From edd10f7a9c149f70d1d92a12d691a0d230aebba5 Mon Sep 17 00:00:00 2001
From: Corey Bryant <corey.bryant@canonical.com>
Date: Thu, 29 Sep 2022 11:51:52 -0400
Subject: [PATCH] Allow bmemcached to be optional for memcache_pool

This allows oslo_cache.memcache_pool to be used without the
python-binary-memcached package being installed, as it is
only required if sasl_enabled is set to True.

Closes-Bug: #1991250
Change-Id: I7e6cc83864be68e946d86b1f4b44847b95ea8b05
---
 oslo_cache/backends/memcache_pool.py                 | 10 +++++++++-
 releasenotes/notes/bug-1991250-23bc3463273e5a91.yaml |  7 +++++++
 2 files changed, 16 insertions(+), 1 deletion(-)
 create mode 100644 releasenotes/notes/bug-1991250-23bc3463273e5a91.yaml

diff --git a/oslo_cache/backends/memcache_pool.py b/oslo_cache/backends/memcache_pool.py
index fa640dc3..cf68a884 100644
--- a/oslo_cache/backends/memcache_pool.py
+++ b/oslo_cache/backends/memcache_pool.py
@@ -19,7 +19,13 @@ import functools
 
 from dogpile.cache.backends import memcached as memcached_backend
 
-from oslo_cache import _bmemcache_pool
+try:
+    from oslo_cache import _bmemcache_pool
+except ImportError as e:
+    if str(e) == "No module named 'bmemcached'":
+        _bmemcache_pool = None
+    else:
+        raise
 from oslo_cache import _memcache_pool
 
 
@@ -57,6 +63,8 @@ class PooledMemcachedBackend(memcached_backend.MemcachedBackend):
     def __init__(self, arguments):
         super(PooledMemcachedBackend, self).__init__(arguments)
         if arguments.get('sasl_enabled', False):
+            if not _bmemcache_pool:
+                raise ImportError("python-binary-memcached package is missing")
             self.client_pool = _bmemcache_pool.BMemcacheClientPool(
                 self.url,
                 arguments,
diff --git a/releasenotes/notes/bug-1991250-23bc3463273e5a91.yaml b/releasenotes/notes/bug-1991250-23bc3463273e5a91.yaml
new file mode 100644
index 00000000..43316ed4
--- /dev/null
+++ b/releasenotes/notes/bug-1991250-23bc3463273e5a91.yaml
@@ -0,0 +1,7 @@
+---
+fixes:
+  - |
+    [`bug 1991250 <https://bugs.launchpad.net/oslo.cache/+bug/1991250>`_]
+    The python-binary-memcached package is only required if sasl_enabled=True.
+    When sasl_enabled=False (default), the memcache_pool backend can be used
+    without the python-binary-memcached package installed.