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chunkstore.py
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chunkstore.py
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import hashlib
import logging
from collections import defaultdict
from itertools import groupby
import pymongo
from bson.binary import Binary
from pandas import DataFrame, Series
from pymongo.errors import OperationFailure
from .date_chunker import DateChunker, START, END
from .passthrough_chunker import PassthroughChunker
from .._util import indent, mongo_count, enable_sharding
from ..decorators import mongo_retry
from ..exceptions import NoDataFoundException
from ..serialization.numpy_arrays import FrametoArraySerializer, DATA, METADATA, COLUMNS
logger = logging.getLogger(__name__)
CHUNK_STORE_TYPE = 'ChunkStoreV1'
SYMBOL = 'sy'
SHA = 'sh'
CHUNK_SIZE = 'cs'
CHUNK_COUNT = 'cc'
SEGMENT = 'sg'
APPEND_COUNT = 'ac'
LEN = 'l'
SERIALIZER = 'se'
CHUNKER = 'ch'
USERMETA = 'u'
MAX_CHUNK_SIZE = 15 * 1024 * 1024
SER_MAP = {FrametoArraySerializer.TYPE: FrametoArraySerializer()}
CHUNKER_MAP = {DateChunker.TYPE: DateChunker(),
PassthroughChunker.TYPE: PassthroughChunker()}
class ChunkStore(object):
@classmethod
def initialize_library(cls, arctic_lib, hashed=True, **kwargs):
ChunkStore(arctic_lib)._ensure_index()
logger.info("Trying to enable sharding...")
try:
enable_sharding(arctic_lib.arctic, arctic_lib.get_name(), hashed=hashed, key=SYMBOL)
except OperationFailure as e:
logger.warning("Library created, but couldn't enable sharding: %s. This is OK if you're not 'admin'" % str(e))
@mongo_retry
def _ensure_index(self):
self._symbols.create_index([(SYMBOL, pymongo.ASCENDING)],
unique=True,
background=True)
self._collection.create_index([(SYMBOL, pymongo.HASHED)],
background=True)
self._collection.create_index([(SYMBOL, pymongo.ASCENDING),
(SHA, pymongo.ASCENDING)],
unique=True,
background=True)
self._collection.create_index([(SYMBOL, pymongo.ASCENDING),
(START, pymongo.ASCENDING),
(SEGMENT, pymongo.ASCENDING),
(END, pymongo.ASCENDING)],
unique=True, background=True)
self._collection.create_index([(SYMBOL, pymongo.ASCENDING),
(START, pymongo.ASCENDING),
(SEGMENT, pymongo.ASCENDING)],
unique=True, background=True)
self._collection.create_index([(SEGMENT, pymongo.ASCENDING)],
unique=False, background=True)
self._mdata.create_index([(SYMBOL, pymongo.ASCENDING),
(START, pymongo.ASCENDING),
(END, pymongo.ASCENDING)],
unique=True, background=True)
def __init__(self, arctic_lib):
self._arctic_lib = arctic_lib
self.serializer = FrametoArraySerializer()
# Do we allow reading from secondaries
self._allow_secondary = self._arctic_lib.arctic._allow_secondary
self._reset()
@mongo_retry
def _reset(self):
# The default collection
self._collection = self._arctic_lib.get_top_level_collection()
self._symbols = self._collection.symbols
self._mdata = self._collection.metadata
self._audit = self._collection.audit
def __getstate__(self):
return {'arctic_lib': self._arctic_lib}
def __setstate__(self, state):
return ChunkStore.__init__(self, state['arctic_lib'])
def __str__(self):
return """<%s at %s>\n%s""" % (self.__class__.__name__, hex(id(self)),
indent(str(self._arctic_lib), 4))
def __repr__(self):
return str(self)
def _checksum(self, fields, data):
"""
Checksum the passed in dictionary
"""
sha = hashlib.sha1()
for field in fields:
sha.update(field)
sha.update(data)
return Binary(sha.digest())
def delete(self, symbol, chunk_range=None, audit=None):
"""
Delete all chunks for a symbol, or optionally, chunks within a range
Parameters
----------
symbol : str
symbol name for the item
chunk_range: range object
a date range to delete
audit: dict
dict to store in the audit log
"""
if chunk_range is not None:
sym = self._get_symbol_info(symbol)
# read out chunks that fall within the range and filter out
# data within the range
df = self.read(symbol, chunk_range=chunk_range, filter_data=False)
row_adjust = len(df)
if not df.empty:
df = CHUNKER_MAP[sym[CHUNKER]].exclude(df, chunk_range)
# remove chunks, and update any remaining data
query = {SYMBOL: symbol}
query.update(CHUNKER_MAP[sym[CHUNKER]].to_mongo(chunk_range))
self._collection.delete_many(query)
self._mdata.delete_many(query)
self.update(symbol, df)
# update symbol metadata (rows and chunk count)
sym = self._get_symbol_info(symbol)
sym[LEN] -= row_adjust
sym[CHUNK_COUNT] = mongo_count(self._collection, filter={SYMBOL: symbol})
self._symbols.replace_one({SYMBOL: symbol}, sym)
else:
query = {SYMBOL: symbol}
self._collection.delete_many(query)
self._symbols.delete_many(query)
self._mdata.delete_many(query)
if audit is not None:
audit['symbol'] = symbol
if chunk_range is not None:
audit['rows_deleted'] = row_adjust
audit['action'] = 'range delete'
else:
audit['action'] = 'symbol delete'
self._audit.insert_one(audit)
def list_symbols(self, partial_match=None):
"""
Returns all symbols in the library
Parameters
----------
partial_match: None or str
if not none, use this string to do a partial match on symbol names
Returns
-------
list of str
"""
symbols = self._symbols.distinct(SYMBOL)
if partial_match is None:
return symbols
return [x for x in symbols if partial_match in x]
def _get_symbol_info(self, symbol):
if isinstance(symbol, list):
return list(self._symbols.find({SYMBOL: {'$in': symbol}}))
return self._symbols.find_one({SYMBOL: symbol})
def rename(self, from_symbol, to_symbol, audit=None):
"""
Rename a symbol
Parameters
----------
from_symbol: str
the existing symbol that will be renamed
to_symbol: str
the new symbol name
audit: dict
audit information
"""
sym = self._get_symbol_info(from_symbol)
if not sym:
raise NoDataFoundException('No data found for %s' % (from_symbol))
if self._get_symbol_info(to_symbol) is not None:
raise Exception('Symbol %s already exists' % (to_symbol))
mongo_retry(self._collection.update_many)({SYMBOL: from_symbol},
{'$set': {SYMBOL: to_symbol}})
mongo_retry(self._symbols.update_one)({SYMBOL: from_symbol},
{'$set': {SYMBOL: to_symbol}})
mongo_retry(self._mdata.update_many)({SYMBOL: from_symbol},
{'$set': {SYMBOL: to_symbol}})
mongo_retry(self._audit.update_many)({'symbol': from_symbol},
{'$set': {'symbol': to_symbol}})
if audit is not None:
audit['symbol'] = to_symbol
audit['action'] = 'symbol rename'
audit['old_symbol'] = from_symbol
self._audit.insert_one(audit)
def read(self, symbol, chunk_range=None, filter_data=True, **kwargs):
"""
Reads data for a given symbol from the database.
Parameters
----------
symbol: str, or list of str
the symbol(s) to retrieve
chunk_range: object
corresponding range object for the specified chunker (for
DateChunker it is a DateRange object or a DatetimeIndex,
as returned by pandas.date_range
filter_data: boolean
perform chunk level filtering on the data (see filter in _chunker)
only applicable when chunk_range is specified
kwargs: ?
values passed to the serializer. Varies by serializer
Returns
-------
DataFrame or Series, or in the case when multiple symbols are given,
returns a dict of symbols (symbol -> dataframe/series)
"""
if not isinstance(symbol, list):
symbol = [symbol]
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException('No data found for %s' % (symbol))
spec = {SYMBOL: {'$in': symbol}}
chunker = CHUNKER_MAP[sym[0][CHUNKER]]
deser = SER_MAP[sym[0][SERIALIZER]].deserialize
if chunk_range is not None:
spec.update(chunker.to_mongo(chunk_range))
by_start_segment = [(SYMBOL, pymongo.ASCENDING),
(START, pymongo.ASCENDING),
(SEGMENT, pymongo.ASCENDING)]
segment_cursor = self._collection.find(spec, sort=by_start_segment)
chunks = defaultdict(list)
for _, segments in groupby(segment_cursor, key=lambda x: (x[START], x[SYMBOL])):
segments = list(segments)
mdata = self._mdata.find_one({SYMBOL: segments[0][SYMBOL],
START: segments[0][START],
END: segments[0][END]})
# when len(segments) == 1, this is essentially a no-op
# otherwise, take all segments and reassemble the data to one chunk
chunk_data = b''.join([doc[DATA] for doc in segments])
chunks[segments[0][SYMBOL]].append({DATA: chunk_data, METADATA: mdata})
skip_filter = not filter_data or chunk_range is None
if len(symbol) > 1:
return {sym: deser(chunks[sym], **kwargs) if skip_filter else chunker.filter(deser(chunks[sym], **kwargs), chunk_range) for sym in symbol}
else:
return deser(chunks[symbol[0]], **kwargs) if skip_filter else chunker.filter(deser(chunks[symbol[0]], **kwargs), chunk_range)
def read_audit_log(self, symbol=None):
"""
Reads the audit log
Parameters
----------
symbol: str
optionally only retrieve specific symbol's audit information
Returns
-------
list of dicts
"""
if symbol:
return [x for x in self._audit.find({'symbol': symbol}, {'_id': False})]
return [x for x in self._audit.find({}, {'_id': False})]
def write(self, symbol, item, metadata=None, chunker=DateChunker(), audit=None, **kwargs):
"""
Writes data from item to symbol in the database
Parameters
----------
symbol: str
the symbol that will be used to reference the written data
item: Dataframe or Series
the data to write the database
metadata: ?
optional per symbol metadata
chunker: Object of type Chunker
A chunker that chunks the data in item
audit: dict
audit information
kwargs:
optional keyword args that are passed to the chunker. Includes:
chunk_size:
used by chunker to break data into discrete chunks.
see specific chunkers for more information about this param.
func: function
function to apply to each chunk before writing. Function
can not modify the date column.
"""
if not isinstance(item, (DataFrame, Series)):
raise Exception("Can only chunk DataFrames and Series")
self._arctic_lib.check_quota()
previous_shas = []
doc = {}
meta = {}
doc[SYMBOL] = symbol
doc[LEN] = len(item)
doc[SERIALIZER] = self.serializer.TYPE
doc[CHUNKER] = chunker.TYPE
doc[USERMETA] = metadata
sym = self._get_symbol_info(symbol)
if sym:
previous_shas = set([Binary(x[SHA]) for x in self._collection.find({SYMBOL: symbol},
projection={SHA: True, '_id': False},
)])
ops = []
meta_ops = []
chunk_count = 0
for start, end, chunk_size, record in chunker.to_chunks(item, **kwargs):
chunk_count += 1
data = self.serializer.serialize(record)
doc[CHUNK_SIZE] = chunk_size
doc[METADATA] = {'columns': data[METADATA][COLUMNS] if COLUMNS in data[METADATA] else ''}
meta = data[METADATA]
for i in range(int(len(data[DATA]) / MAX_CHUNK_SIZE + 1)):
chunk = {DATA: Binary(data[DATA][i * MAX_CHUNK_SIZE: (i + 1) * MAX_CHUNK_SIZE])}
chunk[SEGMENT] = i
chunk[START] = meta[START] = start
chunk[END] = meta[END] = end
chunk[SYMBOL] = meta[SYMBOL] = symbol
dates = [chunker.chunk_to_str(start), chunker.chunk_to_str(end), str(chunk[SEGMENT]).encode('ascii')]
chunk[SHA] = self._checksum(dates, chunk[DATA])
meta_ops.append(pymongo.ReplaceOne({SYMBOL: symbol,
START: start,
END: end},
meta, upsert=True))
if chunk[SHA] not in previous_shas:
ops.append(pymongo.UpdateOne({SYMBOL: symbol,
START: start,
END: end,
SEGMENT: chunk[SEGMENT]},
{'$set': chunk}, upsert=True))
else:
# already exists, dont need to update in mongo
previous_shas.remove(chunk[SHA])
if ops:
self._collection.bulk_write(ops, ordered=False)
if meta_ops:
self._mdata.bulk_write(meta_ops, ordered=False)
doc[CHUNK_COUNT] = chunk_count
doc[APPEND_COUNT] = 0
if previous_shas:
mongo_retry(self._collection.delete_many)({SYMBOL: symbol, SHA: {'$in': list(previous_shas)}})
mongo_retry(self._symbols.update_one)({SYMBOL: symbol},
{'$set': doc},
upsert=True)
if audit is not None:
audit['symbol'] = symbol
audit['action'] = 'write'
audit['chunks'] = chunk_count
self._audit.insert_one(audit)
def __update(self, sym, item, metadata=None, combine_method=None, chunk_range=None, audit=None):
'''
helper method used by update and append since they very closely
resemble eachother. Really differ only by the combine method.
append will combine existing date with new data (within a chunk),
whereas update will replace existing data with new data (within a
chunk).
'''
if not isinstance(item, (DataFrame, Series)):
raise Exception("Can only chunk DataFrames and Series")
self._arctic_lib.check_quota()
symbol = sym[SYMBOL]
if chunk_range is not None:
self.delete(symbol, chunk_range)
sym = self._get_symbol_info(symbol)
ops = []
meta_ops = []
chunker = CHUNKER_MAP[sym[CHUNKER]]
appended = 0
new_chunks = 0
for start, end, _, record in chunker.to_chunks(item, chunk_size=sym[CHUNK_SIZE]):
# read out matching chunks
df = self.read(symbol, chunk_range=chunker.to_range(start, end), filter_data=False)
# assuming they exist, update them and store the original chunk
# range for later use
if len(df) > 0:
record = combine_method(df, record)
if record is None or record.equals(df):
continue
sym[APPEND_COUNT] += len(record) - len(df)
appended += len(record) - len(df)
sym[LEN] += len(record) - len(df)
else:
sym[CHUNK_COUNT] += 1
new_chunks += 1
sym[LEN] += len(record)
data = SER_MAP[sym[SERIALIZER]].serialize(record)
meta = data[METADATA]
chunk_count = int(len(data[DATA]) / MAX_CHUNK_SIZE + 1)
seg_count = mongo_count(self._collection, filter={SYMBOL: symbol, START: start, END: end})
# remove old segments for this chunk in case we now have less
# segments than we did before
if seg_count > chunk_count:
self._collection.delete_many({SYMBOL: symbol,
START: start,
END: end,
SEGMENT: {'$gte': chunk_count}})
for i in range(chunk_count):
chunk = {DATA: Binary(data[DATA][i * MAX_CHUNK_SIZE: (i + 1) * MAX_CHUNK_SIZE])}
chunk[SEGMENT] = i
chunk[START] = start
chunk[END] = end
chunk[SYMBOL] = symbol
dates = [chunker.chunk_to_str(start), chunker.chunk_to_str(end), str(chunk[SEGMENT]).encode('ascii')]
sha = self._checksum(dates, data[DATA])
chunk[SHA] = sha
ops.append(pymongo.UpdateOne({SYMBOL: symbol,
START: start,
END: end,
SEGMENT: chunk[SEGMENT]},
{'$set': chunk}, upsert=True))
meta_ops.append(pymongo.UpdateOne({SYMBOL: symbol,
START: start,
END: end},
{'$set': meta}, upsert=True))
if ops:
self._collection.bulk_write(ops, ordered=False)
self._mdata.bulk_write(meta_ops, ordered=False)
sym[USERMETA] = metadata
self._symbols.replace_one({SYMBOL: symbol}, sym)
if audit is not None:
if new_chunks > 0:
audit['new_chunks'] = new_chunks
if appended > 0:
audit['appended_rows'] = appended
self._audit.insert_one(audit)
def append(self, symbol, item, upsert=False, metadata=None, audit=None, **kwargs):
"""
Appends data from item to symbol's data in the database.
Is not idempotent
Parameters
----------
symbol: str
the symbol for the given item in the DB
item: DataFrame or Series
the data to append
upsert:
write data if symbol does not exist
metadata: ?
optional per symbol metadata
audit: dict
optional audit information
kwargs:
passed to write if upsert is true and symbol does not exist
"""
sym = self._get_symbol_info(symbol)
if not sym:
if upsert:
return self.write(symbol, item, metadata=metadata, audit=audit, **kwargs)
else:
raise NoDataFoundException("Symbol does not exist.")
if audit is not None:
audit['symbol'] = symbol
audit['action'] = 'append'
self.__update(sym, item, metadata=metadata, combine_method=SER_MAP[sym[SERIALIZER]].combine, audit=audit)
def update(self, symbol, item, metadata=None, chunk_range=None, upsert=False, audit=None, **kwargs):
"""
Overwrites data in DB with data in item for the given symbol.
Is idempotent
Parameters
----------
symbol: str
the symbol for the given item in the DB
item: DataFrame or Series
the data to update
metadata: ?
optional per symbol metadata
chunk_range: None, or a range object
If a range is specified, it will clear/delete the data within the
range and overwrite it with the data in item. This allows the user
to update with data that might only be a subset of the
original data.
upsert: bool
if True, will write the data even if the symbol does not exist.
audit: dict
optional audit information
kwargs:
optional keyword args passed to write during an upsert. Includes:
chunk_size
chunker
"""
sym = self._get_symbol_info(symbol)
if not sym:
if upsert:
return self.write(symbol, item, metadata=metadata, audit=audit, **kwargs)
else:
raise NoDataFoundException("Symbol does not exist.")
if audit is not None:
audit['symbol'] = symbol
audit['action'] = 'update'
if chunk_range is not None:
if len(CHUNKER_MAP[sym[CHUNKER]].filter(item, chunk_range)) == 0:
raise Exception('Range must be inclusive of data')
self.__update(sym, item, metadata=metadata, combine_method=self.serializer.combine, chunk_range=chunk_range, audit=audit)
else:
self.__update(sym, item, metadata=metadata, combine_method=lambda old, new: new, chunk_range=chunk_range, audit=audit)
def get_info(self, symbol):
"""
Returns information about the symbol, in a dictionary
Parameters
----------
symbol: str
the symbol for the given item in the DB
Returns
-------
dictionary
"""
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException("Symbol does not exist.")
ret = {}
ret['chunk_count'] = sym[CHUNK_COUNT]
ret['len'] = sym[LEN]
ret['appended_rows'] = sym[APPEND_COUNT]
ret['metadata'] = sym[METADATA] if METADATA in sym else None
ret['chunker'] = sym[CHUNKER]
ret['chunk_size'] = sym[CHUNK_SIZE] if CHUNK_SIZE in sym else 0
ret['serializer'] = sym[SERIALIZER]
return ret
def read_metadata(self, symbol):
'''
Reads user defined metadata out for the given symbol
Parameters
----------
symbol: str
symbol for the given item in the DB
Returns
-------
?
'''
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException("Symbol does not exist.")
x = self._symbols.find_one({SYMBOL: symbol})
return x[USERMETA] if USERMETA in x else None
def write_metadata(self, symbol, metadata):
'''
writes user defined metadata for the given symbol
Parameters
----------
symbol: str
symbol for the given item in the DB
metadata: ?
metadata to write
'''
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException("Symbol does not exist.")
sym[USERMETA] = metadata
self._symbols.replace_one({SYMBOL: symbol}, sym)
def get_chunk_ranges(self, symbol, chunk_range=None, reverse=False):
"""
Returns a generator of (Start, End) tuples for each chunk in the symbol
Parameters
----------
symbol: str
the symbol for the given item in the DB
chunk_range: None, or a range object
allows you to subset the chunks by range
reverse: boolean
return the chunk ranges in reverse order
Returns
-------
generator
"""
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException("Symbol does not exist.")
c = CHUNKER_MAP[sym[CHUNKER]]
# all symbols have a segment 0
spec = {SYMBOL: symbol, SEGMENT: 0}
if chunk_range is not None:
spec.update(CHUNKER_MAP[sym[CHUNKER]].to_mongo(chunk_range))
for x in self._collection.find(spec,
projection=[START, END],
sort=[(START, pymongo.ASCENDING if not reverse else pymongo.DESCENDING)]):
yield (c.chunk_to_str(x[START]), c.chunk_to_str(x[END]))
def iterator(self, symbol, chunk_range=None, **kwargs):
"""
Returns a generator that accesses each chunk in ascending order
Parameters
----------
symbol: str
the symbol for the given item in the DB
chunk_range: None, or a range object
allows you to subset the chunks by range
Returns
-------
generator
"""
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException("Symbol does not exist.")
c = CHUNKER_MAP[sym[CHUNKER]]
for chunk in list(self.get_chunk_ranges(symbol, chunk_range=chunk_range)):
yield self.read(symbol, chunk_range=c.to_range(chunk[0], chunk[1]), **kwargs)
def reverse_iterator(self, symbol, chunk_range=None, **kwargs):
"""
Returns a generator that accesses each chunk in descending order
Parameters
----------
symbol: str
the symbol for the given item in the DB
chunk_range: None, or a range object
allows you to subset the chunks by range
Returns
-------
generator
"""
sym = self._get_symbol_info(symbol)
if not sym:
raise NoDataFoundException("Symbol does not exist.")
c = CHUNKER_MAP[sym[CHUNKER]]
for chunk in list(self.get_chunk_ranges(symbol, chunk_range=chunk_range, reverse=True)):
yield self.read(symbol, chunk_range=c.to_range(chunk[0], chunk[1]), **kwargs)
def stats(self):
"""
Return storage statistics about the library
Returns
-------
dictionary of storage stats
"""
res = {}
db = self._collection.database
conn = db.connection
res['sharding'] = {}
try:
sharding = conn.config.databases.find_one({'_id': db.name})
if sharding:
res['sharding'].update(sharding)
res['sharding']['collections'] = list(conn.config.collections.find({'_id': {'$regex': '^' + db.name + r"\..*"}}))
except OperationFailure:
# Access denied
pass
res['dbstats'] = db.command('dbstats')
res['chunks'] = db.command('collstats', self._collection.name)
res['symbols'] = db.command('collstats', self._symbols.name)
res['metadata'] = db.command('collstats', self._mdata.name)
res['totals'] = {
'count': res['chunks']['count'],
'size': res['chunks']['size'] + res['symbols']['size'] + res['metadata']['size'],
}
return res
def has_symbol(self, symbol):
"""
Check if symbol exists in collection
Parameters
----------
symbol: str
The symbol to look up in the collection
Returns
-------
bool
"""
return self._get_symbol_info(symbol) is not None