Re: [PATCH] Introduce a filter-path argument to git-daemon, for doing custom path transformations

Hi,

On Sat, 14 Mar 2009, Junio C Hamano wrote:

Johan Sørensen [off-list ref] writes:

quoted

quoted

Do you run git-daemon from inetd, or standalone, by the way?

Standalone.

quoted

I am wondering how well it would scale if you spawn an external 
"filter path" script every time you get a request.

A quick test of 250 consecutive requests with ls-remote to localhost
(all without the --verbose flag), slowest run:
- Baseline (no --filter-path agument): 3.39s

$ cat filter.c
#import "stdio.h"
int main (int argc, char const *argv[]) {
	printf("%s", "/existing.git\0");
	return 0;
}
- 3.84s

$ cat filter.rb
#!/usr/bin/ruby
print "/existing.git\0"
- 4.76s

So, obviously highly dependent on how long it takes the script to 
launch and how much work it does. And yes, neither of the above really 
does anything :) nor takes any increased cpu load into account

Another approach is to keep the external script running and feed it on 
stdin, but that would involve a bit more micro-management of the 
external process. I will revisit that idea if I find out that's 
needed.

I actually was hoping (especially we have Dscho on Cc: list) that somebody
like you would start suggesting a "plug in" approach to load .so files,
which would lead to a easy-to-port dso support with the help from msysgit
folks we can use later in other parts of the system (e.g. customizable
filters used for diff textconv, clean/smudge, etc.)

I do not like that at all.  Dynamic libraries -- especially on Windows -- 
are a major hassle.

However, I cannot think of anything Johan might want to do that would not 
be possible using a bunch of regular expressions together with 
substitions.

FWIW I have experimental code in my personal tree that sports 
strbuf_regsub(), a function to replace matches of a regular expression 
(possibly with groups) by a given string (which may contain \0 .. \9, 
being replaced with the respective group's contents).

Ciao,
Dscho