----- Original Message -----
From: "Nir Soffer" <nsoffer@redhat.com> To: "Yaniv Bronheim" <ybronhei@redhat.com> Cc: "Shahar Havivi" <shaharh@redhat.com>, "Richard Jones" <rjones@redhat.com>, "devel" <devel@ovirt.org> Sent: Tuesday, July 19, 2016 4:18:31 PM Subject: Re: [ovirt-devel] execCmd() and storing stdout and stderr in log file
On Tue, Jul 19, 2016 at 5:07 PM, Yaniv Bronheim <ybronhei@redhat.com> wrote:
On Tue, Jul 19, 2016 at 4:56 PM, Tomáš Golembiovský <tgolembi@redhat.com> wrote:
On Thu, 14 Jul 2016 17:25:28 +0300 Nir Soffer <nsoffer@redhat.com> wrote:
After https://gerrit.ovirt.org/#/c/46733/ you should be able to create the pipeline in python like this:
v2v = Popen(["virt-v2v", ...], stdout=PIPE, stderr=STDOUT) tee = Popen(["tee", "-a", logfile], stdin=v2v.stdout, stdout=PIPE, stderr=PIPE)
Now we can read output from tee.stdout, and when tee is finished, we can wait for v2v to get the exit code.
Since all output would go to tee stdout and stderr may only contain tee usage errors, we don't need to use AsyncProc, making this code python 3 compatible.
Yes, this may actualy work. And do we plan to adopt the cpopen 1.4.1, where this is fixed, in VDSM?
cpopen 1.5.1 - and yes but not in ovirt-4.0
It is included in 1.4.1, released ages ago.
$ git log --oneline --decorate 826b5ef (HEAD -> master, origin/master, origin/HEAD) Raise version for 1.5 build a9d2a72 (inherit-fds) Add tests for disabling the close-on-exec flag 7163e79 Do not close inherited fds from parent 1b170fb (gerrit/master) Raising release number and tagging cpopen 1.4.1 69ae841 Sort imports to make it easier to add new imports 1116830 Simplify tests using CPopen.communicate() 58e1b43 Remove unneeded and wrong retry after fork fbf9ff3 Remove wrong and unneeded retry for execv 74ee4a0 Do not retry close() after interrupt 1abde2b Use _exit to terminate child after failure 8709c42 Fix incorrect fd closing
$ git show 1b170fb --format=fuller commit 1b170fb8f2d204457ca66e53936fd3a059f4ed4b Author: Yaniv Bronhaim <ybronhei@redhat.com> AuthorDate: Wed Oct 14 15:40:07 2015 +0300 Commit: Yaniv Bronhaim <ybronhei@redhat.com> CommitDate: Wed Oct 14 09:36:31 2015 -0400
Raising release number and tagging cpopen 1.4.1
Recent patches include only bug fixes. see commit messages
Change-Id: Ia1d32dd5bd7f60681b64251cef217c8d1e41b14b Signed-off-by: Yaniv Bronhaim <ybronhei@redhat.com>
Thanks to everyone for comments and insights. I think is time to wrap up so Tomas can finish his work. So, the options on the table are: 1. Build pipelines in python (Nir's approach above) - looks like the the fix is in cpopen 1.4.1, available 2. add options to execCmd to redirect stderr - make execCmd even bigger, makes everyone grumpy - could require a couple of simple fixes (talked with Tomas privately, nothing groundbreaking - like one between stdout and stderr could be None and we must cope with that) 3. DUP execCmd just for v2v and just to avoid making it more complex - see https://gerrit.ovirt.org/#/c/60660/ - even worse than extending execCmd? - still needs the fixes above 4. use shell tricks and reuse existing execCmd - reviewers/future selves needs to wrap their head on that shell magic - PERHAPS fragile? I don't really know 5. something else I forgot? I think the approaches here are ordered by likeness and feasibility, so I'd actually try in this order (1->2->3->4) Please ACK/NACK the above, so Tomas can conclude this patch for next monday (20160725) -- Francesco Romani RedHat Engineering Virtualization R & D Phone: 8261328 IRC: fromani