slapos.recipe.template 2.4.1

Templating recipe with remote resource support.

======================
slapos.recipe.template
======================

Template recipe which supports remote resource.

Inspired by collective.recipe.template, with minimum set of features, but with
(hopefully) safer buildout-based templating.

"jinja2" entry point allows rendering jinja2 templates.

Usage
=====

Getting started
---------------

You can start by a simple buildout::

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template
... url = template.in
... output = template.out
...
... [section]
... option = value
... ''')

And a simple template::

>>> write('template.in', '${section:option}')

We run buildout::

>>> print system(join('bin', 'buildout')),
Installing template.

And the output file has been parsed by buildout itself::

>>> cat('template.out')
value

Full options
------------

There is two non required options:

``md5sum``
Check the integrity of the input file.

``mode``
Specify the filesystem permissions in octal notation.

Check file integrity
~~~~~~~~~~~~~~~~~~~~

Let's write a file template::

>>> write('template.in', '${buildout:parts}')

Compute its MD5 sum::

>>> import md5
>>> md5sum = md5.new(open('template.in', 'r').read()).hexdigest()

Write the ``buildout.cfg`` using slapos.recipe.template::

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template
... url = template.in
... output = template.out
... md5sum = ''' + md5sum + '''
... ''')

And run buildout, and see the result::

>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing template.

>>> cat('template.out')
template

If the md5sum doesn't match, the buildout fail::

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template
... url = template.in
... output = template.out
... md5sum = 0123456789abcdef0123456789abcdef
... ''')
>>> print system(join('bin', 'buildout')),
While:
Installing.
Getting section template.
Initializing part template.
Error: MD5 checksum mismatch for local resource at 'template.in'.


Specify filesystem permissions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can specify the mode of the written file::

>>> write('template.in', '${buildout:installed}')

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template
... url = template.in
... output = template.out
... mode = 0627
... ''')

>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing template.

And the generated file with have the right permissions::

>>> import stat
>>> import os
>>> print oct(stat.S_IMODE(os.stat('template.out').st_mode))
0627

Section dependency
------------------

You can use other part of buildout in the template. This way this parts
will be installed as dependency::

>>> write('template.in', '${dependency:foobar}')
>>> write('buildout.cfg', '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template
... url = template.in
... output = template.out
...
... [dependency]
... foobar = dependency content
... recipe = zc.buildout:debug
... ''')

>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing dependency.
foobar='dependency content'
recipe='zc.buildout:debug'
Installing template.

This way you can get options which are computed in the ``__init__`` of
the dependent recipe.

Let's create a sample recipe modifying its option dict::

>>> write('setup.py',
... '''
... from setuptools import setup
...
... setup(name='samplerecipe',
... entry_points = {
... 'zc.buildout': [
... 'default = main:Recipe',
... ],
... }
... )
... ''')
>>> write('main.py',
... '''
... class Recipe(object):
...
... def __init__(self, buildout, name, options):
... options['data'] = 'foobar'
...
... def install(self):
... return []
... ''')

Let's just use ``buildout.cfg`` using this egg::

>>> write('template.in', '${sample:data}')
>>> write('buildout.cfg',
... '''
... [buildout]
... develop = .
... parts = template
...
... [template]
... recipe = slapos.recipe.template
... url = template.in
... output = template.out
...
... [sample]
... recipe = samplerecipe
... ''')
>>> print system(join('bin', 'buildout')),
Develop: ...
Uninstalling template.
Uninstalling dependency.
Installing sample.
Installing template.
>>> cat('template.out')
foobar

Jinja2 usage
============

Getting started
---------------

Example buildout demonstrating some types::

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context =
... key bar section:key
... key recipe :recipe
... raw knight Ni !
... json words ["Peng", "Neee-wom"]
... jsonkey later section:later-words
... import json_module json
... section param_dict parameter-collection
...
... [parameter-collection]
... foo = 1
... bar = bar
...
... [section]
... key = value
... later-words = "Ekke Ekke Ekke Ekke Ptangya Ziiinnggggggg Ni!"
... ''')

And according Jinja2 template (kept simple, control structures are possible)::

>>> write('foo.in',
... '{{bar}}\n'
... 'Knights who say "{{knight}}" also protect {{ words | join(", ") }}.\n'
... 'They later say {{later}}\n'
... '${this:is_literal}\n'
... '${foo:{{bar}}}\n'
... 'swallow: {{ json_module.dumps(("african", "european")) }}\n'
... 'parameters from section: {{ param_dict | dictsort }}\n'
... 'Rendered with {{recipe}}'
... )

We run buildout::

>>> print system(join('bin', 'buildout')),
Installing template.

And the template has been rendered::

>>> cat('foo')
value
Knights who say "Ni !" also protect Peng, Neee-wom.
They later say Ekke Ekke Ekke Ekke Ptangya Ziiinnggggggg Ni!
${this:is_literal}
${foo:value}
swallow: ["african", "european"]
parameters from section: [('bar', 'bar'), ('foo', '1')]
Rendered with slapos.recipe.template:jinja2

Parameters
----------

Mandatory:

``template``
Template url/path, as accepted by zc.buildout.download.Download.__call__ .

``rendered``
Where rendered template should be stored.

Optional:

``context``
Jinja2 context specification, one variable per line, with 3
whitespace-separated parts: type, name and expression. Available types are
described below. "name" is the variable name to declare. Expression semantic
varies depending on the type.

Available types:

``raw``
Immediate literal string.

``json``
Immediate json-encoded string.

``key``
Indirect literal string.

``jsonkey``
Indirect json-encoded string.

``import``
Import a python module.

``section``
Make a whole buildout section available to template, as a dictionary.

Indirection targets are specified as: [section]:key .
It is possible to use buildout's buit-in variable replacement instead instead
of ``key`` or ``jsonkey`` types, but keep in mind that different lines are
different variables for this recipe. It might be what you want (factorising
context chunk declarations), otherwise you should use indirect types.

``md5sum``
Template's MD5, for file integrity checking. By default, no integrity check
is done.

``umask``
Umask, in octal notation (no need for 0-prefix), to create output file with.
Defaults to system's umask at the time recipe is instanciated.

``extensions``
Jinja2 extensions to enable when rendering the template,
whitespace-separated. By default, none is loaded.

FAQ
---

Q: How do I generate ${foo:bar} where foo comes from a variable ?

A: ``{{ '${' ~ foo_var ~ ':bar}' }}``
This is required as jinja2 fails parsing "${{{ foo_var }}:bar}". Though,
jinja2 succeeds at parsing "${foo:{{ bar_var }}}" so this trick isn't
needed for that case.

Use jinja2 extensions
~~~~~~~~~~~~~~~~~~~~~

>>> write('foo.in',
... '''{% set foo = ['foo'] -%}
... {% do foo.append(bar) -%}
... {{ foo | join(', ') }}''')
>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context = key bar buildout:parts
... # We don't actually use all those extensions in this minimal example.
... extensions = jinja2.ext.do jinja2.ext.loopcontrols
... jinja2.ext.with_
... ''')
>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing template.

>>> cat('foo')
foo, template

Check file integrity
~~~~~~~~~~~~~~~~~~~~

Compute template's MD5 sum::

>>> write('foo.in', '{{bar}}')
>>> import md5
>>> md5sum = md5.new(open('foo.in', 'r').read()).hexdigest()
>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context = key bar buildout:parts
... md5sum = ''' + md5sum + '''
... ''')
>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing template.

>>> cat('foo')
template

If the md5sum doesn't match, the buildout fail::

>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context = key bar buildout:parts
... md5sum = 0123456789abcdef0123456789abcdef
... ''')
>>> print system(join('bin', 'buildout')),
While:
Installing.
Getting section template.
Initializing part template.
Error: MD5 checksum mismatch for local resource at 'foo.in'.


Specify filesystem permissions
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

You can specify the umask for rendered file::

>>> write('template.in', '{{bar}}')
>>> write('buildout.cfg',
... '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context = key bar buildout:parts
... umask = 570
... ''')
>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing template.

And the generated file with have the right permissions::

>>> import stat
>>> import os
>>> print oct(stat.S_IMODE(os.stat('foo').st_mode))
0206

Section dependency
------------------

You can use other part of buildout in the template. This way this parts
will be installed as dependency::

>>> write('foo.in', '{{bar}}')
>>> write('buildout.cfg', '''
... [buildout]
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context = key bar dependency:foobar
...
... [dependency]
... foobar = dependency content
... recipe = zc.buildout:debug
... ''')

>>> print system(join('bin', 'buildout')),
Uninstalling template.
Installing dependency.
foobar='dependency content'
recipe='zc.buildout:debug'
Installing template.

This way you can get options which are computed in the ``__init__`` of
the dependent recipe.

Let's create a sample recipe modifying its option dict::

>>> write('setup.py',
... '''
... from setuptools import setup
...
... setup(name='samplerecipe',
... entry_points = {
... 'zc.buildout': [
... 'default = main:Recipe',
... ],
... }
... )
... ''')
>>> write('main.py',
... '''
... class Recipe(object):
...
... def __init__(self, buildout, name, options):
... options['data'] = 'foobar'
...
... def install(self):
... return []
... ''')

Let's just use ``buildout.cfg`` using this egg::

>>> write('foo.in', '{{bar}}')
>>> write('buildout.cfg',
... '''
... [buildout]
... develop = .
... parts = template
...
... [template]
... recipe = slapos.recipe.template:jinja2
... template = foo.in
... rendered = foo
... context = key bar sample:data
...
... [sample]
... recipe = samplerecipe
... ''')
>>> print system(join('bin', 'buildout')),
Develop: ...
Uninstalling template.
Uninstalling dependency.
Installing sample.
Installing template.
>>> cat('foo')
foobar


2.4.1 (2012-08-01)
================

* jinja2: Make "context" parameter really optional. [Vincent Pelletier]

2.4 (2012-06-01)
================

* Provide access to zc.buildout.buildout.dumps when it exists. [Vincent
Pelletier]

* Fix missing jinja2 entry point documentation in pacakge description [Vincent
Pelletier]

2.3 (2012-03-29)
================

* Add jinja2 entry point with jinja2 template support. [Vincent Pelletier]

2.2 (2011-10-12)
================

* Include missing files in package. [Łukasz Nowak]

2.1 (2011-10-12)
================

* Description update. [Łukasz Nowak]

2.0 (2011-10-12)
================

* Dropping collective.recipe.template dependency. [Romain Courteaud, Antoine
Catton]

1.1 (2011-05-30)
================

* Moved out from slapos.cookbook in order to minimise depenencies [Łukasz
Nowak]