From c6cb84bd63135d62ccd7ed9b23b245c41e9f105c Mon Sep 17 00:00:00 2001
From: Gorka Eguileor <geguileo@redhat.com>
Date: Wed, 24 Jan 2018 17:00:19 +0100
Subject: [PATCH] Remove logging on Swift backup obj writer

Since change I1f1d9c0d6e3f04f1ecd5ef7c5d813005ee116409 we are running
parts of the backups on native threads, which due to an eventlet bug [1]
have bad interactions with greenthreads, so we have to avoid any logging
when executing code in a native thread.

This patch removes the MD5 logging on the SwiftObjectWriter close
method and adds comments and docstring referring to this limitation.

[1] https://github.com/eventlet/eventlet/issues/432

Closes-Bug: #1745168
Change-Id: I0857cecd7d8ab0ee7e3e9bd6e15f4987ede4d653
---
 cinder/backup/chunkeddriver.py | 20 +++++++++++++++++---
 cinder/backup/drivers/swift.py |  4 ----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/cinder/backup/chunkeddriver.py b/cinder/backup/chunkeddriver.py
index 1752f12e663..a5436154244 100644
--- a/cinder/backup/chunkeddriver.py
+++ b/cinder/backup/chunkeddriver.py
@@ -56,6 +56,11 @@ CONF = cfg.CONF
 CONF.register_opts(chunkedbackup_service_opts)
 
 
+# Object writer and reader returned by inheriting classes must not have any
+# logging calls, as well as the compression libraries, as eventlet has a bug
+# (https://github.com/eventlet/eventlet/issues/432) that would result in
+# failures.
+
 @six.add_metaclass(abc.ABCMeta)
 class ChunkedBackupDriver(driver.BackupDriver):
     """Abstract chunked backup driver.
@@ -138,14 +143,23 @@ class ChunkedBackupDriver(driver.BackupDriver):
     def get_object_writer(self, container, object_name, extra_metadata=None):
         """Returns a writer object which stores the chunk data in backup repository.
 
-           The object returned should be a context handler that can be used
-           in a "with" context.
+        The object returned should be a context handler that can be used in a
+        "with" context.
+
+        The object writer methods must not have any logging calls, as eventlet
+        has a bug (https://github.com/eventlet/eventlet/issues/432) that would
+        result in failures.
         """
         return
 
     @abc.abstractmethod
     def get_object_reader(self, container, object_name, extra_metadata=None):
-        """Returns a reader object for the backed up chunk."""
+        """Returns a reader object for the backed up chunk.
+
+        The object reader methods must not have any logging calls, as eventlet
+        has a bug (https://github.com/eventlet/eventlet/issues/432) that would
+        result in failures.
+        """
         return
 
     @abc.abstractmethod
diff --git a/cinder/backup/drivers/swift.py b/cinder/backup/drivers/swift.py
index 270d032e337..2d2d013130e 100644
--- a/cinder/backup/drivers/swift.py
+++ b/cinder/backup/drivers/swift.py
@@ -281,11 +281,7 @@ class SwiftBackupDriver(chunkeddriver.ChunkedBackupDriver):
                                             content_length=len(self.data))
             except socket.error as err:
                 raise exception.SwiftConnectionFailed(reason=err)
-            LOG.debug('swift MD5 for %(object_name)s: %(etag)s',
-                      {'object_name': self.object_name, 'etag': etag, })
             md5 = hashlib.md5(self.data).hexdigest()
-            LOG.debug('backup MD5 for %(object_name)s: %(md5)s',
-                      {'object_name': self.object_name, 'md5': md5})
             if etag != md5:
                 err = _('error writing object to swift, MD5 of object in '
                         'swift %(etag)s is not the same as MD5 of object sent '