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https://github.com/mpdehaan/jcp

Jinja2-powered, template aware copy tool
https://github.com/mpdehaan/jcp

Last synced: 11 days ago
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Jinja2-powered, template aware copy tool

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README 

        
JCP

=====



jcp is a template aware copy program.



The primary usage of this tool would be to use in something like bash-configured Packer files, or hack-and-slash

shell scripts.  



If you are defining an operating system configuration, often you want to have templates that only vary a

small amount between one system to another.  Most things you can do with bash - like tweak systemd configurations or

enable SELinux configurations, but templates are the one thing you need a tool for.



jcp provides that, and only that.  It's fast, really basic, and and there's not really a lot to it.

All the credit goes to the authors of Python, argparse, and Jinja2.



Advertising: If you are doing immutable systems builds, you might also be interested in http://github.com/mpdehaan/strider.

It's like Packer and Vagrant, just in Python (AWS only at this point), and also pretty fast and basic.



Installation

============



    pip install jcp



Usage

=====



The following example uses a template file, 'foo.conf.j2' in Jinja2 format, feeds in variables from 'answers.yml' and

saves the results in '/etc/foo.conf':



    jcp --input foo.conf.j2 --answers answers.yml --output /etc/foo.conf



Ok, that was easy.  Currently there aren't any more flags than that.  That's it!



Jinja2

======



For how Jinja2 templates work, I recommend the template engine documentation at http://jinja.pocoo.org/docs/dev/templates/.



Assume answers.yml looked like this:



    ---

    dog: fido

    cat: delicious



Here's a really basic example of an input file.



    My dog is named {{ dog }} and the cat is {{ cat }}.

    

The output file would look like:



    My dog is named fido and the cat is delicious.

    

Of course, most likely  you're using this for config files. If you want more, read the Jinja2 docs.  It's easy, and it does

if conditionals, loops, and all sorts of nice things.

    

Ideas

=====



Possibly good pull requests for unimplemented features:



   * Allow multiple --answer parameters (and pass this as an array to the JCopy class).  If any parameters are an array, read all YAML or JSON files in the directory to support conf.d directories.  Allow filesystem globs via fnmatch.

   * If no "--output" parameter, dump to stdout instead.

   * Support an "--engine" parameter to use things other than Jinja2 (anything Python goes, shelling out to ruby for erb is cool too, I don't care!).  Actually this should probably go by the file extension and just default to Jinja, and be explicit only when --engine is specified.

   * Support other important flags from coreutils cp, if any are desired.

   * Support extra variables from the command line via --vars "key1=value1 key2=value2"

   * Basic unit tests using input files in the test/ directory, and shelling out to the binary in scripts/

   * Python 3 compliance



License

=======



Apache 2.  Program (C) Michael DeHaan, 2015