Multipackage Cookbook

Description

This cookbook supplies an LWRP multipackage_install which provides a backwards-compatability
layer around supplying an array of packages to the package resource which was introduced in
Chef 12.1.0. By using this LWRP a cookbook will execute a single resource with an array argument
on Chef 12.1.0, but will dispatch multiple resources to handle each individual resource to maintain
compatibility with previous versions of Chef.

This cookbook also supplies a definition multipackage which wraps multipackage_install with
additional functionality not present in core chef which implements an accumulator pattern to
gather packages from many different cookbooks and install them in a single resource call (assuming
it runs on Chef 12.1.0 or greater).

Supports

This should run fine on any distro on any version of Chef. For installing multiple packages in a
single resource call the core chef provider that is being used will need to support that (as of
Chef 12.1.0 this is only apt on Ubuntu and yum on RHELs/Fedora).

Cookbook Dependencies

None

Resources

multipackage_install

This takes an array of packages and installs them. On chef versions that do not support array arguments to the package
resource it will explode the package_name argument into multiple package resources for backwards compatibility.

Example

multipackage_install [ "lsof, "tcpdump", "zsh" ] do
  version [ "1.1.1", "2.2.2", "3.3.3" ]
  options { "some" => "options" }
  timeout 86400
end

Actions

• :install - install the packages

Parameters

• package_name - This must be an array
• version - This must be an array and, if present, must have the same number of elements as package_name
• options - Options to pass to package provider(s).
• timeout - Timeout to pass to package provider(s).

Definitions

multipackage

This implements an accumulator pattern to gather all its arguments across every cookbook and issue a single
multipackage_install resource to install all of the gathered packages. The resource will be placed in the
resource collection at the point where the first definition is encountered -- in other words it will run very early
in converge phase as opposed to being implemented as a delayed notification which would run too late for
cookbooks to depend upon the packages being installed.

Example

In my_zlib/default.rb:

multipackage "zlib-dev"

In my_zsh/default.rb:

multipackage "zsh"

In my_xml/default.rb:

multipackage [ "xml2-dev", "xslt-dev" ]

On Chef >= 12.1.0 and Ubuntu/RHEL this will result in a single resource that installs all 4 packages at once.

Actions

• :install - Setup the symlinks

Parameters

• package_name - This must be an array
• version - This must be an array and, if present, must have the same number of elements as package_name
• options - Options to pass to package provider, currently there is no merging, last-writer-wins
• timeout - Timeout to pass to package provider, last-writer-wins

Recipes

None

Attributes

None

Usage

Put 'depends multipackage' in your metadata.rb to gain access to the LWRP and definition in your code.

NOTE on Using Definitions

This cookbook uses a definition for a specific purpose to implement an accumulator or scatter-gather pattern so that
many statements across multiple recipes and cookbooks produce one resource which is executed. This is done with a
definition so that the accumulating/gathering process occurs at compile-time. When compile-time is finished all of
the data has been accumulated. This lets a resource run very early in the run-list and do its work early.

If this was implemented as an LWRP it would have to do its accumulation work late, at converge time in the provider
That would make it impossible to install the packages early. An LWRP implementation is possible in conjunction with a
delayed notification to a resource to consume the accumulated data, but then recipe code could not depend on the
packages having been installed. Since a definition is a compile-time macro this cookbook takes advantage of that
distinction to more elegantly solve this problem without forcing providers to run at compile_time which is more of
an antipattern than definitions are.

In general LWRPs should always be used over definitions. This is the one case where they should be used.

Bugs

• options could be merged in the definition
• timeout could update the timeout in the definition only if its larger than the current one or something like that
• there's other paramters to package, yum_package, etc that are not implemented

Contributing

Just open a PR or Issue on GitHub.

License and Author

• Author:: Lamont Granquist (lamont@scriptkiddie.org)

Copyright:: 2015 Lamont Granquist

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.