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arbitrator.py
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arbitrator.py
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import logging
import logging.handlers
import Queue
import os
import stat
import threading
import time
import sys
import sqlite3
from UserList import UserList
import os.path
import signal
# Insert the dependencies directory (which includes copies of parts of Django
# and a full, yet extend, copy django-storages) at the beginning of sys.path,
# to prevent File Conveyor from using the code of a possible Django
# installation on this system.
FILE_CONVEYOR_PATH = os.path.abspath(os.path.dirname(__file__))
sys.path.insert(1, os.path.abspath(os.path.join(FILE_CONVEYOR_PATH, 'dependencies')))
from fileconveyor.settings import *
from fileconveyor.config import *
from fileconveyor.persistent_queue import *
from fileconveyor.persistent_list import *
from fileconveyor.fsmonitor import *
from fileconveyor.filter import *
from fileconveyor.processors.processor import *
from fileconveyor.transporters.transporter import *
from fileconveyor.daemon_thread_runner import *
# Copied from django.utils.functional
def curry(_curried_func, *args, **kwargs):
def _curried(*moreargs, **morekwargs):
return _curried_func(*(args+moreargs), **dict(kwargs, **morekwargs))
return _curried
class AdvancedQueue(UserList):
"""queue that supports peeking and jumping"""
def peek(self):
return self[0]
def jump(self, item):
self.insert(0, item)
def put(self, item):
self.append(item)
def get(self):
return self.pop(0)
def qsize(self):
return len(self)
# Define exceptions.
class ArbitratorError(Exception): pass
class ArbitratorInitError(ArbitratorError): pass
class ConfigError(ArbitratorInitError): pass
class ProcessorAvailabilityTestError(ArbitratorInitError): pass
class TransporterAvailabilityTestError(ArbitratorInitError): pass
class ServerConnectionTestError(ArbitratorInitError): pass
class FSMonitorInitError(ArbitratorInitError): pass
class Arbitrator(threading.Thread):
"""docstring for arbitrator"""
DELETE_OLD_FILE = 0xFFFFFFFF
PROCESSED_FOR_ANY_SERVER = None
def __init__(self, configfile="config.xml", restart=False):
threading.Thread.__init__(self, name="ArbitratorThread")
self.lock = threading.Lock()
self.die = False
self.processorchains_running = 0
self.transporters_running = 0
self.last_retry = 0
# Set up logger.
self.logger = logging.getLogger("Arbitrator")
self.logger.setLevel(FILE_LOGGER_LEVEL)
# Handlers.
fileHandler = logging.handlers.RotatingFileHandler(LOG_FILE, maxBytes=5242880, backupCount=5)
consoleHandler = logging.StreamHandler()
consoleHandler.setLevel(CONSOLE_LOGGER_LEVEL)
# Formatters.
formatter = logging.Formatter("%(asctime)s - %(name)-25s - %(levelname)-8s - %(message)s")
fileHandler.setFormatter(formatter)
consoleHandler.setFormatter(formatter)
self.logger.addHandler(fileHandler)
self.logger.addHandler(consoleHandler)
if restart:
self.logger.warning("File Conveyor has restarted itself!")
self.logger.warning("File Conveyor is initializing.")
# Load config file.
self.configfile = configfile
self.logger.info("Loading config file.")
self.config = Config("Arbitrator")
self.config_errors = self.config.load(self.configfile)
self.logger.warning("Loaded config file.")
if self.config_errors > 0:
self.logger.error("Cannot continue, please fix the errors in the config file first.")
raise ConfigError("Consult the log file for details.")
# TRICKY: set the "symlinkWithin" setting for "symlink_or_copy"
# transporters First calculate the value for the "symlinkWithin"
# setting.
source_paths = []
for source in self.config.sources.values():
source_paths.append(source["scan_path"])
symlinkWithin = ":".join(source_paths)
# Then set it for every server that uses this transporter.
for name in self.config.servers.keys():
if self.config.servers[name]["transporter"] == "symlink_or_copy":
self.config.servers[name]["settings"]["symlinkWithin"] = symlinkWithin
# Verify that all referenced processors are available.
processors_not_found = 0
for source in self.config.rules.keys():
for rule in self.config.rules[source]:
if not rule["processorChain"] is None:
for processor in rule["processorChain"]:
(modulename, classname) = processor.rsplit(".", 1)
try:
module = __import__(modulename, globals(), locals(), [classname])
processor_class = getattr(module, classname)
except ImportError:
self.logger.error("The Processor module '%s' could not be found." % (modulename))
processors_not_found += 1
except AttributeError:
self.logger.error("The Processor module '%s' was found, but its Processor class '%s' could not be found." % (modulename, classname))
processors_not_found += 1
if processors_not_found > 0:
raise ProcessorAvailabilityTestError("Consult the log file for details")
# Verify that all referenced transporters are available.
transporters_not_found = 0
for server in self.config.servers.keys():
transporter_name = self.config.servers[server]["transporter"]
modulename = transporter_name
try:
module = __import__(modulename, globals(), locals(), ["TRANSPORTER_CLASS"], -1)
classname = module.TRANSPORTER_CLASS
module = __import__(modulename, globals(), locals(), [classname])
transporter_class = getattr(module, classname)
except ImportError:
self.logger.error("The Transporter module '%s' could not be found." % (modulename))
transporters_not_found += 1
except AttributeError:
self.logger.error("The Transporter module '%s' was found, but its Transporter class '%s' could not be found." % (modulename, classname))
transporters_not_found += 1
if transporters_not_found > 0:
raise TransporterAvailabilityTestError("Consult the log file for details")
# Verify that each of the servers works.
successful_server_connections = 0
for server in self.config.servers.keys():
transporter = self.__create_transporter(server)
if transporter:
successful_server_connections += 1
del transporter
failed_server_connections = len(self.config.servers) - successful_server_connections
if failed_server_connections > 0:
self.logger.error("Server connection tests: could not connect with %d servers." % (failed_server_connections))
raise ServerConnectionTestError("Consult the log file for details.")
else:
self.logger.warning("Server connection tests succesful!")
def __setup(self):
self.processor_chain_factory = ProcessorChainFactory("Arbitrator", WORKING_DIR)
# Create transporter (cfr. worker thread) pools for each server.
# Create one initial transporter per pool, possible other transporters
# will be created on-demand.
self.transporters = {}
for server in self.config.servers.keys():
self.transporters[server] = []
self.logger.warning("Setup: created transporter pool for the '%s' server." % (server))
# Collecting all necessary metadata for each rule.
self.rules = []
for source in self.config.sources.values():
# Create a function to prepend the source's scan path to another
# path.
prepend_scan_path = lambda path: os.path.join(source["scan_path"], path)
if self.config.rules.has_key(source["name"]):
for rule in self.config.rules[source["name"]]:
if rule["filterConditions"] is None:
filter = None
else:
if rule["filterConditions"].has_key("paths"):
# Prepend the source's scan path (effectively the
# "root path") for a rule to each of the paths in
# the "paths" condition in the filter.
paths = map(prepend_scan_path, rule["filterConditions"]["paths"].split(":"))
rule["filterConditions"]["paths"] = ":".join(paths)
filter = Filter(rule["filterConditions"])
# Store all the rule metadata.
self.rules.append({
"source" : source["name"],
"label" : rule["label"],
"filter" : filter,
"processorChain" : rule["processorChain"],
"destinations" : rule["destinations"],
})
self.logger.info("Setup: collected all metadata for rule '%s' (source: '%s')." % (rule["label"], source["name"]))
# Initialize the the persistent 'pipeline' queue, the persistent
# 'files in pipeline' and 'failed files' lists and the 'discover',
# 'filter', 'process', 'transport', 'db' and 'retry' queues. Finally,
# initialize the 'remaining transporters' dictionary of lists.
self.pipeline_queue = PersistentQueue("pipeline_queue", PERSISTENT_DATA_DB)
self.logger.warning("Setup: initialized 'pipeline' persistent queue, contains %d items." % (self.pipeline_queue.qsize()))
self.files_in_pipeline = PersistentList("pipeline_list", PERSISTENT_DATA_DB)
num_files_in_pipeline = len(self.files_in_pipeline)
self.logger.warning("Setup: initialized 'files_in_pipeline' persistent list, contains %d items." % (num_files_in_pipeline))
self.failed_files = PersistentList("failed_files_list", PERSISTENT_DATA_DB)
num_failed_files = len(self.failed_files)
self.logger.warning("Setup: initialized 'failed_files' persistent list, contains %d items." % (num_failed_files))
self.discover_queue = Queue.Queue()
self.filter_queue = Queue.Queue()
self.process_queue = Queue.Queue()
self.transport_queue = {}
for server in self.config.servers.keys():
self.transport_queue[server] = AdvancedQueue()
self.db_queue = Queue.Queue()
self.retry_queue = Queue.Queue()
self.remaining_transporters = {}
# Move files from the 'files_in_pipeline' persistent list to the
# pipeline queue. This is what prevents files from being dropped from
# the pipeline!
pipelined_items = []
for item in self.files_in_pipeline:
pipelined_items.append(item)
self.pipeline_queue.put(item)
for item in pipelined_items:
self.files_in_pipeline.remove(item)
self.logger.warning("Setup: moved %d items from the 'files_in_pipeline' persistent list into the 'pipeline' persistent queue." % (num_files_in_pipeline))
# Move files from the 'failed_files' persistent list to the
# pipeline queue. This is what ensures that even problematic files
# are not forgotten!
self.__allow_retry()
# Create connection to synced files DB.
self.dbcon = sqlite3.connect(SYNCED_FILES_DB)
self.dbcon.text_factory = unicode # This is the default, but we set it explicitly, just to be sure.
self.dbcur = self.dbcon.cursor()
self.dbcur.execute("CREATE TABLE IF NOT EXISTS synced_files(input_file text, transported_file_basename text, url text, server text)")
self.dbcur.execute("CREATE UNIQUE INDEX IF NOT EXISTS file_unique_per_server ON synced_files (input_file, server)")
self.dbcon.commit()
self.dbcur.execute("SELECT COUNT(input_file) FROM synced_files")
num_synced_files = self.dbcur.fetchone()[0]
self.logger.warning("Setup: connected to the synced files DB. Contains metadata for %d previously synced files." % (num_synced_files))
# Initialize the FSMonitor.
fsmonitor_class = get_fsmonitor()
self.fsmonitor = fsmonitor_class(self.fsmonitor_callback, True, True, self.config.ignored_dirs.split(":"), "fsmonitor.db", "Arbitrator")
self.logger.warning("Setup: initialized FSMonitor.")
# Monitor all sources' scan paths.
for source in self.config.sources.values():
self.logger.info("Setup: monitoring '%s' (%s)." % (source["scan_path"], source["name"]))
self.fsmonitor.add_dir(source["scan_path"], FSMonitor.CREATED | FSMonitor.MODIFIED | FSMonitor.DELETED)
def run(self):
if self.config_errors > 0:
return
# Do all setup within the run() method to ensure all thread-bound
# objects are created in the right thread.
self.__setup()
self.fsmonitor.start()
self.clean_up_working_dir()
self.logger.warning("Fully up and running now.")
try:
while not self.die:
self.__process_discover_queue()
self.__process_pipeline_queue()
self.__process_filter_queue()
self.__process_process_queue()
self.__process_transport_queues()
self.__process_db_queue()
self.__process_retry_queue()
self.__allow_retry()
# Processing the queues 5 times per second is more than sufficient
# because files are modified, processed and transported much
# slower than that.
time.sleep(0.2)
except Exception, e:
self.logger.exception("Unhandled exception of type '%s' detected, arguments: '%s'." % (e.__class__.__name__, e.args))
self.logger.error("Stopping File Conveyor to ensure the application is stopped in a clean manner.")
os.kill(os.getpid(), signal.SIGTERM)
self.logger.warning("Stopping.")
# Stop the FSMonitor and wait for its thread to end.
self.fsmonitor.stop()
self.fsmonitor.join()
self.logger.warning("Stopped FSMonitor.")
# Sync the discover queue one more time: now that the FSMonitor has
# been stopped, no more new discoveries will be made and we can safely
# sync the last batch of discovered files.
self.__process_discover_queue()
self.logger.info("Final sync of discover queue to pipeline queue made.")
# Stop the transporters and wait for their threads to end.
for server in self.transporters.keys():
if len(self.transporters[server]):
for transporter in self.transporters[server]:
transporter.stop()
transporter.join()
self.logger.warning("Stopped transporters for the '%s' server." % (server))
# Log information about the persistent data.
self.logger.warning("'pipeline' persistent queue contains %d items." % (self.pipeline_queue.qsize()))
self.logger.warning("'files_in_pipeline' persistent list contains %d items." % (len(self.files_in_pipeline)))
self.logger.warning("'failed_files' persistent list contains %d items." % (len(self.failed_files)))
# Log information about the synced files DB.
self.dbcur.execute("SELECT COUNT(input_file) FROM synced_files")
num_synced_files = self.dbcur.fetchone()[0]
self.logger.warning("synced files DB contains metadata for %d synced files." % (num_synced_files))
# Clean up working directory.
self.clean_up_working_dir()
# Final message, then remove all loggers.
self.logger.warning("File Conveyor has shut down.")
while len(self.logger.handlers):
self.logger.removeHandler(self.logger.handlers[0])
logging.shutdown()
def __process_discover_queue(self):
# No QUEUE_PROCESS_BATCH_SIZE limitation here because the data must
# be moved to a persistent datastructure ASAP.
self.lock.acquire()
while self.discover_queue.qsize() > 0:
# Discover queue -> pipeline queue.
(input_file, event) = self.discover_queue.get()
item = self.pipeline_queue.get_item_for_key(key=input_file)
# If the file does not yet exist in the pipeline queue, put() it.
if item is None:
self.pipeline_queue.put(item=(input_file, event), key=input_file)
# Otherwise, merge the events, to prevent unnecessary actions.
# See https://github.com/wimleers/fileconveyor/issues/68.
else:
old_event = item[1]
merged_event = FSMonitor.MERGE_EVENTS[old_event][event]
if merged_event is not None:
self.pipeline_queue.update(item=(input_file, merged_event), key=input_file)
self.logger.info("Pipeline queue: merged events for '%s': %s + %s = %s." % (input_file, FSMonitor.EVENTNAMES[old_event], FSMonitor.EVENTNAMES[event], FSMonitor.EVENTNAMES[merged_event]))
# The events being merged cancel each other out, thus remove
# the file from the pipeline queue.
else:
self.pipeline_queue.remove_item_for_key(key=input_file)
self.logger.info("Pipeline queue: merged events for '%s': %s + %s cancel each other out, thus removed this file." % (input_file, FSMonitor.EVENTNAMES[old_event], FSMonitor.EVENTNAMES[event], FSMonitor.EVENTNAMES[merged_event]))
self.logger.info("Discover queue -> pipeline queue: '%s'." % (input_file))
self.lock.release()
def __process_pipeline_queue(self):
processed = 0
# As soon as there's room in the pipeline, move the file from the
# pipeline queue into the pipeline.
while processed < QUEUE_PROCESS_BATCH_SIZE and self.pipeline_queue.qsize() > 0 and len(self.files_in_pipeline) < MAX_FILES_IN_PIPELINE:
self.lock.acquire()
# Peek the first item from the pipeline queue and store it in the
# persistent 'files_in_pipeline' list. By peeking instead of
# getting, ththe data can never get lost.
self.files_in_pipeline.append(self.pipeline_queue.peek())
# Pipeline queue -> filter queue.
(input_file, event) = self.pipeline_queue.get()
self.filter_queue.put((input_file, event))
self.lock.release()
self.logger.info("Pipeline queue -> filter queue: '%s'." % (input_file))
processed += 1
def __process_filter_queue(self):
processed = 0
while processed < QUEUE_PROCESS_BATCH_SIZE and self.filter_queue.qsize() > 0:
# Filter queue -> process/transport queue.
self.lock.acquire()
(input_file, event) = self.filter_queue.get()
self.lock.release()
# The file may have already been deleted, e.g. when the file was
# moved from the pipeline list into the pipeline queue after the
# application was interrupted. When that's the case, drop the
# file from the pipeline.
touched = event == FSMonitor.CREATED or event == FSMonitor.MODIFIED
if touched and not os.path.exists(input_file):
self.lock.acquire()
self.files_in_pipeline.remove((input_file, event))
self.lock.release()
self.logger.info("Filtering: dropped '%s' because it no longer exists." % (input_file))
continue
# Find all rules that apply to the detected file event.
match_found = False
file_is_deleted = event == FSMonitor.DELETED
for rule in self.rules:
# Try to find a rule that matches the file.
if input_file.startswith(self.config.sources[rule["source"]]["scan_path"]) and \
(rule["filter"] is None
or
rule["filter"].matches(input_file, file_is_deleted=file_is_deleted)):
match_found = True
self.logger.info("Filtering: '%s' matches the '%s' rule for the '%s' source!" % (input_file, rule["label"], rule["source"]))
# If the file was deleted, also delete the file on all
# servers.
self.lock.acquire()
servers = rule["destinations"].keys()
self.remaining_transporters[input_file + str(event) + repr(rule)] = servers
if event == FSMonitor.DELETED:
# Look up the transported file's base name. This might
# be different from the input file's base name due to
# processing.
self.dbcur.execute("SELECT transported_file_basename FROM synced_files WHERE input_file=?", (input_file, ))
result = self.dbcur.fetchone()
if event == FSMonitor.DELETED and not result is None:
transport_file_basename = result[0]
# The output file that should be transported doesn't
# exist anymore, because it was deleted. So we create
# a filename that is the same as the original, except
# with the different base name.
fake_output_file = os.path.join(os.path.dirname(input_file), transport_file_basename)
# Queue the transport (deletion).
for server in servers:
self.transport_queue[server].put((input_file, event, rule, Arbitrator.PROCESSED_FOR_ANY_SERVER, fake_output_file))
self.logger.info("Filtering: queued transporter to server '%s' for file '%s' to delete it ('%s' rule)." % (server, input_file, rule["label"]))
else:
# If a processor chain is configured, queue the file
# to be processed. Otherwise, immediately queue the
# file to be transported
if not rule["processorChain"] is None:
# Check if there is at least one processor that
# will create output that is different per server.
per_server = False
for processor_classname in rule["processorChain"]:
# Get a reference to this processor class.
(modulename, classname) = processor_classname.rsplit(".", 1)
module = __import__(modulename, globals(), locals(), [classname])
processor_class = getattr(module, classname)
if getattr(processor_class, 'different_per_server', False) == True:
# This processor would create different
# output per server, but will it also
# process this file?
if processor_class.would_process_input_file(input_file):
per_server = True
break
if per_server:
for server in servers:
# If the event for the file is creation
# and the file has been synced to this
# server already, don't process it again
# (which will lead to it being resynced
# and reinserted into the database, which
# will cause a IntegrityError).
if event == FSMonitor.CREATED:
self.dbcur.execute("SELECT COUNT(*) FROM synced_files WHERE input_file=? AND server=?", (input_file, server))
file_is_synced = self.dbcur.fetchone()[0] == 1
if event == FSMonitor.CREATED and file_is_synced:
self.logger.info("Filtering: not processing '%s' for server '%s', because it has been synced already to this server (rule: '%s')." % (input_file, server, rule["label"]))
self.remaining_transporters[input_file + str(event) + repr(rule)].remove(server)
else:
self.process_queue.put((input_file, event, rule, server))
self.logger.info("Filter queue -> process queue: '%s' for server '%s' (rule: '%s')." % (input_file, server, rule["label"]))
else:
self.process_queue.put((input_file, event, rule, Arbitrator.PROCESSED_FOR_ANY_SERVER))
self.logger.info("Filter queue -> process queue: '%s' (rule: '%s')." % (input_file, rule["label"]))
else:
output_file = input_file
for server in servers:
self.transport_queue[server].put((input_file, event, rule, Arbitrator.PROCESSED_FOR_ANY_SERVER, output_file))
self.logger.info("Filter queue -> transport queue: '%s' (rule: '%s')." % (input_file, rule["label"]))
self.lock.release()
# Log the lack of matches.
if not match_found:
self.lock.acquire()
self.files_in_pipeline.remove((input_file, event))
self.lock.release()
self.logger.info("Filter queue: dropped '%s' because it doesn't match any rules." % (input_file))
processed += 1
def __process_process_queue(self):
processed = 0
while processed< QUEUE_PROCESS_BATCH_SIZE and self.process_queue.qsize() > 0 and self.processorchains_running < MAX_SIMULTANEOUS_PROCESSORCHAINS:
# Process queue -> ProcessorChain -> processor_chain_callback -> transport/db queue.
self.lock.acquire()
(input_file, event, rule, processed_for_server) = self.process_queue.get()
self.lock.release()
# Create curried callbacks so we can pass additional data to the
# processor chain callback without passing it to the processor
# chain itself (which cannot handle sending additional data to its
# callback functions).
curried_callback = curry(self.processor_chain_callback,
event=event,
rule=rule,
processed_for_server=processed_for_server
)
curried_error_callback = curry(self.processor_chain_error_callback,
event=event
)
# Start the processor chain.
document_root = None
base_path = None
if self.config.sources[rule["source"]].has_key("document_root"):
document_root = self.config.sources[rule["source"]]["document_root"]
if self.config.sources[rule["source"]].has_key("base_path"):
base_path = self.config.sources[rule["source"]]["base_path"]
processor_chain = self.processor_chain_factory.make_chain_for(input_file,
rule["processorChain"],
document_root,
base_path,
processed_for_server,
curried_callback,
curried_error_callback
)
processor_chain.start()
self.processorchains_running += 1
# Log.
processor_chain_string = "->".join(rule["processorChain"])
if processed_for_server == Arbitrator.PROCESSED_FOR_ANY_SERVER:
self.logger.debug("Process queue: started the '%s' processor chain for the file '%s'." % (processor_chain_string, input_file))
else:
self.logger.debug("Process queue: started the '%s' processor chain for the file '%s' for the server '%s'." % (processor_chain_string, input_file, processed_for_server))
processed += 1
def __process_transport_queues(self):
for server in self.config.servers.keys():
processed = 0
while processed < QUEUE_PROCESS_BATCH_SIZE and self.transport_queue[server].qsize() > 0:
# Peek at the first item from the queue. We cannot get the
# item from the queue, because there may be no transporter
# available, in which case the file should remain queued.
self.lock.acquire()
(input_file, event, rule, processed_for_server, output_file) = self.transport_queue[server].peek()
self.lock.release()
# Derive the action from the event.
if event == FSMonitor.DELETED:
action = Transporter.DELETE
elif event == FSMonitor.CREATED or event == FSMonitor.MODIFIED:
action = Transporter.ADD_MODIFY
elif event == Arbitrator.DELETE_OLD_FILE:
# TRICKY: if the event is neither of DELETED, CREATED, nor
# MODIFIED, which everywhere else in the arbitrator it
# should be, then it must be the special case of a file
# that has been modified and already transported, but the
# old file must still be deleted. Hence we map this event
# to the Transporter's DELETE action.
action = Transporter.DELETE
else:
raise Exception("Non-existing event set.")
# Get the additional settings from the rule.
dst_parent_path = ""
if rule["destinations"][server].has_key("path"):
dst_parent_path = rule["destinations"][server]["path"]
(id, place_in_queue, transporter) = self.__get_transporter(server)
if not transporter is None:
# A transporter is available!
# Transport queue -> Transporter -> transporter_callback -> db queue.
self.lock.acquire()
(input_file, event, rule, processed_for_server, output_file) = self.transport_queue[server].get()
self.lock.release()
# Create curried callbacks so we can pass additional data
# to the transporter callback without passing it to the
# transporter itself (which cannot handle sending
# additional data to its callback functions).
curried_callback = curry(self.transporter_callback,
input_file=input_file,
event=event,
rule=rule,
processed_for_server=processed_for_server,
server=server
)
curried_error_callback = curry(self.transporter_error_callback,
input_file=input_file,
event=event
)
# Calculate src and dst for the file.
# - The src is the output file of the processor.
# - The dst is the output file, but its source parent path
# (the working directory or its source root path) must
# be stripped and the destination parent path must be
# prepended.
# e.g.:
# - src -> dst
# - /htdocs/mysite/dir/the_file -> dir/the_file
# - /tmp/dir/the_file -> dir/the_file
src = output_file
relative_paths = [WORKING_DIR, self.config.sources[rule["source"]]["scan_path"]]
dst = self.__calculate_transporter_dst(output_file, dst_parent_path, relative_paths)
# Start the transport.
transporter.sync_file(src, dst, action, curried_callback, curried_error_callback)
self.logger.info("Transport queue: '%s' to transfer to server '%s' with transporter #%d (of %d), place %d in the queue." % (output_file, server, id + 1, len(self.transporters[server]), place_in_queue))
else:
self.logger.debug("Transporting: no more transporters are available for server '%s'." % (server))
break
processed += 1
def __process_db_queue(self):
processed = 0
while processed < QUEUE_PROCESS_BATCH_SIZE and self.db_queue.qsize() > 0:
# DB queue -> database.
self.lock.acquire()
(input_file, event, rule, processed_for_server, output_file, transported_file, url, server) = self.db_queue.get()
self.lock.release()
# Commit the result to the database.
remove_server_from_remaining_transporters = True
transported_file_basename = os.path.basename(output_file)
if event == FSMonitor.CREATED:
try:
self.dbcur.execute("INSERT INTO synced_files VALUES(?, ?, ?, ?)", (input_file, transported_file_basename, url, server))
self.dbcon.commit()
except sqlite3.IntegrityError, e:
self.logger.critical("Database integrity error: %s. Duplicate key: input_file = '%s', server = '%s'." % (e, input_file, server))
elif event == FSMonitor.MODIFIED:
self.dbcur.execute("SELECT COUNT(*) FROM synced_files WHERE input_file=? AND server=?", (input_file, server))
if self.dbcur.fetchone()[0] > 0:
# Look up the transported file's base name. This
# might be different from the input file's base
# name due to processing.
self.dbcur.execute("SELECT transported_file_basename FROM synced_files WHERE input_file=? AND server=?", (input_file, server))
old_transport_file_basename = self.dbcur.fetchone()[0]
# Update the transported_file_basename and url fields for
# the input_file that has been transported.
self.dbcur.execute("UPDATE synced_files SET transported_file_basename=?, url=? WHERE input_file=? AND server=?", (transported_file_basename, url, input_file, server))
self.dbcon.commit()
# If a file was modified that had already been synced
# before and now has a different basename for the
# transported file than before, we first have to delete
# the old transported file before all work is done.
# remove_server_from_remaining_transporters is set to
# False for this case.
if old_transport_file_basename != transported_file_basename:
remove_server_from_remaining_transporters = False
# The output file that should be transported only
# exists on the server. So we create a filename that
# is the same as the old transported file.
fake_output_file = os.path.join(os.path.dirname(input_file), old_transport_file_basename)
# Change the event to Arbitrator.DELETE_OLD_FILE,
# which __process_transport_queues() will recognize
# and perform a deletion for. After the transporter
# callback gets called, this pseudo-event will end up
# in __process_db_queue() (this method) once again and
# will change the event back the original,
# FSMonitor.MODIFIED, so we can remove it from the
# 'files_in_pipeline' persistent list.
pseudo_event = Arbitrator.DELETE_OLD_FILE
# Queue the transport (deletion), but jump the queue!.
self.transport_queue[server].jump((input_file, pseudo_event, rule, Arbitrator.PROCESSED_FOR_ANY_SERVER, fake_output_file))
self.logger.info("DB queue -> transport queue (jumped): '%s' to delete its old transported file '%s' on server '%s'." % (input_file, old_transport_file_basename, server))
else:
self.dbcur.execute("INSERT INTO synced_files VALUES(?, ?, ?, ?)", (input_file, transported_file_basename, url, server))
self.dbcon.commit()
elif event == FSMonitor.DELETED:
self.dbcur.execute("DELETE FROM synced_files WHERE input_file=? AND server=?", (input_file, server))
self.dbcon.commit()
elif event == Arbitrator.DELETE_OLD_FILE:
# This is a pseudo-event. See the comments for the
# FSMonitor.MODIFIED-branch for details.
event = FSMonitor.MODIFIED
else:
raise Exception("Non-existing event set.")
self.logger.debug("DB queue -> 'synced files' DB: '%s' (URL: '%s')." % (input_file, url))
key = input_file + str(event) + repr(rule)
# Remove this server from the 'remaining transporters' list for
# this input file/event/rule.
if remove_server_from_remaining_transporters:
# TRICKY: This is wrapped in a try/except block because it's
# possible that for example multiple "CREATED" and "DELETED"
# events on the same file have been logged, which are then
# potentially being synced at the same time. It is then
# possible that one instance of the file syncing process has
# already synced to one server and another instance has done
# the same, but later. Because the key here is not universally
# unique, but merely on the input file, event and rule,
# collisions are possible.
# Yes, this is a design flaw in the current version. It cannot
# cause any problems though, merely duplicate work in highly
# active environments.
try:
self.remaining_transporters[key].remove(server)
except ValueError, e:
pass
# Only remove the file from the pipeline if no transporters are
# remaining.
if len(self.remaining_transporters[key]) == 0:
# Delete the output file, but only if it's different from the
# input file.
touched = event == FSMonitor.CREATED or event == FSMonitor.MODIFIED
if touched and not input_file == output_file and os.path.exists(output_file):
os.remove(output_file)
# The file went all the way through the pipeline, so now it's safe
# to remove it from the persistent 'files_in_pipeline' list.
self.lock.acquire()
self.files_in_pipeline.remove((input_file, event))
self.lock.release()
self.logger.warning("Synced: '%s' (%s)." % (input_file, FSMonitor.EVENTNAMES[event]))
processed += 1
def __process_retry_queue(self):
processed = 0
while processed < QUEUE_PROCESS_BATCH_SIZE and self.retry_queue.qsize() > 0:
# Retry queue -> failed files list.
# And remove from files in pipeline.
self.lock.acquire()
(input_file, event) = self.retry_queue.get()
# It's possible that the file is already in the failed_files
# persistent list or in the pipeline queue (if it is being retried
# already) if it is being processed per server and now a second
# (or third or ...) processor is requesting a retry.
if (input_file, event) not in self.failed_files and (input_file, event) not in self.pipeline_queue:
self.failed_files.append((input_file, event))
already_in_failed_files = False
else:
already_in_failed_files = True
self.files_in_pipeline.remove((input_file, event))
self.lock.release()
# Log.
if not already_in_failed_files:
self.logger.warning("Retry queue -> 'failed_files' persistent list: '%s'. Retrying later." % (input_file))
else:
self.logger.warning("Retry queue -> 'failed_files' persistent list: '%s'. File already being retried later." % (input_file))
processed += 1
def __allow_retry(self):
num_failed_files = len(self.failed_files)
should_retry = self.last_retry + RETRY_INTERVAL < time.time()
pipeline_queue_almost_empty = self.pipeline_queue < MAX_FILES_IN_PIPELINE
if num_failed_files > 0 and (should_retry or pipeline_queue_almost_empty):
failed_items = []
processed = 0
while processed < QUEUE_PROCESS_BATCH_SIZE and processed < len(self.failed_files):
item = self.failed_files[processed]
failed_items.append(item)
self.pipeline_queue.put(item)
processed += 1
for item in failed_items:
self.failed_files.remove(item)
self.last_retry = time.time()
# Log.
self.logger.warning("Moved %d items from the 'failed_files' persistent list into the 'pipeline' persistent queue." % (processed))
def __get_transporter(self, server):
"""get a transporter; if one is ready for new work, use that one,
otherwise try to start a new transporter"""
# Try to find a running transporter that is ready for new work.
for id in range(0, len(self.transporters[server])):
transporter = self.transporters[server][id]
# Don't put more than MAX_TRANSPORTER_QUEUE_SIZE files in each
# transporter's queue.
if transporter.qsize() <= MAX_TRANSPORTER_QUEUE_SIZE:
place_in_queue = transporter.qsize() + 1
return (id, place_in_queue, transporter)
# Don't run more than the allowed number of simultaneous transporters.
if not self.transporters_running < MAX_SIMULTANEOUS_TRANSPORTERS:
return (None, None, None)
# Don't run more transporters for each server than its "maxConnections"
# setting allows.
num_connections = len(self.transporters[server])
max_connections = self.config.servers[server]["maxConnections"]
if max_connections == 0 or num_connections < max_connections:
transporter = self.__create_transporter(server)
id = len(self.transporters[server]) - 1
# If a transporter was succesfully created, add it to the pool.
if transporter:
self.transporters[server].append(transporter)
transporter.start()
self.transporters_running += 1
# Since this transporter was just created, it's obvious that we're
# first in line.
place_in_queue = 1
return (id, 1, transporter)
return (None, None, None)
def __create_transporter(self, server):
"""create a transporter for the given server"""
transporter_name = self.config.servers[server]["transporter"]
settings = self.config.servers[server]["settings"]
# Determine which class to import.
transporter_modulename = transporter_name
_temp = __import__(transporter_modulename, globals(), locals(), ["TRANSPORTER_CLASS"], -1)
transporter_classname = _temp.TRANSPORTER_CLASS
# Get a reference to that class.
module = __import__(transporter_modulename, globals(), locals(), [transporter_classname])
transporter_class = getattr(module, transporter_classname)
# Attempt to create an instance of the transporter.
try:
transporter = transporter_class(settings, self.transporter_callback, self.transporter_error_callback, "Arbitrator")
except ConnectionError, e:
self.logger.error("Could not start transporter '%s'. Error: '%s'." % (transporter_name, e))
return False
else:
self.logger.warning("Created '%s' transporter for the '%s' server." % (transporter_name, server))
return transporter
def __calculate_transporter_dst(self, src, parent_path=None, relative_paths=[]):
dst = src
# Strip off any relative paths.
for relative_path in relative_paths:
if dst.startswith(relative_path):
dst = dst[len(relative_path):]
# Ensure no absolute path is returned, which would make os.path.join()
# fail.
dst = dst.lstrip(os.sep)
# Prepend any possible parent path.
if not parent_path is None:
dst = os.path.join(parent_path, dst)
return dst
def fsmonitor_callback(self, monitored_path, event_path, event, discovered_through):
# Map FSMonitor's variable names to ours.
input_file = event_path
if CALLBACKS_CONSOLE_OUTPUT:
print """FSMONITOR CALLBACK FIRED:
input_file='%s'
event=%d"
discovered_through=%s""" % (input_file, event, discovered_through)
# The file may have already been deleted!
deleted = event == FSMonitor.DELETED
touched = event == FSMonitor.CREATED or event == FSMonitor.MODIFIED
if deleted or (touched and os.path.exists(event_path)):
# Ignore directories (we cannot test deleted files to see if they
# are directories, because they obviously don't exist anymore).
if touched:
try:
if stat.S_ISDIR(os.stat(event_path)[stat.ST_MODE]):
return
except OSError, e:
# The file (or directory, we can't be sure at this point)
# does no longer exist (despite the os.path.exists() check
# above!): it must *just* have been deleted.
if e.errno == os.errno.ENOENT:
return
# Map FSMonitor's variable names to ours.
input_file = event_path
# Add to discover queue.
self.lock.acquire()
self.discover_queue.put((input_file, event))
self.lock.release()
def processor_chain_callback(self, input_file, output_file, event, rule, processed_for_server):
if CALLBACKS_CONSOLE_OUTPUT:
print """PROCESSOR CHAIN CALLBACK FIRED:
input_file='%s'
(curried): event=%d
(curried): rule='%s'
(curried): processed_for_server='%s'
output_file='%s'""" % (input_file, event, rule["label"], processed_for_server, output_file)
# Decrease number of running processor chains.
self.lock.acquire()
self.processorchains_running -= 1
self.lock.release()
# If the input file was not processed for a specific server, then it
# should be synced to all destinations. Else, it should only be synced
# to the server it was processed for.
if processed_for_server == Arbitrator.PROCESSED_FOR_ANY_SERVER:
for server in rule["destinations"].keys():
# Add to transport queue.
self.lock.acquire()
self.transport_queue[server].put((input_file, event, rule, processed_for_server, output_file))
self.lock.release()
self.logger.info("Process queue -> transport queue: '%s'." % (input_file))
else:
# Add to transport queue.
self.lock.acquire()
self.transport_queue[processed_for_server].put((input_file, event, rule, processed_for_server, output_file))
self.lock.release()
self.logger.info("Process queue -> transport queue: '%s' (processed for server '%s')." % (input_file, processed_for_server))
def processor_chain_error_callback(self, input_file, event):
if CALLBACKS_CONSOLE_OUTPUT:
print """PROCESSOR CHAIN ERROR CALLBACK FIRED:
input_file='%s'
(curried): event=%d""" % (input_file, event)
# Add to retry queue.
self.lock.acquire()
self.retry_queue.put((input_file, event))
self.processorchains_running -= 1
self.lock.release()
def transporter_callback(self, src, dst, url, action, input_file, event, rule, processed_for_server, server):
# Map Transporter's variable names to ours.
output_file = src
transported_file = dst
if CALLBACKS_CONSOLE_OUTPUT:
print """TRANSPORTER CALLBACK FIRED:
(curried): input_file='%s'
(curried): event=%d
(curried): rule='%s'
(curried): processed_for_server='%s'
output_file='%s'
transported_file='%s'
url='%s'
server='%s'""" % (input_file, event, rule["label"], processed_for_server, output_file, transported_file, url, server)
# Add to db queue.
self.lock.acquire()
self.db_queue.put((input_file, event, rule, processed_for_server, output_file, transported_file, url, server))
self.lock.release()