[Kimchi-devel] [PATCH V4] [Kimchi] Handle Libvirt host ENOSPC event

[Lucio Correia]

When storage pool is out of space and guest requires more,
guest is paused and nothing is told to the user. This patch
uses Libvirt Event handling and Asynchronous Notifications
mechanism to tell web users about what happened.

Signed-off-by: Lucio Correia <luciojhc at linux.vnet.ibm.com>
---
 i18n.py                |  1 +
 model/libvirtevents.py | 28 ++++++++++++++++++++++++++++
 model/model.py         |  3 +++
 3 files changed, 32 insertions(+)

V4: try/except added for libvirt event callback registration

diff --git a/i18n.py b/i18n.py
index 3a5a9d1..2d8390f 100644
--- a/i18n.py
+++ b/i18n.py
@@ -335,6 +335,7 @@ messages = {
     "KCHEVENT0001E": _("Failed to register the default event implementation."),
     "KCHEVENT0002E": _("Failed to register timeout event."),
     "KCHEVENT0003E": _("Failed to Run the default event implementation."),
+    "KCHEVENT0004W": _("I/O error on guest '%(vm)s': storage pool out of space for %(devAlias)s (%(srcPath)s)."),
 
     # These messages (ending with L) are for user log purposes
     "KCHNET0001L": _("Created %(connection)s virtual network '%(name)s'"),
diff --git a/model/libvirtevents.py b/model/libvirtevents.py
index ab5c17d..6425f9b 100644
--- a/model/libvirtevents.py
+++ b/model/libvirtevents.py
@@ -22,6 +22,9 @@ import libvirt
 import time
 
 from wok.exception import OperationFailed
+from wok.message import WokMessage
+from wok.model.notifications import add_notification
+from wok.utils import wok_log
 
 
 class LibvirtEvents(object):
@@ -57,3 +60,28 @@ class LibvirtEvents(object):
     # Event loop handler used to limit length of waiting for any other event.
     def _kimchi_EventTimeout(self, timer, opaque):
         time.sleep(1)
+
+    def event_enospc_cb(self, conn, dom, path, dev, action, reason, args):
+        if reason == "enospc":
+            info = {
+                "vm": dom.name(),
+                "srcPath": path,
+                "devAlias": dev,
+            }
+            add_notification("KCHEVENT0004W", info, '/plugins/kimchi')
+            msg = WokMessage("KCHEVENT0004W", info, '/plugins/kimchi')
+            wok_log.warning(msg.get_text())
+
+    def handleEnospc(self, conn):
+        """
+        Register Libvirt IO_ERROR_REASON event to handle host ENOSPC
+        """
+        try:
+            conn.get().domainEventRegisterAny(
+                None,
+                libvirt.VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON,
+                self.event_enospc_cb,
+                libvirt.VIR_DOMAIN_EVENT_ID_IO_ERROR_REASON
+            )
+        except libvirt.libvirtError as e:
+            wok_log.error("Register of ENOSPC event failed: %s" % e.message)
diff --git a/model/model.py b/model/model.py
index ed474d2..327d5a7 100644
--- a/model/model.py
+++ b/model/model.py
@@ -50,6 +50,9 @@ class Model(BaseModel):
                  'eventsloop': self.events}
         models = []
 
+        # Register for Libvirt's host ENOSPC event and notify UI if it happens
+        self.events.handleEnospc(self.conn)
+
         # Import task model from Wok
         instances = get_instances('wok.model.tasks')
         for instance in instances:
-- 
1.9.1