db: Unify 'nova.db.api', 'nova.db.sqlalchemy.api'

Merge these, removing an unnecessary layer of abstraction, and place
them in the new 'nova.db.main' directory. The resulting change is huge,
but it's mainly the result of 's/sqlalchemy import api/main import api/'
and 's/nova.db.api/nova.db.main.api/' with some necessary cleanup. We
also need to rework how we do the blocking of API calls since we no
longer have a 'DBAPI' object that we can monkey patch as we were doing
before. This is now done via a global variable that is set by the 'main'
function of 'nova.cmd.compute'.

The main impact of this change is that it's no longer possible to set
'[database] use_db_reconnect' and have all APIs automatically wrapped in
a DB retry. Seeing as this behavior is experimental, isn't applied to
any of the API DB methods (which don't use oslo.db's 'DBAPI' helper),
and is used explicitly in what would appear to be the critical cases
(via the explicit 'oslo_db.api.wrap_db_retry' decorator), this doesn't
seem like a huge loss.

Change-Id: Iad2e4da4546b80a016e477577d23accb2606a6e4
Signed-off-by: Stephen Finucane <stephenfin@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/nova/hacking/checks.py b/nova/hacking/checks.py
index 4bdba6991b..b45f7254b5 100644
--- a/nova/hacking/checks.py
+++ b/nova/hacking/checks.py
@@ -184,8 +184,8 @@ def import_no_db_in_virt(logical_line, filename):
     N307
     """
     if "nova/virt" in filename and not filename.endswith("fake.py"):
-        if logical_line.startswith("from nova.db import api"):
-            yield (0, "N307: nova.db.api import not allowed in nova/virt/*")
+        if logical_line.startswith("from nova.db.main import api"):
+            yield (0, "N307: nova.db.* import not allowed in nova/virt/*")
 
 
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