On 06:30 am, a...@roiban.ro wrote:
On 4 September 2014 12:59, <exar...@twistedmatrix.com> wrote:
[snip]
What would be really nice is if someone collected *all* of the
complaints
about `spawnProcess` into one place and integrated solutions to them
into a
design for a replacement. :)
Jean-Paul
Since I can not create wiki pages here are my notes:
To do:
* Always return a deferred. #2415
* Provide the option to timeout the execution... and on timeout errback
with
a dedicated failure #2415
* Add childs to the same process group #2415
* allways errback when failing to spawn (rather than raising OSError)
and
errback with a different failure when failing to spawn the executable
#4184
* on Unix provide a method to install SIGCHLD handler, independent of
the
general reactor.run() signal handlers. ... maybe related to #5710
* Allow passing Unicode environment (at least on Windows) maybe needed
for Python3 #5968
* Allow passing Unicode command and arguments on Windows (current not
supported by pywin32 CreateProcess) #6470... maybe needed for Python3
#5968
* Improve fork/exec for speed and memory usage #5710 .... maybe by
creating
a auxiliary process which handles forks and child management.
* Execute as a different account in Windows
* Spawn only after reactor starts ? I am ok with forking before.
* Support client endpoint?
-------
For a new design:
* I like the ProcessProtocol API
I don't. :) ProcessProtocol means you can't re-use any of your existing
IProtocol implementations. Oops.
It seems like a better API would let you say "Here is a protocol, hook
its output up to fd 0 in the process, hook fd 1 in the process up to its
input. Here is another protocol, hook fd 2 in the process up to its
input" (this would probably be a common configuration - "speak some
regular protocol over stdin/stdout, have a little special logic
(probably logging) for stderr).
On the other hand, it's possible to build this on top of ProcessProtocol
and no one ever has...
* spawnProcess will always return a deferred... for backward
compatibility
we need to decide a name for this new method which returns a deferred.
Maybe createProcess or connectProcess
* create spawnUnixProcess which has childFDs uid/gid
* create spawnWindowsProcess which has Windows specific options
* createProcess / connectProcess will call spawnUnixProcess or
spawnWindowsProcess
depending on current OS
* ProcessProtocol.processEnded is similar to connectionLost..
so maybe it can be rename it and add other methods so that
IProcessProtocol
can inherit from IProtocol. I guess that this will help with
connectors.
Let's not introduce new cases where inheritance is encouraged.
------
I think that child management problem, does not affect the public API
so I am
not discussing it here.
Timeouts are handled at protocol level and I see that we have 2 timeout
types:
total execution time and timeout after last child data was received.
-----
Does it make sense to put it on wiki or what should be the Twisted
Enhancement Proposal process?
I think it's easier to maintain a document on the wiki than in threads
on the mailing list.
Can I get 'create page' rights on Trac?
Hm. I thought everyone had wiki edit rights (except for a small number
of privileged pages) by default - so I'm not sure what's going on here
or how to give you permissions. Perhaps something changed in the trac
upgrade or as part of the recent ticket permission reconfiguration.
Jean-Paul
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