Cleanup action for service-list after deploying HA.

This is a workaround for LP: #1493931 in order to keep the
output of cinder service-list clean after deploying a HA.

The rationale behind this is to expose a way to cleanup the
services table on the database from unused ones ,
those services were
created by cinder before the storage relation is joined (particularly
for stateless ones).

This action also exposes the host option to specify
the host to be removed.

By default if no host is provided, this action will
cleanup all the entries different to the ones
specified on the DEFAULT_SERVICES constant.

An example of execution can be found on the comment
section of this proposal.

Change-Id: I4a5e682e44206f7b77d873cb1fc63e3eae86aad5
Related-Bug: 1493931
Signed-off-by: Jorge Niedbalski <jorge.niedbalski@canonical.com>

actions.yaml

@@ -2,3 +2,10 @@ git-reinstall:
   description: Reinstall cinder from the openstack-origin-git repositories.
 openstack-upgrade:
   description: Perform openstack upgrades. Config option action-managed-upgrade must be set to True.
+remove-services:
+  description: Remove unused services entities from the database after enabling HA with a stateless backend such as cinder-ceph.
+  params:
+    host:
+      type: string
+      default: unused
+      description: Hostname of the service to be removed.

actions/remove-services

@@ -0,0 +1 @@
+remove_services.py

actions/remove_services.py

@@ -0,0 +1,82 @@
+#!/usr/bin/env python
+
+import os
+import sys
+import traceback
+import subprocess
+
+sys.path.append('hooks/')
+
+from cinder import context
+from cinder import db
+from cinder.db.sqlalchemy.api import model_query, get_session
+from cinder.db.sqlalchemy import models
+
+from charmhelpers.contrib.openstack.utils import os_release
+
+from sqlalchemy import and_
+from charmhelpers.core.hookenv import (
+    action_set,
+    action_fail,
+    action_get,
+    log,
+)
+
+DEFAULT_SERVICES = (
+    "cinder",
+    "cinder@cinder-ceph",
+)
+
+try:
+    from cinder import flags
+    cfg = flags.FLAGS
+except ImportError:
+    from cinder.common.config import CONF
+    cfg = CONF
+
+
+def load_config_file(conf):
+    cfg(args=[], project='cinder', default_config_files=[conf])
+
+
+def cinder_manage_remove(binary, hostname):
+    return subprocess.check_call(["cinder-manage", "service", "remove", binary,
+                                  hostname])
+
+
+def remove_services():
+    load_config_file(os.path.join(os.path.sep, "etc", "cinder", "cinder.conf"))
+
+    host = action_get(key="host")
+    services = model_query({}, models.Service, read_deleted="no",
+                           session=get_session())
+
+    if host not in ("unused", "",):
+        services = services.filter(models.Service.host == host)
+    else:
+        ands = []
+        for service in DEFAULT_SERVICES:
+            ands.append(and_(models.Service.host != service))
+        services = services.filter(*ands)
+
+    removed_services = []
+    ctxt = context.get_admin_context()
+
+    for service in services.all():
+        log("Removing service:%d, hostname:%s" % (service.id, service.host))
+        try:
+            if os_release("cinder") >= "liberty":
+                cinder_manage_remove(service.binary, service.host)
+            else:
+                db.service_destroy(ctxt, service.id)
+        except:
+            action_set({'traceback': traceback.format_exc()})
+            action_fail("Cannot remove service: %s" % service.host)
+        else:
+            removed_services.append(service.host)
+
+    action_set({'removed': ",".join(removed_services)})
+
+
+if __name__ == "__main__":
+    remove_services()