Convert SetInstanceParams to concurrency

[ganeti-local] / lib / cmdlib.py

diff --git a/lib/cmdlib.py b/lib/cmdlib.py
index 49a557c..1fa6be7 100644 (file)
--- a/lib/cmdlib.py
+++ b/lib/cmdlib.py
@@ -217,6 +217,28 @@ class LogicalUnit(object):
     """
     return lu_result
 
+  def _ExpandAndLockInstance(self):
+    """Helper function to expand and lock an instance.
+
+    Many LUs that work on an instance take its name in self.op.instance_name
+    and need to expand it and then declare the expanded name for locking. This
+    function does it, and then updates self.op.instance_name to the expanded
+    name. It also initializes needed_locks as a dict, if this hasn't been done
+    before.
+
+    """
+    if self.needed_locks is None:
+      self.needed_locks = {}
+    else:
+      assert locking.LEVEL_INSTANCE not in self.needed_locks, \
+        "_ExpandAndLockInstance called with instance-level locks set"
+    expanded_name = self.cfg.ExpandInstanceName(self.op.instance_name)
+    if expanded_name is None:
+      raise errors.OpPrereqError("Instance '%s' not known" %
+                                  self.op.instance_name)
+    self.needed_locks[locking.LEVEL_INSTANCE] = expanded_name
+    self.op.instance_name = expanded_name
+
 
 class NoHooksLU(LogicalUnit):
   """Simple LU which runs no hooks.
@@ -3332,6 +3354,10 @@ class LUConnectConsole(NoHooksLU):
 
   """
   _OP_REQP = ["instance_name"]
+  REQ_BGL = False
+
+  def ExpandNames(self):
+    self._ExpandAndLockInstance()
 
   def CheckPrereq(self):
     """Check prerequisites.
@@ -3339,12 +3365,9 @@ class LUConnectConsole(NoHooksLU):
     This checks that the instance is in the cluster.
 
     """
-    instance = self.cfg.GetInstanceInfo(
-      self.cfg.ExpandInstanceName(self.op.instance_name))
-    if instance is None:
-      raise errors.OpPrereqError("Instance '%s' not known" %
-                                 self.op.instance_name)
-    self.instance = instance
+    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
+    assert self.instance is not None, \
+      "Cannot retrieve locked instance %s" % self.op.instance_name
 
   def Exec(self, feedback_fn):
     """Connect to the console of an instance
@@ -4074,6 +4097,10 @@ class LUSetInstanceParams(LogicalUnit):
   HPATH = "instance-modify"
   HTYPE = constants.HTYPE_INSTANCE
   _OP_REQP = ["instance_name"]
+  REQ_BGL = False
+
+  def ExpandNames(self):
+    self._ExpandAndLockInstance()
 
   def BuildHooksEnv(self):
     """Build hooks env.
@@ -4111,6 +4138,9 @@ class LUSetInstanceParams(LogicalUnit):
     This only checks the instance list against the existing names.
 
     """
+    # FIXME: all the parameters could be checked before, in ExpandNames, or in
+    # a separate CheckArguments function, if we implement one, so the operation
+    # can be aborted without waiting for any lock, should it have an error...
     self.mem = getattr(self.op, "mem", None)
     self.vcpus = getattr(self.op, "vcpus", None)
     self.ip = getattr(self.op, "ip", None)
@@ -4205,13 +4235,9 @@ class LUSetInstanceParams(LogicalUnit):
                                    " like a valid IP address" %
                                    self.op.vnc_bind_address)
 
-    instance = self.cfg.GetInstanceInfo(
-      self.cfg.ExpandInstanceName(self.op.instance_name))
-    if instance is None:
-      raise errors.OpPrereqError("No such instance name '%s'" %
-                                 self.op.instance_name)
-    self.op.instance_name = instance.name
-    self.instance = instance
+    self.instance = self.cfg.GetInstanceInfo(self.op.instance_name)
+    assert self.instance is not None, \
+      "Cannot retrieve locked instance %s" % self.op.instance_name
     return
 
   def Exec(self, feedback_fn):
@@ -4261,7 +4287,7 @@ class LUSetInstanceParams(LogicalUnit):
       instance.vnc_bind_address = self.vnc_bind_address
       result.append(("vnc_bind_address", self.vnc_bind_address))
 
-    self.cfg.AddInstance(instance)
+    self.cfg.Update(instance)
 
     return result