Re: [libvirt-users] stream finish throws exception via python API

On 04/26/2016 09:35 AM, Shahar Havivi wrote: > On 26.04.16 15:30, Shahar Havivi wrote: >> On 26.04.16 14:14, Shahar Havivi wrote: >>> On 25.04.16 09:11, Cole Robinson wrote: >>>> On 04/25/2016 08:10 AM, Shahar Havivi wrote: >>>>> On 17.04.16 15:41, Shahar Havivi wrote: >>>>>> Hi, >>>>>> The following snippet works fine e.g. receiving the data but when calling >>>>>> stream.finish() we get the following error: >>>>>> >>>>>> stream = con.newStream() >>>>>> vol.download(stream, 0, 0, 0) >>>>>> buf = stream.recv(1024) >>>>>> stream.finish() >>>>>> >>>>>> libvirt: I/O Stream Utils error : internal error: I/O helper exited abnormally >>>>>> Traceback (most recent call last): >>>>>> File "./helpers/kvm2ovirt", line 149, in <module> >>>>>> download_volume(vol, item[1], diskno, disksitems, pksize) >>>>>> File "./helpers/kvm2ovirt", line 102, in download_volume >>>>>> stream.finish() >>>>>> File "/usr/lib64/python2.7/site-packages/libvirt.py", line 5501, in finish >>>>>> if ret == -1: raise libvirtError ('virStreamFinish() failed') >>>>>> libvirt.libvirtError: internal error: I/O helper exited abnormally >>>>>> >>>> >>>> The error message sucks, I'll send patches to improve it a little at least. >>>> >>>> What's happening here is that the you haven't read all the data you requested >>>> (it's vol.download(path, offset, length, flags), length == 0 means read the >>>> whole file which I suspect you haven't done). In this case the iohelper >>>> program that libvirt uses won't complete feeding us all the data, and it exits >>>> with SIGPIPE when we close the read end of the pipe. >>>> >>>> Now whether that should actually be an error condition is open to debate. >>>> virStreamFinish docs make it sound like it's legitimate to throw an error if >>>> it appears that all requested data wasn't read. >>> Thanks checking... >> Thanks Cole, >> I modify our script and for checking if stream.recv() returns zero the finish >> works fine. >> Our API needs to know the size of bytes that you are going to stream back >> which is not provided by the allocation and capacity. >> (ie the same as du -s /path/to/disk) >> >> Shahar. > We need the size of the image "Image end offset" you get from "qemu-img check", > Does libvirt have an API for that? > Libvirt doesn't invoke qemu-img check anywhere AFAIK, so if that's the only way to get that info, then it isn't available