[lvs-users] ldirectord SimpleTCP service check [PATCH]

[Aaron Linnen]

Simon Horman wrote:
> On Thu, Nov 29, 2007 at 08:41:27AM -0600, Aaron Linnen wrote:
>   
>> I have a service with a custom protocol that I'm load balancing and I 
>> didn't find an easy way to get that going with ldirectord. I came up 
>> with a quick modification that enabled what I needed, but would 
>> appreciate comments or, ideally including similar functionality in 
>> future releases.
>>
>> It's a new service type called simpletcp, and is configured like so:
>> virtual = 192.168.44.3:10301
>>         protocol = tcp
>>         scheduler = wlc
>>         real = 192.168.45.4:10301 gate 100
>>         real = 192.168.45.5:10301 gate 100
>>         service = simpletcp
>>         request = "command\narg\n.\n"
>>         receive = "^\+OK"
>>
>> The check simply sends the request string down the connection and tests 
>> against the receive regex. My perl-foo is weak these days, so I'm sure 
>> there are some easy improvements that could be made.
>>     
>
> Hi Arron,
>
> thanks for your patch. This idea looks like a good one to me and
> I'm quite happy to push it into the next release (or the one after that,
> as the next release is close to going out the door).
>
> A few things:
>
> * How well have you tested this? Its unlikely to break anything except
>   itself, but its good to get an idea anyway.
> * Can you add something to the documentation at the top of ldirectord?
>   Perhaps doding this as a second patch would work well.
> * Your patch seemed to replace all tabs with spaces so it didn't apply.
>   I manually fixed this up and the fixed version is below.
> * If at all possible could you provide a sign-off line as described
>   in section 5 of http://linux.yyz.us/patch-format.html
>   Thats basically to say this is your work and you are ok with
>   it going into a GPL project.
>   

Hi Horms, thanks for the interest.

We're only in development mode here right now, but it's stood up well 
under the testing we have done including some load testing. The code is 
pretty much just the check_sip code, with the request swapped out.

Patch attached with some tiny bits of documentation. Sorry about the 
previous patch. hopefully this one will come through correctly.

One area I see potential improvement is the \n handling - I can see the 
need for at least \r as well, probably others. I was looking for a quick 
way to have perl parse the line as it does string literals in code so 
that all the same perl escape syntax could be used (enabling embedded 
nulls or other binary data), but didn't see an easy way and I didn't 
need that for the current project so I left it. If someone knows a 
simple, safe and secure way to enable that, I think it would really 
improve this to where it can be used in as many circumstances as possible.

Signed-off-by: Aaron J. Linnen <aaron at lfchosting.com>

Aaron

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