Add 'set-weight' action.

This patchset adds the 'set-weight' action which can be used to set
weight of device(s) based on the search pattern.

Change-Id: I6bbc71f66d948e97d2dd6a5174dedb3212503a3f
Closes-Bug: 1821697

actions.yaml

@@ -58,3 +58,28 @@ remove-devices:
   required:
     - ring
     - search-value
+set-weight:
+  description: Sets the device's weight.
+  params:
+    ring:
+      type: string
+      description: |
+        Swift ring to set the weight for. Valid options are 'account',
+        'container', 'object' or 'all'.
+    search-value:
+      type: string
+      description: |
+        The search-value can be of the form:
+        .
+        d<device_id>r<region>z<zone>-<ip>:<port>R<r_ip>:<r_port>/
+         <device_name>_<meta>
+        .
+        Where <r_ip> and <r_port> are replication ip and port. Any part is
+        optional, but you must include at least one part.
+    weight:
+      type: number
+      description: The device's weight
+  required:
+    - ring
+    - search-value
+    - weight

actions/actions.py

@@ -51,6 +51,7 @@ from lib.swift_utils import (
     balance_rings,
     remove_from_ring,
     services,
+    set_weight_in_ring,
     SWIFT_CONF_DIR,
 )
 
@@ -147,10 +148,36 @@ def remove_devices(args):
     balance_rings()
 
 
+def set_weight(args):
+    """ Sets the device's weight.
+
+    Sets the device's weight based on the search pattern.
+
+    :raises SwiftProxyCharmException: if pattern action_get('search-value')
+        doesn't match any device in the ring.
+    """
+    rings_valid = ['account', 'container', 'object', 'all']
+    ring = action_get('ring')
+    if ring not in rings_valid:
+        action_fail('Invalid ring name.')
+        return
+    if ring == 'all':
+        rings_to_update = ['account', 'container', 'object']
+    else:
+        rings_to_update = [ring]
+    for ring_to_update in rings_to_update:
+        ring_to_update_builder = ring_to_update + '.builder'
+        ring_to_update_path = os.path.join(SWIFT_CONF_DIR,
+                                           ring_to_update_builder)
+        set_weight_in_ring(ring_to_update_path, action_get('search-value'),
+                           str(action_get('weight')))
+    balance_rings()
+
+
 # A dictionary of all the defined actions to callables (which take
 # parsed arguments).
 ACTIONS = {"pause": pause, "resume": resume, 'diskusage': diskusage,
-           'remove-devices': remove_devices}
+           'remove-devices': remove_devices, 'set-weight': set_weight}
 
 
 def main(argv):

actions/set-weight

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

lib/swift_utils.py

@@ -524,6 +524,29 @@ def remove_from_ring(ring_path, search_value):
             "{}".format(search_value, ring_path, e))
 
 
+def set_weight_in_ring(ring_path, search_value, weight):
+    """ Resets the device's weight.
+
+    Resets the device's weight based on the search pattern.
+
+    :param ring_path: path to the ring
+    :type ring_path: str
+    :param search_value: search pattern
+    :type search_value: str
+    :param weight: the device's weight
+    :type weight: str
+    :raises: SwiftProxyCharmException
+    """
+    cmd = ['swift-ring-builder', ring_path, 'set_weight', search_value, weight]
+    try:
+        subprocess.check_call(cmd)
+    except subprocess.CalledProcessError:
+        raise SwiftProxyCharmException(
+            "Failed to set {} weight for {} pattern on {}".format(weight,
+                                                                  search_value,
+                                                                  ring_path))
+
+
 def _ring_port(ring_path, node):
     """Determine correct port from relation settings for a given ring file."""
     for name in ['account', 'object', 'container']:

unit_tests/test_actions.py

@@ -335,3 +335,27 @@ class RemoveDevicesTestCase(CharmTestCase):
         self.action_fail.assert_called()
         self.remove_from_ring.assert_not_called()
         self.balance_rings.assert_not_called()
+
+
+class SetWeightTestCase(CharmTestCase):
+
+    def setUp(self):
+        super(SetWeightTestCase, self).setUp(
+            actions.actions, ["action_fail",
+                              "action_get",
+                              "set_weight_in_ring",
+                              "balance_rings"])
+
+    def test_ring_valid(self):
+        self.action_get.side_effect = ['account', 'd1', '0.0']
+        actions.actions.set_weight([])
+        self.set_weight_in_ring.assert_called_once_with(
+            '/etc/swift/account.builder', 'd1', '0.0')
+        self.balance_rings.assert_called_once()
+
+    def test_ring_invalid(self):
+        self.action_get.side_effect = ['other', 'd1', '0.0']
+        actions.actions.set_weight([])
+        self.action_fail.assert_called()
+        self.set_weight_in_ring.assert_not_called()
+        self.balance_rings.assert_not_called()

unit_tests/test_swift_utils.py

@@ -437,6 +437,15 @@ class SwiftUtilsTestCase(unittest.TestCase):
                                             'remove',
                                             'd1'])
 
+    @mock.patch.object(subprocess, 'check_call')
+    def test_set_weight_in_ring(self, check_call):
+        swift_utils.set_weight_in_ring('/etc/swift/account.builder', 'd1', 0.0)
+        check_call.assert_called_once_with(['swift-ring-builder',
+                                            '/etc/swift/account.builder',
+                                            'set_weight',
+                                            'd1',
+                                            0.0])
+
     @mock.patch('lib.swift_utils.config')
     @mock.patch('lib.swift_utils.set_os_workload_status')
     @mock.patch('lib.swift_utils.SwiftRingContext.__call__')