virt plugin: Open connection on init() #2101
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If we use more than one reader instance, we can spot errors like this in the system logs: Dec 12 09:59:24 $HOST collectd[19338]: reading number of domains: invalid connection pointer in virConnectNumOfDomains Dec 12 09:59:24 benji.rokugan.lan collectd[19338]: read-function of plugin `virt-2' failed. Will suspend it for 20.000 seconds. This causes unnecessary delay in the sampling of libvirt. The reason for this is just one instance (always #0) takes care of establishing the libvirt connection. But this could be done safely in the plugin init callback: according to doc, this function is called at least once before all the read instances. Signed-off-by: Francesco Romani <fromani@redhat.com>
rubenk
reviewed
Dec 12, 2016
| @@ -732,6 +740,8 @@ static int lv_init(void) { | |||
| if (virInitialize() != 0) | |||
| return -1; | |||
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| lv_connect(); | |||
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Any reason you don't check for errors here?
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because we also handle reconnection in lv_read, it is ok if we fail here. But probably deserves a WARNING as well.
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Ah right. A warning could certainly do no harm.
Even though we handle disconnection and reconnection in the read() callback, we expect the libvirt connection to be available most of the time, including the init() stage. Thus, let's fail init() if the connection is not available. Signed-off-by: Francesco Romani <fromani@redhat.com>
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If we use more than one reader instance, we can spot errors like
this in the system logs:
Dec 12 09:59:24 $HOST collectd[19338]: reading number of
domains: invalid connection pointer in virConnectNumOfDomains
Dec 12 09:59:24 benji.rokugan.lan collectd[19338]: read-function of
plugin `virt-2' failed. Will suspend it for 20.000 seconds.
This causes unnecessary delay in the sampling of libvirt.
The reason for this is just one instance (always #0) takes care
of establishing the libvirt connection.
But this could be done safely in the plugin init callback: according
to doc, this function is called at least once before all the read
instances.
Signed-off-by: Francesco Romani fromani@redhat.com