cf.remove(entry['service_type'])
#end delete_service
# return service entry
@cass_error_handler
def lookup_service(self, service_type, service_id=None):
try:
if service_id:
services = self._disco_cf.get(service_type, columns = [('service', service_id, 'service-entry')])
data = [json.loads(val) for col,val in services.items()]
entry = data[0]
col_name = ('subscriber', service_id,)
entry['in_use'] = self._disco_cf.get_count(service_type,
column_start = col_name, column_finish = col_name)
return entry
else:
col_name = ('service',)
services = self._disco_cf.get(service_type,
column_start = col_name, column_finish = col_name)
data = [json.loads(val) for col,val in services.items()]
for entry in data:
col_name = ('subscriber', entry['service_id'],)
entry['in_use'] = self._disco_cf.get_count(service_type,
column_start = col_name, column_finish = col_name)
return data
except pycassa.NotFoundException:
return None
# end lookup_service
@cass_error_handler
def query_service(self, service_type):
return self.lookup_service(service_type, service_id = None)
# end
# this is actually client create :-(
@cass_error_handler
def insert_client_data(self, service_type, client_id, blob):
col_name = ('client', client_id, disc_consts.CLIENT_TAG)
self._disco_cf.insert(service_type, {col_name : json.dumps(blob)})
# end insert_client_data
# insert a subscription (blob/ttl per service_type)
@cass_error_handler
def insert_client(self, service_type, service_id, client_id, blob, ttl):
col_val = json.dumps({'ttl': ttl, 'blob': blob, 'mtime': int(time.time())})
col_name = ('subscriber', service_id, client_id)
self._disco_cf.insert(service_type, {col_name : col_val},
ttl = ttl + disc_consts.TTL_EXPIRY_DELTA)
col_name = ('client', client_id, service_id)
self._disco_cf.insert(service_type, {col_name : col_val},
ttl = ttl + disc_consts.TTL_EXPIRY_DELTA)
# end insert_client
# return client (subscriber) entry
@cass_error_handler
def lookup_client(self, service_type, client_id, subs = False):
r = []
col_name = ('client', client_id, )
try:
subs = self._disco_cf.get(service_type, column_start = col_name,
column_finish = col_name, include_timestamp = True)
# sort columns by timestamp (subs is array of (col_name, (value, timestamp)))
subs = sorted(subs.items(), key=lambda entry: entry[1][1])
# col_name = (client, cliend_id, service_id)
# col_val = (real-value, timestamp)
for col_name, col_val in subs:
foo, client_id, service_id = col_name
if service_id == disc_consts.CLIENT_TAG:
data = json.loads(col_val[0])
continue
entry = json.loads(col_val[0])
r.append((col_name[2], entry['blob']))
return (data, r)
except pycassa.NotFoundException:
return (None, [])
# end lookup_client
# return all subscriptions for a given client
@cass_error_handler
def lookup_subscription(self, service_type, client_id):
r = []
col_name = ('client', client_id, )
try:
subs = self._disco_cf.get(service_type, column_start = col_name,
column_finish = col_name)
# col_name = subscription, cliend_id, service_id
for col_name, col_val in subs.items():
foo, client_id, bar = col_name
if bar == disc_consts.CLIENT_TAG:
continue
entry = json.loads(col_val)
r.append((col_name[2], entry['blob']))
return r
except pycassa.NotFoundException:
return None
# end lookup_subscription
# delete client subscription.
@cass_error_handler
def delete_subscription(self, service_type, client_id, service_id):
self._disco_cf.remove(service_type,
columns = [('client', client_id, service_id)])
self._disco_cf.remove(service_type,
columns = [('subscriber', service_id, client_id)])
# end
# return tuple (service_type, client_id, service_id)