Manifest Entry Unit

A manifest entry unit describes a single entry in a manifest that describes the machine or device under test. The purpose of each entry is to define one specific fact. Plainbox uses such units to create a manifest that associates each entry with a value.

The values themselves can come from multiple sources, the simplest one is the test operator who can provide an answer. In more complex cases a specialized application might look up the type of the device using some identification method (such as DMI data) from a server, thus removing the extra interaction steps.

File format and location

Manifest entry units are regular plainbox units and are contained and shipped with plainbox providers. In other words, they are just the same as job and test plan units, for example.


Following fields may be used by a manifest entry unit.

(mandatory) - Unique identifier of the entry. This field is used to look up and store data so please keep it stable across the lifetime of your provider.

(mandatory) - A human readable name of the entry. This should read as in a feature matrix of a device in a store (e.g., “802.11ac wireless capability”, or “Thunderbolt support”, “Number of hard drive bays”). This is not a sentence, don’t end it with a dot. Please capitalize the first letter. The name is used in various listings so it should be kept reasonably short.

The name is a translatable field so please prefix it with _ as in _name: Example.

(mandatory) - Type of value for this entry. Currently two values are allowed: bool for a yes/no value and natural for any natural number (negative numbers are rejected).
(optional) - Units in which value is measured in. This is only used when value-type is equal to natural. For example a “Screen size” manifest entry could be measured in “inch” units.
(optional) - Name of the resource key used to store the manifest value when representing the manifest as a resource record. This field defaults to the so-called partial id which is just the id: field as spelled in the unit definition file (so without the name space of the provider)


This is an example manifest entry definition:

unit: manifest entry
id: has_thunderbolt
_name: Thunderbolt Support
value-type: bool

Naming Manifest Entries

To keep the code consistent there’s one naming scheme that should be followed. Entries for boolean values must use the has_XXX naming scheme. This will allow us to avoid issues later on where multiple people develop manifest entries and it’s all a bit weird what them mean has_thunderbolt or thunderbolt_supported or tb or whatever we come up with. It’s a convention, please stick to it.

Using Manifest Entries in Jobs

Manifest data can be used to decide if a given test is applicable for a given device under test or not. When used as a resource they behave in a standard way, like all other resources. The only special thing is the unique name-space of the resource job as it is provided by plainbox itself. The name of the resource job is: com.canonical.plainbox. In practice a simple job that depends on data from the manifest can look like this:

unit: job
id: ...
plugin: ...
 manifest.has_thunderbolt == 'True' and manifest.ns == 'com.canonical.checkbox'
imports: from com.canonical.plainbox import manifest

Note that the job uses the manifest job from the com.canonical.plainbox name-space. It has to be imported using the imports: field as it is in a different name-space than the one the example unit is defined in (which is arbitrary). Having that resource it can then check for the has_thunderbolt field manifest entry in the com.canonical.checkbox name-space. Note that the name-space of the manifest job is not related to the manifest.ns value. Since any provider can ship additional manifest entries and then all share the flat name-space of resource attributes looking at the .ns attribute is a way to uniquely identify a given manifest entry.

Collecting Manifest Data

To interactively collect manifest data from a user please include this job somewhere early in your test plan: com.canonical.plainbox::collect-manifest.

Supplying External Manifest

The manifest file is stored in $HOME/.local/share/plainbox/machine-manifest.json. If the provisioning method ships a valid manifest file there it can be used for fully automatic but manifest-based deployments.