Allow importing the owner script.

This change modifies the usage of the script so that it can be imported by
the election module. It also fixes maketrans support for python3.

Change-Id: Ie3b602237625e11651825abc8feb38caa73e9632

tools/owners.py

@@ -94,12 +94,16 @@ import csv
 import datetime
 import json
 import os
-import string
 import sys
 
 import requests
 import yaml
 
+try:
+    from string import maketrans
+except ImportError:  # Python3
+    maketrans = bytes.maketrans
+
 
 def dumper(data, stream):
     """Convenience wrapper to consistently set YAML formatting"""
@@ -119,7 +123,7 @@ def normalize_email(email):
 def normalize_project(project):
     """Replace spaces and hyphens with underscores in project teams
     and then lower-case them, for more convenient filenames"""
-    return project.translate(string.maketrans(' -', '__')).lower()
+    return project.translate(maketrans(' -', '__')).lower()
 
 
 def date_merged(change, after=None, before=None):
@@ -178,14 +182,8 @@ def query_gerrit(query):
     return decoded
 
 
-def main():
-    """The giant pile of spaghetti which does everything else"""
-
-    # Record the start time for use later
-    start = datetime.datetime.utcnow()
-
-    # TODO(fungi): this could be trivially extracted to a separate
-    # function
+def usage(argv):
+    """Parse command line argument"""
     parser = argparse.ArgumentParser(
         description="When run using OpenStack's Gerrit server, this builds "
         "YAML representations of aggregate change owner details and change "
@@ -203,7 +201,16 @@ def main():
     parser.add_argument("-o", "--outdir", help="Create an output directory")
     parser.add_argument("-r", "--ref", help="Specify a Governance refname")
     parser.add_argument("-s", "--sieve", help="Add Gerrit query parameters")
-    options = parser.parse_args()
+    return parser.parse_args(argv[1:])
+
+
+def main(argv=sys.argv):
+    """The giant pile of spaghetti which does everything else"""
+
+    # Record the start time for use later
+    start = datetime.datetime.utcnow()
+
+    options = usage(argv)
 
     # If we're supplied a configuration file, use it
     if options.config:
@@ -638,4 +645,5 @@ def main():
         fd.writelines(electorate)
         fd.close()
 
-main()
+if __name__ == "__main__":
+    main()