Pc @ s d Z d d k Z d d k Z d d k Z d d k Z d d k Z d d k Z d d k l Z l Z d Z
d Z y e e
f Wn e j
o d Z d Z
n Xe a d Z d e f d
YZ d e f d YZ d
e f d YZ d e f d YZ d f d YZ d Z d Z d Z d Z d Z e d j o3 d d k Z d d k Z e e e i d n d S( sI Portable, NFS-safe file locking with timeouts.
This code implements an NFS-safe file-based locking algorithm influenced by
the GNU/Linux open(2) manpage, under the description of the O_EXCL option.
From RH6.1:
[...] O_EXCL is broken on NFS file systems, programs which rely on it
for performing locking tasks will contain a race condition. The
solution for performing atomic file locking using a lockfile is to
create a unique file on the same fs (e.g., incorporating hostname and
pid), use link(2) to make a link to the lockfile. If link() returns
0, the lock is successful. Otherwise, use stat(2) on the unique file
to check if its link count has increased to 2, in which case the lock
is also successful.
The assumption made here is that there will be no `outside interference',
e.g. no agent external to this code will have access to link() to the affected
lock files.
LockFile objects support lock-breaking so that you can't wedge a process
forever. This is especially helpful in a web environment, but may not be
appropriate for all applications.
Locks have a `lifetime', which is the maximum length of time the process
expects to retain the lock. It is important to pick a good number here
because other processes will not break an existing lock until the expected
lifetime has expired. Too long and other processes will hang; too short and
you'll end up trampling on existing process locks -- and possibly corrupting
data. In a distributed (NFS) environment, you also need to make sure that
your clocks are properly synchronized.
Locks can also log their state to a log file. When running under Mailman, the
log file is placed in a Mailman-specific location, otherwise, the log file is
called `LockFile.log' and placed in the temp directory (calculated from
tempfile.mktemp()).
iN( t ST_NLINKt ST_MTIMEi i
i i c C s t d j o y d d k l } | d a Wq t j
oc d d k } t i i | i d } t i i
| d } d d d Y} | | a q Xn t S( Ni( t
StampedLoggert locksi s LockFile.logt SimpleUserFilec B s e Z d Z d Z RS( c S s, t | d d | _ d t i | _ d S( Nt ai s (%d) ( t opent _SimpleUserFile__fpt ost getpidt _SimpleUserFile__prefix( t selft path( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __init__c s c S s3 d t i } | i i | i | d | d S( Ns %.3ft ( t timeR t writeR
( R t msgt now( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR f s ( t __name__t
__module__R
R ( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR b s ( ( t _logfilet Nonet Mailman.Logging.StampedLoggerR t ImportErrort tempfileR R t splitt mktempt join( R R t dirR R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _get_logfileV s
t LockErrorc B s e Z d Z RS( s- Base class for all exceptions in this module.( R R t __doc__( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR o s t AlreadyLockedErrorc B s e Z d Z RS( s4 An attempt is made to lock an already locked object.( R R R ( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR! r s t NotLockedErrorc B s e Z d Z RS( s9 An attempt is made to unlock an object that isn't locked.( R R R ( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR" u s t TimeOutErrorc B s e Z d Z RS( s7 The timeout interval elapsed before the lock succeeded.( R R R ( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR# x s t LockFilec B s e Z d Z d Z e e d Z d Z d Z d Z d e d Z d d Z e d Z
d Z d
Z d Z d Z d
Z d Z d d Z d Z d Z d d Z d Z d Z d Z d Z RS( s' A portable way to lock resources by way of the file system.
This class supports the following methods:
__init__(lockfile[, lifetime[, withlogging]]):
Create the resource lock using lockfile as the global lock file. Each
process laying claim to this resource lock will create their own
temporary lock files based on the path specified by lockfile.
Optional lifetime is the number of seconds the process expects to hold
the lock. Optional withlogging, when true, turns on lockfile logging
(see the module docstring for details).
set_lifetime(lifetime):
Set a new lock lifetime. This takes affect the next time the file is
locked, but does not refresh a locked file.
get_lifetime():
Return the lock's lifetime.
refresh([newlifetime[, unconditionally]]):
Refreshes the lifetime of a locked file. Use this if you realize that
you need to keep a resource locked longer than you thought. With
optional newlifetime, set the lock's lifetime. Raises NotLockedError
if the lock is not set, unless optional unconditionally flag is set to
true.
lock([timeout]):
Acquire the lock. This blocks until the lock is acquired unless
optional timeout is greater than 0, in which case, a TimeOutError is
raised when timeout number of seconds (or possibly more) expires
without lock acquisition. Raises AlreadyLockedError if the lock is
already set.
unlock([unconditionally]):
Relinquishes the lock. Raises a NotLockedError if the lock is not
set, unless optional unconditionally is true.
locked():
Return true if the lock is set, otherwise false. To avoid race
conditions, this refreshes the lock (on set locks).
i c C s | | _ | | _ t i | _ t i d 7_ d | t i t i | i f | _ | | _
t i i | i d | _
t | _ d S( s Create the resource lock using lockfile as the global lock file.
Each process laying claim to this resource lock will create their own
temporary lock files based on the path specified by lockfile.
Optional lifetime is the number of seconds the process expects to hold
the lock. Optional withlogging, when true, turns on lockfile logging
(see the module docstring for details).
i s %s.%s.%d.%dN( t _LockFile__lockfilet _LockFile__lifetimeR$ t COUNTERt _LockFile__countert sockett gethostnameR R t _LockFile__tmpfnamet _LockFile__withloggingR R t _LockFile__logprefixt Truet _LockFile__owned( R t lockfilet lifetimet withlogging( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR
s % c C s= d t | | i | i o d p d | i t i f S( Ns$ <LockFile %s: %s [%s: %ssec] pid=%s>t lockedt unlocked( t idR% R3 R& R R ( R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __repr__ s c C s
| | _ d S( s Set a new lock lifetime.
This takes affect the next time the file is locked, but does not
refresh a locked file.
N( R& ( R R1 ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt set_lifetime s c C s | i S( s Return the lock's lifetime.( R& ( R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt get_lifetime s c C s[ | d j o | i | n | i o+ | o# t d t | | i f n d S( sC Refreshes the lifetime of a locked file.
Use this if you realize that you need to keep a resource locked longer
than you thought. With optional newlifetime, set the lock's lifetime.
Raises NotLockedError if the lock is not set, unless optional
unconditionally flag is set to true.
s %s: %sN( R R7 R3 R" t reprt _LockFile__read( R t newlifetimet unconditionally( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt refresh s
c C s | o t i | } n | i | i | i d d } xt o| d 7} y2 t i | i | i | i d | i PWn t j
o } | i
t
i j o qY| i
t
i j o. | i d | d t t i
| i qY| i d j o! | i d | i d t qY| i | i j o | i d t qYn X| o: | t i j o' t i
| i | i d
t n t i | i t j o! | i | i d d t n | d p | i d
n | i qE Wd S( s? Acquire the lock.
This blocks until the lock is acquired unless optional timeout is
greater than 0, in which case, a TimeOutError is raised when timeout
number of seconds (or possibly more) expires without lock acquisition.
Raises AlreadyLockedError if the lock is already set.
s laying claimii s got the locks unexpected link error: %st importanti s unexpected linkcount: %ds already lockeds timed outs lifetime has expired, breakingid s waiting for claimN( R t _LockFile__writet _LockFile__toucht _LockFile__writelogR. R t linkR+ R% t OSErrort errnot ENOENTt EEXISTt unlinkt _LockFile__linkcountR: R! R# t _LockFile__releasetimet
CLOCK_SLOPt _LockFile__breakt _LockFile__sleep( R t timeoutt timeout_timet loopcountt e( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt lock sP
c C s | i } | o | o
t n | oJ y t i | i Wqw t j
o# } | i t i j o qs qw Xn y t i | i Wn/ t j
o# } | i t i j o q n X| i d d S( s Unlock the lock.
If we don't already own the lock (either because of unbalanced unlock
calls, or because the lock was stolen out from under us), raise a
NotLockedError, unless optional `unconditionally' is true.
R4 N(
R3 R" R RG R% RC RD RE R+ RA ( R R< t islockedRP ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt unlock: s
c C sl y | i Wn0 t j
o$ } | i t i j o t S n X| i d j o t S| i | i j S( s Return true if we own the lock, false if we do not.
Checking the status of the lock resets the lock's lifetime, which
helps avoid race conditions during the lock status test.
i ( R@ RC RD t EPERMt FalseRH R: R+ ( R RP ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR3 Q s c C s | i d t d S( NR< ( RS R. ( R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt finalizef s c C s | i o | i n d S( N( R/ RV ( R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __del__i s
c C s | i | i } d | i t i | f | _ t i | i | i | i t | _
t i | | i d j p t
| i p t
| i d d S( Ns %s.%s.%di s transferred the lock( R@ R: R% R) R* R+ R RB R? RU R/ RG RH t AssertionErrorR3 RA ( R t pidt winner( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _transfer_tot s
c C su d | i t i t i f | _ } x8 | i d j p | i | j o t i d q, W| i
d d S( Ns %s.%s.%di g ?s took possession of the lock( R% R) R* R R R+ RH R: R t sleepRA ( R t tmpfname( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _take_possession s & &c C s
t | _ d S( N( RU R/ ( R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _disown s c C sL | i p | o7 t } | i d | i | f t i d | n d S( Ns %s %s
t file( R, R R R- t tracebackt print_stack( R R R> t logf( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt
__writelog s c C sT t i d } z0 t | i d } | i | i | i Wd t i | Xd S( Ni t w( R t umaskR R+ R t close( R t oldmaskt fp( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __write s c C sd y- t | i } | i } | i | SWn0 t j
o$ } | i t i j o n d SXd S( N( R R% t readRg t EnvironmentErrorRD RE R ( R Ri t filenameRP ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __read s
c C sm t i | i } y$ t i | p | i | | f Wn/ t j
o# } | i t i j o qi n Xd S( N( R R& R t utimeR+ RC RD RE ( R Rm t tRP ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __touch s $ c C sO y t i | i t SWn0 t j
o$ } | i t i j o n d SXd S( Ni( R t statR% R RC RD RE ( R RP ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt
__releasetime s c C sO y t i | i t SWn0 t j
o$ } | i t i j o n d SXd S( Ni( R Rr R% R RC RD RE ( R RP ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __linkcount s c C s y | i | i Wn/ t j
o# } | i t i j o qF n X| i } y t i | i Wn/ t j
o# } | i t i j o q n Xy | o t i | n Wn/ t j
o# } | i t i j o q n Xd S( N( R@ R% RC RD RT R: R RG RE ( R RP RZ ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __break s"
c C s% t i d d } t i | d S( Ng @g{Gz?( t randomR R\ ( R t interval( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt __sleep s N( R R R R' t DEFAULT_LOCK_LIFETIMERU R
R6 R7 R8 R R= RQ RS R3 RV RW R[ R^ R_ RA R? R: R@ RI RH RK RL ( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyR$ } s0 * S
"c C sk d t i } t d d t d d } d t i } d t i } | Gd G| GHt } d } d } d } z y2 t i } | Gd
GH| i | Gd GHt } Wn t j
o | Gd GHn0 Xt i } | Gd
G| | Gd GHt i | Wd | oR y/ | i
t i } | Gd G| | Gd GHWqLt j
o | Gd GHqLXn X| Gd G| GHt i | d S( Ns [%d]s
/tmp/LockTestR2 R1 ix i i s
workinterval:i s acquiring...s acquired...s timed outs acquisition time:t secondss lock hold time:s lock was brokens
webhit sleep:( R R R$ R. Rv RU R RQ R# R\ RS R" ( t prefixR0 t workintervalt hitwaitRR t t0t t1t t2( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _dochild s<
c C s y) t d } | i d } | i Wnc t j
oW } | i t i j o n d d k l } | t i
t
i
i } n Xt i
| d S( Ns /dev/randomi( i( t sha_new( R Rk Rg Rl RD RE t
Mailman.UtilsR R R R t hexdigestRv t seed( Ri t dRP R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _seed s )c C s t i d d } x t | D]} } d | d | f GHt i } | o t i | d \ } } q t y t Wn t j
o n Xt i d q Wd S( Ni id s
Loop %d of %di (
Rv t randintt rangeR t forkt waitpidR R t KeyboardInterruptt _exit( RO t iRY t status( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _onetest* s
c C sC | p d St i d t i \ } } | d j o | | =n d S( Nii ( R R t WNOHANG( t kidsRY R ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _reap< s
c C s h } xj t | D]\ } t i } | o | | | <q t y t Wn t j
o n Xt i d q Wx | o t | qv Wd S( Ni ( R R R R R R R R ( t numtestsR R RY ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt _testD s
t __main__(! R R R) R RD Rv Ra Rr R R Ry RJ R. RU t NameErrorR R R t ExceptionR R! R" R# R$ R R R R R R t syst intt argv( ( ( sY /builddir/build/BUILDROOT/mailman-2.1.12-18.el6.i386//usr/lib/mailman/Mailman/LockFile.pyt <module>5 s> y (
y~or5J ={Eeu磝Qk ᯘG{?+]ן?wM3X^歌>{7پK>on\jy R g/=fOroNVv~Y+ NGuÝHWyw[eQʨSb> >}Gmx[o[<{Ϯ_qF vM IENDB`
