check_slow_queries_digest_result: expect xz compressed pt-query-digest reports

because pt-query-digest are text files that can be large, we should except that
the users have compressed them.

setup.py

@@ -42,6 +42,7 @@ setup(name=name,
         'croniter', # needed to know cron schedule
         'pytz', # needed to manipulate timezone
         'tzlocal', # needed to manipulate timezone
+        'backports.lzma',
         'passlib',
         'netifaces',
         'erp5.util',

slapos/promise/check_slow_queries_digest_result/__init__.py

@@ -13,6 +13,7 @@ import sys
 import time
 import datetime
 import argparse
+from backports import lzma
 
 def checkMariadbDigestResult(mariadbdex_path, mariadbdex_report_status_file,
                              max_query_threshold, slowest_query_threshold):
@@ -28,8 +29,8 @@ def checkMariadbDigestResult(mariadbdex_path, mariadbdex_report_status_file,
         return 0, "Instance has been just deployed. Skipping check.."
   else:
     for date in today_or_yesterday:
-      if mariadbdex_file == date.strftime('slowquery_digest.txt-%Y-%m-%d'):
-        with open(os.path.join(mariadbdex_path, mariadbdex_file)) as f:
+      if mariadbdex_file == date.strftime('slowquery_digest.txt-%Y-%m-%d.xz'):
+        with lzma.open(os.path.join(mariadbdex_path, mariadbdex_file), 'rt') as f:
           content = f.read()
         if content:
           # XXX: if not a lot of usage, skip this

slapos/test/promise/test_check_slow_queries_digest_result.py

@@ -24,13 +24,15 @@
 # Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA  02111-1307, USA.
 #
 ##############################################################################
-
+from __future__ import unicode_literals
 import unittest
 import os
 import time
 import tempfile
 import datetime
 import shutil
+import codecs
+from backports import lzma
 
 from . import data
 from slapos.promise.check_slow_queries_digest_result import checkMariadbDigestResult
@@ -42,17 +44,17 @@ class TestCheckSlowQueriesDigestResult(unittest.TestCase):
   def _create_file(self, date, with_content):
     content = ''
     if with_content:
-      with open(self.base_path + "/ptdigest.html") as f:
+      with codecs.open(self.base_path + "/ptdigest.html", encoding='utf-8') as f:
         content = f.read()
 
-    name = date.strftime('slowquery_digest.txt-%Y-%m-%d')
+    name = date.strftime('slowquery_digest.txt-%Y-%m-%d.xz')
     oldtime = time.mktime(date.timetuple()) + 2000
-    with open( self.base_dir+name, 'a') as the_file:
+    with lzma.open( self.base_dir+name, 'at') as the_file:
       the_file.write(content)
     os.utime(self.base_dir+name, ( oldtime , oldtime ))
     
   def _remove_file(self, date):
-    name = date.strftime('slowquery_digest.txt-%Y-%m-%d')
+    name = date.strftime('slowquery_digest.txt-%Y-%m-%d.xz')
     os.remove(self.base_dir+name)
 
   def setUp(self):