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authorJohn Snow <jsnow@redhat.com>2015-04-17 19:50:06 -0400
committerKevin Wolf <kwolf@redhat.com>2015-04-28 15:36:11 +0200
commit7898f74e78a5900fc079868e255b65d807fa8a8f (patch)
tree98cc9498b00bb5d7f9e39a920bac55803fb11e85 /scripts/qmp
parent9f7264f57c8307bca32e78427348b8b323d5db21 (diff)
iotests: add QMP event waiting queue
A filter is added to allow callers to request very specific events to be pulled from the event queue, while leaving undesired events still in the stream. This allows us to poll for completion data for multiple asynchronous events in any arbitrary order. A new timeout context is added to the qmp pull_event method's wait parameter to allow tests to fail if they do not complete within some expected period of time. Also fixed is a bug in qmp.pull_event where we try to retrieve an event from an empty list if we attempt to retrieve an event with wait=False but no events have occurred. Signed-off-by: John Snow <jsnow@redhat.com> Reviewed-by: Max Reitz <mreitz@redhat.com> Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com> Message-id: 1429314609-29776-19-git-send-email-jsnow@redhat.com Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com> Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Diffstat (limited to 'scripts/qmp')
-rw-r--r--scripts/qmp/qmp.py95
1 files changed, 65 insertions, 30 deletions
diff --git a/scripts/qmp/qmp.py b/scripts/qmp/qmp.py
index 20b6ec795e..1d38e3e9e7 100644
--- a/scripts/qmp/qmp.py
+++ b/scripts/qmp/qmp.py
@@ -21,6 +21,9 @@ class QMPConnectError(QMPError):
class QMPCapabilitiesError(QMPError):
pass
+class QMPTimeoutError(QMPError):
+ pass
+
class QEMUMonitorProtocol:
def __init__(self, address, server=False):
"""
@@ -72,6 +75,44 @@ class QEMUMonitorProtocol:
error = socket.error
+ def __get_events(self, wait=False):
+ """
+ Check for new events in the stream and cache them in __events.
+
+ @param wait (bool): block until an event is available.
+ @param wait (float): If wait is a float, treat it as a timeout value.
+
+ @raise QMPTimeoutError: If a timeout float is provided and the timeout
+ period elapses.
+ @raise QMPConnectError: If wait is True but no events could be retrieved
+ or if some other error occurred.
+ """
+
+ # Check for new events regardless and pull them into the cache:
+ self.__sock.setblocking(0)
+ try:
+ self.__json_read()
+ except socket.error, err:
+ if err[0] == errno.EAGAIN:
+ # No data available
+ pass
+ self.__sock.setblocking(1)
+
+ # Wait for new events, if needed.
+ # if wait is 0.0, this means "no wait" and is also implicitly false.
+ if not self.__events and wait:
+ if isinstance(wait, float):
+ self.__sock.settimeout(wait)
+ try:
+ ret = self.__json_read(only_event=True)
+ except socket.timeout:
+ raise QMPTimeoutError("Timeout waiting for event")
+ except:
+ raise QMPConnectError("Error while reading from socket")
+ if ret is None:
+ raise QMPConnectError("Error while reading from socket")
+ self.__sock.settimeout(None)
+
def connect(self, negotiate=True):
"""
Connect to the QMP Monitor and perform capabilities negotiation.
@@ -140,43 +181,37 @@ class QEMUMonitorProtocol:
"""
Get and delete the first available QMP event.
- @param wait: block until an event is available (bool)
+ @param wait (bool): block until an event is available.
+ @param wait (float): If wait is a float, treat it as a timeout value.
+
+ @raise QMPTimeoutError: If a timeout float is provided and the timeout
+ period elapses.
+ @raise QMPConnectError: If wait is True but no events could be retrieved
+ or if some other error occurred.
+
+ @return The first available QMP event, or None.
"""
- self.__sock.setblocking(0)
- try:
- self.__json_read()
- except socket.error, err:
- if err[0] == errno.EAGAIN:
- # No data available
- pass
- self.__sock.setblocking(1)
- if not self.__events and wait:
- self.__json_read(only_event=True)
- event = self.__events[0]
- del self.__events[0]
- return event
+ self.__get_events(wait)
+
+ if self.__events:
+ return self.__events.pop(0)
+ return None
def get_events(self, wait=False):
"""
Get a list of available QMP events.
- @param wait: block until an event is available (bool)
- """
- self.__sock.setblocking(0)
- try:
- self.__json_read()
- except socket.error, err:
- if err[0] == errno.EAGAIN:
- # No data available
- pass
- self.__sock.setblocking(1)
- if not self.__events and wait:
- ret = self.__json_read(only_event=True)
- if ret == None:
- # We are in blocking mode, if don't get anything, something
- # went wrong
- raise QMPConnectError("Error while reading from socket")
+ @param wait (bool): block until an event is available.
+ @param wait (float): If wait is a float, treat it as a timeout value.
+ @raise QMPTimeoutError: If a timeout float is provided and the timeout
+ period elapses.
+ @raise QMPConnectError: If wait is True but no events could be retrieved
+ or if some other error occurred.
+
+ @return The list of available QMP events.
+ """
+ self.__get_events(wait)
return self.__events
def clear_events(self):