Ensure EMS relationships are established on upgrade.

db/migrate/20171023170841_ensure_cloud_managers.rb

@@ -0,0 +1,27 @@
+class EnsureCloudManagers < ActiveRecord::Migration[5.0]
+  class ExtManagementSystem < ActiveRecord::Base
+    self.inheritance_column = :_type_disabled # disable STI
+
+    def ensure_managers
+      ensure_manager("#{name} Network Manager",     "ManageIQ::Providers::Amazon::NetworkManager")
+      ensure_manager("#{name} EBS Storage Manager", "ManageIQ::Providers::Amazon::StorageManager::Ebs")
+    end
+
+    def ensure_manager(manager_name, manager_type)
+      self.class.create_with(
+        :name            => manager_name,
+        :zone_id         => zone_id,
+        :provider_region => provider_region
+      ).find_or_create_by!(
+        :parent_ems_id => id,
+        :type          => manager_type
+      )
+    end
+  end
+
+  def up
+    say_with_time("Ensuring other managers for all Amazon CloudManagers") do
+      ExtManagementSystem.where(:type => "ManageIQ::Providers::Amazon::CloudManager").each(&:ensure_managers)
+    end
+  end
+end

spec/migrations/20171023170841_ensure_cloud_managers_spec.rb

@@ -0,0 +1,76 @@
+require_migration
+
+describe EnsureCloudManagers do
+  let(:ems_stub) { migration_stub(:ExtManagementSystem) }
+  let(:zone_id)  { anonymous_class_with_id_regions.region_to_range(anonymous_class_with_id_regions.my_region_number).begin }
+
+  let!(:manager) do
+    ems_stub.create!(
+      :name            => "My Amazon",
+      :type            => "ManageIQ::Providers::Amazon::CloudManager",
+      :provider_region => "us-east-1",
+      :zone_id         => zone_id
+    )
+  end
+
+  def assert_managers
+    emses = ems_stub.order(:type).collect do |ems|
+      ems.attributes.slice(*%w[name type provider_region zone_id parent_ems_id])
+    end
+
+    expect(emses).to eq(
+      [
+        {
+          "name"            => "My Amazon",
+          "type"            => "ManageIQ::Providers::Amazon::CloudManager",
+          "provider_region" => "us-east-1",
+          "zone_id"         => zone_id,
+          "parent_ems_id"   => nil
+        },
+        {
+          "name"            => "My Amazon Network Manager",
+          "type"            => "ManageIQ::Providers::Amazon::NetworkManager",
+          "provider_region" => "us-east-1",
+          "zone_id"         => zone_id,
+          "parent_ems_id"   => manager.id
+        },
+        {
+          "name"            => "My Amazon EBS Storage Manager",
+          "type"            => "ManageIQ::Providers::Amazon::StorageManager::Ebs",
+          "provider_region" => "us-east-1",
+          "zone_id"         => zone_id,
+          "parent_ems_id"   => manager.id
+        },
+      ]
+    )
+  end
+
+  migration_context :up do
+    it "creates managers for an Amazon CloudManager without child managers" do
+      migrate
+
+      assert_managers
+    end
+
+    it "handles an Amazon CloudManager already with child managers" do
+      ems_stub.create!(
+        :name            => "My Amazon Network Manager",
+        :type            => "ManageIQ::Providers::Amazon::NetworkManager",
+        :provider_region => "us-east-1",
+        :zone_id         => zone_id,
+        :parent_ems_id   => manager.id
+      )
+      ems_stub.create!(
+        :name            => "My Amazon EBS Storage Manager",
+        :type            => "ManageIQ::Providers::Amazon::StorageManager::Ebs",
+        :provider_region => "us-east-1",
+        :zone_id         => zone_id,
+        :parent_ems_id   => manager.id
+      )
+
+      migrate
+
+      assert_managers
+    end
+  end
+end