> On Wed, Oct 28, 2009 at 05:08:03PM -0400, Mike McLean wrote:
>> On Mon, Oct 26, 2009 at 12:41 AM, Dennis Gilmore <dennis-
OMEdqnBlyiw@public.gmane.org> wrote:
>>
>> The daemon distinction might be wrong thing to fixate on here. There
>> is nothing in that distinction that should exclude python (or most any
>> language). I think the real factors of concern are: size, complexity,
>> speed, system load, robustness, and security.
>>
> <nod> By and large I agree with you. One thing further to think about is that
> becoming dependent on a tool written in an interpreted language means that
> you need to install that language on your system and may become tied to a
> specific version of that language. In theory, this shouldn't be worse than
> tying yourself to a specific C library but in practice I've found that
> parallel installing interpreters and their libraries is a lot less supported
> than parallel installing a C lib.
Hopefully we have 2.4 as the minimum version. I'm pretty sure 2.4 is ubiquitous
even on the enterprise-y distributions, but if we need older, we can try for
that as well.
> Using python in Fedora Infrastructure probably isn't too big a deal as we
> have abundant python programmers here to port things forward if the main
> developers don't but it is something to consider with other languages or
> in other environments.
We're aiming to get it to work on RHEL/CentOS 4 (base, not + EPEL) and Debian
stable so that current mirrors running systems that old don't need to upgrade
the OS to start using our software (I'm pretty sure we have the hardware to run
test instances of the software with various setups). If the libraries we end up
using just aren't available, I think RHEL 5 will be a suitable minimum. When
Python 3 comes looming over any distribution that starts using our software, we
should be able to help port things over. I'd expect Fedora to be the first for
this to happen to, but I could see Gentoo having howtos for getting 3.0 as the
main Python before that (not that servers would be running such a setup
anyways).
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10-29-2009, 03:13 AM
Ben Boeckel
Suitability of Python for daemon processes
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Mike McLean wrote:
> On Mon, Oct 26, 2009 at 12:41 AM, Dennis Gilmore <dennis-
OMEdqnBlyiw@public.gmane.org> wrote:
>> On Sunday 25 October 2009 06:26:49 pm Jeroen van Meeuwen wrote:
>>> And koji.fedoraproject.org, no?
>> koji is a mod_python app. it doesnt run as a daemon at all.
>> but it it all python.
>
> There are python daemons in the system though. The builders run kojid,
> which is a daemon, and the process that triggers repo regeneration
> (kojira) is a daemon. Of course, these are not public facing -- they
> really only talk to the hub.
>
> The daemon distinction might be wrong thing to fixate on here. There
> is nothing in that distinction that should exclude python (or most any
> language). I think the real factors of concern are: size, complexity,
> speed, system load, robustness, and security.
True. I think the speed at which we can deliver with Python makes it much more
attractive, even if not just at first. We could something similar to what git
did with bash and replace the Python with C incrementally if necessary, but I
think that if we go about it right, it shouldn't be much of an issue.
> It's entirely possible to create large and complex systems with
> Python. It's expressiveness and interpreted nature are a big help
> here. Robustness is probably more a factor of design and good coding
> than the language itself. That being said, the relative ease of
> programming in Python, coupled with its exception handling, likely
> give it an advantage over C in this department (over the same
> development time at least). That's my opinion; others may disagree
> (and of course Python is not the only rapid development language with
> good exception handling).
I agree here. This thread is a fact-finding mission and research. We wanted to
make sure we weren't headed down the wrong road before we headed out.
> Security threats are everywhere. With Python at least you have to
> worry much less about buffer overflows, but of course you can
> introduce security flaws in any language.
Of course.
> Obviously, as an interpreted language, system load and speed are where
> Python suffers. There are optimization tricks, but you'll never get
> close to execution speed of C. You can rewrite crucial portions in C,
> though I rarely see that actually done.
One place where we had concerns were when dealing with the "shopping list" I
referred to elsewhere in the thread. This list is 60MB on one of the Ubuntu
mirror directories we have here (our Fedora mirror has been decommissioned while
we await more disk space). I imagine Fedora's will be much larger due to the
drpm files and secondary architectures put even more into it. We have code that
is able to extract information without loading the entire file into our process
space. It's very close to what it would be if it were C except for a .split()
call on a string (but it's simple enough that a sscanf could do it as well if
needed) and the memory/strcmp stuff Python has baked in. Hopefully we will have
unit tests and timing on our code this weekend.
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10-29-2009, 02:38 PM
Toshio Kuratomi
Suitability of Python for daemon processes
On Thu, Oct 29, 2009 at 12:04:08AM -0400, Ben Boeckel wrote:
> Hopefully we have 2.4 as the minimum version. I'm pretty sure 2.4 is ubiquitous
> even on the enterprise-y distributions, but if we need older, we can try for
> that as well.
>
Just a note. If you're targeting RHEL/CentOS4 as your minimum, you need to
target python-2.3 as your minimum python version.
-Toshio
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Suitability of Python for daemon processes
