add basic metadata

Author: ffrank

LICENSE

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+   Copyright (C) 2014 Felix Frank
+
+   Contact: Felix.Frank __AT__ Alumni.TU-Berlin.de
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+       http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License.

Modulefile

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+name 'ffrank-constraints'
+version '0.1'
+author 'Felix Frank'
+summary 'Puppet module that implements the constraint type'
+description 'The constraint type aims to lift the need for both
+  the defined() and ensure_resource() functions. Each constraint
+  defines a set of allowed and/or forbidden resource properties, e.g.
+
+    constraint {
+      "foo": resource => Package["apache2"],
+             { ensure => present };
+    }
+
+  See README.md for more examples.'
+license 'Apache'
+project_page 'https://github.com/ffrank/puppet-constraints'

README.md

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 puppet-constraints
 ==================
 
-Puppet module that introduces the constraint type
+Puppet module that introduces the constraint type.
+
+Origin: https://github.com/ffrank/puppet-constraints
+
+Released under the terms of the Apache 2 License.
+
+This module requires Puppet to be patched in order to perform and respect
+the checks of constraints. The patch is available in
+[a topic branch](https://github.com/ffrank/puppet/tree/ticket/master/PUP-2298-transaction-pre-run-checks).
+
+Authored by Felix Frank.
+
+Overview
+========
+
+This module implements `constraints`, a new meta type that aims
+to make both the `ensure_resources` function and the `defined` function obsolete.
+More information can be found in John Bollinger's
+[original mailing list post](https://groups.google.com/d/msg/puppet-users/Fvl0aOe4RPE/Ph38bq3FmHcJ)
+which explains their motivation, lays out their semantics and sketches their syntax.
+
+Currently, the following syntaxes are implemented:
+
+    # These are all equivalent
+    constraint {
+      'foo': resource => Package['apache2'],
+             { ensure => present };
+      'bar': resource => Package['apache2'],
+             { ensure => [ present ] };
+      'baz': resource => Package['apache2'],
+             { ensure => { allowed => [ present ] } };
+    }
+    # Blacklist instead of whitelist
+    constraint {
+      'oof': resource => Package['apache2'],
+             { ensure => { forbid => [ absent, purged ] } };
+    }
+
+Any failed constraint causes the catalog to be considered invalid (agent side).