[Debconf-devel] Bug#631769: Bug#631769: New Kde frontend based on debconf-kde-helper

[Modestas Vainius]

Hello,

On pirmadienis 27 Birželis 2011 20:31:11 Joey Hess wrote:
> Modestas Vainius wrote:
> > While this is still work in progress, I came across an issue. When
> > Debconf::Frontend::Kde setups FIFO pipes and forks debconf-kde-helper
> > process, it has no way of knowing if or when debconf-kde-helper is ready
> > to accept protocol commands. Therefore, I think it makes sense to add an
> > equivalent of the ping command to the debconf (Passthrough) protocol. It
> > could be as simple as:
> > 
> > ---> PING
> > <--- 0 pong
> 
> Why not just block on receiving the first passthrough command until the
> helper is ready?

But if something does wrong, debconf might block indefinitely. For example, if 
old version of debconf-kde-helper did not know anything about pipes, they 
would stay open until the process terminates and would hang debconf as a 
result. To be precise, I want to implement this ping-pong in 
Debconf::FrontEnd::Kde::init() with timeout of 15 seconds so if something goes 
wrong and there is no answer from the helper in that period of time, debconf 
would still fallback to Dialog frontend. I could get away without this but 
fault tolerance would not be that good then IMHO. ping command would be pretty 
cheap and trivial way, wouldn't it?

-- 
Modestas Vainius <modax at debian.org>
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