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dynamic values in yaml

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  dynamic values in yaml raphinou@gmail.com - 2014-08-19 07:32 -0700
    Re: dynamic values in yaml Laurent Pointal <laurent.pointal@laposte.net> - 2014-08-19 19:01 +0200
      Re: dynamic values in yaml Rustom Mody <rustompmody@gmail.com> - 2014-08-19 10:15 -0700
        Re: dynamic values in yaml raphinou@gmail.com - 2014-08-19 23:50 -0700
          Re: dynamic values in yaml Rustom Mody <rustompmody@gmail.com> - 2014-08-20 00:36 -0700
          Re: dynamic values in yaml Mark Lawrence <breamoreboy@yahoo.co.uk> - 2014-08-20 09:59 +0100
          Re: dynamic values in yaml Laurent Pointal <laurent.pointal@laposte.net> - 2014-08-20 18:59 +0200

#76569 — dynamic values in yaml

Hi,

I'm using pyyaml, and need some values in a yaml files to be dynamic, for example somethin like:

  filename: /tmp/backup_{% time.strftime('%Y-%m-%d') }.tgz

Is there a simple way to achieve this? (Eg with a templating system that would first handle the template parts from the yaml file)

Thanks

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#76578

raphinou@gmail.com wrote:

> Hi,
> 
> I'm using pyyaml, and need some values in a yaml files to be dynamic, 
for
> example somethin like:
> 
>   filename: /tmp/backup_{% time.strftime('%Y-%m-%d') }.tgz
> 
> Is there a simple way to achieve this? (Eg with a templating system 
that
> would first handle the template parts from the yaml file)
> 
> Thanks

I used jinja2 templating system to build (render) the yaml string 
representation before processing it with yaml.

But for a simple use, maybe a direct keyword replacement is easier (but 
gives less control in the template, more in the code).

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#76579

On Tuesday, August 19, 2014 10:31:03 PM UTC+5:30, Laurent Pointal wrote:
> raphinou  wrote:

> > Hi,
> > I'm using pyyaml, and need some values in a yaml files to be dynamic, 
> for
> > example somethin like:
> >   filename: /tmp/backup_{% time.strftime('%Y-%m-%d') }.tgz
> > Is there a simple way to achieve this? (Eg with a templating system 
> that
> > would first handle the template parts from the yaml file)
> > Thanks

> I used jinja2 templating system to build (render) the yaml string 
> representation before processing it with yaml.

> But for a simple use, maybe a direct keyword replacement is easier (but 
> gives less control in the template, more in the code).

Python's format operator -- '%' or the modern variant -- 
is a mini-templating language:

open(templatefile).read() % substitutions

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#76639

On Tuesday, August 19, 2014 7:15:54 PM UTC+2, Rustom Mody wrote:
> On Tuesday, August 19, 2014 10:31:03 PM UTC+5:30, Laurent Pointal wrote:
> 
> > raphinou  wrote:
> 
> 
> 
> > > Hi,
> 
> > > I'm using pyyaml, and need some values in a yaml files to be dynamic, 
> 
> > for
> 
> > > example somethin like:
> 
> > >   filename: /tmp/backup_{% time.strftime('%Y-%m-%d') }.tgz
> 
> > > Is there a simple way to achieve this? (Eg with a templating system 
> 
> > that
> 
> > > would first handle the template parts from the yaml file)
> 
> > > Thanks
> 
> 
> 
> > I used jinja2 templating system to build (render) the yaml string 
> 
> > representation before processing it with yaml.
> 
> 
> 
> > But for a simple use, maybe a direct keyword replacement is easier (but 
> 
> > gives less control in the template, more in the code).
> 
> 
> 
> Python's format operator -- '%' or the modern variant -- 
> 
> is a mini-templating language:
> 
> 
> 
> open(templatefile).read() % substitutions

Note that in my example the content to be inserted is not the result of a variable substitution, but the result of a call to a function. format doesn't seem to work in this case. 
And jinja2 doesn't seem to provide a straight forward solution either

Thx

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#76642

On Wednesday, August 20, 2014 12:20:21 PM UTC+5:30, raph...@gmail.com wrote:
> On Tuesday, August 19, 2014 7:15:54 PM UTC+2, Rustom Mody wrote:
> > On Tuesday, August 19, 2014 10:31:03 PM UTC+5:30, Laurent Pointal wrote:
> > > raphinou  wrote:
> > > > Hi,
> > > > I'm using pyyaml, and need some values in a yaml files to be dynamic, 
> > > for
> > > > example somethin like:
> > > >   filename: /tmp/backup_{% time.strftime('%Y-%m-%d') }.tgz
> > > > Is there a simple way to achieve this? (Eg with a templating system 
> > > that
> > > > would first handle the template parts from the yaml file)
> > > > Thanks
> > > I used jinja2 templating system to build (render) the yaml string 
> > > representation before processing it with yaml.
> > > But for a simple use, maybe a direct keyword replacement is easier (but 
> > > gives less control in the template, more in the code).
> > Python's format operator -- '%' or the modern variant -- 
> > is a mini-templating language:
> > open(templatefile).read() % substitutions

> Note that in my example the content to be inserted is not the result of a variable substitution, but the result of a call to a function. format doesn't seem to work in this case. 
> And jinja2 doesn't seem to provide a straight forward solution either

Dunno jinja
In Cheetah you can use <%= arbitrary python expression %>

http://www.cheetahtemplate.org/docs/users_guide_html/users_guide.html#SECTION000650000000000000000

PS Please read this
https://wiki.python.org/moin/GoogleGroupsPython

Else some folks here get very irritated

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#76645

On 20/08/2014 07:50, raphinou@gmail.com wrote:

Would you please access this list via 
https://mail.python.org/mailman/listinfo/python-list or read and action 
this https://wiki.python.org/moin/GoogleGroupsPython to prevent us 
seeing double line spacing and single line paragraphs, thanks.

-- 
My fellow Pythonistas, ask not what our language can do for you, ask
what you can do for our language.

Mark Lawrence

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#76677

raphinou@gmail.com wrote:

> Note that in my example the content to be inserted is not the result 
of a
> variable substitution, but the result of a call to a function. format
> doesn't seem to work in this case. And jinja2 doesn't seem to provide 
a
> straight forward solution either
> 
> Thx

Yoy may try it, setup an environment (dictionnary) with 'time' mapped 
to the time module, and render the template using this environment. 
Normally Jinja2 manage namespaces and function call.

Your template would be:

    filename: /tmp/backup_{{ time.strftime('%Y-%m-%d') }}.tgz

And the environment for rendering simply:

import time
env = { time: time }

http://jinja.pocoo.org/docs/templates/#other-operators

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