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Aggregating CloudFront logs
#!/usr/bin/env python
# -*- coding: utf-8 -*-
#
# fetch_and_combine.py
#
"""
Scans CloudFront logs in an S3 bucket for any that are new. Combines log files
into a single local file per hour. If logs for multiple CloudFront
distributions are present, combines them all.
"""
import os
import sys
import optparse
import gzip
from collections import namedtuple
from cStringIO import StringIO
import boto
CloudFrontLog = namedtuple('CloudFrontLog', 'distribution date hour hash')
LogSource = namedtuple('LogSource', 'bucket_name is_nested')
BUCKETS = [
LogSource('some-s3-bucket-as-cloudfront-dumps-it', False),
LogSource('some-s3-bucket-by-date', True),
]
# if no credentials are set here, Boto will check the environment for the
# AWS_CREDENTIAL_FILE variable and use the credentials there
AWS_ACCESS_KEY = None
AWS_SECRET_KEY = None
def fetch_new_data(log_source, dest_dir, from_prefix=None):
"Fetch and combine logs from an S3 bucket."
if not os.path.isdir(dest_dir):
os.mkdir(dest_dir)
print 'Checking logs at s3://%s' % log_source.bucket_name
s3 = boto.connect_s3(AWS_ACCESS_KEY, AWS_SECRET_KEY)
bucket = s3.get_bucket(log_source.bucket_name)
store = DirectoryStore(dest_dir)
if log_source.is_nested:
# iterate over one level of subdirectories, e.g. dates
def iter_keys():
for prefix in bucket.list(delimiter='/'):
if from_prefix and prefix.name < from_prefix:
continue
for s3_key in bucket.list(prefix=prefix.name):
yield s3_key
else:
iter_keys = bucket.list
for s3_key in iter_keys():
if not store.is_ingested(s3_key):
print s3_key.key
store.ingest(s3_key)
def parse_filename(filename):
distribution, datehour, hash_str = os.path.basename(filename).split(
'.')[:3]
date, hour = datehour.rsplit('-', 1)
return CloudFrontLog(distribution, date, hour, hash_str)
class DirectoryStore(object):
"A storage mechanism with one directory per day, one file per hour."
def __init__(self, base_path):
self.base_path = base_path
def is_ingested(self, s3_key):
log_key = parse_filename(s3_key.key)
manifest = self._get_keyfile(log_key) + '.manifest'
if os.path.exists(manifest):
ingested = set(l.rstrip() for l in open(manifest))
return os.path.basename(s3_key.key) in ingested
return False
def ingest(self, s3_key):
"Ingest this file into the store."
filename = s3_key.key
log_key = parse_filename(filename)
keyfile = self._get_keyfile(log_key)
manifest = keyfile + '.manifest'
if os.path.exists(manifest):
ingested = set(l.rstrip() for l in open(manifest))
if filename in ingested:
raise Exception('already ingested: %s' % filename)
# fetch the data
s3_key.open_read()
gzdata = s3_key.read()
data = gzip.GzipFile(fileobj=StringIO(gzdata)).read()
# store it and record the manifest
parent_dir = os.path.dirname(keyfile)
if not os.path.isdir(parent_dir):
os.mkdir(parent_dir)
with gzip.open(keyfile + '.gz', 'a') as ostream:
ostream.write(data)
with open(manifest, 'a') as ostream:
print >> ostream, os.path.basename(filename)
def _get_keyfile(self, log_key):
return os.path.join(self.base_path, log_key.date, log_key.hour)
def _create_option_parser():
usage = \
"""%prog [options] dest_dir
Update a directory cache with new snowplow logs."""
parser = optparse.OptionParser(usage)
parser.add_option('--from', action='store', dest='from_prefix',
help='Skip until this prefix.')
return parser
def main(argv):
parser = _create_option_parser()
(options, args) = parser.parse_args(argv)
if len(args) != 1:
parser.print_help()
sys.exit(1)
dest_dir, = args
print 'FETCHING SNOWPLOW LOGS'
for log_source in BUCKETS:
fetch_new_data(log_source, dest_dir, from_prefix=options.from_prefix)
print
if __name__ == '__main__':
main(sys.argv[1:])
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