def load_files(self,
fallback_city: str,
max_workers: Optional[int] = None) -> Tuple[int, int]:
"""Downloads and analyses the actual file for the file entries in the database.
Returns the number of successful and failed files"""
# This is partially bound by waiting on external resources, but mostly very cpu intensive,
# so we can spawn a bunch of processes to make this a lot faster.
# We need to build a list because mysql connections and process pools don't pair well.
files = list(
File.objects.filter(
filesize__isnull=True,
oparl_access_url__isnull=False).order_by("-id").values_list(
"id", flat=True))
logger.info("Downloading and analysing {} files".format(len(files)))
address_pipeline = AddressPipeline(create_geoextract_data())
pbar = None
if sys.stdout.isatty() and not settings.TESTING:
pbar = tqdm(total=len(files))
failed = 0
successful = 0
if not self.force_singlethread:
# We need to close the database connections, which will be automatically reopen for
# each process
# See https://stackoverflow.com/a/10684672/3549270
# and https://brobin.me/blog/2017/05/mutiprocessing-in-python-django-management-commands/
db.connections.close_all()
with ProcessPoolExecutor(max_workers=max_workers) as executor:
for succeeded in executor.map(
self.download_and_analyze_file,
files,
repeat(address_pipeline),
repeat(fallback_city),
):
if not succeeded:
failed += 1
if pbar:
pbar.update()
else:
for file in files:
succeeded = self.download_and_analyze_file(
file, address_pipeline, fallback_city)
if not succeeded:
failed += 1
else:
successful += 1
if pbar:
pbar.update()
if pbar:
pbar.close()
if failed > 0:
logger.error("{} files failed to download".format(failed))
return successful, failed
def handle(self, *args, **options):
importer, body = self.get_importer(options)
if options["ids"]:
address_pipeline = AddressPipeline(create_geoextract_data())
failed = 0
for file in options["ids"]:
succeeded = importer.download_and_analyze_file(
file, address_pipeline, body.short_name)
if not succeeded:
failed += 1
if failed > 0:
logger.error("{} files failed to download".format(failed))
else:
importer.load_files(max_workers=options["max_workers"],
fallback_city=body.short_name)
