Re: [Fab-user] using run on a machine that doesn't have /bin/bash

[Jeff Forcier]

I don't really like having to make that decision (can't set fab_shell
vs opening an edge-case where some strings won't get fully
interpolated). Brainstorming possible solutions:

1. explicitly omit fab_shell from the line below: "if key !=
'fab_shell': value = value % self"
    - good: best of both worlds, fab_shell can be set OK, all other
strings correctly interpolated
    - bad: hardcoding different behavior for a single config key
    - bad: can't do interpolation on the _rest of_ fab_shell (though
that would be a truly odd use-case, given how fab_shell is currently
used, and is not possible now anyways)

2. Alter use of fab_shell to omit the interpolation step, so that its
default value is e.g. "/bin/bash -l -c" and then tack on the literal
double-quotes-plus-actual-command, via string concat instead of x % y.
    - good: also gives us best of both worlds, as above
    - good: allows user to interpolate fab_shell itself, if that was
for some reason necessary
    - good: avoids the 'bad' steps in sol'n #1
    - bad: the two places where we use fab_shell to construct the
final command to run, become slightly less elegant

Unless someone can spot an actual problem with #2, I think it's a
clear winner. I was serious about it being only 'slightly' less
elegant: it still won't be messy or hard to read code, just a bit of
extra string concatenation instead of a single 'string % mapping'
call. And I can't think of any other drawbacks off the top of my head.

-Jeff

On Fri, Nov 21, 2008 at 2:24 PM, Christian Vest Hansen
<address@hidden> wrote:
> Oh my.... That's a bug.
>
> I can't think of any way to fix that other than dropping the eagerness
> of the standard python string interpolation. This in turn introduces
> the possibility of _lazy_format() returning strings with unresolved
> placeholders.
>
> What does the rest of the list think about this fix?
>
> [PATCH] Don't resolve standard python string interpolation eagerly.
>
> This fixes a bug that makes it impossible to set the fab_shell
> variable, but in turn
> make it possible for _lazy_format() to return strings with unresolved
> placeholders.
> ---
>  fabric.py |    2 +-
>  1 files changed, 1 insertions(+), 1 deletions(-)
>
> diff --git a/fabric.py b/fabric.py
> index 609273e..36de95c 100644
> --- a/fabric.py
> +++ b/fabric.py
> @@ -95,7 +95,7 @@ class Configuration(dict):
>         self[key] = value
>     def __setitem__(self, key, value):
>         if isinstance(value, types.StringTypes):
> -            value = (value % self)
> +            value = value
>         dict.__setitem__(self, key, value)
>     def __call__(self, **kwargs):
>         for k, v in kwargs.items():
> --
> 1.6.0.1
>
>
>
> On Fri, Nov 21, 2008 at 7:48 PM, Don Jackson
> <address@hidden> wrote:
>> Yes. It's called the `fab_shell` variable, and it is by default
>> defined like this:
>>
>> /bin/bash -l -c "%s"
>>
>> That helps, but I'm still doing something wrong:
>> set(
>>   fab_hosts = ['svn01'],
>> )
>> set(
>>   fab_shell = '/bin/sh -l -c "%s"'
>> )
>> def pwd():
>>     "prints cwd"
>>     run("pwd")
>>
>> fab pwd
>>
>>
>>    Fabric v. 0.0.9, Copyright (C) 2008 Christian Vest Hansen.
>>    Fabric comes with ABSOLUTELY NO WARRANTY; for details type `fab
>> warranty'.
>>    This is free software, and you are welcome to redistribute it
>>    under certain conditions; type `fab license' for details.
>> Running pwd...
>> Logging into the following hosts as dcj:
>>     svn01
>> [svn01] run: pwd
>> [svn01] err: /bin/sh: {fab_author:: not found
>> Error: The run operation failed on svn01.
>>
>> On Fri, Nov 21, 2008 at 7:01 AM, Don Jackson
>> <address@hidden> wrote:
>>>
>>> Doesn't seem to work.
>>>
>>> $ cat fabfile
>>> set(
>>>  fab_hosts = ['svn01'],
>>> )
>>>
>>> def pwd():
>>>    "prints cwd"
>>>    run("pwd")
>>>
>>> $ fab pwd
>>>   Fabric v. 0.0.9, Copyright (C) 2008 Christian Vest Hansen.
>>>   Fabric comes with ABSOLUTELY NO WARRANTY; for details type `fab
>>> warranty'.
>>>   This is free software, and you are welcome to redistribute it
>>>   under certain conditions; type `fab license' for details.
>>>
>>> Running pwd...
>>> Logging into the following hosts as dcj:
>>>    svn01
>>> [svn01] run: pwd
>>> [svn01] err: ksh: /bin/bash: not found
>>> Error: The run operation failed on svn01.
>>>
>>> Is there a variable I can set that will make fabric use another shell?
>>
>> _______________________________________________
>> Fab-user mailing list
>> address@hidden
>> http://lists.nongnu.org/mailman/listinfo/fab-user
>>
>>
>
>
>
> --
> Venlig hilsen / Kind regards,
> Christian Vest Hansen.
>
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