Re: [Fab-user] Proposal: remote execution of Python code

[Richard Jones]

On Sun, 15 Feb 2009 11:13:23 am you wrote:
 On Sat, Feb 14, 2009 at 6:59 PM, Richard Jones rjo...@ekit-inc.com wrote:
  Actually, no, it's for remote system deployment where we need to perform
  operations on the remote end that currently require us to copy a script
  to that system and execute it (which is your proposed workaround).

 Can you give a concrete example, then? I can't think of anything
 offhand that Fabric cannot currently do along those lines; it can
 execute any remote shell command (normally and via sudo), local shell
 commands, put/get files, and is capable of obtaining the output of the
 remote commands and performing logic based on those results.

Yes, you're pretty much just repeating what I referred to as your proposed 
workaround :)

I'd like to be able to do stuff like:

Debug(WARN, STOPPING SERVER: %s:%s%(ihost, ihome))
killcmds = []
try:
z2pids = open('%s/var/ZEO_SERVER-starting.pid'%ihome).read()
except:
try:
z2pids = open('%s/var/ZEO_SERVER.pid'%ihome).read()
except:
Debug(INFO, no pid file - not running?)
z2pids = None
if z2pids:
z2pids = z2pids.split()
z2pids = filter(lambda x:x!='1', z2pids) # don't kill init :)
z2pids = ' '.join(z2pids)
killcmds.append('-kill -TERM %s 2/dev/null'%z2pids)
if killcmds:
do_commands('stop_server', ihost, killcmds)

without having to write that as a script on the remote end. Currently we do it 
that way, and it just feels inelegant :)

I think I can comfortably say the developer response to my proposal is a solid 
YAGNI, so I'll move on :)


Richard


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Re: [Fab-user] Proposal: remote execution of Python code

[Jeff Forcier]

On Sun, Feb 15, 2009 at 6:34 PM, Richard Jones rjo...@ekit-inc.com wrote:

 I'd like to be able to do stuff like:

 open('%s/var/ZEO_SERVER-starting.pid'%ihome).read()
 do_commands('stop_server', ihost, killcmds)

As far as I can tell, those were the only two kinds of method calls
you had in the script that actually affect anything outside the
script, and thus the only things that could possibly require remote
execution.

'open()' could turn into two lines, download() + open() (and I could
definitely see an argument for making a convenience method
encapsulating the two); or, if one didn't need the file interface, it
can already be done in a one-liner, z2pids = run('cat
/location/of/zeo_pid_file') -- as run() returns its output, and I
assume you know what the cat command does!

I don't know what do_commands() does; does it simply execute a local
shell command? Guessing not since you'd obviously know to turn that
into a run() or sudo(); so is it a method you had to import from some
other Python on that remote system? Which would explain your
insistence that Fabric isn't cutting it right now...:)


Please let me know -- I want to make sure I understand your needs
here, even if I do have to end up saying nope, not happening anytime
soon.

Best,
Jeff


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