[ovirt-devel] Re: Need help in handling catch block in vdsm
On Tue, Sep 29, 2020 at 11:32 AM Michal Skrivanek
<michal.skrivanek(a)redhat.com> wrote:
[adding devel list]
On 29 Sep 2020, at 09:51, Ritesh Chikatwar <rchikatw(a)redhat.com> wrote:
Hello,
i am new to VDSM codebase.
There is one minor bug in gluster and they don't have any near plan to fix this. So i
need to fix this in vdsm.
The bug is when i run command
[root@dhcp35-237 ~]# gluster v geo-replication status
No active geo-replication sessions
geo-replication command failed
[root@dhcp35-237 ~]#
So this engine is piling up with error. i need handle this in vdsm the code at this
place
https://github.com/oVirt/vdsm/blob/master/lib/vdsm/gluster/cli.py#L1231
If i run the above command with xml then i will get
[root@dhcp35-237 ~]# gluster v geo-replication status --xml
geo-replication command failed
[root@dhcp35-237 ~]#
so i have to run one more command before executing this and check in exception that it
contains No active geo-replication sessions this string. for that i did like this
maybe it goes to stderr?
other than that, no idea, sorry
Thanks,
michal
try:
xmltree = _execGluster(command)
except ge.GlusterCmdFailedException as e:
if str(e).find("No active geo-replication sessions") != -1:
return []
The issue is that _execGluster is not implemented correctly, dropping
the stdout, stderror, and return the format string:
"Command {self.cmd} failed with rc={self.rc} out={self.out!r}
err={self.err!r}"
As the error, inside a list.
109 def _execGluster(cmd):
110 try:
111 return commands.run(cmd)
112 except cmdutils.Error as e:
113 raise ge.GlusterCmdFailedException(rc=e.rc, err=[e.msg])
After fixing this issue you will be able to search in the error message
of the original command, like this:
if "needle" in e.err:
But searching for text in an error message is fragile. It will break
if vdsm is running
with a different locale and the error message is localized, or if the
error message
is modified in a future gluster version.
The right thing is to fix the gluster tool so it it succeeds and
passes the error
code/message in a way that can be consumed by another program.
Looking at _getTree(), this is how it already behaves:
116 def _getTree(out):
117 try:
118 tree = etree.fromstring(out)
119 rv = int(tree.find('opRet').text)
120 msg = tree.find('opErrstr').text
121 errNo = int(tree.find('opErrno').text)
122 except _etreeExceptions: # pylint: disable=catching-non-exception
123 raise ge.GlusterXmlErrorException(err=out)
124 if rv == 0:
125 return tree
126 else:
127 if errNo != 0:
128 rv = errNo
129 raise ge.GlusterCmdFailedException(rc=rv, err=[msg])
Did you file a gluster bug for this?
Nir