Re: [Duplicity-talk] duplicity 0.7.02, freebsd and sftp backend -- how to further debug.

[Dirk-Willem van Gulik]

> On 03 May 2015, at 20:55, address@hidden wrote:
> 
> On 03.05.2015 19:16, Dirk-Willem van Gulik wrote:
>> 
>>> On 03 May 2015, at 18:58, address@hidden wrote:
>>> 
>>> On 03.05.2015 18:37, Dirk-Willem van Gulik wrote:
>>>> ------------ ------------ ------------ ------------ ------------ ——————
>>>> 
>>>> On a (new) 0.7.02 upgrade/install; which works fine with a file:/// 
>>>> backend to /tmp as a test — we’re finding that it hangs ‘forever’ on 
>>>> ‘sftp’.
>>>> 
>>>> sftp itself works fine; and when we place a few files there - we can see 
>>>> in the output that they are nicely seen; and ignored (as is the .ssh 
>>>> directory with the right authorized_keys magic).
>>>> 
>>>> Below is the command used and the output. Any suggestion as to where/how 
>>>> to start debugging this ?
>>>> 
>>>> The main change with prior version/use is a sharply increased volume and 
>>>> going to version 0.7.02 (as python needed to be upgraded).
>>>> 
>>> 
>>> the keepalive & EOFError parts suggest that your ssh connection is dropped 
>>> after a while. check if that is disabled for some reason in your ssh server 
>>> settings.
>>> 
>>> alternatively use the old pexpect ssh backend.
>>> 
>> 
>> Thanks - debugging with this (Setting timeout to a few hours) and looking at 
>> tcpdump suggests that after
>> 
>>      ssh: [chan 1] open('/duplicity-full.20150503T171238Z.vol1.difftar.gpg', 
>> 'wb')
>>      ssh: [chan 1] open('/duplicity-full.20150503T171238Z.vol1.difftar.gpg', 
>> 'wb') -> 39323765383430333130396635343637
>> 
>> no traffic is sent at all but for the occasional:
>> 
>>      ssh: Sending global request "address@hidden"
>>      ssh: Sending global request "address@hidden"
>>      ssh: Sending global request "address@hidden
>> 
>> requests. It is almost as if duplicity is not streaming at all. An identical 
>> command to ‘file://' shows the files getting created and sent/written just 
>> fine.
>> 
> 
> well, 
> 
> 1.does '--ssh-backend pexpect' at least work as expected?

Well - I believe/from the code I gather that ‘-ssh-backend' is retired in 
0.7.02; but using pexpect+sftp://address@hidden does the trick.

And yes - it works as expected. Sorry for not being clear there.

> 2. what do you mean by 'setting timeout’?

The client-no data timeout values in sshd; as well as kernel TCP setting to 
avoid the TCP conncetion getting closed that way; as well as ssh-paramiko’s 
globals.timeout driven timeout.

> 3. does duplicity come up with a stacktrace _and_ still hang using paramiko?

The connection hangs (strace shows no data sent on that file descriptor ever 
(after an successful ls earlier) — until the stacktrace at which point all fd’s 
are closed and things are rolled up.

> 4. what is your paramiko version?

Set to 1.14.0.

Dw.