Awesome. Thank you, this is precisely what I was hoping for.
However I think there's a bug in the documentation. On
thishttp://docs.fabfile.org/0.9.1/usage/execution.htmlpage, it says
Since the env vars are checked for each *host*, this means that if you have
the need, you can actually modify env in one task and it will affect all
following tasks
What it should say is:
Since the env vars are checked for each *task*, this means that if you have
the need, you can actually modify env in one task and it will affect all
following tasks
Right?
Martin
On Tue, Aug 10, 2010 at 4:52 PM, Jeff Forcier j...@bitprophet.org wrote:
Hi Martin,
On Tue, Aug 10, 2010 at 4:27 PM, Martin-Louis Bright mlbri...@gmail.com
wrote:
it would be nice if I could specify the file
on the command line and be done with it... Is there a disadvantage to
this approach?
Nope, that would work just fine. You could do something like this:
def set_hosts(filename):
with open(filename) as fd:
env.hosts = [x.strip for x in fd.readlines()]
def do_stuff():
run(foo)
and then execute it like this:
$ fab set_hosts:/path/to/hosts_file.txt do_stuff
Which would execute foo on every host[1] defined in
/path/to/hosts_file.txt.
That approach works because:
* By the time Fabric goes to execute do_stuff(), your set_hosts() has
already run, and has thus modified env.hosts. (This is a common
idiom.)
* Task functions can take arguments on the command line[2]
* Fabfiles are Just Python(tm) and so stuff like opening and reading
in external files works just fine and is totally encouraged.
All of that said -- there've been occasional discussions about various
other ways of pre-setting or bootstrapping your execution environment,
via config files or importing additional Python files. So this is
likely to get even easier in the future.
Hope that helps,
Jeff
[1] http://docs.fabfile.org/0.9.1/usage/execution.html#hosts
[2] http://docs.fabfile.org/0.9.1/usage/fab.html#per-task-arguments
--
Jeff Forcier
Unix sysadmin; Python/Ruby developer
http://bitprophet.org
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