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https://github.com/donnemartin/system-design-primer.git
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58 lines
1.4 KiB
Python
58 lines
1.4 KiB
Python
# -*- coding: utf-8 -*-
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from mrjob.job import MRJob
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class SpendingByCategory(MRJob):
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def __init__(self, categorizer):
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self.categorizer = categorizer
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...
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def current_year_month(self):
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"""Return the current year and month."""
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...
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def extract_year_month(self, timestamp):
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"""Return the year and month portions of the timestamp."""
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...
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def handle_budget_notifications(self, key, total):
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"""Call notification API if nearing or exceeded budget."""
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...
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def mapper(self, _, line):
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"""Parse each log line, extract and transform relevant lines.
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Emit key value pairs of the form:
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(2016-01, shopping), 25
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(2016-01, shopping), 100
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(2016-01, gas), 50
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"""
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timestamp, category, amount = line.split('\t')
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period = self. extract_year_month(timestamp)
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if period == self.current_year_month():
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yield (period, category), amount
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def reducer(self, key, values):
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"""Sum values for each key.
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(2016-01, shopping), 125
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(2016-01, gas), 50
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"""
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total = sum(values)
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self.handle_budget_notifications(key, total)
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yield key, sum(values)
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def steps(self):
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"""Run the map and reduce steps."""
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return [
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self.mr(mapper=self.mapper,
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reducer=self.reducer)
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]
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if __name__ == '__main__':
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SpendingByCategory.run()
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