Package: prep
Prep is a pre-deployment configuration generator that works by parsing template
files using a simple syntax.  Variables are loaded in a cascading fashion so
that you can have granular control based both on intended network zone (e.g.
dev or prod), or specific hostnames or subnets (e.g. www, www.prod,
www.prod.example.com).OverviewWhen I started developing a large web application in Python, I couldn’t find
a simple config generator that wasn’t tied to a much larger system (e.g.
CFEngine), or wasn’t written for a significantly different platform (e.g.
Capistrano).I had the following goals in mind:Easy to configure, and flexible.Simple one-line command to reconfigure every part of my application for any
deployment environment I chose (specifically:  dev, qa, staging, production).Support multiple application pieces (several wsgi apps, nginx, gearman jobs,
elasticsearch)Not interfere with the current deployment system (rsync) or whichever more
robust one I eventually choose to use.I think that Prep meets these, though it also has a lot of room for improvement.UsageSee the included sample files for a working installation:cd /path/to/prep/sample/
prep --devAlternately, you can use the long form, and specify the directory name
manually:prep --mode=production /path/to/prep/sample/When you run prep, it scans the entire specified directory tree for files namedprep.cfg.  These are standard python ConfigParser files (like Windows INI)
containing the directives described below.prep.cfgprepDirectives to control how prep should render templates for this directory.At the moment, this only includes the requiredtemplate = simple.
Eventually there will be more options and probably even other template
parsing engines.varsThese are the variables that will be injected into your template files.All values are stringsfilesList of files to process, specified assource path = destination pathRelative path names will be in relation to prep.cfg but you are welcome
to use absolute pathnames.preItems in this section are processed before prep touches any filesCurrently supports the following commands:run (or run.name1, run.name2, …)set.NAME (runs a shell command and sets var NAME to its output)Values that look like python repr() data for basic structures will be
interpreted as such (e.g.['item1','item2']will be interpreted as a
list object).postIdentical topreabove, but runs after file processingTemplate interpolation is allowed infiles,pre, andpostso you
can do things like use the output of a command to set a variable containing
a password value, or send generated files to environment-specific directory
names.Except forprep, you can also create mode- and host- and user-specific
variants of each directive, which will override the common config options
with the conditional one you have provided:[vars]
var1 = val1
var2 = val2
var3 = val3

[vars:mode=dev]
var1 = dev-val1

[vars:host=www]
var2 = www-val2

[vars:user=root]
var3 = root-val3Please see sample/ directory for a set of working examples.Simple Template SyntaxThere are only 3 things you can do in the simple syntax.  They are listed below
in order of operation.  You can mix and match as necessary.Basic logicPositive and negative matching against mode or host:##if:mode=dev##
This content will only exist in the final file
if prep was invoked with --mode=dev
##endif##

##if:host!=www##
This content will only exist in the final file
if prep was invoked on a host not named www
##endif##

This other content will always be in the final file.Sorry, noelseclause yet.IncludesI have included a basic include command.  It looks for the filename first in
the same directory as the file that requested the include, and second in the
directory containing the prep.cfg file currently being acted on.:##inc:logging.inc##VariablesThe whole point of this system is to parse variables into your config files:[myapp]
domain = ##domain##
port = ##port##In addition to the variables defined in your prep.cfg file, prep provides the
following variables:rootThe absolute pathname for the directory containing prep.cfguser$USER from the current shell environmenttimeThe current unix epoch timestamp.Prep will also include any –variable=value pairs provided on the command line
when it was invoked.  These command line arguments will override any values
from prep.cfg.Downloadhttps://github.com/ex-nerd/prephttp://pypi.python.org/pypi/prep/