Replicas per ring

This patchset implements 'replicas-account' and 'replicas-container'
charm options which can be used to set the desired number of replicas
per ring.

Change-Id: Ie7fa1b8c5619d0a5a278cd0eddaf1051de11f2a3
Closes-Bug: 1823696

config.yaml

@@ -102,7 +102,21 @@ options:
   replicas:
     type: int
     default: 3
-    description: Minimum replicas for each object stored in the cluster.
+    description: Minimum replicas for each item stored in the cluster.
+  replicas-account:
+    type: int
+    default:
+    description: |
+      Minimum replicas for each account stored in the cluster.
+      .
+      NOTE: use only when you want to overwrite the global 'replicas' option.
+  replicas-container:
+    type: int
+    default:
+    description: |
+      Minimum replicas for each container stored in the cluster.
+      .
+      NOTE: use only when you want to overwrite the global 'replicas' option.
   min-hours:
     type: int
     default: 0

hooks/swift_hooks.py

@@ -65,6 +65,7 @@ from lib.swift_utils import (
     assess_status,
     try_initialize_swauth,
     clear_storage_rings_available,
+    determine_replicas,
 )
 
 import charmhelpers.contrib.openstack.utils as openstack
@@ -161,11 +162,11 @@ def config_changed():
     if is_elected_leader(SWIFT_HA_RES):
         log("Leader established, generating ring builders", level=INFO)
         # initialize new storage rings.
-        for path in SWIFT_RINGS.values():
+        for ring, path in SWIFT_RINGS.items():
             if not os.path.exists(path):
                 initialize_ring(path,
                                 config('partition-power'),
-                                config('replicas'),
+                                determine_replicas(ring),
                                 config('min-hours'))
 
     if config('prefer-ipv6'):

lib/swift_utils.py

@@ -1199,7 +1199,12 @@ def customer_check_assess_status(configs):
 
     # Verify allowed_hosts is populated with enough unit IP addresses
     ctxt = SwiftRingContext()()
-    if len(ctxt['allowed_hosts']) < config('replicas'):
+    replicas = [config('replicas'),
+                config('replicas-account'),
+                config('replicas-container')]
+    # Remove 'None' object types from the list
+    replicas = [r for r in replicas if r is not None]
+    if len(ctxt['allowed_hosts']) < max(replicas):
         return ('blocked', 'Not enough related storage nodes')
 
     # Verify there are enough storage zones to satisfy minimum replicas
@@ -1273,3 +1278,27 @@ def assess_status_func(configs, check_services=None):
         configs, required_interfaces,
         charm_func=customer_check_assess_status,
         services=check_services, ports=None)
+
+
+def determine_replicas(ring):
+    """ Determine replicas (lp1823696)
+
+    Determine replicas based on 'replicas', 'replicas-account' and
+    'replicas-container' options.
+
+    :param ring: ring name
+    :type ring: str
+    :returns: replicas for the ring
+    """
+    if ring == 'account':
+        if config('replicas-account'):
+            return config('replicas-account')
+        else:
+            return config('replicas')
+    elif ring == 'container':
+        if config('replicas-container'):
+            return config('replicas-container')
+        else:
+            return config('replicas')
+    else:
+        return config('replicas')

unit_tests/test_swift_utils.py

@@ -437,7 +437,7 @@ class SwiftUtilsTestCase(unittest.TestCase):
     def customer_check_assess_status(
             self, relation_ids, has_min_zones,
             ctxt, workload_status, config):
-        config.return_value = 3
+        config.side_effect = [3, 3, 3]
 
         relation_ids.return_value = []
         s, m = swift_utils.customer_check_assess_status(None)
@@ -596,3 +596,48 @@ class SwiftUtilsTestCase(unittest.TestCase):
              'python-keystonemiddleware'],
             swift_utils.determine_packages('rocky')
         )
+
+    @mock.patch('lib.swift_utils.config')
+    def test_determine_replicas_account_set(self, config):
+        config.side_effect = lambda key: {
+            'replicas': 3,
+            'replicas-account': 2,
+            'replicas-container': None}[key]
+        replicas = swift_utils.determine_replicas('account')
+        self.assertEqual(replicas, 2)
+
+    @mock.patch('lib.swift_utils.config')
+    def test_determine_replicas_account_not_set(self, config):
+        config.side_effect = lambda key: {
+            'replicas': 3,
+            'replicas-account': None,
+            'replicas-container': None}[key]
+        replicas = swift_utils.determine_replicas('account')
+        self.assertEqual(replicas, 3)
+
+    @mock.patch('lib.swift_utils.config')
+    def test_determine_replicas_container_set(self, config):
+        config.side_effect = lambda key: {
+            'replicas': 3,
+            'replicas-account': None,
+            'replicas-container': 2}[key]
+        replicas = swift_utils.determine_replicas('container')
+        self.assertEqual(replicas, 2)
+
+    @mock.patch('lib.swift_utils.config')
+    def test_determine_replicas_container_not_set(self, config):
+        config.side_effect = lambda key: {
+            'replicas': 3,
+            'replicas-account': None,
+            'replicas-container': None}[key]
+        replicas = swift_utils.determine_replicas('container')
+        self.assertEqual(replicas, 3)
+
+    @mock.patch('lib.swift_utils.config')
+    def test_determine_replicas_object(self, config):
+        config.side_effect = lambda key: {
+            'replicas': 3,
+            'replicas-account': 2,
+            'replicas-container': 2}[key]
+        replicas = swift_utils.determine_replicas('object')
+        self.assertEqual(replicas, 3)