packagesmatching

Prototype: packagesmatching(package_regex, version_regex, arch_regex, method_regex)

Return type: data

Description: Return a data container with the list of installed packages matching the parameters.

This function searches for the anchored regular expressions in the list of currently installed packages.

The return is a data container with a list of package descriptions, looking like this:

[
   {
      "arch":"default",
      "method":"dpkg",
      "name":"zsh-common",
      "version":"5.0.7-5ubuntu1"
   }
]

Arguments:

package_regex: string, in the range: .*
version_regex: string, in the range: .*
arch_regex: string, in the range: .*
method_regex: string, in the range: .*

Argument Descriptions:

package_regex - Regular expression matching packge name
version_regex - Regular expression matching package version
arch_regex - Regular expression matching package architecutre
method_regex - Regular expression matching package method (apt-get, rpm, etc ...)

The following code extracts just the package names, then looks for some desired packages, and finally reports if they are installed.

IMPORTANT: Please note that you need to provide package_inventory attribute in body common control in order to be able to use this function. Also depending on the value(s) of package_inventory only packages from selected package modules will be returned. For more information about package_inventory please read package_inventory section.

body common control

{
      bundlesequence => { "missing_packages" };
}


bundle agent missing_packages
{
  vars:
    # List of desired packages
    "desired" slist => { "mypackage1", "mypackage2" };

    # Get info on all installed packages
    "installed" data => packagesmatching(".*",".*",".*",".*");
    "installed_indices" slist => getindices(installed);

    # Build a simple array of the package names so that we can use
    # getvalues to pull a unified list of package names that are installed.
    "installed_name[$(installed_indices)]"
      string => "$(installed[$(installed_indices)][name])";

    # Get unified list of installed packages
    "installed_names" slist => getvalues("installed_name");

    # Determine packages that are missing my differencing the list of
    # desired packages, against the list of installed packages
    "missing_list" slist => difference(desired,installed_names);

  reports:
    # Report on packages that are missing, installed
    # and what we were looking for
    "Missing packages = $(missing_list)";
    "Installed packages = $(installed_names)";
    "Desired packages = $(desired)";
}

This policy can be found in /var/cfengine/share/doc/examples/packagesmatching.cf and downloaded directly from github.

Example:

      "all_packages" data => packagesmatching(".*", ".*", ".*", ".*");

Refresh rules: * installed packages cache used by packagesmatching() is refreshed at the end of each agent run in accordance with constraints defined in the relevant package module body. * installed packages cache is refreshed after installing or removing a package. * installed packages cache is refreshed if no local cache exists. This means a reliable way to force a refresh of CFEngine's internal package cache is to simply delete the local cache:

            $(sys.statedir)/packages_installed_<package_module>.lmdb*

History: Introduced in CFEngine 3.6

packagesmatching

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