[gentoo-catalyst] [PATCH 2/2] lock: gut & replace with snakeoil

[Mike Frysinger]

The hardlink logic is unused, so start by deleting all of that.
If someone wants that (multiple builds on NFS?), we can look at
restoring it.
---
 catalyst/lock.py | 467 ++-----------------------------------------------------
 1 file changed, 15 insertions(+), 452 deletions(-)

diff --git a/catalyst/lock.py b/catalyst/lock.py
index 8095a82..39926dd 100644
--- a/catalyst/lock.py
+++ b/catalyst/lock.py
@@ -1,467 +1,30 @@
 
-
 import os
-import fcntl
-import errno
-import sys
-import time
-from catalyst.support import CatalystError, normpath
 
-def writemsg(mystr):
-	sys.stderr.write(mystr)
-	sys.stderr.flush()
+from snakeoil import fileutils
+from snakeoil import osutils
 
 
-class LockInUse(Exception):
-	def __init__(self, message):
-		if message:
-			#(type,value)=sys.exc_info()[:2]
-			#if value!=None:
-			    #print
-			    #kprint traceback.print_exc(file=sys.stdout)
-			print
-			print "!!! catalyst lock file in use: "+message
-			print
+LockInUse = osutils.LockException
 
 
 class LockDir(object):
-	locking_method=fcntl.flock
-	lock_dirs_in_use=[]
-	die_on_failed_lock=True
-
-	def __del__(self):
-		#print "Lock.__del__() 1"
-		self.clean_my_hardlocks()
-		#print "Lock.__del__() 2"
-		self.delete_lock_from_path_list()
-		#print "Lock.__del__() 3"
-		if self.islocked():
-			#print "Lock.__del__() 4"
-			self.fcntl_unlock()
-		#print "Lock.__del__() finnished"
-
-	def __init__(self,lockdir):
-		self.locked=False
-		self.myfd=None
-		self.set_gid(250)
-		self.locking_method=LockDir.locking_method
-		self.set_lockdir(lockdir)
-		self.set_lockfilename(".catalyst_lock")
-		self.set_lockfile()
-
-		if LockDir.lock_dirs_in_use.count(lockdir)>0:
-			raise "This directory already associated with a lock object"
-		else:
-			LockDir.lock_dirs_in_use.append(lockdir)
-
-		self.myhardlock = None
-		self.hardlock_paths={}
-
-	def delete_lock_from_path_list(self):
-		try:
-			LockDir.lock_dirs_in_use.remove(self.lockdir)
-		except ValueError:
-			pass
-
-	def islocked(self):
-		if self.locked:
-			return True
-		else:
-			return False
+	"""An object that creates locks inside dirs"""
 
-	def set_gid(self,gid):
-		if not self.islocked():
-#			if self.settings["DEBUG"]:
-#				print "setting gid to", gid
-			self.gid=gid
-
-	def set_lockdir(self,lockdir):
-		if not os.path.exists(lockdir):
-			os.makedirs(lockdir)
-		if os.path.isdir(lockdir):
-			if not self.islocked():
-				if lockdir[-1] == "/":
-					lockdir=lockdir[:-1]
-				self.lockdir=normpath(lockdir)
-#				if self.settings["DEBUG"]:
-#					print "setting lockdir to", self.lockdir
-		else:
-			raise "the lock object needs a path to a dir"
-
-	def set_lockfilename(self,lockfilename):
-		if not self.islocked():
-			self.lockfilename=lockfilename
-#			if self.settings["DEBUG"]:
-#				print "setting lockfilename to", self.lockfilename
-
-	def set_lockfile(self):
-		if not self.islocked():
-			self.lockfile=normpath(self.lockdir+'/'+self.lockfilename)
-#			if self.settings["DEBUG"]:
-#				print "setting lockfile to", self.lockfile
+	def __init__(self, lockdir):
+		self.gid = 250
+		self.lockfile = os.path.join(lockdir, '.catalyst_lock')
+		osutils.ensure_dirs(lockdir)
+		fileutils.touch(self.lockfile, mode=0o664)
+		os.chown(self.lockfile, -1, self.gid)
+		self.lock = osutils.FsLock(self.lockfile)
 
 	def read_lock(self):
-		if not self.locking_method == "HARDLOCK":
-			self.fcntl_lock("read")
-		else:
-			print "HARDLOCKING doesnt support shared-read locks"
-			print "using exclusive write locks"
-			self.hard_lock()
+		self.lock.acquire_read_lock()
 
 	def write_lock(self):
-		if not self.locking_method == "HARDLOCK":
-			self.fcntl_lock("write")
-		else:
-			self.hard_lock()
+		self.lock.acquire_write_lock()
 
 	def unlock(self):
-		if not self.locking_method == "HARDLOCK":
-			self.fcntl_unlock()
-		else:
-			self.hard_unlock()
-
-	def fcntl_lock(self,locktype):
-		if self.myfd==None:
-			if not os.path.exists(os.path.dirname(self.lockdir)):
-				raise CatalystError("DirectoryNotFound: %s"
-					% os.path.dirname(self.lockdir), print_traceback=True)
-			if not os.path.exists(self.lockfile):
-				old_mask=os.umask(000)
-				self.myfd = os.open(self.lockfile, os.O_CREAT|os.O_RDWR,0660)
-				try:
-					if os.stat(self.lockfile).st_gid != self.gid:
-						os.chown(self.lockfile,os.getuid(),self.gid)
-				except OSError, e:
-					if e[0] == 2: #XXX: No such file or directory
-						return self.fcntl_locking(locktype)
-					else:
-						writemsg("Cannot chown a lockfile. This could cause inconvenience later.\n")
-
-				os.umask(old_mask)
-			else:
-				self.myfd = os.open(self.lockfile, os.O_CREAT|os.O_RDWR,0660)
-
-		try:
-			if locktype == "read":
-				self.locking_method(self.myfd,fcntl.LOCK_SH|fcntl.LOCK_NB)
-			else:
-				self.locking_method(self.myfd,fcntl.LOCK_EX|fcntl.LOCK_NB)
-		except IOError, e:
-			if "errno" not in dir(e):
-				raise
-			if e.errno == errno.EAGAIN:
-				if not LockDir.die_on_failed_lock:
-					# Resource temp unavailable; eg, someone beat us to the lock.
-					writemsg("waiting for lock on %s\n" % self.lockfile)
-
-					# Try for the exclusive or shared lock again.
-					if locktype == "read":
-						self.locking_method(self.myfd,fcntl.LOCK_SH)
-					else:
-						self.locking_method(self.myfd,fcntl.LOCK_EX)
-				else:
-					raise LockInUse,self.lockfile
-			elif e.errno == errno.ENOLCK:
-				pass
-			else:
-				raise
-		if not os.path.exists(self.lockfile):
-			os.close(self.myfd)
-			self.myfd=None
-			#writemsg("lockfile recurse\n")
-			self.fcntl_lock(locktype)
-		else:
-			self.locked=True
-			#writemsg("Lockfile obtained\n")
-
-	def fcntl_unlock(self):
-		unlinkfile = 1
-		if not os.path.exists(self.lockfile):
-			print "lockfile does not exist '%s'" % self.lockfile
-			#print "fcntl_unlock() , self.myfd:", self.myfd, type(self.myfd)
-			if self.myfd != None:
-				#print "fcntl_unlock() trying to close it "
-				try:
-					os.close(self.myfd)
-					self.myfd=None
-				except Exception:
-					pass
-				return False
-
-			try:
-				if self.myfd == None:
-					self.myfd = os.open(self.lockfile, os.O_WRONLY,0660)
-					unlinkfile = 1
-					self.locking_method(self.myfd,fcntl.LOCK_UN)
-			except Exception, e:
-				#if self.myfd is not None:
-					#print "fcntl_unlock() trying to close", self.myfd
-					#os.close(self.myfd)
-					#self.myfd=None
-				#raise IOError, "Failed to unlock file '%s'\n%s" % (self.lockfile, str(e))
-				try:
-					# This sleep call was added to allow other processes that are
-					# waiting for a lock to be able to grab it before it is deleted.
-					# lockfile() already accounts for this situation, however, and
-					# the sleep here adds more time than is saved overall, so am
-					# commenting until it is proved necessary.
-					#time.sleep(0.0001)
-					if unlinkfile:
-						InUse=False
-						try:
-							self.locking_method(self.myfd,fcntl.LOCK_EX|fcntl.LOCK_NB)
-						except Exception:
-							print "Read lock may be in effect. skipping lockfile delete..."
-							InUse=True
-							# We won the lock, so there isn't competition for it.
-							# We can safely delete the file.
-							#writemsg("Got the lockfile...\n")
-							#writemsg("Unlinking...\n")
-							self.locking_method(self.myfd,fcntl.LOCK_UN)
-					if not InUse:
-						os.unlink(self.lockfile)
-						os.close(self.myfd)
-						self.myfd=None
-#						if self.settings["DEBUG"]:
-#							print "Unlinked lockfile..."
-				except Exception, e:
-					# We really don't care... Someone else has the lock.
-					# So it is their problem now.
-					print "Failed to get lock... someone took it."
-					print str(e)
-
-					# Why test lockfilename?  Because we may have been handed an
-					# fd originally, and the caller might not like having their
-					# open fd closed automatically on them.
-					#if type(lockfilename) == types.StringType:
-					#        os.close(myfd)
-		#print "fcntl_unlock() trying a last ditch close", self.myfd
-		if self.myfd != None:
-			os.close(self.myfd)
-			self.myfd=None
-			self.locked=False
-			time.sleep(.0001)
-
-	def hard_lock(self,max_wait=14400):
-		"""Does the NFS, hardlink shuffle to ensure locking on the disk.
-		We create a PRIVATE lockfile, that is just a placeholder on the disk.
-		Then we HARDLINK the real lockfile to that private file.
-		If our file can 2 references, then we have the lock. :)
-		Otherwise we lather, rise, and repeat.
-		We default to a 4 hour timeout.
-		"""
-
-		self.myhardlock = self.hardlock_name(self.lockdir)
-
-		start_time = time.time()
-		reported_waiting = False
-
-		while time.time() < (start_time + max_wait):
-			# We only need it to exist.
-			self.myfd = os.open(self.myhardlock, os.O_CREAT|os.O_RDWR,0660)
-			os.close(self.myfd)
-
-			self.add_hardlock_file_to_cleanup()
-			if not os.path.exists(self.myhardlock):
-				raise CatalystError("FileNotFound: Created lockfile is missing: "
-					"%(filename)s" % {"filename":self.myhardlock},
-					print_traceback=True)
-			try:
-				os.link(self.myhardlock, self.lockfile)
-			except Exception:
-#				if self.settings["DEBUG"]:
-#					print "lockfile(): Hardlink: Link failed."
-#					print "Exception: ",e
-				pass
-
-			if self.hardlink_is_mine(self.myhardlock, self.lockfile):
-				# We have the lock.
-				if reported_waiting:
-					print
-				return True
-
-			if reported_waiting:
-				writemsg(".")
-			else:
-				reported_waiting = True
-				print
-				print "Waiting on (hardlink) lockfile: (one '.' per 3 seconds)"
-				print "Lockfile: " + self.lockfile
-			time.sleep(3)
-
-		os.unlink(self.myhardlock)
-		return False
-
-	def hard_unlock(self):
-		try:
-			if os.path.exists(self.myhardlock):
-				os.unlink(self.myhardlock)
-			if os.path.exists(self.lockfile):
-				os.unlink(self.lockfile)
-		except Exception:
-			writemsg("Something strange happened to our hardlink locks.\n")
-
-	def add_hardlock_file_to_cleanup(self):
-		#mypath = self.normpath(path)
-		if os.path.isdir(self.lockdir) and os.path.isfile(self.myhardlock):
-			self.hardlock_paths[self.lockdir]=self.myhardlock
-
-	def remove_hardlock_file_from_cleanup(self):
-		if self.lockdir in self.hardlock_paths:
-			del self.hardlock_paths[self.lockdir]
-			print self.hardlock_paths
-
-	@staticmethod
-	def hardlock_name(path):
-		mypath=path+"/.hardlock-"+os.uname()[1]+"-"+str(os.getpid())
-		newpath = os.path.normpath(mypath)
-		if len(newpath) > 1:
-			if newpath[1] == "/":
-				newpath = "/"+newpath.lstrip("/")
-		return newpath
-
-	@staticmethod
-	def hardlink_is_mine(link, lock):
-		import stat
-		try:
-			myhls = os.stat(link)
-			mylfs = os.stat(lock)
-		except Exception:
-			myhls = None
-			mylfs = None
-
-		if myhls:
-			if myhls[stat.ST_NLINK] == 2:
-				return True
-		if mylfs:
-			if mylfs[stat.ST_INO] == myhls[stat.ST_INO]:
-				return True
-		return False
-
-	@staticmethod
-	def hardlink_active(lock):
-		if not os.path.exists(lock):
-			return False
-
-	def clean_my_hardlocks(self):
-		try:
-			for x in self.hardlock_paths.keys():
-				self.hardlock_cleanup(x)
-		except AttributeError:
-			pass
-
-	def hardlock_cleanup(self,path):
-		#mypid  = str(os.getpid())
-		myhost = os.uname()[1]
-		mydl = os.listdir(path)
-		results = []
-		mycount = 0
-
-		mylist = {}
-		for x in mydl:
-			filepath=path+"/"+x
-			if os.path.isfile(filepath):
-				parts = filepath.split(".hardlock-")
-			if len(parts) == 2:
-				filename = parts[0]
-				hostpid  = parts[1].split("-")
-				host  = "-".join(hostpid[:-1])
-				pid   = hostpid[-1]
-			if filename not in mylist:
-				mylist[filename] = {}
-
-			if host not in mylist[filename]:
-				mylist[filename][host] = []
-				mylist[filename][host].append(pid)
-				mycount += 1
-			else:
-				mylist[filename][host].append(pid)
-				mycount += 1
-
-
-		results.append("Found %(count)s locks" % {"count":mycount})
-		for x in mylist.keys():
-			if myhost in mylist[x]:
-				mylockname = self.hardlock_name(x)
-				if self.hardlink_is_mine(mylockname, self.lockfile) or \
-					not os.path.exists(self.lockfile):
-					for y in mylist[x].keys():
-						for z in mylist[x][y]:
-							filename = x+".hardlock-"+y+"-"+z
-							if filename == mylockname:
-								self.hard_unlock()
-								continue
-							try:
-								# We're sweeping through, unlinking everyone's locks.
-								os.unlink(filename)
-								results.append("Unlinked: " + filename)
-							except Exception:
-								pass
-					try:
-						os.unlink(x)
-						results.append("Unlinked: " + x)
-						os.unlink(mylockname)
-						results.append("Unlinked: " + mylockname)
-					except Exception:
-						pass
-				else:
-					try:
-						os.unlink(mylockname)
-						results.append("Unlinked: " + mylockname)
-					except Exception:
-						pass
-		return results
-
-
-if __name__ == "__main__":
-
-	def lock_work():
-		print
-		for i in range(1,6):
-			print i,time.time()
-			time.sleep(1)
-		print
-
-	print "Lock 5 starting"
-	Lock1=LockDir("/tmp/lock_path")
-	Lock1.write_lock()
-	print "Lock1 write lock"
-
-	lock_work()
-
-	Lock1.unlock()
-	print "Lock1 unlock"
-
-	Lock1.read_lock()
-	print "Lock1 read lock"
-
-	lock_work()
-
-	Lock1.unlock()
-	print "Lock1 unlock"
-
-	Lock1.read_lock()
-	print "Lock1 read lock"
-
-	Lock1.write_lock()
-	print "Lock1 write lock"
-
-	lock_work()
-
-	Lock1.unlock()
-	print "Lock1 unlock"
-
-	Lock1.read_lock()
-	print "Lock1 read lock"
-
-	lock_work()
-
-	Lock1.unlock()
-	print "Lock1 unlock"
-
-#Lock1.write_lock()
-#time.sleep(2)
-#Lock1.unlock()
-    ##Lock1.write_lock()
-    #time.sleep(2)
-    #Lock1.unlock()
+		# Releasing a write lock is the same as a read lock.
+		self.lock.release_write_lock()
-- 
2.5.2