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102 lines
3.4 KiB
Python
102 lines
3.4 KiB
Python
import datetime
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from itertools import tee, starmap, chain
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from collections import namedtuple
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from zipline.gens.tradegens import SpecificEquityTrades
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from zipline.gens.utils import roundrobin, hash_args, done_message
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from zipline.gens.sort import date_sort
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from zipline.gens.merge import merge
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from zipline.gens.transform import StatefulTransform
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def date_sorted_sources(*sources):
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"""
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Takes an iterable of sources, generating namestrings and
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piping their output into date_sort.
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"""
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for source in sources:
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assert iter(source), "Source %s not iterable" % source
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assert source.__class__.__dict__.has_key('get_hash'), "No get_hash"
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# Get name hashes to pass to date_sort.
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names = [source.get_hash() for source in sources]
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# Convert the list of generators into a flat stream by pulling
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# one element at a time from each.
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stream_in = roundrobin(sources, names)
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# Guarantee the flat stream will be sorted by date, using
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# source_id as tie-breaker, which is fully deterministic (given
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# deterministic string representation for all args/kwargs)
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return date_sort(stream_in, names)
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def merged_transforms(sorted_stream, *transforms):
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"""
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A generator that takes the expected output of a date_sort, pipes
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it through a given set of transforms, and runs the results
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through a merge to output a unified stream. tnfms should be a
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list of pointers to generator functions. tnfm_args should be a
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list of tuples, representing the arguments to be passed to each
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transform. tnfm_kwargs should be a list of dictionaries
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representing keyword arguments to each transform.
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"""
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for transform in transforms:
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assert isinstance(transform, StatefulTransform)
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transform.set_copying()
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# Generate expected hashes for each transform
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namestrings = [tnfm.get_hash() for tnfm in transforms]
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# Create a copy of the stream for each transform.
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split = tee(sorted_stream, len(transforms))
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# Package a stream copy with each StatefulTransform instance.
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bundles = zip(transforms, split)
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# Convert the copies into transform streams.
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tnfm_gens = [tnfm.transform(stream) for tnfm, stream in bundles]
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# Roundrobin the outputs of our transforms to create a single flat
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# stream.
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to_merge = roundrobin(tnfm_gens, namestrings)
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# Pipe the stream into merge.
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merged = merge(to_merge, namestrings)
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dt_aliased = alias_dt(merged)
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# Return the merged events.
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return add_done(dt_aliased)
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def sequential_transforms(stream_in, *transforms):
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"""
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Apply each transform in transforms sequentially to each event in stream_in.
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Each transform application will add a new entry indexed to the transform's
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hash string.
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"""
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assert isinstance(transforms, (list, tuple))
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for tnfm in transforms:
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tnfm.forward_all = False
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tnfm.update_in_place = False
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tnfm.append_value = True
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# Recursively apply all transforms to the stream.
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stream_out = reduce(lambda stream, tnfm: tnfm.transform(stream),
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transforms,
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stream_in)
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dt_aliased = alias_dt(stream_out)
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return add_done(dt_aliased)
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def alias_dt(stream_in):
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"""
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Alias the dt field to datetime on each message.
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"""
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for message in stream_in:
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message['datetime'] = message['dt']
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yield message
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# Add a done message to a stream.
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def add_done(stream_in):
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return chain(stream_in, [done_message('Composite')])
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