The Automate Explorer

The first menu item that we see takes us to the Explorer. This is our visual interface into the Automate Datastore, and it contains the various kinds of Automate objects that we’ll use throughout this book (see Figure 2-2).

Figure 2-2. Automate Explorer

Before we start our journey into learning CloudForms Automate, we’ll take a tour of the Automate Datastore to familiarize ourselves with the objects that we’ll find there.

The Automate Datastore

The Automate Datastore has a directory-like structure, consisting of several types of organizational units arranged in a hierarchy (see Figure 2-3).

Figure 2-3. Automate Datastore icon styles

Next, we’ll look at each type of object in more detail.

Namespaces

A namespace is a folder-like container for classes, instances, and methods, and is used purely for organizational purposes. We create namespaces to arrange our code logically, and namespaces often contain other namespaces (see Figure 2-7).

Figure 2-7. Namespaces

Classes

A class is similar to a template: it contains a generic definition for a set of automation operations. Each class has a schema that defines the variables, states, relationships, or methods that instances of the class will use.

Schemas

A schema is made up of a number of elements, or fields, that describe the properties of the class. A schema often has just one entry—to run a single method—but in many cases it has several components. Figure 2-8 shows the schema for a placement class, which has several different field types.

Figure 2-8. A more complex schema

Adding or Editing a Schema

We add or edit each schema field in the schema editor by specifying the field type from a drop-down list (see Figure 2-9).

Figure 2-9. Schema field type

Each field type has an associated data type, which is also selectable from a drop-down list (see Figure 2-10).

Figure 2-10. Schema field data type

We can define default values for fields in a class schema. These will be inherited by all instances created from the class but can be optionally overridden in the schema of any particular instance.

Relationships

One of the schema field types is a relationship, which links to other instances elsewhere in the Automate Datastore. We often use relationships as a way of chaining instances together, and relationship values can accept variable substitutions for flexibility (see Figure 2-11).

Figure 2-11. Relationship fields showing variable substitutions

Instances

An instance is a specific instantiation or “clone” of the generic class and is the entity run by the Automation Engine. An instance contains a copy of the class schema but with actual values of the fields filled in (see Figure 2-12).

Figure 2-12. Single class definition with three instances

Methods

A method is a self-contained block of Ruby code that gets executed when we run any automation operation. A typical method looks like this:

#
# Description: This method checks to see if the VM has been powered off or
# suspended
#

# Get vm from root object
vm = $evm.root['vm']

if vm
  power_state = vm.attributes['power_state']
  ems = vm.ext_management_system
  $evm.log('info', "VM:<#{vm.name}> on provider:<#{ems.try(:name)} has Power 
            State:<#{power_state}>")

  # If VM is powered off or suspended exit

  if %w(off suspended).include?(power_state)
    # Bump State
    $evm.root['ae_result']         = 'ok'
  elsif power_state == "never"
    # If never then this VM is a template so exit the retirement state machine
    $evm.root['ae_result']         = 'error'
  else
    $evm.root['ae_result']         = 'retry'
    $evm.root['ae_retry_interval'] = '60.seconds'
  end
end

Methods can have one of three location values: inline, built-in, or URI. In practice most of the methods that we create are inline methods, which means they run as a separate Ruby process outside of Rails.

Summary

In this chapter we’ve learned about the fundamental objects or organizational units that we work with in the Automate Datastore: domains, namespaces, classes, instances, and methods.

We are now ready to use this information to write our first automation script.