pvc/daemon-common/zkhandler.py

905 lines
32 KiB
Python

#!/usr/bin/env python3
# zkhandler.py - Secure versioned ZooKeeper updates
# Part of the Parallel Virtual Cluster (PVC) system
#
# Copyright (C) 2018-2021 Joshua M. Boniface <joshua@boniface.me>
#
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, version 3.
#
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
# GNU General Public License for more details.
#
# You should have received a copy of the GNU General Public License
# along with this program. If not, see <https://www.gnu.org/licenses/>.
#
###############################################################################
import os
import time
import uuid
import json
from functools import wraps
from kazoo.client import KazooClient, KazooState
from kazoo.exceptions import NoNodeError
#
# Function decorators
#
class ZKConnection(object):
"""
Decorates a function with a Zookeeper connection before and after the main call.
The decorated function must accept the `zkhandler` argument as its first argument, and
then use this to access the connection.
"""
def __init__(self, config):
self.config = config
def __call__(self, function):
if not callable(function):
return
@wraps(function)
def connection(*args, **kwargs):
zkhandler = ZKHandler(self.config)
zkhandler.connect()
zkhandler.schema.load(zkhandler.read(zkhandler.schema.path('base.schema.version')), quiet=True)
ret = function(zkhandler, *args, **kwargs)
zkhandler.disconnect()
del zkhandler
return ret
return connection
#
# Exceptions
#
class ZKConnectionException(Exception):
"""
A exception when connecting to the cluster
"""
def __init__(self, zkhandler, error=None):
if error is not None:
self.message = "Failed to connect to Zookeeper at {}: {}".format(zkhandler.coordinators(), error)
else:
self.message = "Failed to connect to Zookeeper at {}".format(zkhandler.coordinators())
zkhandler.disconnect()
def __str__(self):
return str(self.message)
#
# Handler class
#
class ZKHandler(object):
def __init__(self, config, logger=None):
"""
Initialize an instance of the ZKHandler class with config
A zk_conn object will be created but not started
A ZKSchema instance will be created
"""
self.encoding = 'utf8'
self.coordinators = config['coordinators']
self.logger = logger
self.zk_conn = KazooClient(hosts=self.coordinators)
self._schema = ZKSchema()
#
# Class meta-functions
#
def coordinators(self):
return str(self.coordinators)
def log(self, message, state=''):
if self.logger is not None:
self.logger.out(message, state)
else:
print(message)
#
# Properties
#
@property
def schema(self):
return self._schema
#
# State/connection management
#
def listener(self, state):
if state == KazooState.CONNECTED:
self.log('Connection to Zookeeper started', state='o')
else:
self.log('Connection to Zookeeper lost', state='w')
while True:
time.sleep(0.5)
_zk_conn = KazooClient(hosts=self.coordinators)
try:
_zk_conn.start()
except Exception:
del _zk_conn
continue
self.zk_conn = _zk_conn
self.zk_conn.add_listener(self.listener)
break
def connect(self, persistent=False):
"""
Start the zk_conn object and connect to the cluster, then load the current schema version
"""
try:
self.zk_conn.start()
if persistent:
self.zk_conn.add_listener(self.listener)
except Exception as e:
raise ZKConnectionException(self, e)
def disconnect(self):
"""
Stop and close the zk_conn object and disconnect from the cluster
The class instance may be reused later (avoids persistent connections)
"""
self.zk_conn.stop()
self.zk_conn.close()
#
# Schema helper actions
#
def get_schema_path(self, key):
if isinstance(key, tuple):
# This is a key tuple with both an ipath and an item
if len(key) == 2:
# 2-length normal tuple
ipath, item = key
elif len(key) == 4:
# 4-length sub-level tuple
ipath, item, sub_ipath, sub_item = key
return self.schema.path(ipath, item=item) + self.schema.path(sub_ipath, item=sub_item)
else:
# This is an invalid key
return None
elif isinstance(key, str):
# This is a key string with just an ipath
ipath = key
item = None
else:
# This is an invalid key
return None
return self.schema.path(ipath, item=item)
#
# Key Actions
#
def exists(self, key):
"""
Check if a key exists
"""
path = self.get_schema_path(key)
stat = self.zk_conn.exists(path)
if stat:
return True
else:
return False
def read(self, key):
"""
Read data from a key
"""
path = self.get_schema_path(key)
return self.zk_conn.get(path)[0].decode(self.encoding)
def write(self, kvpairs):
"""
Create or update one or more keys' data
"""
if type(kvpairs) is not list:
self.log("ZKHandler error: Key-value sequence is not a list", state='e')
return False
transaction = self.zk_conn.transaction()
for kvpair in (kvpairs):
if type(kvpair) is not tuple:
self.log("ZKHandler error: Key-value pair '{}' is not a tuple".format(kvpair), state='e')
return False
key = kvpair[0]
value = kvpair[1]
path = self.get_schema_path(key)
if not self.exists(key):
# Creating a new key
transaction.create(path, str(value).encode(self.encoding))
else:
# Updating an existing key
data = self.zk_conn.get(path)
version = data[1].version
# Validate the expected version after the execution
new_version = version + 1
# Update the data
transaction.set_data(path, str(value).encode(self.encoding))
# Check the data
try:
transaction.check(path, new_version)
except TypeError:
self.log("ZKHandler error: Key '{}' does not match expected version".format(path), state='e')
return False
try:
transaction.commit()
return True
except Exception as e:
self.log("ZKHandler error: Failed to commit transaction: {}".format(e), state='e')
return False
def delete(self, keys, recursive=True):
"""
Delete a key or list of keys (defaults to recursive)
"""
if type(keys) is not list:
keys = [keys]
for key in keys:
path = self.get_schema_path(key)
if self.exists(key):
try:
self.zk_conn.delete(path, recursive=recursive)
except Exception as e:
self.log("ZKHandler error: Failed to delete key {}: {}".format(path, e), state='e')
return False
return True
def children(self, key):
"""
Lists all children of a key
"""
path = self.get_schema_path(key)
return self.zk_conn.get_children(path)
def rename(self, kkpairs):
"""
Rename one or more keys to a new value
"""
if type(kkpairs) is not list:
self.log("ZKHandler error: Key-key sequence is not a list", state='e')
return False
transaction = self.zk_conn.transaction()
def rename_element(transaction, source_path, destnation_path):
data = self.zk_conn.get(source_path)[0]
transaction.create(destination_path, data)
if self.children(source_path):
for child_path in self.children(source_path):
child_source_path = "{}/{}".format(source_path, child_path)
child_destination_path = "{}/{}".format(destination_path, child_path)
rename_element(transaction, child_source_path, child_destination_path)
transaction.delete(source_path)
for kkpair in (kkpairs):
if type(kkpair) is not tuple:
self.log("ZKHandler error: Key-key pair '{}' is not a tuple".format(kkpair), state='e')
return False
source_key = kkpair[0]
source_path = self.get_schema_path(source_key)
destination_key = kkpair[1]
destination_path = self.get_schema_path(destination_key)
if not self.exists(source_key):
self.log("ZKHander error: Source key '{}' does not exist".format(source_path), state='e')
return False
if self.exists(destination_key):
self.log("ZKHander error: Destination key '{}' already exists".format(destination_path), state='e')
return False
rename_element(transaction, source_path, destination_path)
try:
transaction.commit()
return True
except Exception as e:
self.log("ZKHandler error: Failed to commit transaction: {}".format(e), state='e')
return False
#
# Lock actions
#
def readlock(self, key):
"""
Acquires a read lock on a key
"""
count = 1
lock = None
path = self.get_schema_path(key)
while True:
try:
lock_id = str(uuid.uuid1())
lock = self.zk_conn.ReadLock(path, lock_id)
break
except Exception as e:
if count > 5:
self.log("ZKHandler warning: Failed to acquire read lock after 5 tries: {}".format(e), state='e')
break
else:
time.sleep(0.5)
count += 1
continue
return lock
def writelock(self, key):
"""
Acquires a write lock on a key
"""
count = 1
lock = None
path = self.get_schema_path(key)
while True:
try:
lock_id = str(uuid.uuid1())
lock = self.zk_conn.WriteLock(path, lock_id)
break
except Exception as e:
if count > 5:
self.log("ZKHandler warning: Failed to acquire write lock after 5 tries: {}".format(e), state='e')
break
else:
time.sleep(0.5)
count += 1
continue
return lock
def exclusivelock(self, key):
"""
Acquires an exclusive lock on a key
"""
count = 1
lock = None
path = self.get_schema_path(key)
while True:
try:
lock_id = str(uuid.uuid1())
lock = self.zk_conn.Lock(path, lock_id)
break
except Exception as e:
if count > 5:
self.log("ZKHandler warning: Failed to acquire exclusive lock after 5 tries: {}".format(e), state='e')
break
else:
time.sleep(0.5)
count += 1
continue
return lock
#
# Schema classes
#
class ZKSchema(object):
# Current version
_version = 0
# Root for doing nested keys
_schema_root = ''
# Primary schema definition for the current version
_schema = {
'version': f'{_version}',
'root': f'{_schema_root}',
# Base schema defining core keys; this is all that is initialized on cluster init()
'base': {
'schema': f'{_schema_root}/schema',
'schema.version': f'{_schema_root}/schema/version',
'config': f'{_schema_root}/config',
'config.maintenance': f'{_schema_root}/config/maintenance',
'config.primary_node': f'{_schema_root}/config/primary_node',
'config.primary_node.sync_lock': f'{_schema_root}/config/primary_node/sync_lock',
'config.upstream_ip': f'{_schema_root}/config/upstream_ip',
'config.migration_target_selector': f'{_schema_root}/config/migration_target_selector',
'cmd': f'{_schema_root}/cmd',
'cmd.node': f'{_schema_root}/cmd/nodes',
'cmd.domain': f'{_schema_root}/cmd/domains',
'cmd.ceph': f'{_schema_root}/cmd/ceph',
'node': f'{_schema_root}/nodes',
'domain': f'{_schema_root}/domains',
'network': f'{_schema_root}/networks',
'storage': f'{_schema_root}/ceph',
'storage.util': f'{_schema_root}/ceph/util',
'osd': f'{_schema_root}/ceph/osds',
'pool': f'{_schema_root}/ceph/pools',
'volume': f'{_schema_root}/ceph/volumes',
'snapshot': f'{_schema_root}/ceph/snapshots',
},
# The schema of an individual node entry (/nodes/{node_name})
'node': {
'keepalive': '/keepalive',
'mode': '/daemonmode',
'data.active_schema': '/activeschema',
'data.latest_schema': '/latestschema',
'data.static': '/staticdata',
'running_domains': '/runningdomains',
'count.provisioned_domains': '/domainscount',
'count.networks': '/networkscount',
'state.daemon': '/daemonstate',
'state.router': '/routerstate',
'state.domain': '/domainstate',
'cpu.load': '/cpuload',
'vcpu.allocated': '/vcpualloc',
'memory.total': '/memtotal',
'memory.used': '/memused',
'memory.free': '/memfree',
'memory.allocated': '/memalloc',
'memory.provisioned': '/memprov',
'ipmi.hostname': '/ipmihostname',
'ipmi.username': '/ipmiusername',
'ipmi.password': '/ipmipassword'
},
# The schema of an individual domain entry (/domains/{domain_uuid})
'domain': {
'name': '', # The root key
'xml': '/xml',
'state': '/state',
'profile': '/profile',
'stats': '/stats',
'node': '/node',
'last_node': '/lastnode',
'failed_reason': '/failedreason',
'storage.volumes': '/rbdlist',
'console.log': '/consolelog',
'console.vnc': '/vnc',
'meta.autostart': '/node_autostart',
'meta.migrate_method': '/migration_method',
'meta.node_selector': '/node_selector',
'meta.node_limit': '/node_limit',
'migrate.sync_lock': '/migrate_sync_lock'
},
# The schema of an individual network entry (/networks/{vni})
'network': {
'type': '/nettype',
'rule': '/firewall_rules',
'rule.in': '/firewall_rules/in',
'rule.out': '/firewall_rules/out',
'nameservers': '/name_servers',
'domain': '/domain',
'reservation': '/dhcp4_reservations',
'ip4.gateway': '/ip4_gateway',
'ip4.network': '/ip4_network',
'ip4.dhcp': '/dhcp4_flag',
'ip4.dhcp_start': '/dhcp4_start',
'ip4.dhcp_end': '/dhcp4_end',
'ip6.gateway': '/ip6_gateway',
'ip6.network': '/ip6_network',
'ip6.dhcp': '/dhcp6_flag'
},
# The schema of an individual network DHCP(v4) reservation entry (/networks/{vni}/dhcp4_reservations/{mac})
'reservation': {
'mac': '', # The root key
'ip': '/ipaddr',
'hostname': '/hostname'
},
# The schema for an individual network ACL entry (/networks/{vni}/firewall_rules/(in|out)/{acl}
'rule': {
'rule': '/rule',
'order': '/order'
},
# The schema of an individual OSD entry (/ceph/osds/{osd_id})
'osd': {
'node': '/node',
'device': '/device',
'stats': '/stats'
},
# The schema of an individual pool entry (/ceph/pools/{pool_name})
'pool': {
'pgs': '/pgs',
'stats': '/stats'
},
# The schema of an individual volume entry (/ceph/volumes/{pool_name}/{volume_name})
'volume': {
'stats': '/stats'
},
# The schema of an individual snapshot entry (/ceph/volumes/{pool_name}/{volume_name}/{snapshot_name})
'snapshot': {
'stats': '/stats'
}
}
# Properties
@property
def schema_root(self):
return self._schema_root
@schema_root.setter
def schema_root(self, schema_root):
self._schema_root = schema_root
@property
def version(self):
return int(self._version)
@version.setter
def version(self, version):
self._version = int(version)
@property
def schema(self):
return self._schema
@schema.setter
def schema(self, schema):
self._schema = schema
def __init__(self):
pass
def __repr__(self):
return f'ZKSchema({self.version})'
def __lt__(self, other):
if self.version < other.version:
return True
else:
return False
def __le__(self, other):
if self.version <= other.version:
return True
else:
return False
def __gt__(self, other):
if self.version > other.version:
return True
else:
return False
def __ge__(self, other):
if self.version >= other.version:
return True
else:
return False
def __eq__(self, other):
if self.version == other.version:
return True
else:
return False
# Load the schema of a given version from a file
def load(self, version, quiet=False):
if not quiet:
print(f'Loading schema version {version}')
with open(f'daemon_lib/migrations/versions/{version}.json', 'r') as sfh:
self.schema = json.load(sfh)
self.version = self.schema.get('version')
# Get key paths
def path(self, ipath, item=None):
itype, *ipath = ipath.split('.')
if item is None:
return self.schema.get(itype).get('.'.join(ipath))
else:
base_path = self.schema.get('base').get(itype, None)
if base_path is None:
# This should only really happen for second-layer key types where the helper functions join them together
base_path = ''
sub_path = self.schema.get(itype).get('.'.join(ipath))
if sub_path is None:
sub_path = ''
return f'{base_path}/{item}{sub_path}'
# Get keys of a schema location
def keys(self, itype=None):
if itype is None:
return list(self.schema.get('base').keys())
else:
return list(self.schema.get(itype).keys())
# Get the active version of a cluster's schema
def get_version(self, zkhandler):
try:
current_version = zkhandler.read(self.path('base.schema.version'))
except NoNodeError:
current_version = 0
return current_version
# Validate an active schema against a Zookeeper cluster
def validate(self, zkhandler, logger=None):
result = True
# Walk the entire tree checking our schema
for elem in ['base']:
for key in self.keys(elem):
kpath = f'{elem}.{key}'
if not zkhandler.zk_conn.exists(self.path(kpath)):
if logger is not None:
logger.out(f'Key not found: {self.path(kpath)}', state='w')
result = False
for elem in ['node', 'domain', 'network', 'osd', 'pool']:
# First read all the subelements of the key class
for child in zkhandler.zk_conn.get_children(self.path(f'base.{elem}')):
# For each key in the schema for that particular elem
for ikey in self.keys(elem):
kpath = f'{elem}.{ikey}'
# Validate that the key exists for that child
if not zkhandler.zk_conn.exists(self.path(kpath, child)):
if logger is not None:
logger.out(f'Key not found: {self.path(kpath, child)}', state='w')
result = False
# Continue for child keys under network (reservation, acl)
if elem in ['network'] and ikey in ['reservation', 'rule.in', 'rule.out']:
if ikey in ['rule.in', 'rule.out']:
sikey = 'rule'
else:
sikey = ikey
npath = self.path(f'{elem}.{ikey}', child)
for nchild in zkhandler.zk_conn.get_children(npath):
nkpath = f'{npath}/{nchild}'
for esikey in self.keys(sikey):
nkipath = f'{nkpath}/{esikey}'
if not zkhandler.zk_conn.exists(nkipath):
result = False
# These two have several children layers that must be parsed through
for elem in ['volume']:
# First read all the subelements of the key class (pool layer)
for pchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}')):
# Finally read all the subelements of the key class (volume layer)
for vchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}') + f'/{pchild}'):
child = f'{pchild}/{vchild}'
# For each key in the schema for that particular elem
for ikey in self.keys(elem):
kpath = f'{elem}.{ikey}'
# Validate that the key exists for that child
if not zkhandler.zk_conn.exists(self.path(kpath, child)):
if logger is not None:
logger.out(f'Key not found: {self.path(kpath, child)}', state='w')
result = False
for elem in ['snapshot']:
# First read all the subelements of the key class (pool layer)
for pchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}')):
# Next read all the subelements of the key class (volume layer)
for vchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}') + f'/{pchild}'):
# Finally read all the subelements of the key class (volume layer)
for schild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}') + f'/{pchild}/{vchild}'):
child = f'{pchild}/{vchild}/{schild}'
# For each key in the schema for that particular elem
for ikey in self.keys(elem):
kpath = f'{elem}.{ikey}'
# Validate that the key exists for that child
if not zkhandler.zk_conn.exists(self.path(kpath, child)):
if logger is not None:
logger.out(f'Key not found: {self.path(kpath, child)}', state='w')
result = False
return result
# Apply the current schema to the cluster
def apply(self, zkhandler):
# Walk the entire tree checking our schema
for elem in ['base']:
for key in self.keys(elem):
kpath = f'{elem}.{key}'
if not zkhandler.zk_conn.exists(self.path(kpath)):
zkhandler.zk_conn.create(self.path(kpath), ''.encode(zkhandler.encoding))
for elem in ['node', 'domain', 'network', 'osd', 'pool']:
# First read all the subelements of the key class
for child in zkhandler.zk_conn.get_children(self.path(f'base.{elem}')):
# For each key in the schema for that particular elem
for ikey in self.keys(elem):
kpath = f'{elem}.{ikey}'
# Validate that the key exists for that child
if not zkhandler.zk_conn.exists(self.path(kpath, child)):
zkhandler.zk_conn.create(self.path(kpath, child), ''.encode(zkhandler.encoding))
# Continue for child keys under network (reservation, acl)
if elem in ['network'] and ikey in ['reservation', 'rule.in', 'rule.out']:
if ikey in ['rule.in', 'rule.out']:
sikey = 'rule'
else:
sikey = ikey
npath = self.path(f'{elem}.{ikey}', child)
for nchild in zkhandler.zk_conn.get_children(npath):
nkpath = f'{npath}/{nchild}'
for esikey in self.keys(sikey):
nkipath = f'{nkpath}/{esikey}'
if not zkhandler.zk_conn.exists(nkipath):
zkhandler.zk_conn.create(nkipath, ''.encode(zkhandler.encoding))
# These two have several children layers that must be parsed through
for elem in ['volume']:
# First read all the subelements of the key class (pool layer)
for pchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}')):
# Finally read all the subelements of the key class (volume layer)
for vchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}') + f'/{pchild}'):
child = f'{pchild}/{vchild}'
# For each key in the schema for that particular elem
for ikey in self.keys(elem):
kpath = f'{elem}.{ikey}'
# Validate that the key exists for that child
if not zkhandler.zk_conn.exists(self.path(kpath, child)):
zkhandler.zk_conn.create(self.path(kpath, child), ''.encode(zkhandler.encoding))
for elem in ['snapshot']:
# First read all the subelements of the key class (pool layer)
for pchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}')):
# Next read all the subelements of the key class (volume layer)
for vchild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}') + f'/{pchild}'):
# Finally read all the subelements of the key class (volume layer)
for schild in zkhandler.zk_conn.get_children(self.path(f'base.{elem}') + f'/{pchild}/{vchild}'):
child = f'{pchild}/{vchild}/{schild}'
# For each key in the schema for that particular elem
for ikey in self.keys(elem):
kpath = f'{elem}.{ikey}'
# Validate that the key exists for that child
if not zkhandler.zk_conn.exists(self.path(kpath, child)):
zkhandler.zk_conn.create(self.path(kpath, child), ''.encode(zkhandler.encoding))
zkhandler.zk_conn.create(self.path('base.schema.version'), self.version)
# Migrate key diffs
def run_migrate(self, zkhandler, changes):
diff_add = changes['add']
diff_remove = changes['remove']
diff_rename = changes['rename']
add_tasks = list()
for key in diff_add.keys():
add_tasks.append((diff_add[key], ''))
remove_tasks = list()
for key in diff_remove.keys():
remove_tasks.append(diff_remove[key])
rename_tasks = list()
for key in diff_rename.keys():
rename_tasks.append((diff_rename[key]['from'], diff_rename[key]['to']))
zkhandler.write(add_tasks)
zkhandler.delete(remove_tasks)
zkhandler.rename(rename_tasks)
# Migrate from older to newer schema
def migrate(self, zkhandler, new_version):
# Determine the versions in between
versions = ZKSchema.find_all(start=self.version, end=new_version)
if versions is None:
return
for version in versions:
# Create a new schema at that version
zkschema_new = ZKSchema()
zkschema_new.load(version)
# Get a list of changes
changes = ZKSchema.key_diff(self, zkschema_new)
# Apply those changes
self.run_migrate(zkhandler, changes)
# Rollback from newer to older schema
def rollback(self, zkhandler, old_version):
# Determine the versions in between
versions = ZKSchema.find_all(start=old_version - 1, end=self.version - 1)
if versions is None:
return
versions.reverse()
for version in versions:
# Create a new schema at that version
zkschema_old = ZKSchema()
zkschema_old.load(version)
# Get a list of changes
changes = ZKSchema.key_diff(self, zkschema_old)
# Apply those changes
self.run_migrate(zkhandler, changes)
@classmethod
def key_diff(cls, schema_a, schema_b):
# schema_a = current
# schema_b = new
diff_add = dict()
diff_remove = dict()
diff_rename = dict()
# Parse through each core element
for elem in ['base', 'node', 'domain', 'network', 'osd', 'pool', 'volume', 'snapshot']:
set_a = set(schema_a.keys(elem))
set_b = set(schema_b.keys(elem))
diff_keys = set_a ^ set_b
for item in diff_keys:
elem_item = f'{elem}.{item}'
if item not in schema_a.keys(elem) and item in schema_b.keys(elem):
diff_add[elem_item] = schema_b.path(elem_item)
if item in schema_a.keys(elem) and item not in schema_b.keys(elem):
diff_remove[elem_item] = schema_a.path(elem_item)
for item in set_b:
elem_item = f'{elem}.{item}'
if schema_a.path(elem_item) is not None and \
schema_b.path(elem_item) is not None and \
schema_a.path(elem_item) != schema_b.path(elem_item):
diff_rename[elem_item] = {'from': schema_a.path(elem_item), 'to': schema_b.path(elem_item)}
return {'add': diff_add, 'remove': diff_remove, 'rename': diff_rename}
# Load in the schemal of the current cluster
@classmethod
def load_current(cls, zkhandler):
new_instance = cls()
version = new_instance.get_version(zkhandler)
new_instance.load(version)
return new_instance
# Write the latest schema to a file
@classmethod
def write(cls):
schema_file = 'daemon_lib/migrations/versions/{}.json'.format(cls._version)
with open(schema_file, 'w') as sfh:
json.dump(cls._schema, sfh)
# Static methods for reading information from the files
@staticmethod
def find_all(start=0, end=None):
versions = list()
for version in os.listdir('daemon_lib/migrations/versions'):
sequence_id = int(version.split('.')[0])
if end is None:
if sequence_id > start:
versions.append(sequence_id)
else:
if sequence_id > start and sequence_id <= end:
versions.append(sequence_id)
if len(versions) > 0:
return versions
else:
return None
@staticmethod
def find_latest():
latest_version = 0
for version in os.listdir('daemon_lib/migrations/versions'):
sequence_id = int(version.split('.')[0])
if sequence_id > latest_version:
latest_version = sequence_id
return latest_version