Package ganeti :: Module locking

[frames] | no frames]

Module locking

source code

Module implementing the Ganeti locking code.

Classes

[hide private]

_SingleNotifyPipeConditionWaiter
Helper class for SingleNotifyPipeCondition

_BaseCondition
Base class containing common code for conditions.

SingleNotifyPipeCondition
Condition which can only be notified once.

PipeCondition
Group-only non-polling condition with counters.

_PipeConditionWithMode

SharedLock
Implements a shared lock.

_AcquireTimeout
Internal exception to abort an acquire on a timeout.

LockSet
Implements a set of locks.

GanetiLockManager
The Ganeti Locking Library

LockMonitor

Functions

[hide private]

ssynchronized(mylock, shared=0)
Shared Synchronization decorator.

source code

_TimeoutZero()
Returns the number zero.

source code

tuple

_GetLsAcquireModeAndTimeouts(want_all, timeout, opportunistic)
Determines modes and timeouts for LockSet.acquire.

source code

_MonitorSortKey((item, idx, num))
Sorting key function.

source code

Variables

[hide private]

_EXCLUSIVE_TEXT = "exclusive"

_SHARED_TEXT = "shared"

_DELETED_TEXT = "deleted"

_DEFAULT_PRIORITY = 0

_LOCK_ACQUIRE_MIN_TIMEOUT = 1.0/ 1000
Minimum timeout required to consider scheduling a pending acquisition (seconds)

_LS_ACQUIRE_MODES = compat.UniqueFrozenset([_LS_ACQUIRE_EXACT,...

ALL_SET = None

LEVELS = [LEVEL_CLUSTER, LEVEL_INSTANCE, LEVEL_NODE_ALLOC, LEV...

LEVELS_MOD = compat.UniqueFrozenset([LEVEL_NODE_RES, LEVEL_NOD...

LEVEL_NAMES = {LEVEL_CLUSTER: "cluster", LEVEL_INSTANCE: "inst...
Lock level names (make sure to use singular form)

BGL = "BGL"

NAL = "NAL"
Node allocation lock

Imports: os, select, threading, errno, weakref, logging, heapq, itertools, time, errors, utils, compat, query

Function Details

[hide private]

ssynchronized(mylock, shared=0)

source code

Shared Synchronization decorator.

Calls the function holding the given lock, either in exclusive or shared mode. It requires the passed lock to be a SharedLock (or support its semantics).

Parameters:

mylock (lockable object or string) - lock to acquire or class member name of the lock to acquire

_GetLsAcquireModeAndTimeouts(want_all, timeout, opportunistic)

source code

Determines modes and timeouts for LockSet.acquire.

Parameters:

want_all (boolean) - Whether all locks in set should be acquired
timeout - Timeout in seconds or None
opportunistic - Whther locks should be acquired opportunistically

Returns: tuple

Tuple containing mode to be passed to LockSet.__acquire_inner (one of _LS_ACQUIRE_MODES), a function to calculate timeout for acquiring the lockset-internal lock (might be None) and a function to calculate the timeout for acquiring individual locks

_MonitorSortKey((item, idx, num))

source code

Sorting key function.

Sort by name, registration order and then order of information. This provides a stable sort order over different providers, even if they return the same name.

Variables Details

[hide private]

_LS_ACQUIRE_MODES

Value:

compat.UniqueFrozenset([_LS_ACQUIRE_EXACT, _LS_ACQUIRE_ALL, _LS_ACQUIR
E_OPPORTUNISTIC,])

LEVELS

Value:

[LEVEL_CLUSTER, LEVEL_INSTANCE, LEVEL_NODE_ALLOC, LEVEL_NODEGROUP, LEV
EL_NODE, LEVEL_NODE_RES, LEVEL_NETWORK,]

LEVELS_MOD

Value:

compat.UniqueFrozenset([LEVEL_NODE_RES, LEVEL_NODE, LEVEL_NODEGROUP, L
EVEL_INSTANCE, LEVEL_NETWORK,])

LEVEL_NAMES

Lock level names (make sure to use singular form)

Value:

{LEVEL_CLUSTER: "cluster", LEVEL_INSTANCE: "instance", LEVEL_NODE_ALLO
C: "node-alloc", LEVEL_NODEGROUP: "nodegroup", LEVEL_NODE: "node", LEV
EL_NODE_RES: "node-res", LEVEL_NETWORK: "network",}