[PEAK] peak events tasks...
Phillip J. Eby
pje at telecommunity.com
Wed Jul 7 13:04:30 EDT 2004
At 11:36 AM 7/7/04 -0500, darryl wrote:
>Does anyone have example code or publicly visible projects which use
>peak events etc. especially with respect to twisted support?
>The whole pseudothread (Tasks) thing sounds cool. I just dont' know how to
>use it :P
The 'peak.tools.supervisor' app uses them a lot. It's primarily a FastCGI
application runner, for Unix-ish platforms. It doesn't do anything with
It spawns at least a couple of Tasks for every subprocess it has running,
plus several watchdog tasks. For example, one task keeps track of how many
subprocesses are running, and if it's less than desired it starts one, then
waits a preset interval before checking to see if more are needed. When it
reaches the number of "desired" processes, it resets the "desired" number
to the "minimum" number.
Another task monitors how many subprocesses are busy, and if all of them
are busy, and a HTTP connection is pending, it raises the number of
"desired" processes, so that the other task can "notice" and start new
A task for each subprocess monitors a pipe from the child to track whether
the child process is "busy" or not, and update the count of busy processes
So, between these various tasks, the system dynamically enforces the rules
it has been given regarding the maximum frequency of starting subprocesses,
the minimum number to have running, and so on.
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