package_bundles.markdown

layout	title	published	tags
default	Managing Software	false	Examples Policy Packages

Package Promises Examples

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Package promises allow you to make promises about the state of software installed on a host. Seven basic use cases are presented here which represent the majority of scenarios typically encountered. Irregular or unconventional package names can often be accommodated by studying the implementation of Package Promises and creating special package methods. Central to the way package promises are implemented is the standard library, which makes use of regular expressions to match package names.

Add a Package

In this case, only the name of the desired package is supplied. e.g. "zip". The rest is taken care of by the software, which in turn, makes use of the package manager native to the platform.

Here is a simple example of a bundle that installs the zip package for supported architectures.

bundle agent AddPackage
{
 methods:
    "ensureZip" usebundle => package_present("zip");
}

This code shows how to use the bundles package_present() from the [packages][Packages Bundles and Bodies] standard library.

Upgrade a Package

In this case, we would like to ensure our named package is the latest available. This type of promise attempts to ensure that the latest version of zip is installed. If the installed version is already the latest, it does nothing. Otherwise it either upgrades to the latest available or installs it if it's not already installed.

Usage

[package_latest(name)][package_latest()]

name: string

A simple example follows.

bundle agent UpgradePackage
{
 methods:
    "latestZip" usebundle => package_latest("zip");
}

This code shows how to use the bundles package_latest() from the [packages][Packages Bundles and Bodies] standard library.

Remove a Package

For this case, we would like to ensure that the named package is removed or absent from the target system.

Usage

[package_absent(name)][package_absent()]

name: string

bundle agent RemovePackage
{
 methods:
    "noZip" usebundle => package_absent("zip");
}

This code shows how to use the bundles package_absent() from the [packages][Packages Bundles and Bodies] standard library.

Add a Specific Version of a Named Package for Specific Architecture

For cases where you would like to ensure a specific version and a specific platform and architecture is present on the host, you can use this method. A selection method is supplied which tells the software to select a specified version. In this case "==" means we want the version to be selected if it's equal to the supplied version string.

Usage

[package_specific_present(name, selector, version, architecture)][package_specific_present()]

name: string

selector: ==, => or <=

version: package version string

architecture: amd64, i386, x86_64

Let's see how this looks as an example in which version 2.99 of the zip package for the Debian amd64 architecture is promised to be installed.

bundle agent SpecificPackageFromDebianRepo
{
 methods:
       "ensureSpecificZip" usebundle => package_specific_present("zip","==","2.99","amd64");
}

This code shows how to use the bundles package_specific_present() from the [packages][Packages Bundles and Bodies] standard library.

Specific Version of a Named Package for Specific Architecture (from a file)

This use case is identical to the last except for the fact that our package resides in a local directory as a platform specific package file

• e.g. .rpm or .deb.

Usage

[package_specific_present(path_to_package,selector,version,architecture)][package_specific_present()]

name: string

selector: ==, => or <=

version: package version string

architecture: amd64, i386, x86_64

As an example, see the policy snippet below. We wish to install a package on a Redhat system from an rpm file.

bundle agent SpecificPackageFromRpmFile
{
 methods:
      "addZipFromRpmFile" usebundle =>
         package_specific_present("/local/repo/zip-3.0-7_x86_64.rpm","==","3.0-7","x86_64");
}

This code shows how to use the bundles package_specific_present() from the [packages][Packages Bundles and Bodies] standard library.

Ensure Present or Upgrade Named Package for Specific Architecture from File

Upgrade or install the package from a named package file. This is similar to the previous example except that an existing package will be upgraded if it is older, to the version specified.

Usage

[package_specific_latest(path_to_package,selector,version,architecture)][package_specific_latest()]

name: string

selector: ==, => or <=

version: package version string

architecture: amd64, i386, x86_64

For example, the following policy illustrates a debian based upgrade of an existing package.

bundle agent SpecificPackageUpgradeFromDebianFile
{
 methods:
        "upgradeZipFromDebFile" usebundle =>
           package_specific_latest("/local/repo/zip-3.0-7_amd64.deb","==","3.0-7","amd64");
}

This code shows how to use the bundles package_specific_latest() from the [packages][Packages Bundles and Bodies] standard library.

Ensure Present or Upgrade Named Package for Specific Architecture

Upgrade or install the package. This promises to upgrade the package to the specified version and architecture.

Usage

[package_specific_latest(name,selector,version,architecture)][package_specific_latest()]

name: string

selector: ==, => or <=

version: package version string

architecture: amd64, i386, x86_64

For example, the following policy upgrades the zip package to the specificed version.

bundle agent SpecificPackageUpgradeDebian
{
 methods:
       "upgradeZip" usebundle =>
          package_specific_latest("zip","==","3.0-7","amd64");
}

This code shows how to use the bundles package_specific_latest() from the [packages][Packages Bundles and Bodies] standard library.