Files
cellxgene/server/data_common/matrix_loader.py
bmccandless f69d141336 refactor config to support different config options for datasets in different dataroots. (#1596)
This will give us the ability to specify different config options for
different dataroots.

the key of the dataroot dictionary is no longer the same as the dataroot_url.
Previously key==dataroot_url, and now those are separated.

Added an "is_multi_dataset" function to simplify logic where it branched on single vs multi.

Simplified the rest.py interface by no longer passing in the user annotations object, since
that can be retrieved from the dataset.
2020-07-10 16:21:40 -07:00

287 lines
11 KiB
Python

from enum import Enum
import threading
import time
from server.data_common.rwlock import RWLock
from server.common.errors import DatasetAccessError
from server.common.data_locator import DataLocator
from contextlib import contextmanager
from http import HTTPStatus
class MatrixDataCacheItem(object):
"""This class provides access and caching for a dataset. The first time a dataset is accessed, it is
opened and cached. Later accesses use the cached version. It may also be deleted by the
MatrixDataCacheManager to make room for another dataset. While a dataset is actively being used
(during the lifetime of a api request), a reader lock is locked. During that time, the dataset cannot
be removed."""
def __init__(self, loader):
self.loader = loader
self.data_adaptor = None
self.data_lock = RWLock()
def acquire_existing(self):
"""If the data_adaptor exists, take a read lock and return it, else return None"""
self.data_lock.r_acquire()
if self.data_adaptor:
return self.data_adaptor
self.data_lock.r_release()
return None
def acquire_and_open(self, app_config, dataset_config=None):
"""returns the data_adaptor if cached. opens the data_adaptor if not.
In either case, the a reader lock is taken. Must call release when
the data_adaptor is no longer needed"""
self.data_lock.r_acquire()
if self.data_adaptor:
return self.data_adaptor
self.data_lock.r_release()
self.data_lock.w_acquire()
# the data may have been loaded while waiting on the lock
if not self.data_adaptor:
try:
self.loader.pre_load_validation()
self.data_adaptor = self.loader.open(app_config, dataset_config)
except Exception as e:
# necessary to hold the reader lock after an exception, since
# the release will occur when the context exits.
self.data_lock.w_demote()
raise DatasetAccessError(str(e))
# demote the write lock to a read lock.
self.data_lock.w_demote()
return self.data_adaptor
def release(self):
"""Release the reader lock"""
self.data_lock.r_release()
def delete(self):
"""Clear resources used by this dataset"""
with self.data_lock.w_locked():
if self.data_adaptor:
self.data_adaptor.cleanup()
self.data_adaptor = None
def attempt_delete(self):
"""Delete, but only if the write lock can be immediately locked. Return True if the delete happened"""
if self.data_lock.w_acquire_non_blocking():
if self.data_adaptor:
try:
self.data_adaptor.cleanup()
self.data_adaptor = None
except Exception:
# catch all exceptions to ensure the lock is released
pass
self.data_lock.w_release()
return True
else:
return False
class MatrixDataCacheInfo(object):
def __init__(self, cache_item, timestamp):
# The MatrixDataCacheItem in the cache
self.cache_item = cache_item
# The last time the cache_item was accessed
self.last_access = timestamp
# The number of times the cache_item was accessed (used for testing)
self.num_access = 1
class MatrixDataCacheManager(object):
"""A class to manage the cached datasets. This is intended to be used as a context manager
for handling api requests. When the context is created, the data_adator is either loaded or
retrieved from a cache. In either case, the reader lock is taken during this time, and release
when the context ends. This class currently implements a simple least recently used cache,
which can delete a dataset from the cache to make room for a new one.
This is the intended usage pattern:
m = MatrixDataCacheManager(max_cached=..., timelimmit_s = ...)
with m.data_adaptor(location, app_config) as data_adaptor:
# use the data_adaptor for some operation
"""
# FIXME: If the number of active datasets exceeds the max_cached, then each request could
# lead to a dataset being deleted and a new only being opened: the cache will get thrashed.
# In this case, we may need to send back a 503 (Server Unavailable), or some other error message.
# NOTE: If the actual dataset is changed. E.g. a new set of datafiles replaces an existing set,
# then the cache will not react to this, however once the cache time limit is reached, the dataset
# will automatically be refreshed.
def __init__(self, max_cached, timelimit_s=None):
# key is tuple(url_dataroot, location), value is a MatrixDataCacheInfo
self.datasets = {}
# lock to protect the datasets
self.lock = threading.Lock()
# The number of datasets to cache. When max_cached is reached, the least recently used
# cache is replaced with the newly requested one.
# TODO: This is very simple. This can be improved by taking into account how much space is actually
# taken by each dataset, instead of arbitrarily picking a max datasets to cache.
self.max_cached = max_cached
# items are automatically removed from the cache once this time limit is reached
self.timelimit_s = timelimit_s
@contextmanager
def data_adaptor(self, url_dataroot, location, app_config):
# create a loader for to this location if it does not already exist
delete_adaptor = None
data_adaptor = None
cache_item = None
key = (url_dataroot, location)
with self.lock:
self.evict_old_datasets()
info = self.datasets.get(key)
if info is not None:
info.last_access = time.time()
info.num_access += 1
self.datasets[key] = info
data_adaptor = info.cache_item.acquire_existing()
cache_item = info.cache_item
if data_adaptor is None:
while True:
if len(self.datasets) < self.max_cached:
break
items = list(self.datasets.items())
items = sorted(items, key=lambda x: x[1].last_access)
# close the least recently used loader
oldest = items[0]
oldest_cache = oldest[1].cache_item
oldest_key = oldest[0]
del self.datasets[oldest_key]
delete_adaptor = oldest_cache
loader = MatrixDataLoader(location, app_config=app_config)
cache_item = MatrixDataCacheItem(loader)
item = MatrixDataCacheInfo(cache_item, time.time())
self.datasets[key] = item
try:
assert cache_item
if delete_adaptor:
delete_adaptor.delete()
if data_adaptor is None:
dataset_config = app_config.get_dataset_config(url_dataroot)
data_adaptor = cache_item.acquire_and_open(app_config, dataset_config)
yield data_adaptor
except DatasetAccessError:
cache_item.release()
with self.lock:
del self.datasets[key]
cache_item.delete()
cache_item = None
raise
finally:
if cache_item:
cache_item.release()
def evict_old_datasets(self):
# must be called with the lock held
if self.timelimit_s is None:
return
now = time.time()
to_del = []
for key, info in self.datasets.items():
if (now - info.last_access) > self.timelimit_s:
# remove the data_cache when if it has been in the cache too long
to_del.append((key, info))
for key, info in to_del:
# try and get the write_lock for the dataset.
# if this returns false, it means the dataset is being used, and should
# not be removed.
if info.cache_item.attempt_delete():
del self.datasets[key]
class MatrixDataType(Enum):
H5AD = "h5ad"
CXG = "cxg"
UNKNOWN = "unknown"
class MatrixDataLoader(object):
def __init__(self, location, matrix_data_type=None, app_config=None):
""" location can be a string or DataLocator """
region_name = None if app_config is None else app_config.server_config.data_locator__s3__region_name
self.location = DataLocator(location, region_name=region_name)
if not self.location.exists():
raise DatasetAccessError("Dataset does not exist.", HTTPStatus.NOT_FOUND)
# matrix_data_type is an enum value of type MatrixDataType
self.matrix_data_type = matrix_data_type
# matrix_type is a DataAdaptor type, which corresonds to the matrix_data_type
self.matrix_type = None
if matrix_data_type is None:
self.matrix_data_type = self.__matrix_data_type()
if not self.__matrix_data_type_allowed(app_config):
raise DatasetAccessError("Dataset does not have an allowed type.")
if self.matrix_data_type == MatrixDataType.H5AD:
from server.data_anndata.anndata_adaptor import AnndataAdaptor
self.matrix_type = AnndataAdaptor
elif self.matrix_data_type == MatrixDataType.CXG:
from server.data_cxg.cxg_adaptor import CxgAdaptor
self.matrix_type = CxgAdaptor
def __matrix_data_type(self):
if self.location.path.endswith(".h5ad"):
return MatrixDataType.H5AD
elif ".cxg" in self.location.path:
return MatrixDataType.CXG
else:
return MatrixDataType.UNKNOWN
def __matrix_data_type_allowed(self, app_config):
if self.matrix_data_type == MatrixDataType.UNKNOWN:
return False
if not app_config:
return True
if not app_config.is_multi_dataset():
return True
if len(app_config.server_config.multi_dataset__allowed_matrix_types) == 0:
return True
for val in app_config.server_config.multi_dataset__allowed_matrix_types:
try:
if self.matrix_data_type == MatrixDataType(val):
return True
except ValueError:
# Check case where multi_dataset_allowed_matrix_type does not have a
# valid MatrixDataType value. TODO: Add a feature to check
# the AppConfig for errors on startup
return False
return False
def pre_load_validation(self):
if self.matrix_data_type == MatrixDataType.UNKNOWN:
raise DatasetAccessError("Dataset does not have a recognized type: .h5ad or .cxg")
self.matrix_type.pre_load_validation(self.location)
def file_size(self):
return self.matrix_type.file_size(self.location)
def open(self, app_config, dataset_config=None):
# create and return a DataAdaptor object
return self.matrix_type.open(self.location, app_config, dataset_config)