bpo-46063: Improve algorithm for computing which rolled-over log files to delete.

Author: vsajip

Lib/logging/handlers.py

@@ -366,9 +366,21 @@ def getFilesToDelete(self):
         fileNames = os.listdir(dirName)
         result = []
         # See bpo-44753: Don't use the extension when computing the prefix.
-        prefix = os.path.splitext(baseName)[0] + "."
+        n, e = os.path.splitext(baseName)
+        prefix = n + '.'
         plen = len(prefix)
         for fileName in fileNames:
+            if self.namer is None:
+                # Our files will always start with baseName
+                if not fileName.startswith(baseName):
+                    continue
+            else:
+                # Our files could be just about anything after custom naming, but
+                # likely candidates are of the form
+                # foo.log.DATETIME_SUFFIX or foo.DATETIME_SUFFIX.log
+                if not fileName.startswith(baseName) and fileName.endswith(e) and len(fileName) > (plen + 1) and not fileName[plen+1].isdigit():
+                    continue
+
             if fileName[:plen] == prefix:
                 suffix = fileName[plen:]
                 # See bpo-45628: The date/time suffix could be anywhere in the

Lib/test/test_logging.py

@@ -36,6 +36,7 @@
 import queue
 import random
 import re
+import shutil
 import socket
 import struct
 import sys
@@ -5434,6 +5435,53 @@ def test_compute_rollover_weekly_attime(self):
             finally:
                 rh.close()
 
+    def test_compute_files_to_delete(self):
+        # See bpo-46063 for background
+        wd = tempfile.mkdtemp(prefix='test_logging_')
+        self.addCleanup(shutil.rmtree, wd)
+        times = []
+        dt = datetime.datetime.now()
+        for i in range(10):
+            times.append(dt.strftime('%Y-%m-%d_%H-%M-%S'))
+            dt += datetime.timedelta(seconds=5)
+        prefixes = ('a.b', 'a.b.c', 'd.e', 'd.e.f')
+        files = []
+        rotators = []
+        for prefix in prefixes:
+            p = os.path.join(wd, '%s.log' % prefix)
+            rotator = logging.handlers.TimedRotatingFileHandler(p, when='s',
+                                                                interval=5,
+                                                                backupCount=7)
+            rotators.append(rotator)
+            if prefix.startswith('a.b'):
+                for t in times:
+                    files.append('%s.log.%s' % (prefix, t))
+            else:
+                rotator.namer = lambda name: name.replace('.log', '') + '.log'
+                for t in times:
+                    files.append('%s.%s.log' % (prefix, t))
+        # Open empty files
+        for fn in files:
+            p = os.path.join(wd, fn)
+            with open(p, 'wb') as f:
+                pass
+        # Now the checks that only the correct files are offered up for deletion
+        for i, prefix in enumerate(prefixes):
+            rotator = rotators[i]
+            candidates = rotator.getFilesToDelete()
+            self.assertEqual(len(candidates), 3)
+            if prefix.startswith('a.b'):
+                p = '%s.log.' % prefix
+                for c in candidates:
+                    d, fn = os.path.split(c)
+                    self.assertTrue(fn.startswith(p))
+            else:
+                for c in candidates:
+                    d, fn = os.path.split(c)
+                    self.assertTrue(fn.endswith('.log'))
+                    self.assertTrue(fn.startswith(prefix + '.') and
+                                    fn[len(prefix) + 2].isdigit())
+
 
 def secs(**kw):
     return datetime.timedelta(**kw) // datetime.timedelta(seconds=1)