Hi Vinny,
Thanks for your suggestions. As a redhead, I'll try not to take offence to
that :)
I have been working with app engine only for a couple of months, so all
code is relatively new. My *guess* is that I've been having a similar issue
pretty much from the start, it just took me a while to debug it (I think I
was being fooled by log messages prior to me flushing them). However, I was
originally working with the blobstore. Since I was having issues and that
has become deprecated, I switched to GCS - and have been having this exact
problem since.
I tried switching back to regular backends and removing my modules - same
behaviour.
I tried your suggestion of writing a single character, closing the file and
trying the larger write:
gcs_file = cloudstorage.open(filename, 'w', content_type=
'text/plain' )
self.debugMessage("opened file")
gcs_file.write("f")
self.debugMessage("One character written")
gcs_file.close()
self.debugMessage("file closed. Sleeping")
time.sleep(int(suffix) * 10)
gcs_file = cloudstorage.open(filename, 'w', content_type=
'text/plain')
self.debugMessage("opened file")
gcs_file.write("f" * 1024 * 1024 * 1 + '\n')
self.debugMessage("data written")
gcs_file.close()
self.debugMessage("file closed")
I ran this three times (10 instances each time) - in all cases the file is
written with the single character successfully, but a number of the larger
writes then hang.
I also enabled AppStats. However, it looks to me like the requests that
hang never reach the state of writing the AppStat log (e.g. I never see
something like "Saved; key: __appstats__:073900, part: 29 bytes, full: 1364
bytes" in the log), so I am not sure how that will be useful. Nonetheless,
I modified the AppStat code to allow public access (this is a test
application, no sensitive data), so if you wish to do so, you can check for
yourself at http://benstoragetest.appspot.com/stats
Thanks for your input,
Ben
On Wednesday, September 11, 2013 2:45:04 AM UTC+1, Vinny P wrote:
>
> On Tue, Sep 10, 2013 at 5:14 AM, Ben Smithers
> <smithe...@googlemail.com<javascript:>
> > wrote:
>
>> Has anyone else observed this behaviour? Does anyone have any suggestions
>> for what I am doing wrong?
>>
>>
>
> Backends are the red headed stepchild of GAE - they exhibit weird behavior
> periodically. Did these errors start happening recently, or is this new
> code? If you're using the Modules version of backends, can you try using
> regular backends (and not defining any modules whatsoever)?
>
> Can you try seeing what an AppStats profile of this request looks like?
> Here's the link:
> https://developers.google.com/appengine/docs/python/tools/appstats .
> Specifically, what I'm looking for is whether the library is hanging during
> the connection to GCS, and what the connection information looks like.
>
> If you don't want to install AppStats, you can also try splitting up file
> creation and writing to the file: create the file through the GCS library,
> write a single character, then close the connection. Sleep for a bit, then
> try writing to the file. The problem might isolate itself to a particular
> part of the file writing process.
>
> -----------------
> -Vinny P
> Technology & Media Advisor
> Chicago, IL
>
> App Engine Code Samples: http://www.learntogoogleit.com
>
>
>
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