Re: [Twisted-Python] ugh open-ssl and twisted python

[Glyph]

On Jul 27, 2013, at 3:12 PM, gary clark  wrote:

> Ok finally fixed the damn thing. I made the packets smaller and created a 
> task in the .tac file to call a  routine that send the message parts piece by 
> piece.
>  
> Thanks,
> Gazza
> 

That's the wrong way to implement that.  You can't rely on any particular MTU 
over the internet, or even over one particular stream; it can change over time. 
 TCP connections are streams of bytes.  Please see the following FAQ:



-glyph

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Re: [Twisted-Python] ugh open-ssl and twisted python

[gary clark]

Ok finally fixed the damn thing. I made the packets smaller and created a task 
in the .tac file to call a  routine that send the message parts piece by piece.
 
Thanks,
Gazza

From: gary clark 
To: gary clark ; Twisted general discussion 
; Twisted general discussion 
 
Sent: Saturday, July 27, 2013 2:38 PM
Subject: Re: [Twisted-Python] ugh open-ssl and twisted python



Ok split my data up into smaller fragments. It still look like its reassembing 
the whole payload
before sending it to the client. I'm calling transport.write(partdata) multiple 
times with a 0.5 second delay running in a twisted thread. How can I force the 
write to happen straight away in twisted.
 
Sorry for all the questions.
 
Thanks,
Gazza

From: gary clark 
To: Twisted general discussion  
Sent: Saturday, July 27, 2013 12:36 PM
Subject: Re: [Twisted-Python] ugh open-ssl and twisted python



Guys,

Its the MTU size. Anything bigger than 1500 bytes is getting fragmented.
Using wireshark I'm seeing TCP Previous segment lost anything bigger than 1500. 
However once that
happens things go south and remain there.

Oh boy one day I will learn but not today.

Cheers,
Gazza

From: "exar...@twistedmatrix.com" 
To: Twisted general discussion  
Sent: Saturday, July 27, 2013 12:27 PM
Subject: Re: [Twisted-Python] ugh open-ssl and twisted python


On 04:08 pm, burslem2...@yahoo.com wrote:
> Hello,
> 
> This problem has been driving me crazy for a couple of days. I'm hoping 
> someone can shed some light
> on this. I have a twisted server its using open-ssl (using certificates) and 
> runs on linux and communicates great with a windows client thats send 
> messages every second.
> 
> However when I send data back to the client "sometimes" it doesnt receive the 
> packet and there is no indication of failure at the client whats more I dont 
> see any failure on the twisted server end. Is there any way I can tell what 
> could cause this failure? It just look like the transport.write(data) fails 
> just dont know why it would when receiving works like a charm.
> 
> Any help on this would relieve the pain I'm feeling right now.

Please see http://sscce.org/

Jean-Paul

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Re: [Twisted-Python] ugh open-ssl and twisted python

[gary clark]

Ok split my data up into smaller fragments. It still look like its reassembing 
the whole payload
before sending it to the client. I'm calling transport.write(partdata) multiple 
times with a 0.5 second delay running in a twisted thread. How can I force the 
write to happen straight away in twisted.
 
Sorry for all the questions.
 
Thanks,
Gazza

From: gary clark 
To: Twisted general discussion  
Sent: Saturday, July 27, 2013 12:36 PM
Subject: Re: [Twisted-Python] ugh open-ssl and twisted python



Guys,

Its the MTU size. Anything bigger than 1500 bytes is getting fragmented.
Using wireshark I'm seeing TCP Previous segment lost anything bigger than 1500. 
However once that
happens things go south and remain there.

Oh boy one day I will learn but not today.

Cheers,
Gazza

From: "exar...@twistedmatrix.com" 
To: Twisted general discussion  
Sent: Saturday, July 27, 2013 12:27 PM
Subject: Re: [Twisted-Python] ugh open-ssl and twisted python


On 04:08 pm, burslem2...@yahoo.com wrote:
> Hello,
> 
> This problem has been driving me crazy for a couple of days. I'm hoping 
> someone can shed some light
> on this. I have a twisted server its using open-ssl (using certificates) and 
> runs on linux and communicates great with a windows client thats send 
> messages every second.
> 
> However when I send data back to the client "sometimes" it doesnt receive the 
> packet and there is no indication of failure at the client whats more I dont 
> see any failure on the twisted server end. Is there any way I can tell what 
> could cause this failure? It just look like the transport.write(data) fails 
> just dont know why it would when receiving works like a charm.
> 
> Any help on this would relieve the pain I'm feeling right now.

Please see http://sscce.org/

Jean-Paul

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Re: [Twisted-Python] ugh open-ssl and twisted python

[gary clark]

Guys,
 
Its the MTU size. Anything bigger than 1500 bytes is getting fragmented.
Using wireshark I'm seeing TCP Previous segment lost anything bigger than 1500. 
However once that
happens things go south and remain there.
 
Oh boy one day I will learn but not today.
 
Cheers,
Gazza
 
From: "exar...@twistedmatrix.com" 
To: Twisted general discussion  
Sent: Saturday, July 27, 2013 12:27 PM
Subject: Re: [Twisted-Python] ugh open-ssl and twisted python


On 04:08 pm, burslem2...@yahoo.com wrote:
> Hello,
> 
> This problem has been driving me crazy for a couple of days. I'm hoping 
> someone can shed some light
> on this. I have a twisted server its using open-ssl (using certificates) and 
> runs on linux and communicates great with a windows client thats send 
> messages every second.
> 
> However when I send data back to the client "sometimes" it doesnt receive the 
> packet and there is no indication of failure at the client whats more I dont 
> see any failure on the twisted server end. Is there any way I can tell what 
> could cause this failure? It just look like the transport.write(data) fails 
> just dont know why it would when receiving works like a charm.
> 
> Any help on this would relieve the pain I'm feeling right now.

Please see http://sscce.org/

Jean-Paul

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Re: [Twisted-Python] ugh open-ssl and twisted python

[exarkun]

On 04:08 pm, burslem2...@yahoo.com wrote:

Hello,

This problem has been driving me crazy for a couple of days. I'm hoping 
someone can shed some light
on this. I have a twisted server its using open-ssl (using 
certificates) and runs on linux and communicates great with a windows 
client thats send messages every second.


However when I send data back to the client "sometimes" it doesnt 
receive the packet and there is no indication of failure at the client 
whats more I dont see any failure on the twisted server end. Is there 
any way I can tell what could cause this failure? It just look like the 
transport.write(data) fails just dont know why it would when receiving 
works like a charm.


Any help on this would relieve the pain I'm feeling right now.


Please see http://sscce.org/

Jean-Paul

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Re: [Twisted-Python] ugh open-ssl and twisted python

[Laurens Van Houtven]

Hi Gary,

On Sat, Jul 27, 2013 at 6:08 PM, gary clark  wrote:

> Hello,
>
> This problem has been driving me crazy for a couple of days. I'm hoping
> someone can shed some light
> on this. I have a twisted server its using open-ssl (using certificates)
> and runs on linux and communicates great with a windows client thats send
> messages every second.
>
> However when I send data back to the client "sometimes" it doesnt receive
> the packet and there is no indication of failure at the client whats more I
> dont see any failure on the twisted server end.
>

When you say "packet", does that mean "actual IP packet that you observed
leaving the server", or do you mean "the thing I passed to transport.write"?


> Is there any way I can tell what could cause this failure? It just look
> like the transport.write(data) fails just dont know why it would when
> receiving works like a charm.
>

So, it fails silently? Keep in mind that transport.write working doesn't
necessarily mean that anything on the other end has successfully read it:
that's why good RPC mechanisms like AMP have positive acknowedgement :)


> Any help on this would relieve the pain I'm feeling right now.
>

How are these two servers connected? Can you reliably reproduce the
problem? Does it persist with other transports? Could you shed some more
light on what you mean by "sometimes"?

cheers
lvh
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[Twisted-Python] ugh open-ssl and twisted python

[gary clark]

Hello,
 
This problem has been driving me crazy for a couple of days. I'm hoping someone 
can shed some light
on this. I have a twisted server its using open-ssl (using certificates) and 
runs on linux and communicates great with a windows client thats send messages 
every second.
 
However when I send data back to the client "sometimes" it doesnt receive the 
packet and there is no indication of failure at the client whats more I dont 
see any failure on the twisted server end. Is there any way I can tell what 
could cause this failure? It just look like the transport.write(data) fails 
just dont know why it would when receiving works like a charm.
 
Any help on this would relieve the pain I'm feeling right now.
 
Much Appreciated,
Gazza___
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Re: [Twisted-Python] Trial & the mock library

[Jonathan Lange]

On Sat, Jul 27, 2013 at 5:26 AM, Glyph  wrote:

>
> On Jul 26, 2013, at 7:12 AM, exar...@twistedmatrix.com wrote:
>
> To address this problem, I suggest you get into the habit of watching your
> unit tests fail in the expected way before you make the necessary
> implementation changes to make them pass.
>
> This is only one of an unlimited number of ways your unit tests can be
> buggy.  It might be tempting to try to fix the test runner to prevent you
> from ever falling into this trap again - and who knows, it might even be a
> good idea.
> However, if you run your tests and see them fail in the way you expected
> them to fail before you write the code that makes them pass, then you will
> be sure to avoid the many, many, many *other* pitfalls that have nothing to
> do with accidentally returning the wrong object.
>
> This is just one of the attractions of test-driven development for me.
>
>
> On a more serious note than our previous digression, perhaps *this* is the
> thing we should be modifying Trial to support.
>
> The vast majority of Twisted committers do development this way - or at
> least aspire to, most of the time - but to someone new to automated
> testing, it's not entirely clear *how* you're supposed to use something
> like Trial, or how important it is that you see the tests fail first.
>
> Perhaps if trial had a bit more of a memory of things that happened
> between test runs it would be useful.  For example, a mode where you could
> tell it what you're working on, and you could just re-run the same thing
> and you'd only get a 'success' when you went back and forth between red and
> green.
>
> Here's a silly little narrative about how one might use such a thing:
>
> $ tribulation begin myproject
> Beginning a time of turmoil for python package 'myproject', in
> './myproject/'.
> myproject.test_1
>   Case1
> test_1 ...
>   [OK]
>
>
> ---
> Ran 2 tests in 0.033s
>
> PROCEED (successes=1) - All tests passing, an auspicious beginning. Now
> write a failing test.
> $ tribulation continue
> myproject.test_1
>   Case1
> test_1 ...
>   [OK]
> myproject.test_2
>   Case2
> test_2 ...
>   [OK]
>
>
> ---
> Ran 2 tests in 0.033s
>
> *AGAIN* (successes=2) - a test should have failed.
> # oops, 'test_2' was just 'pass'... let me fix that
> $ tribulation continue
> $ tribulation begin myproject
> Beginning a time of turmoil for python package 'myproject', in
> './myproject/'.
> myproject.test_1
>   Case1
> test_1 ...
>   [OK]
> myproject.test_2
>   Case2
> test_2 ...
> [FAIL]
>
>
> ---
> Ran 2 tests in 0.450s
>
> PROCEED (successes=2) - we are working on myproject.Case2.test_2 now.
> $ tribulation continue
> myproject.test_2
>   Case2
> test_2 ...
> [FAIL]
>
>
> ---
> Ran 1 tests in 0.020s
> *AGAIN* (successes=2) - you should have made the test pass.
> $ tribulation continue
> myproject.test_2
>   Case2
> test_2 ...
>   [OK]
>
>
> ---
> Ran 1 tests in 0.01s
> PROCEED (successes=1) - myproject.Case2.test_2 works now, let's make sure
> nothing else broke.
> $ tribulation continue
> myproject.test_1
>   Case1
> test_1 ...
>   [OK]
> myproject.test_2
>   Case2
> test_2 ...
>   [OK]
>
>
> ---
> Ran 2 tests in 0.033s
> PROCEED (successes=2) - no regressions, find the next thing to work on
> $ tribulation conclude
> You have received one billion points, congratulations you have defeated
> software.
>
>
> Does this seem like it might be a useful feature for someone to work on?
>  Not shown here is the part that when you do introduce a regression, it
> runs just the tests that failed until you fix all of them, then goes back
> up the suite until it reaches the top and you move on to the next thing...
>
>
I like the idea.

testrepository  stores
tests results in a database and already has support for running just the
tests that failed, etc.  It just runs whatever executable you give it,
provided that executable outputs subunit.

Not on a computer with it installed (and can't find a good webpage), but
here's the basic gist:

$ testr init  # initialize the database
$ testr run  # runs everything
... # test output goes here
$ testr run  # runs everything, shows delta of tests failed & time taken
$ testr run --failing  # just run what failed

It doesn't have the TDD straightjacket you describe, but that would be a
fun thing to make.

jml
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