Docs: Language: Tags


Language: Tags

Resources, classes, and defined type instances may have any number of tags associated with them, plus they receive some tags automatically. Tags are useful for:

Tag Names

See here for the characters allowed in tag names.

Assigning Tags to Resources

A resource may have any number of tags. There are several ways to assign a tag to a resource.

Automatic Tagging

Every resource automatically receives the following tags:

  • Its resource type
  • The full name of the class and/or defined type in which the resource was declared
  • Every namespace segment of the resource’s class and/or defined type

For example, a file resource in class apache::ssl would get the tags file, apache::ssl, apache, and ssl.

Class tags are generally the most useful, especially when setting up tagmail or testing refactored manifests.

Containment

Like relationships and most metaparameters, tags are passed along by containment. This means a resource will receive all of the tags from the class and/or defined type that contains it. In the case of nested containment (e.g. a class that declares a defined resource, or a defined type that declares other defined resources), a resource will receive tags from all of its containers.

The tag Metaparameter

You can use the tag metaparameter in a resource declaration to add any number of tags:

    apache::vhost {'docs.puppetlabs.com':
      port => 80,
      tag  => ['us_mirror1', 'us_mirror2'],
    }

The tag metaparameter can accept a single tag or an array. These will be added to the tags the resource already has. Also, tag can be used with normal resources, defined resources, and classes (when using the resource-like declaration syntax). Since containment applies to tags, the example above would assign the us_mirror1 and us_mirror2 tags to every resource contained by Apache::Vhost['docs.puppetlabs.com'].

The tag Function

You can use the tag function inside a class definition or defined type to assign tags to the surrounding container and all of the resources it contains:

    class role::public_web {
      tag 'us_mirror1', 'us_mirror2'
      
      apache::vhost {'docs.puppetlabs.com':
        port => 80,
      }
      ssh::allowgroup {'www-data': }
      @@nagios::website {'docs.puppetlabs.com': }
    }

The example above would assign the us_mirror1 and us_mirror2 tags to all of the defined resources being declared in the class role::public_web, as well as to all of the resources each of them contains.

Using Tags

Collecting Resources

Tags can be used as an attribute in the search expression of a resource collector. This is mostly useful for realizing virtual and exported resources.

Restricting Catalog Runs

Puppet agent and puppet apply can use the tags setting to only apply a subset of the node’s catalog. This is useful when refactoring modules, and allows you to only apply a single class on a test node.

The tags setting can be set in puppet.conf (to permanently restrict the catalog) or on the command line (to temporarily restrict it):

$ sudo puppet agent --test --tags apache,us_mirror1

The value of the tags setting should be a comma-separated list of tags (with no spaces between tags).

Sending Tagmail Reports

The built-in tagmail report handler can send emails to arbitrary email addresses whenever resources with certain tags are changed. See the following for more info:

Reading Tags in Custom Report Handlers

Resource tags are available to custom report handlers and out-of-band report processors: Each Puppet::Resource::Status object and Puppet::Util::Log object has a tags key whose value is an array containing every tag for the resource in question. See the following pages for more info:

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