system-design-primer/solutions/system_design/mint/mint_mapreduce.py

58 lines
1.5 KiB
Python

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